7
Hearing Loss in Children

Spoken communication is uniquely human. If the sense of hearing is damaged or absent, individuals with the loss are denied the opportunity to sample an important feature of their environment, the sounds emitted by nature and by humans themselves. People who are deaf or hard-of-hearing will have diminished enjoyment for music or the sound of a babbling brook. We recognize that some deaf and hard-of-hearing children are born to deaf parents who communicate through American Sign Language. Without hearing, these children have full access to the language of their home environment and that of the deaf community. However, the majority of deaf and hard-of-hearing children are born to hearing parents. For these families, having a child with hearing loss may be a devastating situation. The loss or reduction of the sense of hearing impairs children’s ability to hear speech and consequently to learn the intricacies of the spoken language of their environment. Hearing loss impairs their ability to produce and monitor their own speech and to learn the rules that govern the use of speech sounds (phonemes) in their native spoken language if they are born to hearing parents. Consequently, if appropriate early intervention does not occur within the first 6-12 months, hearing loss or deafness, even if mild, can be devastating to the development of spoken communication with hearing family and peers, to the development of sophisticated language use, and to many aspects of educational development, if environmental compensation does not occur.

Hearing loss can affect the development of children’s ability to engage in age-appropriate activities, their functional speech communication skills, and their language skills. Before we consider the effects of hearing



The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement



Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page 180
Hearing Loss: Determining Eligibility for Social Security Benefits 7 Hearing Loss in Children Spoken communication is uniquely human. If the sense of hearing is damaged or absent, individuals with the loss are denied the opportunity to sample an important feature of their environment, the sounds emitted by nature and by humans themselves. People who are deaf or hard-of-hearing will have diminished enjoyment for music or the sound of a babbling brook. We recognize that some deaf and hard-of-hearing children are born to deaf parents who communicate through American Sign Language. Without hearing, these children have full access to the language of their home environment and that of the deaf community. However, the majority of deaf and hard-of-hearing children are born to hearing parents. For these families, having a child with hearing loss may be a devastating situation. The loss or reduction of the sense of hearing impairs children’s ability to hear speech and consequently to learn the intricacies of the spoken language of their environment. Hearing loss impairs their ability to produce and monitor their own speech and to learn the rules that govern the use of speech sounds (phonemes) in their native spoken language if they are born to hearing parents. Consequently, if appropriate early intervention does not occur within the first 6-12 months, hearing loss or deafness, even if mild, can be devastating to the development of spoken communication with hearing family and peers, to the development of sophisticated language use, and to many aspects of educational development, if environmental compensation does not occur. Hearing loss can affect the development of children’s ability to engage in age-appropriate activities, their functional speech communication skills, and their language skills. Before we consider the effects of hearing

OCR for page 180
Hearing Loss: Determining Eligibility for Social Security Benefits loss on this development, we will review briefly the extensive literature on the development of speech and language in children with normal hearing. Although the ages at which certain development milestones occur may vary, the sequence in which they occur is usually constant (Menyuk, 1972). This chapter discusses the nature of the emergence of communication skills in normally hearing children as well as the unique effects of early hearing loss and deafness on this process for infants and children. We give details of the special nature of assessments and rehabilitation strategies appropriate for infants and children with hearing loss and finally discuss how considerations for disability determination need to be tailored to the special needs of this population. DEVELOPMENT OF PERCEPTION, SPEECH PRODUCTION, AND LANGUAGE Children with Normal Hearing Speech Skills Infants begin to differentiate among various sound intensities almost immediately after birth and, by 1 week of age, can make gross distinctions between tones. By 6 weeks of age, infants pay more attention to speech than to other sounds, discriminate between voiced and unvoiced speech sounds, and prefer female to male voices (Nober and Nober, 1977). Infants begin to vocalize at birth, and those with normal hearing proceed through the stages of pleasure sounds, vocal play, and babbling until the first meaningful words begin to occur at or soon after 1 year of age (Bangs, 1968; Menyuk, 1972; Quigley and Paul, 1984; Stark, 1983). Speech-like stress patterns begin to emerge during the babbling stages (Stark, 1983), along with pitch and intonational contours (Bangs, 1968; Quigley and Paul, 1984; Stark, 1983). According to Templin (1957), most children (75 percent) can produce all the vowel sounds and diphthongs by 3 years of age; by 7 years of age, 75 percent of children are able to produce all the phonemes, with the exception of “r.” Consonant blends are usually mastered by 8 years of age, and overall speech production ability is generally adult-like by that time (Menyuk, 1972; Quigley and Paul, 1984). Language Skills Language studies have described vocabulary and grammatical development of children with normal hearing. Studies of grammatical devel-

OCR for page 180
Hearing Loss: Determining Eligibility for Social Security Benefits opment have focused on both word structure (e.g., prefixes and suffixes), termed “morphology,” and the rules for arranging words into sentences, termed “syntax.” Vocabulary development up to young adulthood is estimated at roughly 1,000 word families per year, with vocabulary size estimated at approximately 4,000-5,000 word families for 5-year-olds and 20,000 word families for 20-year-olds (see Schmitt, 2000, for discussion). A word family is defined as a word plus its derived and inflectional forms. Most morphological and syntactic skills are fully developed by the age of 5 years, and grammatical skills are fully developed by age 8 (Nober and Nober, 1977). By age 10 to 12, most children with normal hearing have reached linguistic maturity (Quigley and Paul, 1984). In summary, by age 4½ years, children with normal hearing are producing complex sentences. Although a majority of the speech sounds in English are mastered by age 4, and most of the grammatical categories by age 5, it is not until age 8 that a normally hearing child has fully mastered grammar and phonology and has an extensive vocabulary (Nober and Nober, 1977). Children with Hearing Loss A review of speech and language development in children with hearing loss is complicated by the heterogeneity of childhood hearing loss, such as differences in age at onset and in degree of loss; we review these complicating factors separately following a more general overview. Mental and physical incapacities (mental retardation, cerebral palsy, etc.) may also coexist with hearing loss. Approximately 25-33 percent of children with hearing loss have multiple potentially disabling conditions (Holden-Pitt and Diaz, 1998; McCracken, 1994; Moeller, Coufal, and Hixson, 1990). In addition, independent learning disabilities and language disabilities due to cognitive or linguistic disorders not directly associated with hearing loss may coexist (Mauk and Mauk, 1992; Sikora and Plapinger, 1994; Wolgemuth, Kamhi, and Lee, 1998). For example, Holden-Pitt and Diaz (1998) reported the following incidences of additional impairments in a group of children with some degree of hearing loss: blind/uncorrected vision problem (4 percent), emotional/behavioral problem (4 percent), mental retardation (8 percent), and learning disability (9 percent). The coexistence of other disabilities with hearing impairment may impact the way in which sensory aids are fitted or the benefit that children receive from them (Tharpe, Fino-Szumski, and Bess, 2001). A recent technical report from the American Speech-Language-Hearing Associa-

OCR for page 180
Hearing Loss: Determining Eligibility for Social Security Benefits tion stated that pediatric cochlear implant recipients with multiple impairments often demonstrate delayed or reduced communication gains compared with their peers with hearing loss alone (American Speech-Language-Hearing Association, 2004). In this chapter, we focus on speech and language development in children with prelingual onset of hearing loss (before 2 years of age) without comorbidity. However, it should be kept in mind that the presence of multiple handicapping conditions may place a child at greater risk for the development of communication or emotional disorders (Cantwell, as summarized by Prizant et al., 1990). In addition, these children may require adaptations to standard testing routines to accommodate their individual capacities. Natural acquisition of speech and spoken language is not often seen in individuals with profound hearing loss unless appropriate intervention is initiated early. One of the primary goals in fitting deaf or hard-of-hearing children with auditory prostheses (hearing aid or cochlear implant) is to improve the ease and the extent to which they can access and acquire speech and spoken language. It should be kept in mind that the children under discussion typically are not born to deaf parents; those children may acquire American Sign Language as their native language. Speech Skills Speech and voice characteristics of persons who are deaf or hard-of-hearing are generally acknowledged to differ significantly from those of individuals with normal hearing (Abberton and Fourcin, 1975; Hood and Dixon, 1969; Monsen, 1974, 1978, 1983b; Monsen and Engebretson, 1977; Monsen, Engebretson, and Vemula, 1978, 1979; Nickerson, 1975; Nober and Nober, 1977; Stark, 1983; Wirz, Subtelny, and Whitehead, 1981). A congenital or prelingually acquired hearing loss reduces the intelligibility of talkers who are deaf or hard-of-hearing and impairs the production and tonal aspects of their speech (John and Howarth, 1965; Markides, 1970; McGarr and Osberger, 1978; Monsen, 1979; Osberger and Levitt, 1979; Smith, 1975). Difficulties with speech sound production include problems with the articulation of vowels and consonants, such as substitutions, distortions, and omissions (Hudgins and Numbers, 1942; Zimmerman and Rettaliata, 1981); excessive use of a neutral vowel, such as schwa the unstressed vowel sound in the second syllable of the word “kitten” (Markides, 1970); lack of adequate differentiation between various vowels (Angelocci, Kopp, and Holbrook, 1964; Levitt and Stromberg, 1983); and failure to differentiate between voiced and voiceless consonant sounds, for example “b” and “p” (Calvert, 1962; Monsen, 1976; White-

OCR for page 180
Hearing Loss: Determining Eligibility for Social Security Benefits head, 1983). These problems are accompanied by a significantly slowed rate of general speech sound awareness (phonological development) in children with hearing loss (Subtelny, 1983). Although many talkers who are deaf or hard-of-hearing can correctly produce phonemes in isolation, they may still be unable to smoothly combine the phonemes in connected speech. Thus, reduced speech intelligibility can result. Language Skills Vocabulary knowledge in children with hearing loss may be age appropriate or reduced, with results showing large variability (Gilbertson and Kamhi, 1995; Seyfried and Kricos, 1996; Yoshinaga-Itano, 1994). In general, however, the rate of vocabulary growth is slowed, and may plateau prematurely (Briscoe, Bishop, and Norbury, 2001; Carney and Moeller, 1998; Davis, 1974; Davis, Elfenbein, Schum, and Bentler, 1986; Moeller, Osberger, and Eccarius, 1986). Word entries may have less breadth or flexibility of meaning (Moeller et al., 1986; Yoshinaga-Itano, 1994). In particular, nonliteral or abstract word usage may be impoverished. The dynamic time course of accessing the meanings of words may also be slowed (slowed lexical retrieval) in children with hearing loss, although again, large unpredictable variability among individuals occurs (Jerger, Lai, and Marchman, 2002). In concert with vocabulary development, grammatical knowledge is also reduced in children with hearing loss. For example, in a sentence construction task, 14-year-old children who were deaf or hard-of-hearing performed similarly to 6- to 8-year-old children with normal hearing (Templin, 1966). In spoken language samples, the sentences of children who were deaf or hard-of-hearing were of shorter lengths with simpler sentence constructions and syntax (Brannon and Murray, 1966; Seyfried and Kricos, 1996). Sentences in the passive voice were not successfully comprehended or produced by about half of 17- to 18-year-old children who were deaf or hard-of-hearing (Power and Quigley, 1973). In studies of the morphological rules for different types of suffixes (e.g., -s as in sings and -er as in singer), children who are deaf or hard-of-hearing generally show inferior performance (Bunch and Clarke, 1978; Cooper, 1967; Elfenbein, Hardin-Jones, and Davis, 1994). The extent to which specific language skills are delayed versus deviant in the presence of childhood hearing loss continues to be pursued. It should also be noted that language proficiency is a strong predictor of reading achievement (Carney and Moeller, 1998). Thus, age-appropriate literacy skills typically are not observed in children with hearing loss and language problems.

OCR for page 180
Hearing Loss: Determining Eligibility for Social Security Benefits Complicating Factors One factor that influences the extent to which speech and language development is affected by hearing loss is the child’s age when the loss occurs. Auditory deprivation early in life has serious consequences for subsequent development (Davis, 1965). In general, children with early, prelingual hearing losses more frequently display deficits in the respiratory, articulatory, and phonatory aspects of speech (Binnie, Daniloff, and Buckingham, 1982; de Quiros, 1980; Itoh, Horii, Daniloff, and Binnie, 1982; Nober and Nober, 1977). Three important periods for onset of hearing loss have been described by de Quiros (1980). Children whose hearing loss occurs during the first 2 years of life are considered prelingually deafened. If profound deafness occurs prior to 2 years of age and intervention is delayed, speech can be severely disturbed. Hearing losses that occur between ages 2 and 5 will result in the loss of speech skills unless appropriate sensory aids and aural rehabilitation are provided. Finally, de Quiros suggests that deafness occurring after age 5 can result in appropriate articulation; however, good articulation skills may deteriorate if sensory input is not reestablished with amplification. Again, these detrimental outcomes may be ameliorated if the child is provided with a sensory aid that can provide auditory access to the acoustic properties of speech. Age at onset of hearing loss is not the only important prognostic indicator for speech and language development in children who are deaf or hard-of-hearing. A second critical factor is the degree of hearing loss. In a classic study, Hudgins and Numbers (1942) described an inverse relationship between articulatory errors and audiometric scores. Other authors have suggested that speech intelligibility decreases as the degree of hearing loss increases (Jensema, Karchmer, and Trybus, 1978; McGarr and Osberger, 1978; Monsen, 1983a). Similarly, Quigley and Paul (1984) reported that deficits in language comprehension and usage increase with degree of hearing loss. In spite of this overall trend, however, a general finding is that degree of hearing loss cannot perfectly predict speech and language abilities in individual children (Davis et al., 1986; Gilbertson and Kamhi, 1995; Mayne, Yoshinaga-Itano, and Sedey, 1998; Seyfried and Kricos, 1996). Unilateral Hearing Loss A study published in 1998 estimated that the prevalence of unilateral hearing loss in school-age children ranged from 6.4 to 12.3 per 1,000 and at that time there were 391,000 school-age children with unilateral hearing loss (Lee, Gomez-Marin, and Lee, 1998). There is a pervasive misun-

OCR for page 180
Hearing Loss: Determining Eligibility for Social Security Benefits derstanding that unilateral hearing loss is of no consequence and that this problem can be disregarded. Consequently, children with unilateral hearing loss often receive no direct intervention, such as amplification or therapeutic services. However, research now has shown that children with unilateral hearing loss are disadvantaged. In particular, children with unilateral hearing loss have difficulty in understanding speech in noisy environments and are deficient relative to their peers in localization of a sound source (Bess, Tharpe, and Gibler, 1986). Another study found that 32 percent of children in a cohort with unilateral hearing loss failed a grade in school and were significantly delayed in language compared with a matched group of children with normal hearing (Klee and Davis-Dansky, 1986). Age at Intervention Because speech and language develop rapidly during the early years in children’s lives (up to age 5), the importance of early intervention, including suitable amplification or cochlear implantation, can be seen. It is generally agreed that such intervention procedures are most effective when initiated as early as possible after the identification of the hearing loss (Silverman, 1983). According to Ling (1979), the motor skills required for speech can be learned at any time, but they are most likely to be transferred to the spontaneous level if children have not developed firmly established error patterns. Intervention techniques should be initiated at an early stage and should mirror the pattern of development in children with normal hearing (Ling, 1979). EFFECTS OF HEARING LOSS ON LITERACY AND EDUCATION Recent data from the Gallaudet Research Institute’s annual survey indicate that approximately 51.2 percent of children and youth with hearing loss are white, 15.4 percent black, 24.5 percent Hispanic, 4.3 percent Asian-Pacific Islander, and 0.8 percent American Indian, with the rest falling under the “other” or multiethnic categories (Gallaudet Research Institute, 2002). About 54 percent are male and 46 percent are female. This survey represents a database of roughly 60 percent of children in the United States who are deaf and hard-of-hearing and is based on reports from educational programs in which these children are enrolled (Karchmer and Mitchell, 2003). Current racial/ethnic proportions now mirror those found in the United States (Holden-Pitt and Diaz, 1998). The following is a condensation of information presented by Karchmer and Mitchell (2003). In terms of educational placement, 31.7 percent are in regular education settings, 12.6 percent are in resource rooms in these

OCR for page 180
Hearing Loss: Determining Eligibility for Social Security Benefits settings, 27.5 percent are in self-contained classrooms in regular education settings, 24.7 percent are in specialized schools, and the rest of the children (3.5 percent) are in other types of settings. In essence, two-thirds of all such children are now receiving at least some academic instruction in a regular classroom. Slightly more than 90 percent come from homes where only one spoken or written language (primarily English or Spanish) is used regularly. Self-contained educational settings have a larger percentage (almost 25 percent) of students from Spanish-speaking homes, almost twice the percentage found in the other three settings taken in aggregate. Special schools tend to enroll children with profound hearing impairments while self-contained classrooms serve students across the hearing spectrum, and regular school settings serve mostly those with less than severe degrees of hearing loss. The primary communication mode in educational settings is strongly related to degree of hearing loss. Specifically, those with profound losses are typically educated in programs that use signing or signing with speech, while students with milder hearing losses are most typically in speech-based programs. Students in regular education settings are least likely to have additional disabilities. With regard to academic achievement, children who lose their hearing after learning English generally achieve higher scores on standardized tests, including reading, than those with hearing loss at younger ages. The exception is deaf children of deaf parents, who tend to have higher English-language achievement scores than those with limited access to linguistic interaction both inside and outside the home. It is important to keep in mind, however, that the range of results is considerable. Mathematics performance, while higher than for language-based achievement, is not equivalent to that for hearing peers. In addition, students with hearing loss tend to demonstrate the same relative academic performance differences as their hearing peers across racial and ethnic groups. Karchmer and Mitchell (2003) emphasize the confound between race/ethnicity and lower socioeconomic status (SES), which makes it difficult to identify the impact of SES for students who are deaf and hard-of-hearing. Sex differences are minimal. In the recent past, it has been reported that the vast majority of persons educated in deaf schools (95 percent) reach a reading age of only 9 years (Stern, 2001; Traxler, 2000). Reading achievement scores are reduced even for students with minimal sensorineural hearing loss (Bess, Dodd-Murphy, and Parker, 1998). Reading deficits are exacerbated by reduced vocabulary, as previously discussed. More important, however, are deaf children’s deficits in phonological awareness. This is a crucial skill in the development of sound-symbol associations and consequently in reading ability. Paul (2003) emphasizes that deaf readers who use phonological codes for processing print do better than those who use nonphonological

OCR for page 180
Hearing Loss: Determining Eligibility for Social Security Benefits codes. Consequently, access to phonological information is critical. Reading and generalized linguistic difficulties can also be manifested in deficits in other areas of academics, including mathematics (Hyde, Zevenbergen, and Power, 2003) and science (McIntosh, Sulzen, Reeder, and Kidd, 1994). Although children are not in the workforce, they do spend considerable time in school. It is known that poor classroom acoustics (Acoustical Society of America, 2000) exacerbate difficulties in development of speech perception and eventually contribute to language and cognitive problems (Nelson, Soli, and Seltz, 2002). Perceptual difficulties in children due to poor classroom acoustics are especially challenging for children with even mild to moderate hearing loss (Bess et al., 1998), especially if English is not their primary language (Nelson et al., 2002). Poor classroom acoustics can result from too much noise intruding into the classroom from outside, leading to a poor signal-to-noise ratio for speech communication (Soli and Sullivan, 1997). Many classrooms also are poorly designed in terms of controlling for reverberation time (Knecht, Nelson, Whitelaw, and Feth, 2002). As explained earlier, reverberation time is a measure of the amount of time that a sound remains in the room after the original sound source has ceased, due to the reflections within the room (Acoustical Society of America, 2000). Long reverberation times mean that sounds already produced can interfere with newly produced sounds, leading to low speech intelligibility. It is known that normally hearing children’s auditory processing capabilities are adversely affected by long reverberation times (Johnson, 2000; Litovsky, 1997). Children with hearing loss are at risk in their ability to understand spoken communication in many schools. This difficulty can lead to reduced language and cognitive development. A clinical entity known as central auditory processing disorder (CAPD) is a dysfunction in perceiving auditory signals that is not attributed to peripheral hearing loss (McFarland and Cacace, 1995). CAPD is believed to subsume specific language and reading disabilities in school-age children. The area of CAPD assessment and remediation is not considered in this report, because this disability by definition is not attributed to hearing impairment. Children suspected of this disorder would be evaluated more appropriately in the domain of developmental disabilities. In summary, even mild hearing loss places children at risk for speech, language, and educational problems. A view expressed in the literature, however, is that strong familial support and early enrollment in high-quality intervention programs can increase the chances of successful speech and language outcomes in the presence of childhood hearing loss (Moeller, 2000; Yoshinaga-Itano and Apuzzo, 1998a, 1998b; Yoshinaga-Itano, Sedey, Coulter, and Mehl, 1998). Appropriate early intervention,

OCR for page 180
Hearing Loss: Determining Eligibility for Social Security Benefits for example, educational intervention, hearing aids, or cochlear implantation, can help to improve the performance of deaf children in areas of language and academic performance (Boothroyd and Boothroyd-Turner, 2002; Tomblin, Spencer, and Gantz, 2000). Next we turn to diagnosing and quantifying hearing loss in infants and children. INFANT HEARING SCREENING Hearing loss in infants is not obvious, and without specific measures to test for the condition it will go undetected for a significant period of time. As recently as 1996, the average age of identification of hearing loss in the United States was 30 months (Harrison and Roush, 1996). The means to evaluate infants for hearing loss with clinical tools, such as auditory brainstem response (ABR) and otoacoustic emissions (OAEs) have emerged in the past 20 years. However, until recently newborn hearing loss screening programs have existed in only a few hospitals for high-risk infants. In 1993, the National Institute on Deafness and Other Communication Disorders (NIDCD) of the National Institutes of Health issued a consensus statement (National Institutes of Health, 1993) calling for screening of all infants for hearing loss by 3 months of age. By 2000, the American Academy of Pediatrics (1999, 2000) endorsed universal newborn hearing screening for all infants prior to hospital release. Currently all 50 states have legislation either passed or pending to mandate universal newborn hearing screening, or they are conducting screening for most newborns without legislation. Neonatal hearing screening programs have proven effective as the first step in early identification of infants with congenital hearing loss. These programs identify infants at risk for a mild or more serious hearing loss. It is important to note that screening identifies only which infants are in need of a more complete assessment to determine if hearing loss exists. Infants failing this screening require a diagnostic audiological assessment by a qualified audiologist to confirm the presence of hearing loss and determine the exact type and degree of hearing loss in each ear. Results of the diagnostic evaluation are used to determine the degree of disability, to determine eligibility for rehabilitation programs and financial assistance, and to form the basis for fitting of amplification and placement in appropriate educational settings. Although the screening process for newborn hearing loss is excellent, it is not perfect. Children with mild hearing loss or hearing loss in restricted frequency regions may pass the screening. Some children develop significant permanent hearing loss after the newborn period, which is not detected by the screening. Infants with neural hearing loss, such as auditory neuropathy, will pass a screening if an OAE test alone is used for

OCR for page 180
Hearing Loss: Determining Eligibility for Social Security Benefits screening (Sininger, 2002). Infants with late-onset hearing loss will be missed in the newborn screening; and constant surveillance is needed by the medical community to find these infants and begin remediation as soon as possible (Joint Committee on Infant Hearing, 2000). The screening and diagnostic testing process is designed to expedite intervention for children with hearing loss and maximize the opportunity to provide audition during critical learning periods (Sininger, Doyle, and Moore, 1999; Yoshinaga-Itano et al., 1998). The goal of early hearing detection and intervention programs is to identify hearing loss and begin intervention including fitting of hearing aids at or before 6 months of age. Assessment of hearing loss in infants requires age-appropriate procedures. Infants under 6 months of age cannot give an accurate response to sounds at threshold levels, regardless of their ability to detect them. These infants require an audiological test battery based on objective physiological tests that reveal threshold-level responses, as well as information regarding the functioning of the peripheral auditory system. AUDIOMETRIC DIAGNOSTIC EVALUATION General agreement exists in the United States regarding the essential elements of an appropriate protocol for diagnostic audiological assessments of infants and young children. An audiologist with appropriate state licensure or equivalent credentials must perform such assessments. The complete battery includes a history and parent interview, evaluation of middle ear function, OAE testing, and an age-appropriate assessment of auditory behaviors. The core of the diagnostic evaluation protocol is an estimate of audiometric thresholds using auditory brainstem response or other proven electrophysiological assessment with frequency-specific stimuli. According to the American Academy of Pediatrics (2000, p. 804): Audiologists providing the initial test battery to confirm the existence of a hearing loss in infants must include physiological measures and developmentally appropriate behavioral techniques… For infants birth to six months of age, the test battery … must contain an electrophysiological measure of threshold such as ABR or other appropriate electrophysiological test using frequency-specific stimuli. Threshold Audiometry Unlike vision, human auditory sensitivity is adult-like within a few days of birth (Adelman, Levi, Linder, and Sohmer, 1990; Klein, 1984; Sininger, Abdala, and Cone-Wesson, 1997). Consequently, hearing loss degree and configuration are judged by the same standards for newborns as for adults.

OCR for page 180
Hearing Loss: Determining Eligibility for Social Security Benefits ligence quotient (IQ), longer use of the newest generation of speech processing strategies, a fully active electrode array and higher electrical dynamic range, and a greater growth of loudness on the electrodes. When these characteristics were controlled, educational placement did have a significant impact on cochlear implant outcomes (Geers et al., 2003a; Tobey et al., 2003). That is, children who were educated in settings that emphasized the development and use of speaking and listening skills had the best prognosis for spoken language processing. Predictors of good language skills included a higher nonverbal IQ, smaller family size, higher SES, and being female (Geers et al., 2003b). These factors similarly impacted language development for children who used oral communication and those who used total communication. Finally, predictors of reading success included a higher nonverbal IQ, higher SES, being female, and later onset of deafness within the period from birth to 36 months (Geers, 2003). When the variance due to these factors was controlled, the development of good reading skills was associated with mainstream educational placement, use of a current generation of speech processor strategy with a wide dynamic range, a longer memory span, and the use of phonological coding strategies. Geers (2003) reported that reading competence was best predicted by language competence and speech production abilities. In summary, cochlear implant technology and candidacy criteria have evolved greatly over the past 20 years. Today, patients with severe to profound deafness as young as 12 months old may be implanted. With earlier implantation and improved cochlear implant systems come continued increases in the benefits of cochlear implantation. Although wide variability in outcomes is noted, cochlear implant use by children with severe to profound hearing loss promotes the development of speaking and listening skills and the development of a spoken language system beyond what previously could be achieved with hearing aids. Children who are implanted at a young age and use oral communication have the best prognosis for developing intelligible speech and age-appropriate language abilities. However, it is also helpful to note that data from a Gallaudet Research Institute survey returned by 439 parents of children with cochlear implants indicate that roughly 50 percent continue to use sign language with their children as a supplement to spoken language (Christiansen and Leigh, 2002). The potential for optimal speech and language development in young children is greatly influenced by parent intervention. This requires considerable time commitment on the part of motivated parents, directed toward ongoing activities that reinforce spoken language, as well as extensive speech and auditory therapy (Christiansen and Leigh, 2002). Generally, parents believe that their children’s communication skills improve following implant (Christiansen and Leigh, 2002; Kluwin and Stewart,

OCR for page 180
Hearing Loss: Determining Eligibility for Social Security Benefits 2000). While this improvement does result in improved socialization with hearing peers, obstacles related to speech intelligibility and receptive understanding of what is communicated as well as attitudes of hearing peers continue to be ongoing factors (Bat-Chava and Deignan, 2001; Boyd, Knutson, and Dahlstrom, 2000). Psychological difficulties following implant, as reported by parents, are generally associated with getting the implant closer to adolescence and not being happy with it (Christiansen and Leigh, 2002). RECOMMENDATIONS Disability Determination Tests and Criteria Action Recommendation 7-1. The recommended criteria for determination of disability in children who are deaf or hard-of-hearing are presented in tabular format in Table 7-2. To be considered disabled, children under 3 years of age must meet the criterion for hearing level only. Children older than 3 years must meet the pure-tone average criterion and either the criterion for deficit in speech perception or the criterion for delay in language. Children with marked mental retardation who cannot be evaluated for speech perception or language should be considered disabled if the hearing level criterion alone is met. Action Recommendation 7-2. Speech perception tests are administered in quiet using recorded test materials at 70 dB SPL (based on peak levels or the equivalent in dB HL if available). Presentation of the speech perception test is via sound field using personal amplification or cochlear implant if such is used by the child. A preliminary check of the functioning and appropriateness of the cochlear implant or amplification should precede the aided testing (see Chapter 5). If no device is used by the child, testing is performed unaided. Action Recommendation 7-3. In general, average hearing levels will be determined from thresholds at 500, 1000, 2000, and 4000 Hz (PTA 5124). This differs from the PTA of 500, 1000, and 2000 Hz (PTA 512) used for adults. When thresholds are obtained with ABR, a minimum of two frequencies, one low (500 to 1000 Hz) and one high (2000 to 4000 Hz), can be used to determine average hearing level. It should be noted that when conditions indicate that auditory neuropathy may be present (absent ABR and normal OAE), it will not be possible to determine hearing thresholds by ABR. In those cases, disability should be presumed unless or until proven otherwise by age-appropriate behavioral testing (see Table 7-1). Behavioral threshold testing by VRA should be possible once the infant is older than 6 months of developmental age. Action Recommendation 7-4. The committee carefully considered

OCR for page 180
Hearing Loss: Determining Eligibility for Social Security Benefits TABLE 7-2 Summary of Recommended Disability Determination for Children Who Are Deaf or Hard-of-Hearing Age in Years: Months Hearing Levels: Pure-tone average (.5, 1, 2, 4), better ear, air conduction Speech Perception Test Criterion Language Test Criterion 0 to 2:11 > = 35 dB HL Not Applicable Not Applicable 3 to 5:11 > = 35 dB HL Agea-ppropriate, standardized test with normative data by age. Scores that are significantly (P <= 0.05) below expected normal (see Table 7-3). Agea-ppropriate, standardized test with published normative data by age. Age > = 1.64 standard score below norm for age. 6-14:11 > = 50 dB HL Age-appropriate, standardized test with normative data by age. Scores that are significantly (P <= 0.05) below expected normal (see Table 7-3). Age-appropriate, standardized test with published normative data by age. > = 1.64 standard score below norm for age. 15-18 years > = 70 dB HL NU-6 Scores that are significantly (P <= 0.05) below expected normal (see Table 7-3). PPVT-III > = 1.64 standard score below norm for age.

OCR for page 180
Hearing Loss: Determining Eligibility for Social Security Benefits these guidelines in the preparation of recommendations. In contrast to the suggested adult standards for PTA hearing level, we are suggesting that the degree of hearing loss that is considered disabling in infants and children is 35 dB HL or greater before the age of 6 years, 50 dB from 6 to 12 years, and 70 dB from 12 to 18 years of age. We have selected these criteria for the reasons stated below. As emphasized in the text of this chapter, a loss of hearing sensitivity can have a more detrimental effect on infants and children who are in critical learning periods for speech, language, and general communication ability than on their adult counterparts. School-age children depend on communication skills for all means of learning. Development of communication skills may be the most important task for an infant because it provides the basis for almost all subsequent learning. The committee chose 35 dB HL as the minimum hearing loss criterion on the basis of studies that have documented significant delays in speech production, language, verbal intelligence, and associated areas of learning (Briscoe et al., 2001; Davis et al., 1986) in children with hearing loss, including those with mild loss. The strongest evidence that even mild bilateral hearing loss is debilitating to young children comes from the endorsement of groups like the National Institutes of Health (1993), the American Academy of Pediatrics Task Force on Newborn and Infant Hearing (1999), and the American Academy of Pediatrics (2000), that endorse programs for early detection of mild hearing loss of 30 to 40 dB because of evidence that this degree of loss will cause significant communication and educational delays. The needs for intervention for children with hearing loss are particularly acute in the infant and preschool period, when peak gains are attained in language and speech. Particularly if language skills are developing well, the elementary-school-age child should be able to tolerate slightly more hearing loss and the criterion level for disability is adjusted to moderate (50 dB) rather than mild. It should be noted that at this age and older, assessments of speech perception and language skills are also recommended as part of the disability determination evaluation. Although the hearing level criterion for disability is less stringent at this age for a child than for an adult, it should be noted that a child with a moderate hearing loss whose speech perception skills and language ability are normal for his or her age may not be considered disabled. As these communication skills emerge, more emphasis is placed on them and the criterion for hearing level is raised. Finally, we recommend a 70 dB HL criterion for high school students, which is less strict than the 90 dB recommended for adults. The child of high school age with a hearing loss is significantly challenged by the

OCR for page 180
Hearing Loss: Determining Eligibility for Social Security Benefits hostile acoustic environment in which he or she must function and learn and by the increased social-emotional pressure that accompanies this period of development. Therefore, we do not recommend the adult standard of 90 dB HL average hearing loss until the child has reached 18 years of age. We recommend that speech perception be evaluated in the auditory mode that is optimal for individual children. In most instances, the optimal mode will be binaural, well-fitted amplification or a cochlear implant. We recognize, however, that some children may not use amplification devices for a variety of reasons. The determination of disability in these children should be without amplification. A guiding principle is that disability determination should reflect the real-world situation of the child. It is clear that the degree of hearing loss alone is not a perfect predictor of functional communication competencies. Therefore, the determination of disability requires assessment of a variety of communication skills. We chose the domains of speech perception and language processing because they are directly affected by childhood hearing loss and provide an important foundation for spoken language communication, reading, and multiple facets of educational achievement. Given the SSA criterion, it would be ideal to select and administer standardized measures that yield normative scores allowing comparable cutoff criteria for both types of tests. At present, this may be possible for language testing but not for speech perception testing. Standardized language measures provide normative data for children as a function of their age at time of testing. That is, within a given age range, normally developing, hearing children exhibit a normally distributed range of performance scores. By using normative data, we can determine where on the normal distribution an individual child’s performance lies. Standard language assessment scores are normalized to a mean of zero and a standard deviation of 1. Because abnormally poor performance occurs in only one tail of the distribution, we use a standard score of > = 1.64 units below the age norm to indicate performance below the 5th percentile. In contrast, spoken word recognition instruments containing age-appropriate vocabulary and response tasks should yield a skewed distribution with expected scores of 90-100 percent in normally developing, hearing children. This homogeneity of performance on speech perception tasks makes it impossible to derive a standard score for performance. Thus, we have taken a different approach in recommending guidelines for determining marked or extreme impairment in the areas of speech perception performance. We specified as the criterion for abnormality, scores that are significantly different from 90 percent correct (P <= 0.05). The percentage

OCR for page 180
Hearing Loss: Determining Eligibility for Social Security Benefits TABLE 7-3 Cutoff Scores Determined to Be Significantly < 90 Percent at p <= 0.05   Number of Test Items   15 20 25 40 50 Items correct < 10 < 15 < 19 < 32 < 40 Percentage correct 66% 75% 76% 80% 80% NOTE: 90 percent correct is low end of normal performance range. score deemed abnormal will vary based on the number of items in the test as indicated in Table 7-3. Table 7-4 summarizes the characteristics of the spoken word recognition measures described in this chapter. The committee has not recommended assessment of speech perception in noise for children, although to do so in our view would increase the sensitivity of the testing for disability. Such testing was not recom- TABLE 7-4 Description of Speech Recognition Tests for Children Test Recommended Age Range Test Format Presentation Format NU-Chips > 3 years Closed set Auditory only PSI 3-10 years Closed set Auditory only WIPI > 5 years for children with mild loss; > 7 years with severe loss Closed set Auditory only MLNT > 3 years Open set Auditory only LNT > 5 years Open set Auditory only Common phrases > 5 years Open set Auditory only; visual only; auditory + visual HINT-C > 6 years Open set Auditory only aThis criterion applies only for whole word scoring of tests of isolated word recognition. It cannot be applied to phoneme scores or to words tested in a sentence context.

OCR for page 180
Hearing Loss: Determining Eligibility for Social Security Benefits mended because of the lack of appropriately standardized tests across the age groups of interest. When tests exist, they may not be readily available to audiologists. With young children, test time and cooperation often are limited, and these test scores are not often available for scrutiny. However, checks for functional disability in Step 3 testing should detect the child’s significant difficulty hearing in noise. As standardized testing protocols to assess this function become more available, this information should be incorporated into a complete assessment of ability of children with hearing loss. Action Recommendation 7-5. In addition to the administration of standard audiometric and language tests, the evaluation for determination of disability for children who are deaf or hard-of-hearing should include a checklist to be completed by the audiologist. The checklist presented in Box 7-1 will ensure that information needed for test interpretation is available to SSA. For each checklist item, a response in the shaded box indicates that the response is invalid or needs explanation, as discussed below. Stimuli Test Items per List / # of Lists Response Score significantly < 90 percent correcta Monosyllabic words 50 / 4 Picture pointing < 40 words correct Monosyllabic words Sentences 20 / 1 10 / 1 Picture pointing < 15 words correct Not applicable Monosyllabic words 25 /4 Picture pointing < 19 words correct 2-3 syllable words 24 /2 Imitation < 18 words correct Monosyllabic words 50 / 2 Imitation < 40 words correct Sentences 10 / 6 Imitation Not applicable Sentences 10 / 13 Imitation Not applicable

OCR for page 180
Hearing Loss: Determining Eligibility for Social Security Benefits BOX 7-1 Pediatric Checklist for Audiological Evaluation for Disability Determination Question Response 1. Are hearing thresholds indicated for individual ears? 2. Are hearing thresholds obtained for at least two frequencies in each ear? 3. Is the test validity/reliability indicated on the audiogram? 4. Was the child cooperative during the testing? 5. Was speech testing performed with age- and language-appropriate materials? 6. Were tympanograms normal at the time of the threshold testing? 7. Does the child use personal amplification or a cochlear implant? 8. If yes to question 7, was the device functioning as expected on the day of testing? 9. If yes to question 7, was the child tested with the device? Comments from audiologist: ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ Interpretation of the checklist above is as follows. Item 1. For a variety of reasons including lack of patient cooperation, some pediatric evaluations are performed without earphones; rather the stimuli are presented through speakers or in the “sound field.” In this instance, thresholds will be Recommendations for Further Research This chapter reveals many unresolved issues with respect to determination of disability status for infants and children with hearing loss. Persons involved in the care and management of these children rely on published laboratory and clinical science for direction. Many of the questions raised could be answered with appropriate scientific investigation.

OCR for page 180
Hearing Loss: Determining Eligibility for Social Security Benefits indicated with the symbol “S” rather than O or X. These scores indicate the hearing thresholds of the better-hearing ear. These scores may serve to indicate the overall hearing loss level until ear-specific scores can be obtained. Item 2. When ABR is used to predict thresholds, occasionally only a click stimulus is used for the evaluation. For purposes of disability determination, we recommend that a minimum of two frequency-specific stimuli should be tested to determine average hearing level in each ear. A click threshold alone may not give an accurate estimate of the degree of hearing loss and could underestimate the average loss. In special circumstances, if a click threshold alone is available as an indication of hearing level, it can be used as evidence of disability until a more complete evaluation is available. Item 3. It is important to obtain cooperation when testing a young child. There are a variety of reasons why the test results might not be considered valid or reliable on any given test date. If results are not valid and reliable, additional testing should be considered. Item 4. Augments item three. If the child was not cooperative during testing, the results should be deemed unreliable and additional testing should be considered. Item 5. Examples of measures for speech perception that are appropriate for various ages of children are listed in Table 7-4. If the test is not age appropriate or the language level is beyond the skills of the child, the test will not be valid. Item 6. The tympanogram is a measure of the mobility of the eardrum. If the tympanogram is not normal, the child may have had a transient middle ear condition, such as fluid behind the eardrum, on the day of the test. This condition can exacerbate the degree of loss. When “no” is indicated on item 6, a treatment plan from a physician, preferably an otolaryngologist, should indicate if the hearing loss is stable or if treatment may improve the hearing levels. The status of the hearing may need to be reevaluated after treatment to determine accurate hearing levels. During treatment, the average bone conduction threshold, if available, can give an indication of the degree of permanent hearing loss. Item 7. Speech testing should be performed with the child using the hearing aid or cochlear implant if it is regularly used. Item 8. The audiologist should perform basic checks of the status of devices before testing. This information should be in the report. If not, it is possible that the maximum ability of the child was not assessed. Item 9. If the device was not worn for testing, it is possible that the maximum ability of the child was not assessed. We recommend that the SSA partner with other research funding agencies for whom these questions are also relevant, such as the U.S. Department of Education and the National Institutes of Health, particularly the NIDCD and the National Institute of Child Health and Human Development. Issues that are particularly relevant to SSA are emphasized below. The top three listed here are considered highest priority research aims for SSA purposes; the others listed are not in order of priority.

OCR for page 180
Hearing Loss: Determining Eligibility for Social Security Benefits Research Recommendation 7-1. There is a distinct need for standardized speech perception measures for infants and children that take into account developmental age and degree of hearing loss. Such tests should be developed in English as well as in other languages spoken in homes across the United States. When possible, such tests should incorporate evaluation of perception both in quiet and with relevant competing messages to simulate real-life situations, such as classrooms. Research Recommendation 7-2. Often children with similar audiograms have very different higher-level auditory abilities, such as spoken word recognition. There are even less-direct relationships between severity of hearing loss and such long-term outcomes as educational achievement, vocational status, and overall psychosocial development. It is important to identify other factors that contribute to these outcomes in persons who have been deaf or hard-of-hearing since early childhood. Specifically, it is important to determine how the following factors influence long-term outcomes for children who are deaf or hard-of-hearing: complexities of linguistic environment in the home and in the educational setting, such as multilingual environments, signed or spoken instruction. the complexities of educational intervention, including the types of intervention, age at inception and duration, educational setting (mainstream, self-contained, home), and training of intervention specialists. Research Recommendation 7-3. Many studies have documented the expected outcomes for children using cochlear implants, yet documenting benefits and outcomes of amplification use in children is a more complex task, and few controlled studies exist. More prospective studies of children using amplification are needed to determine related outcomes for communication, socialization, and educational achievement. For example, better studies are needed to determine how factors specific to the amplification fitting process and specific to the child influence such outcomes as language development, speech production, perception development, and social development. Examples of factors surrounding amplification fitting include type of aid fitted, features used such as directional microphones, feedback suppression, type of compression, or specific fitting formula selected. Factors specific to the child that could influence outcomes include the child’s age at fitting, degree of hearing loss, and other disabling conditions. The following research aims may do less to refine disability criteria for SSA but are extremely important in terms of understanding auditory issues relevant to communication development in infants and children who are deaf and hard-of-hearing.

OCR for page 180
Hearing Loss: Determining Eligibility for Social Security Benefits Research Recommendation 7-4. Little is known about the interaction between vision and audition in the development of communication skills. Children with hearing loss often rely heavily on visual perception of speech (speech reading or speech feature cueing) to supplement their auditory capacity. Large individual differences may occur in the reliance on visual information when auditory information is incomplete. Currently, there are no standards for measuring visual, auditory, or combined perception of speech. There is a great need for the development of standard clinical measures that incorporate auditory and visual assessments. Research Recommendation 7-5. There is a need to understand the effects of slight and unilateral hearing loss on the development of communication skills, educational performance, and social adjustment. Studies are needed to reveal the true nature of the dysfunction these children experience, especially in educational settings, and the possibilities for intervention that may help to mitigate such disturbances.