AIOU Solved Assignments code 683 M.A. Autumn & Spring 2020 Assignment 1& 2 Course: Audiology & Audiometery (683) Spring 2021. AIOU past papers
ASSIGNMENT No: 1& 2
Audiology & Audiometery (683) Semester
Autumn & Spring 2020
AIOU Solved Assignment 1& 2 Code 683 Autumn & Spring 2020
Q.1 Discuss function of auditory system and in particular the neurological pathways to the cortex.
The key structure in the vertebrate auditory and vestibular systems is the hair cell. The hair cell first appeared in fish as part of a long, thin array along the side of the body, sensing movements in the water. In higher vertebrates the internal fluid of the inner ear (not external fluid as in fish) bathes the hair cells, but these cells still sense movements in the surrounding fluid. Several specializations make human hair cells responsive to various forms of mechanical stimulation. Hair cells in the Organ of Corti in the cochlea of the ear respond to sound. Hair cells in the cristae ampullares in the semicircular ducts respond to angular acceleration (rotation of the head). Hair cells in the maculae of the saccule and the utricle respond to linear acceleration (gravity). (See the chapter on Vestibular System: Structure and Function). The fluid, termed endolymph, which surrounds the hair cells is rich in potassium. This actively maintained ionic imbalance provides an energy store, which is used to trigger neural action potentials when the hair cells are moved. Tight junctions between hair cells and the nearby supporting cells form a barrier between endolymph and perilymph that maintains the ionic imbalance.
Figure 12.1 illustrates the process of mechanical transduction at the tips of the hair cell cilia. Cilia emerge from the apical surface of hair cells. These cilia increase in length along a consistent axis. There are tiny thread-like connections from the tip of each cilium to a non-specific cation channel on the side of the taller neighboring cilium. The tip links function like a string connected to a hinged hatch. When the cilia are bent toward the tallest one, the channels are opened, much like a trap door. Opening these channels allows an influx of potassium, which in turns opens calcium channels that initiates the receptor potential. This mechanism transduces mechanical energy into neural impulses. An inward K+ current depolarizes the cell, and opens voltage-dependent calcium channels. This in turn causes neurotransmitter release at the basal end of the hair cell, eliciting an action potential in the dendrites of the VIIIth cranial nerve.
Press the “play” button to see the mechanical-to-electrical transduction. Hair cells normally have a small influx of K+ at rest, so there is some baseline activity in the afferent neurons. Bending the cilia toward the tallest one opens the potassium channels and increases afferent activity. Bending the cilia in the opposite direction closes the channels and decreases afferent activity. Bending the cilia to the side has no effect on spontaneous neural activity.
12.2 Sound: Intensity, Frequency, Outer and Middle Ear Mechanisms, Impedance Matching by Area and Lever Ratios
The auditory system changes a wide range of weak mechanical signals into a complex series of electrical signals in the central nervous system. Sound is a series of pressure changes in the air. Sounds often vary in frequency and intensity over time. Humans can detect sounds that cause movements only slightly greater than those of Brownian movement. Obviously, if we heard that ceaseless (except at absolute zero) motion of air molecules we would have no silence.
Depicts these alternating compression and rarefaction (pressure) waves impinging on the ear. The pinna and external auditory meatus collect these waves, change them slightly, and direct them to the tympanic membrane. The resulting movements of the eardrum are transmitted through the three middle-ear ossicles (malleus, incus and stapes) to the fluid of the inner ear. The footplate of the stapes fits tightly into the oval window of the bony cochlea. The inner ear is filled with fluid. Since fluid is incompressible, as the stapes moves in and out there needs to be a compensatory movement in the opposite direction. Notice that the round window membrane, located beneath the oval window, moves in the opposite direction.
Because the tympanic membrane has a larger area than the stapes footplate there is a hydraulic amplification of the sound pressure. Also because the arm of the malleus to which the tympanic membrane is attached is longer than the arm of the incus to which the stapes is attached, there is a slight amplification of the sound pressure by a lever action. These two impedance matching mechanisms effectively transmit air-born sound into the fluid of the inner ear. If the middle-ear apparatus (ear drum and ossicles) were absent, then sound reaching the oval and round windows would be largely reflected.
The Cochlea: three scalae, basilar membrane, movement of hair cells
The cochlea is a long coiled tube, with three channels divided by two thin membranes. The top tube is the scala vestibuli, which is connected to the oval window. The bottom tube is the scala tympani, which is connected to the round window. The middle tube is the scala media, which contains the Organ of Corti. The Organ of Corti sits on the basilar membrane, which forms the division between the scalae media and tympani.
Figure 12.3 illustrates a cross section through the cochlea. The three scalae (vestibuli, media, tympani) are cut in several places as they spiral around a central core. The cochlea makes 2-1/2 turns in the human (hence the 5 cuts in midline cross section). The tightly coiled shape gives the cochlea its name, which means snail in Greek (as in conch shell). As explained in Tonotopic Organization, high frequency sounds stimulate the base of the cochlea, whereas low frequency sounds stimulate the apex. This feature is depicted in the animation of Figure 12.3 with neural impulses (having colors from red to blue representing low to high frequencies, respectively) emerging from different turns of the cochlea. The activity in Figure 12.3 would be generated by white noise that has all frequencies at equal amplitudes. The moving dots are meant to indicate afferent action potentials. Low frequencies are transduced at the apex of the cochlea and are represented by red dots. High frequencies are transduced at base of the cochlea and are represented by blue dots. A consequence of this arrangement is that low frequencies are found in the central core of the cochlear nerve, with high frequencies on the outside.
Sound waves cause the oval and round windows at the base of the cochlea to move in opposite directions. This causes the basilar membrane to be displaced and starts a traveling wave that sweeps from the base toward the apex of the cochlea. The traveling wave increases in amplitude as it moves, and reaches a peak at a place that is directly related to the frequency of the sound. The illustration shows a section of the cochlea that is moving in response to sound.
Figure 12.5 illustrates a higher magnification of the Organ of Corti. The traveling wave causes the basilar membrane and hence the Organ of Corti to move up and down. The organ of Corti has a central stiffening buttress formed by paired pillar cells. Hair cells protrude from the top of the Organ of Corti. A tectorial (roof) membrane is held in place by a hinge-like mechanism on the side of the Organ of Corti and floats above the hair cells. As the basilar and tectorial membranes move up and down with the traveling wave, the hinge mechanism causes the tectorial membrane to move laterally over the hair cells. This lateral shearing motion bends the cilia atop the hair cells, pulls on the fine tip links, and opens the trap-door channels. The influx of potassium and then calcium causes neurotransmitter release, which in turn causes an EPSP that initiates action potentials in the afferents of the VIIIth cranial nerve. Most of the afferent dendrites make synaptic contacts with the inner hair cells.
Look down on the Organ of Corti. There are two types of hair cells, inner and outer. There is one row of inner hair cells and three rows of outer hair cells. Most of the afferent dendrites synapse on inner hair cells. Most of efferent axons synapse on the outer hair cells. The outer hair cells are active. They move in response to sound and amplify the traveling wave. The outer hair cells also produce sounds that can be detected in the external auditory meatus with sensitive microphones. These internally generated sounds, termed otoacoustic emissions, are now used to screen newborns for hearing loss. Figure 12.6 shows an immunofluorescent whole mount image of a neonatal mouse cochlea showing the three rows of outer hair cells and the single row of inner hair cells. The mature human cochlea would look approximately the same. Superimposed schematically-depicted neurons show the typical pattern of afferent connections. Ninety-five percent of the VIIIth nerve afferents synapse on inner hair cells. Each inner hair cell makes synaptic connections with many afferents. Each afferent connects to only one inner hair cell. About five percent of the afferents synapse on outer hair cells. These afferents travel a considerable distance along the basilar membrane away from their ganglion cells to synapse on multiple outer hair cells. Less than one percent (~0.5%) of the afferents synapse on multiple inner hair cells. The below micrograph is courtesy of Dr. Douglas Cotanche, Department of Otolaryngology, Children’s Hospital of Boston, Harvard Medical School. Reprinted with permission.
Physical characteristics of the basilar membrane cause different frequencies to reach maximum amplitudes at different positions. Much as on a piano, high frequencies are at one end and low frequencies at the other. High frequencies are transduced at the base of the cochlea whereas low frequencies are transduced at the apex. Figure 12.7 illustrates the way in which the cochlea acts as a frequency analyzer. The cochlea codes the pitch of a sound by the place of maximal vibration. Note the position of the traveling wave at different frequencies. (Beware! It may initially seem backwards that low frequencies are not associated with the base.) Select different frequencies by turning the dial. If audio on your computer is enabled, you will hear the sound you selected. Hearing loss at high frequencies is common. The average loss of hearing in American males is about a cycle per second per day (starting at about age 20, so a 50-year old would likely have difficulty hearing over 10 kHz). If you can’t hear the high frequencies, it may be due to the speakers on your computer, but it is always worth thinking about hearing preservation.
As you listen to these sounds, note that the high frequencies seem strangely similar. Think about cochlear-implant patients. These patients have lost hair-cell function. Their auditory nerve is stimulated by a series of implanted electrodes. The implant can only be placed in the base of the cochlea, because it is surgically impossible to thread the fine wires more than about 2/3 of a turn. Thus, cochlear implant patients probably experience something like high frequency sounds.
The Range of Sounds to Which We Respond; Neural Tuning Curves
Figure 12.8 shows the range of frequencies and intensities of sound to which the human auditory system responds. Our absolute threshold, the minimum level of sound that we can detect, is strongly dependent on frequency. At the level of pain, sound levels are about six orders of magnitude above the minimal audible threshold. Sound pressure level (SPL) is measured in decibels (dB). Decibels are a logarithmic scale, with each 6 dB increase indicating a doubling of intensity. The perceived loudness of a sound is related to its intensity. Sound frequencies are measured in Hertz (Hz), or cycles per second. Normally, we hear sounds as low as 20 Hz and as high as 20,000 Hz. The frequency of a sound is associated with its pitch. Hearing is best at about 3-4 kHz. Hearing sensitivity decreases at higher and lower frequencies, but more so at higher than lower frequencies. High-frequency hearing is typically lost as we age. The neural code in the central auditory system is complex. Tonotopic organization is maintained throughout the auditory system. Tonotopic organization means that cells responsive to different frequencies are found in different places at each level of the central auditory system, and that there is a standard (logarithmic) relationship between this position and frequency. Each cell has a characteristic frequency (CF). The CF is the frequency to which the cell is maximally responsive. A cell will usually respond to other frequencies, but only at greater intensities. The neural tuning curve is a plot of the amplitude of sounds at various frequencies necessary to elicit a response from a central auditory neuron. The tuning curves for several different neurons are superimposed on the audibility curves in Figure 12.8. The depicted neurons have CFs that vary from low to high frequencies (and are shown with red to blue colors, respectively). If we recorded from all auditory neurons, we would basically fill the area within the audibility curves. When sounds are soft they will stimulate only those few neurons with that CF, and thus neural activity will be confined to one set of fibers or cells at one particular place. As sounds get louder they stimulate other neurons, and the area of activity will increase.
AIOU Solved Assignment 1& 2 Code 683 Autumn & Spring 2020
Q.2 Child history is a document has importance at all levels. As a teacher of hearing impaired children you counsel their parents too. How and what information of child history will be helpful, while counseling the parents? Support your answer with examples.
More than 6 million students with disabilities are enrolled in public schools (National Education Association, n.d.), and growing numbers are being included in general education classrooms (Sciarra, 2004). The role that school counselors play in the education of students with special needs is increasingly important (Lockhart, 2003). As school counselors work with students with disabilities within their schools, they also frequently have the opportunity, or the need, to work with the parents of those students. Parents of students with disabilities share the concerns of all parents about child-rearing and about education and also have additional concerns related to their children’s disabilities. Professional school counselors can serve an important role as advocates for students with disabilities and their parents: “Professional school counselors are often the designated (and sometimes lone) advocates for children with special needs and their parents in an intricate and often intimidating educational bureaucracy” (Erford, House, & Martin, 2003, p. 18). Understanding the concerns and perspectives of these parents is essential to working with them effectively as partners in their children’s education.
Just as it is unwise to generalize about students as if all students were the same or about parents as if all parents or all families were the same, so it is unwise to generalize about all parents of children with special needs, making the assumption that they are all the same. Not only is the range of special needs and disabling conditions vast, but parents and families also vary in their styles, concerns, approaches, values, involvement, and backgrounds.
Having said that, it is possible to articulate a set of issues and concerns that commonly arise for many parents of children with disabilities. Not every issue will apply to every student and every student’s family; however, it is useful for school counselors to be sensitized to some common concerns that are unique to families of children with disabilities. Understanding these concerns will help school counselors be more effective in their work not only with parents of students with disabilities, but with the broader school community as well.
Grief, loss, and the “dream child”
Not all children with special needs enter the educational system already identified as having a disability. Although the movement for early identification and early intervention has been successful in identifying many children with special needs at the preschool level, some students’ needs may not become apparent until sometime after they begin formal school. Furthermore, a disability that is the result of an accident (e.g., traumatic brain injury) or an illness (e.g., loss of hearing or vision) may occur at any point during a child’s school years. This means that issues related to the labeling of the child as disabled may arise for parents at any level of schooling. Parents develop wishes, expectations, and dreams for their children, even before the child is born. At a minimum, parents wish for a healthy baby (“We don’t care whether it’s a boy or a girl, just as long as it’s healthy” is the cliché that is repeated over and over), and they assume that it will be so. The discovery that the wished-for child has a disability can be seen as destroying the hopes and dreams held by the parents. Parents need to grieve the loss of these hopes and dreams (Bristor, 1991; Klein & Schive, 2001; Witt, 2004). Then, they can begin to “dream new dreams” (Klein & Schive, p. xix). However, sadness related to the child’s disability may be ongoing or may recur periodically — around previously anticipated events that do not occur or around anniversary dates, for instance (Quinn, 1998).
School counselors can respond by forming parent support groups or referring parents to existing support groups, either school based or in the community. Such groups can normalize these and other concerns for parents and serve as a source of support and encouragement. However, not all parents are able to attend or are interested in attending support groups. A lack of transportation, lack of child care, and work schedules may prevent parents from being involved in groups; therefore, the counselor should not assume that not participating in an offered group indicates that the parent “just doesn’t care” about the child. There also may not be enough parents of students with disabilities within a school or a community to form a viable group. In addition, the school counselor can recommend books, especially those with personal accounts, such as You Will Dream New Dreams (Klein & Schive, 2001). Such books also offer a way for school counselors to learn about the feelings and perspectives of a range of parents of children with disabilities and, therefore, to develop greater understanding and empathy for parents of children with disabilities.
Safety concerns and “over-protectiveness”
Among the defining characteristics of the current Millennial Generation of schoolchildren (born between 1982 and 2002) is that they have been sheltered and protected to a much greater extent than the previous generation of students (Howe & Strauss, 2000). The parents of Millennial children typically desire to be involved in all aspects of their children’s development and education (Howe & Strauss). Therefore, to an even greater extent than in the past, the parents of Millennial children with disabilities can be expected to be involved and concerned about the safety of their children. Ysseldyke, Algozzine, and Thurlow (2000) indicated that many parents of students with disabilities view schools as unsafe.
Concerns about safety at school can encompass a number of areas. Parents of children with disabilities may perceive that their children are more vulnerable to accidents and injuries as a result of their disabilities (Quinn, 1998). They may worry, for instance, that their children with physical or sensory impairments are in danger of falling on stairways, on playgrounds, and in other parts of the school. They may worry about the potential for injury while using equipment in the science laboratory, art room, or family and consumer science classroom. Field trips and transportation may present other opportunities for concerns about safety and injury. In addition, parents may be concerned that school personnel might inadvertently injure the student, due to a lack of knowledge about how to handle transfers in and out of a wheelchair, for example. Furthermore, parents may be concerned that their children with disabilities may be bullied and injured by other students, with their disabilities making them both a more likely target and more vulnerable. These concerns are more complicated for the parents of students with limited communication ability; parents may worry that such students will be unable to report injury or bullying to school personnel or to them.
Although concerns about safety are real and may be well-founded, they also can lead parents to overprotect their children to an extent that is not helpful to the students’ development. In a study of adolescents with physical disabilities, Blum, Resnick, Nelson, and St. Germaine (1991) found that the adolescents “almost without exception” (p. 280) described their relationships with their parents as good and positive. However, many of the adolescents in the study reported that they felt that their parents did not treat them in an age-appropriate manner, and about one-quarter perceived that their parents were overprotective in ways that the adolescents found objectionable.
Parents of students with disabilities share the concerns of all parents about child-rearing and about education and also have additional concerns related to their children’s disabilities.
It is important for the school counselor to respect these very real and serious parental concerns. School counselors can serve an important role in, on one hand, reassuring and educating parents regarding measures taken at school to insure children’s safety and, on the other hand, alerting school officials to safety concerns that need attention. An additional important role for school counselors working with parents of students with disabilities is to encourage parents to help their children develop independence by not overprotecting them. Although making such adjustments may be difficult for parents, they can be helped to see that fostering independence is in the long-term best interests of the child. It may be helpful to refer parents to the research literature, such as Blum et al. (1991), cited above, and first-hand accounts, such as those contained in Klein and Kemp’s (2004) Reflections from a Different Journey. The Klein and Kemp book is a compilation of essays written by adults with disabilities especially for the parents of children with disabilities.
Attitudes of other parents and other children
The number of students with disabilities included in general education classrooms continues to increase (Sciarra, 2004; Ysseldyke et al., 2000). However, parents of students with disabilities may have concerns about the attitudes and acceptance of other, nondisabled students and those students’ parents (Heward, 2003). As Heward pointed out, parents of children with disabilities “cannot necessarily depend on other’s appropriate actions and reactions” (p. 131). At a social event the author encountered a woman who expressed considerable resentment about the amount of school resources that were being “wasted” on a student with a disability who was in her son’s classroom; she further saw the money being spent on that little girl’s education as being money that could have been directed toward her own, nondisabled (and, therefore, presumed to be more worthy and more educable) child. This woman can be seen as the embodiment of what the parents of children with disabilities fear about the parents of their children’s classmates.
Despite the movement toward classroom inclusion, many classmates without disabilities may have had little or no exposure to people with disabilities. The former may be curious or fearful or rejecting or respond in yet other ways. School counselors have a role to play in the education of all students about disabilities in general and about a classmate’s disability in particular. As Sciarra (2004) stated, “Accurate information is one way of reducing bias in our schools and in the larger society” (p. 194).
The discovery that the wished-for child has a disability can be seen as destroying the hopes and dreams held by the parents.
Parents of children with disabilities may have concerns about the content of the information being presented to their child’s peers about disabilities or about the manner in which it is presented. Among these concerns may be accuracy of the information presented, potential violations of the child’s privacy, whether the focus is on what the child cannot do versus what the child can, and whether emotions such as pity are likely to be evoked. The school counselor should consult with parents about information to be provided to the student’s classmates, respect concerns that the parents may raise, and make appropriate adjustments if requested. The question of whether the student with a disability should be present for the presentation or excused from the classroom may arise. Although it is respectful and appropriate to include parents in this decision, the optimal approach is also to give the child himself or herself a voice in the matter.
Events such as back-to-school nights, school open houses, and parent-teacher organization meetings provide opportunities for school counselors to present information and education about students with disabilities to the broader parent population of the school. Such presentations might include general information about disabilities, the law governing the education of students with disabilities, and how one’s school is approaching the inclusion of students with disabilities. School counselors may want to consult with the parents of students with disabilities within the school about any concerns they may have about such a presentation. Again, such concerns need to be heard and responded to with care and respect.
School counselors should take care not to violate the confidentiality of individual students in such presentations. Both the Family Educational Rights and Privacy Act (FERPA; U.S. Department of Education, 2005a) and the Individuals with Disabilities Education Improvement Act of 2004 (IDEA; U.S. Department of Education, 2005b) protect the confidentiality of all information contained within a student’s Individualized Education Program (IEP). Information contained in students’ IEPs may not be shared outside the IEP team without consent from the student’s parents. Members of the team have access only to those portions of the IEP that are essential for each individual to provide educational programming and/or services to the student (typically, the pertinent goals and objectives). Care must be taken not to disclose information that would make a student personally identifiable; the confidentiality of this information is protected by FERPA and IDEA. Therefore, individual students should not be identified in such presentations nor should information about their diagnoses or their educational programs be shared. Particularly in small schools or in small communities, it takes very little information to make an individual student identifiable even when the name is not used.
Finally, school counselors may want to invite parents of children with disabilities and students with disabilities themselves to be part of their educational efforts. Parents and/or students may be interested in making presentations to classes, teachers, or groups of parents. Often, such presenters, speaking from personal experience, are particularly effective educators.
Friendships play an important role in the life of the developing child. Relationships with peers play an integral role in adolescents’ identity formation (Erikson, 1963; Quinn, 1998). All parents want their children to have friends. Parents of children with disabilities may be particularly concerned about their children’s abilities to make and keep friends.
These concerns may have a variety of origins. Children with mild disabilities, such as learning disabilities or mild mental retardation, may be socially immature (Heward, 2003; Sciarra, 2004). Children with disabilities may have communication difficulties, such as little or no speech or speech that is difficult to understand, making it more difficult for them to converse with peers and to make friends. Children with chronic health problems or frequent surgeries may have frequent school absences, making it difficult for them, as well, to make friends. In addition, paraprofessional teaching assistants who are with a child with a disability during the school day may serve as an obstacle to making friends, as peers communicate with the aide rather than with the child or as children are inhibited by the hovering presence of an adult. In addition, the student with a disability may, in turn, be more comfortable and accustomed to interacting with adults than with peers and may have difficulties understanding how to relate to peers. Peers without disabilities also may be frightened of the child’s adaptive equipment (such as a wheelchair or walker) or of the child’s different appearance or behavior (Heward). Furthermore, children with visible disabilities may be concerned that their classmates will reject them because of their differences; Mattingly (2004) related that as a child he was convinced that the special shoes that he needed to wear as a result of cerebral palsy were responsible for making him the target of classmates’ teasing and bullying.
In addition, parents may perceive some of the avenues for making friends to be less open to their children with disabilities. Children with physical disabilities may be unable to participate in games and activities that lead to the development of friendships. These children may not be invited to play dates and birthday parties, as other parents are uncertain about what would be necessary to facilitate the child’s participation. After-school and out-of-school programs may not appear accessible; parents of children with disabilities understandably worry about specialized transportation, safety issues, and whether staff members are adequately trained. School-sponsored extracurricular activities also may appear inaccessible, and parents may not realize that access to such activities must be provided and can be included in their student’s IEP. Witt (2004) pointed out the difficulties that typically keep children with disabilities out of organized group activities and deny them the valuable lessons that they can learn from participating in such groups, including making friends, communication skills (listening and speaking), responsibility, and independence.
School counselors can be active in many ways in helping students with disabilities to establish friendships within the school community. Educating the school community, discussed above, is an important step toward breaking down attitudinal and informational barriers that might impede the development of friendships for students with disabilities. In addition, as part of a small-group counseling program, school counselors can create friendship groups and include students with disabilities in those groups along with their nondisabled peers. School counselors also can work with individual children with a focus on their difficulties in forming friendships, helping them to identify the source of their difficulties and ways to overcome them. School counselors can serve as a source of information and evaluation in terms of students’ progress toward social development goals in their IEPs. School counselors can communicate these possibilities to parents of students with disabilities, partnering with them to help students with disabilities make friends.
Potential for discounting child’s abilities
Parents also may be concerned that the child’s disability may overshadow the child’s abilities in the eyes of teachers. Perhaps the teacher will focus on the child’s “label” and not see the learner. Maybe the teacher will see the student’s struggles with math but miss his or her gift for art. Perhaps the teacher will be unable to see past the wheelchair to the bright and eager young person using it (see Heward, 2003). Parents may have concerns that the teacher will make erroneous assumptions about the child’s ability to learn because the child has some kind of disability — perhaps a disability that does not affect the child’s cognitive functioning at all. Parents also will likely be concerned that teachers may focus on what the child cannot do to the exclusion of what the child can do. School counselors can serve as advocates for children with disabilities within their schools and can help to educate teachers to look beyond the child’s disability to his or her abilities.
School counselors can serve as advocates for children with disabilities within their schools and can help to educate teachers to look beyond the child’s disability to his or her abilities.
The underestimate of the child’s abilities may be an area of particular concern to the parents of twice exceptional children, who have a disability and are gifted. Identification of giftedness in children with disabilities is problematic, because the methods commonly used for identification such as standardized tests may not be appropriate for use with students with disabilities without modifications and adaptations (Olenchak & Reis, 2002; Willard-Holt, 1998). Another common method of identification is referral and recommendation by teachers, which also may be less likely to occur for students with disabilities whose potential may be hidden (Willard-Holt). Giftedness may be expressed differently in students with disabilities (Willard-Holt). In cases in which students have paraprofessional instructional aides, teachers may have concerns about whether classroom work is that of the student or of the adult aide (Willard-Holt), or parents may worry that the teacher will have these concerns.
These same concerns also may carry over to homework and fuel debate over whether work represents the student’s efforts or the parents’. Further, in the case of twice-exceptional children, parents may be concerned that their children will be penalized for mistakes made by the aide, such as misspellings that occur when the aide is scribing for the child who cannot write independently. Finally, in cases in which the student’s giftedness has been identified, teachers may see accommodations for the student’s disability as unnecessary because the child is so bright; Sibley (2004) related such an incident from her own school experience as a twice-exceptional student.
Understanding the concerns of parents of children with disabilities is an important first step to school counselors serving as an advocate for students with disabilities and their parents.
There are a number of ways that school counselors can respond to the concerns of parents of twice-exceptional children. School counselors have a role to play as advocates for twice-exceptional children. Schools may need to be encouraged to broaden the ways in which students are identified for and referred to gifted programs in order to identify gifted children with disabilities. School counselors can consult with special education teachers or school psychologists about assessment options or with teachers in gifted education about the characteristics of gifted children, and they can communicate with parents about alternative methods for student identification. School counselors also can advocate for twice-exceptional students with teachers, reminding them that both the disability and the giftedness need to be accommodated. Twice-exceptional children may benefit from small-group counseling or individual counseling (Moon, 2002a). Moon (2002b) pointed out that parents of twice-exceptional children need to learn about their children’s disabilities and about giftedness. School counselors can invite parents of twice-exceptional children to participate in support groups for parents of gifted children as a way of gaining greater understanding of issues related to giftedness and of the stresses giftedness can create for families (Moon, 2002a).
School transitions, whether from one level of schooling to another (such as from elementary to middle school) or into a new school (such as after family relocation), are stressful for all families. However, these transitions typically are easier for students without disabilities than for their peers with disabilities (Ysseldyke et al., 2000). Therefore, transitions may raise particular concerns for the parents of students with disabilities. School transitions mean establishing new relationships with principals, teachers, support-service providers, other school personnel, and students and their parents. Parents may feel depressed, pessimistic, and overwhelmed about the need to start all over again with this new cast of characters. These new people will need to be educated about the child’s disability and trained in all pertinent special procedures or equipment. Meanwhile, the child will need to adapt to the new school, new people, and new schedules and routines (Ysseldyke et al.). These changes may be particularly unsettling to a student with a disability who already feels little control over many aspects of his or her life. The accompanying stress may manifest in previously unseen behavioral problems in school or in verbal or somatic expressions of anxiety at home or in school.
School counselors can be extremely helpful in easing these transitions for students with disabilities and their families. Opportunities to visit and become familiar with the new school before the transition can be beneficial. Including future classmates (current students) of the incoming student in these visits can help to build familiarity in both the incoming student and the future classmates. It also is important for the incoming student to meet teachers during such visits. If appropriate to the age of the student, parents can be included in such a visit, or parents might be accommodated in a separate visit to allow the student more independence. These pre-entry visits should be in addition to, not in place of, new-student orientations attended by all new students to the school. To leave students with disabilities out of the regular new-student orientation programs singles them out and deprives them of the opportunity to participate in an important school event and the opportunity to make social contacts. Careful, thorough transition planning, including pre-entry training for school personnel, will be reassuring to parents. School counselors also should acknowledge that school transitions are stressful and normalize those stress reactions for parents and students. Transitions offer another appropriate opportunity to invite parents to participate in parent support groups.
AIOU Solved Assignment 1& 2 Code 683 Autumn & Spring 2020
Q.3 Describe in detail the procedures of pure-tone and bon-conduction tests. Why this information is important for the teachers of deaf?
Pure tone audiometric air conduction testing is performed by presenting a pure tone to the ear through an earphone and measuring the lowest intensity in decibels (dB) at which this tone is perceived 50% of the time. This measurement is called threshold. The testing procedure is repeated at specific frequencies from 250 to 8000 hertz (Hz, or cycles per second) for each ear, and the thresholds are recorded on a graph called an audiogram. Bone conduction testing is done by placing an oscillator on the mastoid process and measuring threshold at the same frequencies. Masking noise is sometimes used in the nontest ear to prevent its participation in the test.
The audiogram is a graph depicting hearing thresholds in decibels on the ordinate and frequency in hertz on the abscissa. The symbols are used to plot thresholds for pure-tone air and bone conduction testing. The zero level on the audiogram is an arbitrary sound pressure level which indicates ideal normal hearing in young adults.
Audiometry results. The right ear shows thresholds that are within normal limits for air and bone conduction. The left ear shows a mixed hearing loss. The bone conduction thresholds show a sensorineural hearing loss.
Speech testing is the measurement of a patient’s ability to hear and understand speech. The speech reception threshold (SRT) is the lowest decibel level at which a patient can correctly repeat 50% of test words. The speech threshold should be within ± 10 dB of the pure tone average at frequencies of 500, 1000, and 2000 Hz. The speech discrimination score is obtained using phonetically balanced, one-syllable words usually presented at 25 to 40 dB above the hearing threshold obtained from the pure-tone audiogram.
Speech discrimination is usually good in purely conductive hearing losses when the presentation level is loud enough. Speech discrimination scores are variable in sensorineural losses. Poor speech discrimination (75% or less) in the presence of little loss for pure tones raises the index of suspicion for retrocochlear disease.
For impedance audiometry, a hermetic seal is obtained by inserting a probe tip in the external ear canal. The pressure in the enclosed cavity is varied from + 200 to − 200 mm H2O and the change in sound pressure level of a probe tone is graphed. This shows the movement of the middle ear system as pressure is varied.
Five common tympanograms. The lighter lines with a peak at 0 enclose a space that represents the range of normal middle ear system mobility and pressure. Type A: Normal tympanic membrane (TM) mobility and normal middle ear (ME) pressure.
The contraction of the stapedius muscle in response to a loud sound can be measured on the impedance bridge. In the normal ear, these reflex thresholds should be seen at 70 to 90 dB above the pure-tone thresholds. At 10 to 15 dB above the reflex threshold at 500 and 1000 Hz, the contraction of the stapedius should be sustained for at least 10 seconds. Reflex decay, or failure to sustain contraction for 10 seconds, is one of the earliest signs of retrocochlear disease.
For auditory brainstem response (ABR) audiometry, electrodes are placed on the patient’s vertex, earlobes, and forehead. Clicks are delivered through earphones, and a computer sums the time-locked responses (potentials) for the first 10 msec after sound stimulation. From these responses, a display of five characteristic waves is generated at predictable latencies. This response must be reliably repeatable for an evaluation to be made.
Audiometry consists of tests of function of the hearing mechanism. This includes tests of mechanical sound transmission (middle ear function), neural sound transmission (cochlear function), and speech discrimination ability (central integration). A complete evaluation of a patient’s hearing must be done by trained personnel using instruments designed specifically for this purpose.
Pure tones (single frequencies) are used to test air and bone conduction. These and speech testing are done with an audiometer. The audiometer is an electric instrument consisting of a pure tone generator, a bone conduction oscillator for measuring cochlear function, an attenuator for varying loudness, a microphone for speech testing, and earphones for air conduction testing.
Other tests include impedance audiometry, which measures the mobility and air pressure of the middle ear system and middle ear (stapedial) reflexes, and auditory brainstem response (ABR), which measures neural transmission time from the cochlea through the brainstem.
The prevalence of hearing loss varies with age, affecting at least 25 percent of patients older than 50 years and more than 50 percent of those older than 80 years. Adolescents and young adults represent groups in which the prevalence of hearing loss is increasing and may therefore benefit from screening. If offered, screening can be performed periodically by asking the patient or family if there are perceived hearing problems, or by using clinical office tests such as whispered voice, finger rub, or audiometry. Audiometry in the family medicine clinic setting is a relatively simple procedure that can be interpreted by a trained health care professional. Pure-tone testing presents tones across the speech spectrum (500 to 4,000 Hz) to determine if the patient’s hearing levels fall within normal limits. A quiet testing environment, calibrated audiometric equipment, and appropriately trained personnel are required for in-office testing. Pure-tone audiometry may help physicians appropriately refer patients to an audiologist or otolaryngologist. Unilateral or asymmetrical hearing loss can be symptomatic of a central nervous system lesion and requires additional evaluation.
Audiometry is a relatively simple procedure that can be performed and interpreted by a trained health care professional. Family physicians should feel comfortable performing this testing on adults and cooperative children. Physicians may consider performing audiometry when a patient reports a subjective sense of diminished hearing, or when a family member reports a patient’s decreased conversational interaction.
Although the USPSTF also found insufficient evidence to recommend for or against routinely screening asymptomatic working-age adolescents and adults younger than 50 years for hearing impairment,3 other organizations have recommended regular periodic objective testing throughout childhood and adolescence. One survey of adolescents and young adults (mean age 19.2 years) revealed that 43 percent of respondents experienced hearing loss associated with exposure to loud music within the past six months. Adolescents often listen to music through headphones at maximum volume, and underestimate their vulnerability to music-induced hearing loss. Therefore, patients reporting exposure to loud music or occupational noise are good candidates for audiometry.
Testing may be expanded to include patients who are exposed to excessive noise while at work or at play who have not used adequate hearing protection. Unilateral or asymmetrical hearing loss is common in hunters and military veterans exposed to acoustic trauma from prolonged use of firearms.
When hearing loss is suspected, pure-tone audiometry may be used to evaluate hearing deficits by spot-checking certain frequencies, or to evaluate deficits more completely.15 Pure-tone audiometry is performed with the use of an audiometer. Handheld audiometers have a sensitivity of 92 percent and a specificity of 94 percent in detecting sensorineural hearing impairment.16 There are several types of audiometers available, but all function similarly by allowing the tester to increase and decrease the intensity (loudness, in decibels [dB]) and frequency (pitch, in cycles per second or Hz) of the signal as desired.
Pure-tone audiometry is broadly defined as either screening or threshold search. Screening audiometry presents tones across the speech spectrum (500 to 4,000 Hz) at the upper limits of normal hearing (25 to 30 dB for adults, and 15 to 20 dB for children).17 Results are recorded as pass, indicating that the patient’s hearing levels are within normal limits, or refer, indicating that hearing loss is possible and a repeat screening test or a threshold search test is recommended.
Threshold search audiometry determines the softest sound a patient can hear at each frequency 50 percent of the time. This testing requires more time and expertise than screening audiometry. The American Speech-Language-Hearing Association has a recommended procedure for pure-tone threshold search tests known as the modified Hughson-Westlake method.18 Testing begins with the ear in which the patient perceives to have better hearing. The tester presents a pure tone at a clearly audible level. After the patient responds to the pure-tone signal, the tester decreases intensity by 10 dB and presents the tone again. If the patient responds to this tone, a “down 10” pattern is employed, with the tester decreasing the intensity of the tone by 10 dB and presenting a tone until the patient no longer responds.18 The tester then increases tone intensity by 5 dB until the patient responds. This is the patient’s initial ascending response.
To check for accuracy, the tester should decrease the intensity of the tone by 10 dB one more time to check for no response, then increase the intensity of the signal in 5 dB increments until the patient responds again to the signal. If the patient responds consistently (minimum two out of three responses in ascending order), the tester records the dB level at which the patient responds as the air conduction threshold. After testing the ear that is perceived to have better hearing, the tester then performs the same tests on the patient’s other ear.
AIOU Solved Assignment 1& 2 Code 683 Autumn & Spring 2020
Q.4 How a teacher of deaf can be confident and capable of applying the information available from speech audiometery in rehabilitation programs for the hearing impaired children?
A number of different things affect what goes on in the classroom. How fast is the classroom instruction? Is the teacher going very quickly, or is there a lot of time for children to think about what is going on and to learn from each other? How rigorous is the curriculum? We know that, in some classrooms, the curriculum will be more rigorous than others, and if we have a hearing-impaired child who is in a classroom that has very high standards, that child has to be able to function differently than a child who is in a classroom where the expectations are low. How much are the children we are talking about able to glean from incidental learning? How much do they have to be told directly in order to learn, and how much can they learn from the people around them from overhearing conversations? What is their language like and how good is it? Can they hear the teacher well? Equally as important, can they hear other students? When other students comment on something the teacher has asked, can they get the message? Do they have the language foundation and vocabulary to understand everything that is happening in the classroom, or are they functioning at a significantly lower language level, therefore, not able to pick up what is going on in the classroom?
Is the technology the children are using working? Research from 1966 through 2011 is showing that more than 50% of the time technology in the classroom is not working the way we expect it to work. The sad part is that the statistics have not changed. The most common problem continues to be dead batteries, but unless we have someone in the school that can check the equipment daily, we do not know that a child’s equipment is actually working.
Figure 1 shows a form that Karen Anderson (2013) developed, which I think is very helpful in thinking about how much a child is going to understand. If a child has an aided audiogram that is at about the 25 dB level, they have 40% audibility for soft speech in the classroom. For the teacher’s voice , if they have a 25 dB aided audiogram, their audibility in the classroom is going to be 81% to 98%. But if they are hearing at 35 dB, they only have 10% audibility for soft speech and 45% to 60% audibility for the teacher’s voice. Think about how much that means they are missing. If they have 25% audibility for soft speech, that means they are not able to hear the children around them, and they are not going to have good incidental learning.
Figure 1. Comparison of audibility as a function of hearing threshold in dB HL (Anderson, 2013).
Figure 2 is an audiogram which gives you a sense about where this child may be hearing. At first glance, this child seems to have a pretty good audiogram, yet they are still not getting everything that they need to get.
Figure 2. Audiogram overlaid on audibility chart; even a slight-to-mild audiogram limits audibility (Anderson, 2013)
Classroom acoustics are critical. If you were in a classroom with one 40-watt light bulb, you know you would not have adequate lighting. What about the acoustics of that classroom? We know that acoustic treatment in a classroom is critical. We also know that it only costs between 1% and 5% of the construction budget, but meanwhile only 10% to 30% of classrooms meet the current ANSI (American National Standards Institute) standards for noise. Thirty percent of the classrooms are judged to be too noisy by educators, primarily the result of heating, ventilation, and air conditioning systems. We also know how critical noise is. Children under 13 years of age are the children most challenged by noise. Those are the critical years for beginning academic learning. If a child does not get what they need to get in those first six to seven years of school, that child is not going to be able to compete when they get to high school. We need to always pay attention to how much noise there is the classroom. We know that teachers have to talk loud in order to overcome the amount of noise in the classroom and they have significant problems with noise in their voices. Teachers have a 20% greater risk of damaging their voice than in other professions.
When a teacher raises her voice to be heard over the noise, what sounds are heard? Vowels. Vowels are louder. Those are the sounds these hearing-impaired children can hear pretty well by themselves, but the consonants do not get louder. You cannot make /s/, /f/, and /t/ louder by shouting. We know that strategic seating is critical. In order to hear the teacher’s voice, the teacher’s voice has to be 15 dB louder than the noise around them. That means that the child has to be really close to the teacher or has to have a really good, working FM system. We know that in children who are normal hearing and are not native English speakers, the effect on them for listening in the classroom is the equivalent effect of a 25 to 40 dB hearing loss. What does that mean for a child with a hearing loss? It is a significant difference.
Effect of Acoustics on Classroom Learning
Classroom acoustics affect learning in a lot of ways, such as how fast and how well a child learns. The rate at which a child learns is going to be a significant factor. How persistent the child is and how well the child can pay attention and pull themselves together in a noisy classroom will make an enormous difference. There have been a number of research studies which have shown that children who are in classrooms close to noisy areas like subways in New York or freeways in other places have a one-year drop in academic equivalent for every 10 dB of traffic noise in the classroom. We need to pay attention to classroom acoustics and see whether we can improve them.
Children do not habituate to noise. In fact, they tend to tune out. If you cannot hear, you cannot hear; that is the long and short of it. One of the things we want to know is what we can do to fix that and how many children should have FM systems. We need a good high-quality FM system to work. Jace Wolfe did a study comparing the Phonak Dynamic FM with audio enhancement to personal FM only. He discussed this study at the Phonak pediatric conference in 2012 (Wolfe & Vickers, 2012), and the results should be published soon. With personal FM and Phonak dynamic FM, the children did best. We absolutely know that if a child is hearing only with a soundfield system, no matter how good the soundfield system is, they are not getting enough information. Children with hearing loss absolutely have to have personal FM systems in order to hear well in the classroom. The gold standard for how well a child should hear means that at any child with hearing loss has to at least have a personal FM system, and ideally a wearable personal FM system, with a soundfield FM system.
Here are some data from Erin Schafer and Mary Pat Kleineck (2009) looking at the benefit of FM with a cochlear implant versus cochlear implant alone (Figure 3). It is interesting to me to see that they have compared a personal direct audio input FM with the desktop FM with the soundfield FM. They are clearly showing that a personal FM results in significantly better speech perception than a desktop or a soundfield system. The soundfield system has the same problem of distance from the microphone.. The speaker is just in a different place. The desktop system, even though it is sitting right in front of the child, is still not providing the appropriate speech perception. If the question is, “What kind of FM does a child need in the classroom?” the answer is always direct audio input.
Figure 3. Benefit in terms of increase of speech perception scores using FM systems over CI alone (Schafer & Kleineck, 2009).
Let’s talk for a minute about what is required for success. Every child must be evaluated to know how they are doing. We cannot assume. For a child who comes into school with delays, the goal is obviously to close those delays. If a child comes in with typical skills, the goal is to keep those skills where they are so that the child can stay on par with their peers. The Individuals with Disabilities Education Act (IDEA), as we all know, specifies that we need to support the development and use of technology, including assistive technology devices for maximizing accessibility for children with disabilities. For children who have hearing loss, this also includes providing a communication system where the child can hear, and if the family has chosen listening and spoken language, FM access is part of the communication system that these children will need. Equal access is the goal of IDEA, and that is our goal in allowing our children to function well in the classroom. Our goal is to give them equal access so that they can hear what they need to hear to learn.
For the children to succeed and learn what they need to learn in the classroom, they need to be able to understand the teacher. They need to be able to express their thoughts and ideas. They need to be able to tell us what they are thinking. They need to know when they do not understand, and they need to ask for help if they do not understand. They need to have social relationships with their classmates. If they do not, then school is not going to be successful.
What does the school staff need to know in order to make this work? The school staff needs to understand what is involved in helping children succeed. They need to know what is involved in listening and in developing conversational skills. They need to develop a hierarchy of skills the child needs to develop, and that the teacher needs to recognize when a child does not understand and help the child determine what to do when they do not understand. The school needs to understand what they can do to help build skills in different listening environments and in different academic settings. They need to help this child develop self-advocacy skills so that the child can learn and move on.
It is important that we know how a child is hearing. How does this particular child’s hearing loss impact how they participate in the classroom? What are they hearing? Does a child have sufficient acoustic access to be able to hear what is happening (Figure 1)? How well do they hear with the technology? What are their aided thresholds, and are they hearing well throughout the frequency range or only in the low to mid frequencies? What has been happening in the classroom to accommodate the child’s acoustic access? Are they making an effort to keep the classroom quiet? Is there a rule that you do not sharpen pencils while someone is talking? How is the student’s academic achievement compared to their peers? It is not all right to say he is doing well for a “deaf child,” because that is not our goal here. Our goal is to have this child doing as well as all of the children around them. Is this child continuing to make progress? How are they compared to their peers? Is this child consistently at the bottom of the class? Is this child being sent on to the next grade even though they do not have the skills to really compete equally? What kind of interventions does this child need in order to make them do better in the classroom? We need to know that, and we can see part of that when we observe. Part of it we get by looking at the academic records.
What about their communication skills? How well does the child understand what is happening in the classroom? What is the child’s language level and how does it compare to the other children in the classroom? It is not enough to say this is how this child’s language compares to nationwide surveys of where a child’s language should be. This child is in a particular classroom with particular children and has to compete with those children. It is not how well this child compares to everybody in the United States. It is how this child compares to the children who are sitting next to him, so that he can learn to function with those children. Is his language as good as those children? Are the classroom’s expectations the same for this child as they are for other children?
One critical thing we want to know is if the child is following what the teacher says. When you sit at the back of the classroom, you can see whether the child is looking at the teacher, looking at the paper, or whether their mind is wandering. If their mind is wandering, it is likely because they are not hearing. We need to know that, because we need to know what we have to fix. Can this child follow directions without assistance or does he need his neighbor’s help? When the teacher says go to page 43, does the hearing-impaired child have to look at their neighbor and see what page that child is on? Does this child have to check to see what is happening around him? Does the child answer questions appropriately, or is the question that the child answers not really the question that was asked? Does he volunteer or does he just sit back? Some of that is personality, but a lot of it is confidence in your ability to communicate. Does the child listen to what other children are saying or when other children are speaking, or does the child wander off because they know they cannot hear them? Where is the child seated? Are they seated in a place where they can both hear and see what is happening? How does the child manage as the day progresses? Does the child become more and more tired and just have a very hard time tuning in? Is the child socializing?
What about the teacher? Is the teacher using an FM microphone? Is she using it appropriately? I have done two classroom visits recently, one in which the FM microphone was sitting on the teacher’s desk, and she was not sitting at her desk, and in the other the FM microphone was at the teacher’s waist. How much is that child going to hear? Not enough. Does she know to turn it on and turn it off when she is talking to other children and it is not the hearing-impaired child’s business? It is annoying to have to listen to somebody talking about something not related to you. Is there a pass mic? Is the pass mic being used appropriately? Are the children waiting for the pass mic in order to speak? Is it a quiet room or is it a noisy room? What about street traffic? What about the pencil sharpener? What about the air-conditioning? All of those things matter.
Does this child manage with a standard test time or the does the child need extended test time? How well is the child able to keep up during the time that the child is listening to whatever is going on in the classroom? Where does the student stand academically in this particular classroom? Is this child in the middle, which is what we would hope? It would be lovely to be at the top, but we want to know where this child stands and what the teacher’s goals are for this child. Does the teacher want this child to learn at the level where the child is, or does this teacher say or think that that child is hearing-impaired and thinks about what we can expect? We really want to know what the teacher thinks about how the child is functioning and what kind of accommodations is the teacher willing to make for this hearing-impaired student. Will she repeat or does she get annoyed?
I did a classroom visit for child with a cochlear implant not long ago in which the teacher was so clearly annoyed, even with an observer in the room, about the need to repeat. When the child raised his hand and said, “I am sorry, I do not understand.” She said, “I will talk to you afterwards.” That is an unfortunate situation for anyone who is trying to learn.
It is important to know who is conducting the observation and what that person is looking at. We want the person who conducts the observation to be able to look at classroom acoustics, at what the child is hearing, at how the child’s language compares to the language level in the classroom, what the child’s socialization skills are, and how the child is communicating with peers. The person has to have a breadth of knowledge, but the observer also has to understand the acoustics. If it is an auditory-verbal therapist, a teacher of the deaf, or an audiologist, we know that they are going to have that information. If it is the special education supervisor, they may not have information about audition or recognize what is going on and where the FM should or should not be. Those are all things we have to think about when we are looking at a classroom observation.
When we have completed the classroom observation, what are we going to do next? Do we need to educate the teacher about how to use the FM, and when to turn it on and off? If there is not a pass mic, we can counsel about repeating the comments of the children in the classroom, and how to know when a student is missing something and what to do about it. When you do a school visit, we also need to observe speech-language services. While some speech-language pathologists have a lot of information about hearing loss, the majority of speech-language pathologists have very little experience with hearing loss. Many have not been exposed to children with hearing loss. If they took a class in graduate school, it was probably only part of a class that worked on teaching children to use audition. We need to know whether they know how to help children with hearing loss develop auditory skills. Are they helping to build the children’s auditory skills so they can learn new things and what are they focusing on? Are they working on language using an auditory model? We hope they are working on language, but they need to be working on audition also.
Any child with a hearing loss will benefit from the services of a teacher of the deaf. The teacher of the deaf has lots of responsibilities. Certainly, the teacher of the deaf is there to observe what is going on the classroom, see how well the child understands, and help the classroom teacher use the FM appropriately, but once a child gets into second or third grade, a significant part of what a teacher of the deaf should do is a preview and review of academic material. A lot of the time that is not happening. We want to know that the child is getting the information that they need. We want to know that they are hearing the things they need to hear and that they have the language. The reason for preview and review is to make sure that the child has the language ahead of time so that they can learn from the material presented by the teacher in the classroom. That is a critical part of the role of the teacher of the deaf. Even if there is not a full-time teacher of the deaf, the boards of cooperative educational services (BOCES) in the area should be able to provide a teacher of the deaf to come in and provide preview and review services on a regular basis.
We need to inform special education staff about the observations and make sure they understand what the good and bad things are that happened here and figure out what we have to do to make sure that this child gets what they need in the classroom. In fact, it is the special educators who are going to be the people who have to carry out the program in the end.
Let’s talk for a minute about how we know when hearing loss may compromise a student’s performance in the classroom. Something very obvious would be if they give the wrong answers to questions. You know they are not hearing. If they have to ask for repetition a lot, you know they are not hearing. If their attention wanders, they do not have good social skills with their peers, or they get very tired as the day goes on, those are all suggestions that this child is not hearing well in the classroom. Their hearing loss is compromising their ability to manage.
- i) Discuss the relationship between the pure-tone audiogram and hearing for speech development at primary level.
Pure tone audiometry or pure-tone audiometry is the main hearing test used to identify hearing threshold levels of an individual, enabling determination of the degree, type and configuration of a hearing loss and thus providing a basis for diagnosis and management. Pure-tone audiometry is a subjective, behavioural measurement of a hearing threshold, as it relies on patient responses to pure tone stimuli. Therefore, pure-tone audiometry is only used on adults and children old enough to cooperate with the test procedure. As with most clinical tests, standardized calibration of the test environment, the equipment and the stimuli is needed before testing proceeds (in reference to ISO, ANSI, or other standardization body). Pure-tone audiometry only measures audibility thresholds, rather than other aspects of hearing such as sound localization and speech recognition. However, there are benefits to using pure-tone audiometry over other forms of hearing test, such as click auditory brainstem response (ABR). Pure-tone audiometry provides ear specific thresholds, and uses frequency specific pure tones to give place specific responses, so that the configuration of a hearing loss can be identified. As pure-tone audiometry uses both air and bone conduction audiometry, the type of loss can also be identified via the air-bone gap. Although pure-tone audiometry has many clinical benefits, it is not perfect at identifying all losses, such as ‘dead regions’ of the cochlea and neuropathies such as auditory processing disorder (APD). This raises the question of whether or not audiograms accurately predict someone’s perceived degree of disability.
Pure tone audiometry or pure-tone audiometry is the main hearing test used to identify hearing threshold levels of an individual, enabling determination of the degree, type and configuration of a hearing loss  and thus providing a basis for diagnosis and management. Pure-tone audiometry is a subjective, behavioural measurement of a hearing threshold, as it relies on patient responses to pure tone stimuli. Therefore, pure-tone audiometry is only used on adults and children old enough to cooperate with the test procedure. As with most clinical tests, standardized calibration of the test environment, the equipment and the stimuli is needed before testing proceeds (in reference to ISO, ANSI, or other standardization body). Pure-tone audiometry only measures audibility thresholds, rather than other aspects of hearing such as sound localization and speech recognition. However, there are benefits to using pure-tone audiometry over other forms of hearing test, such as click auditory brainstem response (ABR). Pure-tone audiometry provides ear specific thresholds, and uses frequency specific pure tones to give place specific responses, so that the configuration of a hearing loss can be identified. As pure-tone audiometry uses both air and bone conduction audiometry, the type of loss can also be identified via the air-bone gap. Although pure-tone audiometry has many clinical benefits, it is not perfect at identifying all losses, such as ‘dead regions’ of the cochlea and neuropathies such as auditory processing disorder (APD). This raises the question of whether or not audiograms accurately predict someone’s perceived degree of disability.
AIOU Solved Assignment 1& 2 Code 683 Autumn & Spring 2020
Q.5 Discuss current researches into improving the signal-to-ration in hearing aid systems. Support your answer with reference to research consulate.
Signal-to-noise ratio (abbreviated SNR or S/N) is a measure used in science and engineering that compares the level of a desired signal to the level of background noise. SNR is defined as the ratio of signal power to the noise power, often expressed in decibels. A ratio higher than 1:1 (greater than 0 dB) indicates more signal than noise.
SNR, bandwidth, and channel capacity of a communication channel are connected by the Shannon–Hartley theorem.
Difficulty in speech discrimination, particularly in challenging auditory situations such as noisy places and/or when attempting to trace fast speech, is the most common complaint among the elderly. This difficulty is often attributed to reduced peripheral hearing sensitivity in the elderly (1,2). There is evidence that speech perception in noisy situations is difficult even for normal peripheral hearing sensitivity in the elderly (3). Speech discrimination in noise depends on auditory and extra-auditory factors (4). Spatial hearing, auditory input representation in different regions of the central auditory system, and spectrotemporal cues for speech processing such as F0 (the number of human vocal cord vibrations that are affected by age and gender) are known as auditory elements for speech perception in noise (5). Cognitive system functions (as an internal element) and physical environmental characteristics (as external elements) are known as extra-auditory participating factors for speech perception in noise. Attention and memory are the most important cognitive elements that result from bottom-up and top-down mechanisms (6). Therefore, auditory–cognitive system interactions are the basis of target signal and background noise segregation in the auditory system (7–12). The physical characteristics of a communicative environment are the other extra-auditory elements that influence target stimulus detection in the presence of competing background noise (13). The signal-to-noise ratio (SNR) is the most effective physical characteristic factor for speech perception in noise, and it is defined as the target stimulus power compared with the background noise power, measured in decibels (dB) (3). Several studies have supported the effect of aging on perceptual abilities. A comparison of these potencies in older and younger people revealed that older people required a 3–4 dB higher SNR than younger people to have the same proper perception under similar noise conditions. It appears that age-related changes in auditory–cognitive system functions are responsible for the requirement of an enhanced SNR in the elderly (14–16).
Most of the studies on the speech discrimination abilities of the elderly focused on their hearing impaired abilities, clarifying the causes of decreasing perceptual ability. Pichora-Fuller et al. (17) ascribed elderly speech difficulties in noise to a deficit in central auditory processing. Clark et al. (1) and Fostick et al. (2) attributed elderly speech difficulty in noise to peripheral hearing sensitivity loss, known as presbycusis. Wong et al. (7) found that the speech discrimination ability of the elderly declined more than younger people at a similar SNR. Anderson et al. (11,15) and Sung Hee et al. (18) noted that in the elderly, a decreased speech perception in noise ability was the result of chemical changes in the central nervous system neurotransmitters. Parthasarathy et al. (19), Souza et al. (1), Kamal et al. (20), Anderson et al. (11), Bidelman et al. (21), and Getzmann (22) attributed the elderly decreased speech in noise discrimination ability to temporal synchronization changes in sub-cortical auditory structures. Walton (23) also reported prefrontal and hippocampus atrophy in the brains of the elderly. Gordon-Salant (24) found that a decreased discriminative ability in spectro–temporal processing slows the central nervous system of the elderly. According to Zekveld et al. (25), Shannon et al. (26), Denise and Schwartz (27), and Sohoglu et al. (28), attention and working memory declines are the causes of decreased discriminative skills in the elderly. Wong et al. (29) studied the role of auditory-cognitive system interactions in speech discrimination and noted inadequate results for higher SNR requirements in the elderly compared with younger people under similar noise conditions. As noted above, the majority of related studies evaluated the effects of auditory–cognitive elements on speech perception in noise of the elderly. Because of the important role of the magnitude of SNR on perceptual abilities, it appears that more studies should evaluate auditory and extra-auditory element interactions.
Although it is well known that decreased hearing sensitivity and/or cognitive system dysfunction has a negative effect on the perceptual abilities of the elderly, the importance of physical environmental characteristics such as SNR has received less consideration. In this newly designed study, we investigated the role of the SNR magnitude as an extra-auditory effect element for the speech in noise perception ability of the elderly. This greatly controlled the auditory and cognitive elements legends.
This study revealed considerably reduced speech perception ability in the presence of background noise in normal, low–mid frequencies peripheral hearing, and cognitive system function. Moreover, decreasing the signal level and increasing the competing noise significantly reduced the perceptual abilities of the elderly. It appears that the SNR has an important critical role for proper speech perception in noise for the elderly, even those who have normal peripheral auditory–cognitive function systems. According to recent findings, elderly people may need adaptive strategies such as auditory training to facilitate speech perception in the presence of background noise.
No significant correlation was found between age and word discrimination scores in silence and at 0, +5, and +10dB SNRs. This finding is in agreement with Wong et al. (29) who found that the ability of speech discrimination in noise was not only related to the auditory system function, but also to the compensatory interaction of the auditory–cognitive systems. Therefore, one can say there is an assistive factor in the central nervous system of the elderly that prevents further speech in noise discrimination deterioration at higher ages. It appears that increased activity in general cortical cognitive regions such as the prefrontal area acts as an assistive factor to compensate for the sensory representation deficit in other cortical areas. This enhanced prefrontal activity following attention has been supported by behavioral-neurophysiologic studies (15-21). The ability of speech perception in the elderly affects peripheral/central auditory, cognitive, and environmental elements. Peripheral age-related hearing loss effects on elderly perceptual abilities is caused by a reduced auditory input transition from the cochlea to the higher auditory centers. Central auditory system dysfunction resulted from processing declines at the brainstem and in higher auditory regions (15,21). Conversely, cognitive system dysfunction reduces the working memory and attention capacity of the elderly. Physical environmental characteristic deterioration reduces the speech sound transportation from the speaker to the listener (37). These factors interact and facilitate the speech message perception of the listener. Although we greatly controlled auditory–cognitive element effects by screening the elders’ normal hearing at low–mid frequencies, the participants’ speech perception dropped considerably even at equal signal and noise levels. It appears that reparative strategies such as prosodic rhythm tracing at the phoneme level can help reduce speech sounds transition and processing compensation. Increasing the background noise and decreasing the signal level is helpful for maintaining conversation (38,39). Moreover, the effect of auditory training to improve perceptual ability through neural plasticity in the central nervous system of the elderly is supported in various studies. It appears that acetylcholine levels increase following auditory training and is responsible for exhibitory-inhibitory mechanism interactions resulting in speech representation improvements at sub-cortical and cortical levels (40). Therefore, simple stimuli based auditory training and/or memory auditory based cognitive training (IMPACT: Improvement in Memory with Plasticity-based Adaptive Cognitive Training) (45) is the best strategy to improve brain plasticity in the elderly and improve their speech in noise perception (41–44).
Recent findings are only reliable in the frame of this research because of our small sample size. Our general findings are dependent on similar studies with adequate sample sizes. We could not eliminate the effect of peripheral high frequency loss of speech in noise perception in the elderly. Another study at 250–8000 Hz with normal hearing elders may control this effect. More audiology perceptual tests are recommended to confirm our findings. A study of the SNR effect on hearing impaired elders perceptual abilities and the effect of negative SNRs on speech perception in noise is recommended to evaluate auditory/extra-auditory element interactions.