Dr. Ross on Hearing Loss
Definitions and Descriptions
by Mark Ross, Ph.D.
When our editor asked me to write on this topic for the third time, I wondered what if anything I could add to what I already wrote. While there has definitely been significant technical advances in the detection and management of children with hearing loss, these are areas that other authors in subsequent chapters will cover. Fortunately for my contribution, however, there has been some interesting new research regarding the demographics of hearing loss and the performance of hard of hearing (HOH) children, information that can be woven into the existing text. Most importantly, however, as I thought about her request, this third time around offers me an opportunity to reemphasize what I feel are some fundamental issues concerning the education of HOH children. In short, our editor made me an offer I couldn’t refuse!
It is still too easy to “forget” HOH children. There is nothing about them that immediately calls attention to itself or tugs at one’s heartstrings. Most HOH children have little difficulty understanding face-to-face conversational speech. Their speech is ordinarily perfectly intelligible, even if often marked by evident articulation deficiencies. Their voice quality and speech rhythmic patterns are usually not too different from that exhibited by normally hearing children. In other words, little about them marks them as handicapped, unless they wear visible hearing aids (which is one important reason why many object to wearing them). Ironically, their superficially normal appearance and abilities may make the situation worse for them. HOH children do not get the services they need and deserve because their very real problems are masked by an apparently normal facade.
When we get past this facade, however, when we explicitly focus upon the impact of a hearing loss upon their speech, language, academic performance and behavior, it is apparent that the potential consequences of the condition are far from trivial. And what has often happened in the past, and no doubt still happens, is that if a hearing loss is not understood to be the basic genesis of their problems, then other reasons (i.e. intelligence, emotional adjustment, attention deficit disorder, etc.) may be ascribed as the responsible agent. A hearing loss in a child, of whatever degree, is not a benign condition. It has ramifications that can pervade every aspect of the child’s life.
The main purpose of this chapter is to review and discuss the possible implications of a hearing loss upon the life and well-being of HOH children. Before these implications are discussed, however, it is necessary to distinguish as clearly as possible between HOH and deaf children. This is not just an exercise in academic taxonomy; the educational practices we prescribe for children can’t help but be strongly influenced by the labels that are used to characterize them (Ross and Calvert, l967).
The connotations of the term “hard of hearing” is – or should be - different from that of the terms “deaf” and “hearing-impaired” (Wilson, Ross, and Calvert, l974). An educational program designed for one category of children, such as a classroom for deaf children using a primarily visual mode of communication, would not be appropriate for another category, i.e. HOH children requiring an auditory-based approach. The sloppy, almost interchangeable use of the three terms suggests a malnourished information base for understanding and dealing with all people with hearing loss. If we cannot define and describe the most salient characteristics of the children we are concerned about, how can we hope to devise the most appropriate educational program for them? It is a therapeutic truism that one most first understand a condition in order to deal effectively with that condition. Clearly, at a minimum, this requires diagnostic labels that accurately describe the condition.
Definitions and Incidence
A Semantic Introduction
In some ways, since I first started writing on my concerns with the “Semantics of Deafness” well over thirty years ago, the current situation seems to have gotten even worse than it was then. In previous years, the labels “deaf” and “hard of hearing” were most often employed as subcategories of the term “hearing-impaired”, then used generically to refer to anybody with any type and degree of auditory disorder. Some deaf people and their supporters objected to the term “hearing-impaired” because in their opinion it had several negative connotations. For one, they did not believe that their auditory status should be characterized as “impaired” when for them it was a normative condition. The fact that they were unable, or unwilling to hear, was considered a component of their identity, that they were primarily part of a visual and not auditory world. Another objection was their judgment that the term carried an implication that the person was “impaired” rather than just the hearing, even though this was far from the intention of those who employed the term routinely (as I did).
Because of these reasons, however, and regardless of their merits, this generic usage of the label “hearing-impaired” now appears to be in disfavor. Now we see the term “deaf and hard of hearing” being employed instead. (Or, sometimes, “deaf and hearing-impaired – which leaves me completely confused as to what is meant!). In part, it seems, the term “deaf and hard of hearing” is being used as a substitute generic label, to refer to all people with hearing loss, and partly to reflect an extension of the original mission of agencies that heretofore only ostensibly dealt with “deaf” people. Thus, a number of organizations, agencies and educational settings at the national, state and local levels have recently relabeled themselves to include the term “hard of hearing” as well as “deaf.” Accordingly, state commissions originally called “State Commission for the Deaf” are now often titled “Commission for the Deaf and Hard of Hearing.” Vocational Rehabilitation agencies now claim as their mission to service both “deaf and hard of hearing” people as clients. Local, regional, and national educational programs, from the elementary to the college level, are ostensibly designed to assist both “deaf and hard of hearing students. Well, so what? Does changing a label change the reality in any way?
I believe it does for two reasons. The first is that although the label of an agency or institution may have changed, the services, actual functions and budgetary allocations are often basically the same. Thus, the need for interpreters, note-takers and real-time captioning are stressed for the deaf clients, as well they should be, but not assistive listening systems or acoustical modifications for their hard of hearing clients. In a way the lumping together of deaf and hard of hearing people is understandable, simply because both deaf and hard of hearing people display auditory deficiencies of some degree or another. In actuality, however, in spite of some overlapping needs and the presence of some people who fall into a “gray” area, these groups are fundamentally very different.
The second reason, and the one most germane in this context, is how this generic classification plays out with children in schools. There are many educational programs in this country that purport to serve both deaf and hard of hearing students. However, a large number of such programs only provide one educational philosophy for any child with a known hearing loss regardless of severity. Almost always in these classrooms, a Total Communication (TC) approach is the one employed. While theoretically, hard of hearing children (or those potentially so, given appropriate auditory management) should also receive the auditory access they require in a TC program, in reality the auditory-oral mode is often given short shrift. Because the teacher is simultaneously signing while speaking, the oral language component is rarely complete and grammatical (Ross and Calvert 1984). Hearing aids and auditory training systems are often not monitored and sometimes not even used. In some schools that claim to care for both deaf and hard of hearing students, American Sign Language (ASL) with "voice-off" is the instructional language. While perhaps not explicitly forbidden, the value system developed in such schools often discourages the use of audition. No educational program for “deaf and hard of hearing” children that is not also committed to fully utilize residual hearing can be considered appropriate for HOH children. This is the kind of educational experience that can and does “create” functionally deaf people from audiologically HOH children.
Right now, it is considered inappropriate to refer to “hearing-impaired children” because of an increasing acceptance of a “people first” verbal convention in referring to anybody with any type of disability. Thus, “children with hearing impairment” or “children with hearing loss” are generally acceptable as a generic term - except for those who do not agree that their or their children’s hearing is “impaired” or that they have suffered a “loss” - but not “hearing-impaired children.” Putting the “child” first is meant to remind us of the humanity of people with disabilities, that their problems do not define them as human beings. Although, I don’t know of any reality situation that has ever been changed by this kind of terminological correctness, it is a position that, theoretically at least, I find sympathetic. In practical terms, however, while it is not difficult to substitute “children with hearing-impairment” for “hearing-impaired children,’’ it is less natural (at least for me) to follow the “child first” convention when referring to “hard of hearing” or “deaf” children. So I’m afraid that in this chapter, I will not be completely politically correct.
From an audiological perspective, the term “deaf” has its own meaning and should be used in a precise manner. It refers to any person whose development of communication skills occurred primarily though the visual channel, and whose current mode of communication is primarily visually-based. Note that I am emphasizing an “audiological definition,” and not a psycho-social one. Some audiological hard of hearing people identify themselves as “Deaf” and prefer to associate with the Deaf community. This is their prerogative. Note also that “primarily” is employed as a qualifier when describing development or mode of communication. This is to remind us that we should not rule out the possible contribution of audition, even for children with the most profound hearing losses. From an audiological perspective, the term “deaf” denotes any person whose auditory system is sufficiently damaged so as to preclude the auditory-alone development and comprehension of oral language, even with the best sound amplification. As it happens, most deaf children possess some residual hearing whose proper use can provide important supplement cues that are valuable for improving speech perception and production (Ross and Levitt, 2000).
These are necessary distinctions to draw because much of the emphasis in educating children with hearing loss is directed (or should be) to the exploitation of residual hearing. When the descriptive label “deaf” is improperly applied to a child, the fact that the child does have usable residual hearing is easily ignored. After all, a “deaf” child is not supposed to be able to “hear” any more than a “blind” child can “see”. The possible consequence of an erroneously applied diagnostic label is that educational placement, expectations, and programming are often devised to be consistent with the connotations of the term, rather than the child’s auditory potential. We should not be surprised when the educational, social, and communication “product” of a program devised for deaf children is a functionally deaf child.
The currently available evidence suggests that the audiological separation between the deaf and hard of hearing categories occurs around the pure-tone threshold average (500 Hz, 1000 Hz, and 2000 Hz ) of 90 dB. Actually, there is no sharp audiological demarcation point between children who are potentially hard of hearing and those who are functionally deaf. (It must be emphasized that this cut-off was developed prior to the advent of the cochlear implant; with an implant, just about any child with any degree of hearing loss is potentially capable of functioning as a hard of hearing person). The only really valid defining measure is a functional one. If the person with a hearing impairment cannot comprehend verbal messages through the ear alone, then that person is audiologically deaf, regardless of the degree of hearing loss.
For demographic purposes, most of the previous studies on the incidence of deaf children have employed the 90 dB figure. Using this figure, approximately, one child per thousand is born deaf. Several states have reported higher incidence figures as a result of their Universal Newborn Hearing Screening programs. Rhode Island, for example, reports an incidence figure of two per thousand, while in Texas an average of 11 hospitals found that three children per thousand had significant and permanent hearing loss. In both these instances, because of the methodology used to detect hearing loss, children with lesser degrees of hearing loss are included in the overall statistics (Vohr, Carty, Moore and Letourneau 1998; Finitzo, Albright and O’Neal 1998). Insofar as truly deaf children are concerned, we are probably safe in assuming an incidence rate of one per thousand births.
Hard of Hearing
A HOH child develops speech and language skills primarily through the auditory mode and employs (or is capable of employing) a primarily auditory-verbal system of communication. Note that the word “primarily” is again employed as a modifier. While many of these children are more or less dependent upon visual cues for interpersonal communication, vision is still a secondary channel compared to audition. In this respect, HOH children are much more like normally hearing children than they are like deaf children, exactly the opposite of what is commonly presumed. Thus, a HOH child is frequently treated as a high-achieving deaf child rather than as a lower achieving normally hearing child. It makes a difference. In the latter case, parents and teachers would be expected to increase the pressure for higher accomplishments. Expectations are higher if they are based on normally hearing children. In the former instance, the child would be considered to already be doing quite well for a “deaf” child. Expectations are lower, since the educational achievement of deaf children are much lower than that of normally hearing children (i.e. average reading levels at the fifth grade for those deaf children who graduate from High School). Many of the educational aberrations to which many HOH children are exposed follow from this erroneous, limiting, and basically pessimistic conception.
Educationally, when HOH children are conceptualized or treated as deaf children, the visual channel receives the primary educational emphasis rather than the auditory channel. Although it may seem counter-intuitive, it is through audition and not vision that English language development can be developed most effectively, and thus can serve as the basis for English literacy. And it is reading capability that is the key to educational accomplishments and vocational success in our modern age. The implication of this point of view is that in educating HOH children, it is first necessary to ensure the optimum use of their residual hearing. Only after this is accomplished should other remediation services, as required, be provided them. In no case should any of these other services be offered as substitutes for an optimal auditory management program.
It has been estimated that there are approximately 16 per 1000 school children with an average hearing loss between 26 and 70 dB in the better ear. These are children whose hearing losses have usually been identified and who are clearly candidates for some type of hearing enhancement device and other remedial services. What has not been so clearly apparent is that children with lesser degrees of hearing loss, of whom there are many more in the school than 16 per 1000, may also be “at risk” for educational/social problems as a consequent of their hearing loss. In considering the demographics of hearing loss, our primary concern is not only the actual incidence of various degrees of loss, but whether or not these hearing losses have educational consequences. What, in other words, are the lower limits of hearing loss where a child can be considered “hard of hearing?” Several recent, well-controlled studies provide the most accurate and up-to-date information regarding these questions.
In the first study (Bess, Dodd-Murphy and Parker l998), the primary focus was the academic achievement and functional status of children with minimal sensorineural hearing loss (MSHL). In the course of the study, the overall incidence of hearing loss in a public school setting was also determined. Just the incidence figures will be given here; the educational and psychosocial findings will be described in a later section. The authors defined MSHL for three distinct groups of children. One consisted of children with unilateral sensorineural hearing loss (equal to or greater than a 20 dB threshold average at 500 Hz, 1000 Hz, and 2000 Hz in the poorer ear). The second comprised those with bilateral sensorineural hearing loss (average pure-tone thresholds between 20 dB and 40 dB bilaterally). Children with high frequency sensorineural hearing loss (air-conduction thresholds greater than 25 dB at two or more frequencies above 2000 Hz in one or both ears) formed the third group.
The study sample included 1228 children in grades 3, 6, and 9 from the Nashville Metropolitan School District. Using carefully controlled procedures to test the children’s hearing, the investigators found an overall hearing loss prevalence rate of 11.3%, of which 5.4% displayed a minimal sensorineural hearing loss (MSHL). The other children had conductive (perhaps fluctuating) or mixed hearing losses. Given the care with which this study was conducted, it is very possible that these results can be generalized to the overall school population in the United States. Considering the educational implications of MSHL (to be discussed below), it is apparent that these incidence figures should be a cause of national concern. We are no longer dealing with a “low incidence” handicap, but one that affects one in ten school children in our country.
In the second recent study that evaluated the prevalence of hearing loss among school age children (Niskar, Kieszak, Holmes, Esteban, Rubin and Brody l998), the incidence figures are even greater than reported in the previous study. The hearing thresholds of over six thousand children were tested as a component of the Third National Health and Nutrition Survey. The results indicated that a total of 14.9% had either low frequency or high frequency hearing losses, defined as 16 dB or greater at 500 Hz,,1000 Hz and 2000 Hz (low frequency) or at 3000 Hz, 4000 Hz and 6000 Hz (high frequency hearing loss). While these criteria for defining “hearing loss” are rather strict, there is some evidence of possible educational consequences of even this minimal degree of hearing loss. A study conducted by Saarf (1981) of children with similar degrees of hearing loss showed that such children are educationally “at risk.” He found that of the 33% of children who failed a stringent hearing-screening test (failure to respond at 10 dB at 6 out of 14 test frequencies in both ears), 57% exhibited academic deficits of some kind.
Unilateral and Conductive Hearing Losses
Using the yardstick “educationally at risk”, it is clear that children with unilateral hearing loss should also be considered hard of hearing. Although their speech and language ordinarily develops normally, there is evidence that such children fail at school and repeat grades at a much higher rate than children with bilaterally normal hearing (Bess l986; Oyler, Oyler and Matkin l988). These studies indicate that approximately 24% to 35% of children with unilateral hearing loss failed at least one grade in school, and that an additional 13% to 41% required special services. From a behavioral point of view, these children are often rated more negatively than children with bilateral hearing losses are. They apparently “hear” normally, but because the nature of their hearing condition, they have more difficulty in localizing sound sources as well as comprehending speech under adverse acoustical conditions.
Many children with chronic and fluctuating middle ear problems can also be considered functionally hard of hearing, again if we consider the possible educational consequences of these conditions. In the past 30 years, a vast body of literature has arisen on this topic. While the details vary, the general consensus of the research is that some impairment of auditory processing skills may be related to a history of chronic and fluctuating hearing loss secondary to middle ear effusions. (Feagons, Blood and Tubman l988; Gravel and Wallace l998). On the average, such children demonstrate more difficulty than children without this background on such tasks as selective attention, sequential memory, phonemic synthesis, and oral spelling. They have also been reported to display more academic, phonological, and linguistic deficiencies than comparable children without this history. The many variables associated with this type of research suggest caution in reaching firm conclusions (Ventry l980), but few would doubt that a long-standing hearing loss associated with middle ear problems would not be a source of potential educational problems.
Perception of Hearing Loss
In presenting the demographic data regarding hearing loss, I reviewed several studies in which children with thresholds as low as 16 dB in one ear were identified as having a “hearing loss” (Niskar et al l998). These are children who are usually classified as those with slight (sometimes termed “minimal”), mild or moderate hearing losses. In counseling parents and other interested parties, audiologists employ these terms on the basis of the audiometric results. Thus children with average pure-tone thresholds (at 500 Hz, 1000 Hz, and 2000 Hz) between 15 dB and 25 dB are considered to have a “slight” hearing loss; those whose average thresholds fall between 26 dB and 40 dB are presumed to have a “mild” hearing loss; while those who fall in the 41 dB to 45 dB category are considered to have “moderate” hearing losses (Clark l980). It is important to note that we use these relatively benign labels without reference to the actual auditory experience of having such a hearing loss. Is, in other words, a “slight” or “mild” hearing loss perceived by the affected person in accord with the ordinary connotations of the terms? Basically, this was the research question posed by Haggard and Primus (l999), in a study that related the actual perception of various degrees of hearing loss to the labels used to describe them.
What they did was to ask thirty parents of young normally-hearing children to compare their listening impressions to speech filtered to simulate slight, mild, and a moderate hearing loss to that of a unfiltered and unattentuated speech signal. The simulated thresholds for the “slight” loss was 10 dB at 500 Hz, 20 dB at a 1000 Hz, and 36 dB at 2000 Hz, or an average of 22 dB. The pure-tone threshold averages for the “mild” and “moderate” hearing losses was 34 dB and 49 dB respectively. After listening to the simulations, the subjects were asked to select from a list of 17 options, taken from various classification scales, for two terms that best represented their experience with each simulated hearing loss. In addition, they were asked to select the percentage of hearing loss they felt the simulation represented.
The results showed that the most frequent terms chosen for the “slight” hearing loss simulation was “difficult” and “handicapping”. For the “mild” simulation, the choices were “serious” and “handicapping”, while “severe” and “extreme” were the terms most often selected for the “moderate” simulation. Insofar as percentage ratings are concerned, for the slight, mild and moderate simulations, the subjects assigned percentage ratings of 46%, 64% and 82% respectively. These should be compared to the percentage rating assigned by the American Academy of Otolaryngology (2%, 20% and 42% respectively).
In other part of the study, the subjects were asked to assume the degree of difficulty a child with a given degree of simulated hearing loss would have in nine different situations. This was compared to how they rated probable degrees of difficult just to the labels of slight, mild, and moderate. In all cases and in all nine situations, the subject judged that the child would have much greater difficulty when they actually experienced the listening simulation compared to the judgements they made when using only the connotations of the terms.
What this study shows is how the labels used to describe hearing loss can cause parents (and other professionals) to underestimate the magnitude of the problems faced by children with so-called slight, minimal, mild, and moderate hearing losses. Verbal classifications of hearing loss in the 15 dB to 25 dB and 26 to 40 dB as slight (minimal) or mild (Clark l980) are completely misleading. These classification may be comforting to parents, and are relatively easy for audiologists to convey (“don’t worry, it’s only a mild hearing loss”), but the very real problems a child will confront are still going to be present. Using a softer label is not going to change the auditory reality. Moreover, by minimizing the likely impact of a “mild” hearing loss, it is less likely that professional and professionals alike will be strongly motivated to ensure that appropriate remedial measures are taken. While we may not be able to change how descriptive labels are used, we can at least strive to ensure that we do not equate the connotations of the classification term with the potential impact of the hearing loss.
Performance of Hard of Hearing Children
For the most part, the HOH children whose performance is reviewed in the following sections are those who are classified as having mild, moderate, to severe hearing losses. Clearly, these child vary widely, not only in the same attributes, experiences, and backgrounds that characterize all children, but also in the one dimension that defines them as “hard of hearing” – the type, degree, and nature of their hearing losses. A few examples will illustrate this point.
The kinds of difficulty children with unilateral hearing loss experience are quite different from those manifested by children with bilateral hearing losses. These children seem to “hear” better and usually manifest no speech or language problems but, as reported earlier, will have more academic deficiencies than their normally hearing peers. They are also likely to have more difficulty localizing sound sources and understanding speech in adverse acoustical circumstances than children with bilateral hearing losses. Because their behavior is harder to predict, they tend to be rated more negatively by parents and teachers than children with bilateral hearing losses (Bess l986).
As another example, children with sharply sloping audiometeric configurations present a different behavioral picture than presented by children with flat hearing losses, even though children in both groups may display the same average hearing loss. Consider a child with 40 dB hearing thresholds at each of the frequencies 500 Hz, 1000 Hz and 2000 Hz. The average is 40 dB, and it is this figure that it used when the degree of hearing loss is described. Now consider another child, one with a zero threshold at 500 Hz, a 40 dB threshold at 1000 Hz, and an 80 dB threshold at 2000 Hz. The average hearing loss for this child is also 40 dB.
The auditory performance and general behavior of these children will, however, differ considerably. The child with the flat hearing loss is consistent in his or her diminished ability to respond to speech and other sounds. All sounds are equally difficult to hear. The child with the high frequency loss, on the other hand, can respond to low frequency sounds normally, but because he or she cannot perceive the full spectrum of speech frequencies, the child’s responses to speech are inconsistent. Sometimes, the child’s responses appear quite “normal”, particularly to vowels and other low frequency speech sounds. Other times it will be clearly aberrant. The presence of low frequency noise will further diminish this child’s awareness of meaningful stimuli, since such noise masks the speech information that is available. Compared to the child with a flat hearing loss, the one with a high frequency hearing loss is likely to display more severe speech and language problems but less abnormalities with vocal quality and speech rhythm.
So here we have two children, each with the same average hearing loss, manifesting quite different behavioral pictures. Both these children are hard of hearing; both have average 40 dB hearing loss; the auditory consequences of the hearing for both, however, are quite different. It is not enough to ensure the proper classification and labeling children as hard of hearing or deaf; it is always absolutely essential, regardless of classification, to ensure that each child is viewed as an individual and not just as a member of some category.
The amount of auditory-verbal information a child can receive is related to how well the child can detect, identify, and discriminate the acoustical elements in a speech signal. In general, the poorer and more problematical speech perception is, the poorer and more deviant will be the child’s auditory-verbal development (see Ross, Brackett and Maxon l991 for a detailed review of the literature). Actually, there is a reciprocal relationship between speech perception and language development: The greater the child’s competency in a language, the better his/her speech perception is likely to be. This is because the child is better able to impose a predicted linguistic order on the fragments of sounds that are perceived. In other words, because the child knows more language, he or she is more able to fill in speech fragments that may not be completely audible. In this view, therefore, as Fry (l978) pointed out years ago, speech perception may only be only 10% “earwork” and 90% “brainwork.” The ears are simply a conduit for passing acoustical signals on to the brain, where the final perceptual decisions are made. Of course, the more speech acoustical information passed on to the brain (in relevant experiential situations), the easier the brain’s task would be (Ross, Bracket and Maxon 1991).
Speech sounds are categorized by their manner, place of articulation, vowels and consonants, and whether or not they are voiced or unvoiced. Manner of articulation refers to how sounds are produced. These include the categories of plosives (i.e. /t/, /b/ /p/), fricatives (i.e. /s/, /f/, /sh/ ), nasals (i.e. /m/ and /n/) and affricates (i.e. /ch/). Place of articulation refers to the location in the vocal tract where the sound is generated. These include the bilabial (i.e. /p/, /b/, /m/), alveolar (i.e. /t/, /d/, /n/) and velar (i.e. /k/, /g/). For examples, consonants such as /p/, /t/, and /k/ are all unvoiced plosives which share manner and voice, but differ in place of articulation.
This bit of phonetics is included to more precisely describe how HOH children perceive speech sounds. The research shows that they have a greater degree of difficulty in accurately distinguishing between sounds that have the same “place of articulation” than they do between sounds that differ by manner of articulation or voicing. The basic reason for this is that sounds that differ only by place of articulation have similar acoustic characteristics, making them difficult for an impaired ear to identify. For example, HOH children often confuse the voiceless plosives ( /p/, /t/, and /d/ ) as well as the voiceless fricatives ( /s/, /f/ and /th/). Place of articulation errors also occur more frequently in the final consonants in words (which also happens to be the location of bound morphemes, such as the plural /s/ and the past tense /t/) because phonemes are usually acoustically weaker in the final position.
The configuration of a child’s audiogram is directly related to the types of speech perception errors that are made. Children with sharply sloping hearing losses at 1000 Hz will have difficulty distinguishing speech sounds that are easily perceived by children whose hearing thresholds drop off at 2000 Hz. Only the children with the most severe hearing losses will have difficulty distinguishing between the various vowels, between the nasals and other sounds, or between voiced and unvoiced sounds. Residual hearing in the low frequencies permits voicing, nasality, manner of articulation and speech rhythm to be perceived fairly readily, whereas higher frequency residual hearing contributes to the perception of place of articulation and fricatives. For these reasons, most HOH children can distinguish between the /p/ (unvoiced), /b/ (voiced) and /m/ (nasal) sounds, even though all three have the same place of articulation. The same children may have problems, however, distinguishing between the /p/, /t/, and /k/, all of which are voiceless plosives differing only in place of articulation.
Vision has an important role to play in enhancing the speech perception capabilities of HOH children, but as a supplemental and not a substitute sensory avenue. We know for certain that speech recognition scores are almost always greater when a child can both see and hear the talker. This is particularly true when the acoustical environment. reduces the available auditory information. Even under favorable acoustical conditions, however, many HOH child find that vision enables them to more fully comprehend a message and to do it with less effort. The reason for their enhanced ability in the bisensory mode is that the speech cues they receive through vision and audition are quite complementary. What is missed with one mode can often be identified with the other mode.
For example, as was pointed out earlier, the most frequent speech perception errors made by HOH children concern place of articulation (such as distinguishing between /p/, /t/, and /k/, or /f/, /s/ and /th/). Within each category, however, these sounds are relatively distinct visually. What cannot be heard, then, can be seen. Now consider the bilabial sounds /p/, /b/, and /m/. These look exactly alike on the lips and cannot be distinguished visually. But since they differ in both manner and voicing, they can be easily identified through audition. What cannot be seen can be heard. To review: Voicing and manner of articulation can usually be perceived by HOH listeners through audition alone, while a speech sound’s place of articulation is ordinarily available visually. Put both together and the result is usually improved speech perception capabilities.
Many HOH children have articulation problems. Within broad limits, the more severe the hearing loss, the more deviant the speech produced by a child (Gordon l987). While HOH children may make same kind of articulation errors that deaf children do, they make fewer of them. Their errors often resemble the speech of younger normally hearing children (McDermott and Jones l984). Still, as Elfenbein, Hardin-Jones and Davis (l994) report, the oral communication skills of HOH children are more similar to children with normal hearing than they are to those who have profound hearing losses. This supports the point of view expressed earlier, i.e. that HOH children are more like normally hearing children than they are like deaf children.
The most frequent speech error made by severely HOH children is the omission of consonants, particularly in the word-final position. Accompanying the omission of the final consonant, there is often a prolongation of the preceding vowel. It is as if such children are aware of the proper duration of the utterance, but being unable to hear or produce the final consonant, they prolong the preceding vowel to fill the durational space. This tends to occur only with those HOH children with the most severe hearing losses. The next most frequent error (though some report that it occurs most frequently) is the substitution of one sound for another, particularly for the fricative and affricate sounds. Finally, these children also often produce sounds which are somewhat distorted, particularly when they attempt to blend several consonants together.
If we examine the frequency of specific speech production errors made by HOH children, we can observe that affricates show the greatest number of errors (e.g. /ts/), followed by the fricatives (e.g. /s/), plosives (e.g. /t/), lingua-dental (/th/), labio-dental ( /f/) , glottal (/h/) and finally bilabials ( /p/). The type and frequency of speech production errors are related to the type of errors the children make in speech perception. That, is, children tend to produce what they perceive. Consonants using tongue-tip placement, as well as fricatives and affricates are more likely to be omitted than are other consonants. These category of sounds require fine motor coordination and accurate timing for their correct articulation. They are also ordinarily developed later than other types of phonemes by normally hearing children. Generally, HOH children do not have any difficulty producing vowels correctly. They also do not manifest the kind of voice and speech rhythm deviations observed in deaf children. The differences between in speech production between deaf and HOH children testify to the vital role of audition in the development and maintenance of speech and voice production.
Perhaps the most glaring deficiency in the language capabilities of HOH children is the status of their vocabulary. All studies of vocabulary usage by these children indicate that they know and use many fewer words in their utterances than do normally hearing children (Davis, Elfenbein, Schum, and Bentler l986). HOH children often learn, or are taught, a single meaning for a word or, conversely, a single word to express some general concept. For example, the word “run” may mean an act of rapid, bipedal locomotion, but not striving for a political office, having difficulty with a nylon stocking, or the nasal consequences of a bad cold.
HOH children appear to be bound by the literal meaning of words, in much the same way as someone who is learning a second language. Words expressing nuances of meaning may be either lacking or seriously reduced. Because a great deal of normal conversation is made up of idiomatic or metaphoric expressions, slang, and colloquialisms, these children are often linguistic strangers in their own homes. Often, they “just don’t get it.” Most children pick up vocabulary almost automatically. All parents have experienced the “big ears” of their normally hearing children who overhear conversations they were not supposed to. These children can hear and learn new vocabulary from any direction within “earshot”, whether the words are intended to be heard or not. HOH children, on the other hand, tend to master only those words are directed right to them. But who, for example, will take the time to teach a HOH child the new meanings of such words as “cool”? (I’m sure there are many other examples; but being “uncool” myself, I can’t think of any others!)
A landmark study that demonstrated the problems that HOH have with vocabularly was reported by Davis in l974. She administered the Boehm Test of Basic Concepts to 24 HOH children. The test includes vocabulary designed to assess a child’s ability to identify time, space, quantity and other miscellaneous concepts. Half of the six year old children scored at or below the 10th percentile, while 67% of the seven year old and 83% of the eight year old HOH children scored at that same level. In other words, the relative performance of the children appeared to be worsening with age. It should be noted that the vocabulary used in this test represents the language of directions that are often used in the first three years of school. Clearly, it would be difficult for HOH children to complete many academic tasks if they cannot even understand the directions in which the tasks are explained. One can but hope that the situation has improved since l974, but we have no direct evidence that I’m aware of that it has. Still, given the proven linguistic benefits of early detection and management of children with hearing loss (Calderon and Naidu 2000), I expect that this type of evidence will soon be available.
The differences in syntax between HOH children and those who are normally hearing appear to be differences in degree rather than kind, with the older children showing little difficulty with simple syntactic constructions. Deviations apparently are due to inadequate linguistic input at the appropriate developmental age. HOH children apply their innate linguistic rule-generating ability to what they hear and thus create functional, though deviant, strategies that allow them to comprehend and produce complex syntactic constructions. In face-to-face communication, because they can select their own strategies and material, effective verbal interchanges can occur (Elfenbein, et al 1994).
When HOH children are asked to generate or comprehend complex syntactic structures, a large percentage of them demonstrate difficulty with formulations involving auxiliary verbs and passive sentences (Wilcox and Tobin l974). Their communication strategies appear to break down most when they are asked to employ two transformation rules simultaneously, as in the negative passive sentence, “The glass was not dropped by Mary.” In this instance, the child may believe that Mary either dropped the glass or that it wasn’t dropped at all (rather than by somebody else).
The difficulty that HOH children have with more complex syntactic structures was investigated by Davis and Blasdel (l975). The children were faced with a task of comprehending sentences that contained medially embedded relative clauses. An analysis of the children’s responses showed that they adopted a processing strategy that focused on the latter part of the sentence as the source of the underlying meaning. Thus when presented with four pictures and asked to point to the one that represented the sentence “The sheep that chased the man ate the grass,” the children often selected a picture of a man eating the grass, even though this choice made no sense. Evidently, their strategy in processing such a sentence was to interpret all sentences with medially embedded clause in terms of the contiguous subject, verb, and object sequence. In this particular study, the HOH children misunderstood complex sentences almost 50% of the time.
Other syntactic constructions that are difficult for HOH children are relativization, complementation, verb conjugation, and pronomilization. Levitt, McGarr and Geffner (l987) administered the Test of Syntactic Abilities (TSA) to a large number of children with hearing loss. The TSA is a pencil and paper task that requires the child to read and understand many different syntactic forms. The results revealed a wide range of performance among the children, who ranged from HOH children in a mainstream setting to deaf children in special settings. One of the noteworthy observations of this study is that those children who received early special education performed better than those who did not, a conclusion that is becoming even more apparent in recent years.
The difficulty that HOH children have in decoding complex syntactic forms becomes particularly troublesome when they are confronted with academic tasks (Davis et al l978). Quigley reports that complex grammatical structures, such as relative clauses, appear regularly in the second primer of the typical reading series used in public schools. The fact that HOH children are unable to fully comprehend (or produce) complex syntactic forms affects their academic performance, and is undoubtedly least partly responsible for their problems in this area.
Most of the research reviewed above was concerned with receptive language. The same types of problems are apparent when the oral communication skills of HOH children are investigated. In the study conducted by Elfenbein, et al (l994), the results showed that the most frequent errors made by the children related to verb voice (conjugation) and tense. Other errors included inaccurate production of complex syntactic structures, and the omission or misuse of verbs. The children in this study displayed the same order of difficulty with syntactic structures as do children with normal hearing. Most of the structures on which the children had problems involved bound morphemes (such as a past tense /t/, and the possessive and plural /s/). These forms, occurring at the end of a word, are typically weaker, unstressed, and composed of higher frequencies, and thus would be much more difficult for a HOH child to hear. And if they can’t hear the acoustic correlates of a linguistic structure, they are surely going to have more difficulty learning it. It seems clear that their oral language problems stem from a relative lack of auditory exposure to complete language samples at early ages, a fact that reinforces the need for early detection and management programs.
The vast majority of the studies investigating the academic performance of those HOH children with moderate and severe hearing losses have reported two or three year performance delays (Ross, Brackett and Maxon l991). Poorest performance occurs in areas that most directly depend upon reading comprehension and word-meaning skills. Not only are the children two and three years delayed according to standardized academic achievement tests, they also tend to be one or two years older than their classmates, a fact that may well have psycho-social implications (Brackett and Maxon l986). Academic lags in excess of one year has also been found with children with milder hearing losses, in the range of 15 dB to 26 dB (Quigley l978). As with their language status, the academic achievement levels of HOH children tend to fall between that observed with normally hearing and deaf children.
The most comprehensive data now available regarding the performance of children with minimal and mild hearing losses was reported in the Bess, et al (l998) study. As reported earlier, they found an incidence rate of about 11%, with about 5.4% of these children exhibiting minimal sensorineural hearing loss (MSHL). In the study, the investigators examined the academic and functional status of the MSHL children, using both existing school achievement tests and special measures of functional status. These latter tests were administered only to the MSHL children and a random group of their age peers. The results showed the academic performance of children with MSHL was poorer than their classmates, particularly in the third grade (children in grades 3, 6, and 9 were examined in this study). The teachers were asked to complete the Screening Instrument for Targeting Education Risk (the SIFTER) on the MSHL children and a random control group. When both failure rates and marginal passes are considered, more than one-half the MSHL children experienced difficulty in academics, attention and communication.
The authors also employed another measure of functional status, the “COOP” chart. In this five-point scale, the sixth and ninth grade children self-rated themselves on emotional feelings, school work, social support, stress, family, self-esteem, behavior, energy, getting along, and overall health. Particularly in the ninth grade, the children with MSHL exhibited higher dysfunctional scores on nine of the ten tested dimensions, most significantly in the areas of stress, social support and self-esteem. What is particularly noteworthy about this study is that, generally, neither the children nor the teachers were aware of a hearing problem. What these rating display are the effects of a minimal hearing loss separate from an awareness of the loss itself.
Perhaps the most significant finding of the Bess, et al (l998) study is their observation that fully 37% of the children with minimal sensorineural hearing loss failed at least one grade. This should be compared to the much lower retention rates in the district as a whole, which are less than 1/10th this figure. The authors point out the economic burden that this high retention rate imposes on the educational system in our country. They multiply the predicted number of children with MSHL by $6000, the average cost to educate a child for one year, and arrive at a figure that exceeds five billion. Even allowing for a little exaggeration and hyperbole, this is an exceedingly large number.
The academic failure of HOH children is not preordained. These children display the same range of intelligence as do normally hearing children. The fact that, on the average, they do poorly academically is more a commentary on the nature of the remediation programs provided them than it is the inherent limitations imposed by the hearing loss. Although it is hardly realistic to expect that a moderate or severe hearing loss will have absolutely no academic and behavioral implications, we can reasonably expect to significantly reduce these implication through appropriate interventions. There are grounds for optimism as we observe the achievements of HOH children in exemplary programs. For example, McClure (l977) reported grade level scores in most academic areas for 14 moderately and severely HOH children. Given the tools we now have available to ensure good auditory and academic management, we should expect that the academic achievements of HOH children will be comparable to that seen by normally hearing children. Two to three year delays in performance relative to normally hearing children is simply unacceptable.
Superficially, there is nothing about the appearance of HOH children that sets them apart from their peers. Some of them may exhibit behavioral problems, but so do many normally hearing children. They may be withdrawn or aggressive, socially adjusted or maladjusted, quiet or outspoken. Rarely do HOH children behave in ways that are not also frequently found in some of their normally hearing classmates. Even the fact that they have hearing losses does not mark them uniquely. These children are not deaf: They can and do respond to speech and other sounds. When they do respond, or respond incorrectly or inappropriately, their reactions are not necessarily attributed to a hearing loss. Instead, they are often accused of not listening, not paying attention, or daydreaming. They are sometimes described as children who “can hear when they want to.” who are deliberately provoking their parents and teachers by willfully ignoring or misunderstanding them. Professionals and parents cannot understand why these children are able to comprehend sometimes, but not in other, superficially comparable situations.
The effect of language complexity, dialectical or poorly articulated speech, distance from the speech source, and poor room acoustics will often have a disproportionate effect upon the ability of HOH children to understand spoken messages. Levels of reverberation and room noise, for example, that normally hearing children can easily tolerate may make speech comprehension extremely difficult or impossible for HOH children. Although they can “hear” in almost all situations, they cannot “understand” in many of them. Because of their unpredictable responses, observers often expect communication behaviors beyond their ability. Adults assume that they will “understand” because they can so evidently “hear.” Other children may consider them less than desirable playmates for reasons that neither group really comprehends. The resulting, reciprocally reinforcing conflicts, between societal expectations and the capabilities of the children, and between the needs of the children and the elusive and blocked gratification of those needs by an insensitive and ignorant environment, can affect these children all through their school years.
HOH children appear to depend more upon the teachers for mediating classroom activities than do normally hearing children, who rely much more on their peers (Kennedy, Northcott, McCauley and Williams 1976). This is understandable when one considers the difficulty many HOH children have in following classroom discussions (ensuring effective child-to-child communication in a classroom may be the major acoustic challenge). As the children get older and become peer-dominated (just like other adolescents), their personal and social problems may increase (Reich, Hambleton and Houldin 1977). During adolescence, they may rebel against wearing visible hearing devices (hearing aids or personal FM systems) and personal identity problems may occur. As has been emphasized time and again in this chapter, HOH children are not “deaf”, but neither are they normally hearing. A HOH of hearing child wearing, or requiring personal amplification, may be the only such student in the school. Oddly enough, HOH children often do not fully understand the implications of their own impairment because hearing abnormally is “normal” for them. Nevertheless, they often feel different and isolated. In one study, for example, half the HOH children interviewed expressed concern about making friends or being accepted socially by their normally hearing peers, of whom only 15 percent expressed similar social concerns (Davis et al l986). Insofar as children with lesser degrees of hearing loss are concerned, even though they may not be aware of their own hearing loss, it can still have an impact upon them, as we have seen from the Bess et al (l998) study. In their results, the children with minimal hearing losses demonstrated more dysfunctional ratings in such areas as stress, self-esteem, behavior, energy and social support.
Their situation, however, need not be so unremittingly gloomy. Social maladjustment and problems with self-esteem are not inevitable (Elser, l959; Kennedy, et al l976; Reich, et al l977; Ross l978). Many of the apparent differences between HOH children and their normally hearing peers fall within an accepted range of behaviors. This is not to deny the existence of problems, potential or existing, but to affirm that the problems can be alleviated or reduced with proper psychosocial management (Schwartz l989). Before this can be done, however, the psychosocial problems must be recognized for what they are, problems secondary to the hearing loss and not an inherent personality factor. The key is understanding the perceptual implications of all types of hearing loss. Once this is done, behaviors that are apparently inexplicable become clear, as does the range of potential solutions.
Some Summary Comments
It should be understood that not every HOH child will display communication or educational problems secondary to the hearing loss. What has been presented in the foregoing review are averages, group results. Ultimately, each child has to be evaluated and managed on an individual basis. Average findings are helpful in developing a frame of reference, but cannot be applied in any predictive sense to a specific child. What can be asserted, however, is that based on the research, children with any type and degree of hearing loss are “at risk” for possible problems due to the hearing loss. The fact that a child has a minimal, fluctuating, unilateral, or high-frequency hearing loss does not exempt him or her from this possibility.
It would not be difficult to criticize the terminological distinctions I have attempted to make in this chapter. There are children who appear to fall somewhat in the gray area between the deaf and HOH categories. However, overlooking the real distinctions between these groups because of the occasional exceptions is an educationally self-defeating exercise; it would result in underestimating the potential value of residual hearing and thus create more exceptions. I would suggest opting for an optimistic interpretation and view such “gray” area children as potentially HOH, while taking the necessary means to fulfill this prediction.
On the other hand, I would not suggest exposing a deaf child to frustrating and fruitless attempts to create one who is HOH, when his or her residual hearing is insufficient for this goal. We should not belabor the physiological impossible. Since the advent and improvement in cochlear implants, however, the choice of whether a child should enter the “hearing world” by becoming functionally HOH, or the “Deaf” world and associate with the deaf community, no longer depends upon the extent of a child’s residual hearing. It is now a matter of resources and parental choice. Parents of young children with severe and profound hearing losses require, and deserve, an objective look at all the options available for their child. Some may select a sign language option, as is their right. Still, amplification and implant choices have to be made early, to minimize the impact of auditory sensory deprivation and to take advantage of the critical early years for auditory-verbal linguistic development (Ross 1990). But these decisions are not cast in stone. Once made, children as they grow older can make their own choices regarding their own identity (Ross 1992). What has been described above must be viewed as guidelines, not specific prescriptions for some services or the proscription of other services.
Above all, what must be kept in mind is that an individual’s needs and unique personality transcend any categorization that divides children into those who are deaf or HOH, or somewhere in between. It may be a cliche’, but it is one with a great deal of truth: Children are children first, and only secondarily a member of any defining category.