Pure tone audiograms from hearing-impaired children. II. Predicting speech-hearing from the audiogram

What Can a Child Do With One Normal-Hearing Ear? Speech Perception and Word Learning in Children With Unilateral and Bilateral Hearing Losses Relative to Peers With Normal Hearing

OBJECTIVES

To examine the effects of unilateral hearing loss on children's ability to perceive familiar words and to learn and retain new words. Because children with unilateral hearing loss receive full auditory input in one ear, their performance was expected to be consistent with that of children with normal hearing rather than that of children with moderate bilateral hearing loss.

DESIGN

Participants were 36 school-age children with normal hearing bilaterally, 11 children with moderate bilateral hearing loss, and 11 children with mild-to-profound unilateral hearing loss (six right and five left). Half of the normally hearing children and two-thirds of the children with unilateral hearing loss were from bilingual Spanish/English-speaking homes. One of the 11 children with bilateral hearing loss was from a bilingual Spanish/English-speaking home. All children completed a word recognition test in English and in Spanish, a word-learning task comprised of nonsense words constructed using the phonotactic rules of English, Spanish, and Arabic, and a next-day word-retention test.

RESULTS

Word recognition did not differ across groups in English or Spanish. Learning and retention of nonsense words was highest for the children with normal hearing in all three languages. The children with unilateral and bilateral losses learned and recalled the English nonsense words as well as their normally hearing peers, but performance for the Spanish and Arabic nonsense words was significantly and similarly reduced by hearing loss in either ear.

CONCLUSIONS

Failure to learn and retain new words given a full auditory representation in one ear suggests that children with unilateral and bilateral hearing losses may share a unifying feature of impairment at the level of the central auditory system.

Relationship between consonant recognition in noise and hearing threshold

PURPOSE

Although poorer understanding of speech in noise by listeners who are hearing-impaired (HI) is known not to be directly related to audiometric hearing threshold, HT (f), grouping HI listeners with HT (f) is widely practiced. In this article, the relationship between consonant recognition and HT (f) is considered over a range of signal-to-noise ratios (SNRs).

METHOD

Confusion matrices (CMs) from 25 HI ears were generated in response to 16 consonant-vowel syllables presented at 6 different SNRs. Individual differences scaling (INDSCAL) was applied to both feature-based matrices and CMs in order to evaluate the relationship between HT (f) and consonant recognition among HI listeners.

RESULTS

The results showed no predictive relationship between the percent error scores (Pe) and HT (f) across SNRs. The multiple regression models showed that the HT (f) accounted for 39% of the total variance of the slopes of the Pe. Feature-based INDSCAL analysis showed consistent grouping of listeners across SNRs, but not in terms of HT (f). Systematic relationship between measures was also not defined by CM-based INDSCAL analysis across SNRs.

CONCLUSIONS

HT (f) did not account for the majority of the variance (39%) in consonant recognition in noise when the complete body of the CM was considered.

Audiologic management of auditory neuropathy spectrum disorder in children: a systematic review of the literature

PURPOSE

This review summarizes current evidence related to the audiologic management of children with auditory neuropathy spectrum disorder (ANSD).

METHOD

A systematic search of the literature was conducted in 25 electronic databases (e.g., PubMed, CINAHL, and ERIC) using key words such as auditory neuropathy, auditory neuropathy spectrum disorder, auditory neuropathy/dyssynchrony, and hearing loss. Eighteen studies met the inclusion criteria by addressing 1 or more of 8 clinical questions. Studies were evaluated for methodological quality, and data regarding participant, intervention, and outcome variables are reported.

RESULTS

Fifteen of the 18 studies addressed the use of cochlear implantation, and 4 addressed conventional acoustic amplification. All participants demonstrated improved auditory performance; however, all 18 studies were considered exploratory, and many had methodological limitations.

CONCLUSION

The clinical evidence related to intervention for ANSD is at a very preliminary stage. Additional research is needed to address the efficacy of acoustic amplification and cochlear implantation in children with ANSD and the impact of this disorder on developmental outcomes.

Speech Perception in Noise for Children with Auditory Neuropathy/Dys-Synchrony Type Hearing Loss

OBJECTIVE

To evaluate the effect of background noise on speech perception in children with auditory neuropathy/dys-synchrony (AN/AD) type hearing loss.

DESIGN

Open and closed-set speech perception abilities were assessed in 12 school-age children who had been diagnosed with AN/AD in infancy. Data were also obtained from a cohort of subjects with sensorineural (SN) hearing loss and from a group of normal-hearing children.

RESULTS

Closed-set speech understanding was more affected by the presence of a competing signal in the hearing impaired than in the normal-hearing subjects. The mean S/N ratio required to identify a spondee in noise was -11.5 +/- 2.0 dB for the normal group, whereas the ratio required for the SN group was -5.4 +/- 5.1 dB and for the AN/AD group was -2.5 +/- 4.7 dB. Closed-set perception in noise was not significantly different for the AN/AD children and their SN counterparts although there was a trend toward poorer performance in the AN/AD group. The effect of background noise on open-set speech perception was also similar across hearing-impaired subjects although again, the AN/AD cohort tended to show greater difficulties in noise than their SN peers.

CONCLUSIONS

Listening in background noise was more difficult for our group of children with AN/AD-type hearing loss than for their normal-hearing peers. However, the noise effects were not consistent across subjects and some children demonstrated reasonable perceptual ability at low signal-to-noise ratios. The ways in which speech understanding is affected by competing signals may be different for different types of hearing deficit, but the results of this investigation indicate that significant perceptual disruption occurs both in children with auditory neuropathy/dys-synchrony and sensorineural type hearing loss.

An exploration of demographic bias in a questionnaire survey of hearing-impaired children: implications for comparisons of children with and without cochlear implants

OBJECTIVES

Responders to questionnaire surveys, who are self-selecting, are generally accepted to be unrepresentative of the total available population, at least in demographic terms. Since demographic and other variables are known to be predictive of outcome, it is important to understand the extent of that unrepresentativeness when using survey data to report comparisons of outcome. This paper aims (i) to evaluate the extent to which a sample of hearing-impaired children surveyed by postal questionnaire was representative of the population of hearing-impaired children in the United Kingdom (UK), and (ii) to identify demographic differences between children with and without cochlear implants.

METHODS

Data from a previously reported total ascertainment of hearing-impaired children in the UK which identified 17,160 with permanent bilateral hearing impairment >40 dB HL were compared with data collected by postal questionnaire for a sample of 3224 children, including 527 with cochlear implants.

RESULTS

The sampled children were similar to the ascertained population in gender, age at onset of hearing impairment, and number of additional disabilities, but came from more recent birth cohorts and from more affluent families. Compared with profoundly impaired non-implanted children, implanted children had greater degrees of hearing loss, fewer additional disabilities, a later age of onset, were younger, came from more affluent families, were more likely to use spoken language at home, and to be taught using spoken language only.

CONCLUSIONS

Comparisons of outcomes and generalisation of results require adjustment for relevant variables to avoid confounding estimates of the effectiveness of interventions including cochlear implantation.

Hearing-impaired children in the United Kingdom, I: Auditory performance, communication skills, educational achievements, quality of life, and cochlear implantation

OBJECTIVES

The objectives of this study were to identify variables that are associated with differences in outcome among hearing-impaired children and to control those variables while assessing the impact of cochlear implantation.

STUDY DESIGN

In a cross-sectional study, the parents and teachers of a representative sample of hearing-impaired children were invited to complete questionnaires about children's auditory performance, spoken communication skills, educational achievements, and quality of life. Multiple regression was used to measure the strength of association between these outcomes and variables related to the child (average hearing level, age at onset of hearing impairment, age, gender, number of additional disabilities), the family (parental occupational skill level, ethnicity, and parental hearing status), and cochlear implantation.

RESULTS

Questionnaires were returned by the parents of 2858 children, 468 of whom had received a cochlear implant, and by the teachers of 2241 children, 383 of whom had received an implant. Across all domains, reported outcomes were better for children with fewer disabilities in addition to impaired hearing. Across most domains, reported outcomes were better for children who were older, female, with a more favorable average hearing level, with a higher parental occupational skill level, and with an onset of hearing-impairment after 3 years. When these variables were controlled, cochlear implantation was consistently associated with advantages in auditory performance and spoken communication skills, but less consistently associated with advantages in educational achievements and quality of life. Significant associations were found most commonly for children who were younger than 5 years when implanted, and had used implants for more than 4 years. These children, whose mean (preoperative, unaided) average hearing level was 118 dB, were reported to perform at the same level as nonimplanted children with average hearing levels in the range from 80 dB to 104 dB, depending on the outcome measure.

CONCLUSIONS

When rigorous statistical control is exercised in comparing implanted and nonimplanted children, pediatric cochlear implantation is associated with reported improvements both in spoken communication skills and in some aspects of educational achievements and quality of life, provided that children receive implants before 5 years of age.

Auditory neuropathy/dys-synchrony and its perceptual consequences

Auditory neuropathy/dys-synchrony is a form of hearing impairment in which cochlear outer hair cell function is spared but neural transmission in the auditory pathway is disordered. This condition, or group of conditions with a common physiologic profile, accounts for approximately 7% of permanent childhood hearing loss and a significant (but as yet undetermined) proportion of adult impairment. This paper presents an overview of the mechanisms underlying auditory neuropathy/dys-synchrony-type hearing loss and the clinical profile for affected patients. In particular it examines the perceptual consequences of auditory neuropathy/dys-synchrony, which are quite different from those associated with sensorineural hearing loss, and considers currently available, and future management options.

Speech perception and cortical event related potentials in children with auditory neuropathy

OBJECTIVES

1) To investigate the unaided and aided speech perception abilities of children with auditory neuropathy (AN) and to compare their performance to children with sensorineural hearing loss. 2) To establish whether cortical event related potentials (ERPs) could be recorded in children with AN, and to determine the relationship between the presence of these responses and speech perception.

DESIGN

Unaided and aided speech perception assessments (PBK words), and cortical-ERP testing was carried out in a group of 18 children with AN. Data also were obtained from a cohort of age and hearing level matched children with sensorineural hearing loss.

RESULTS

The speech perception performance of the 15 children with AN able to complete a PBK-word assessment, fell into two distinct categories. The children either showed no open-set speech perception ability (7/15 cases), or performance levels similar to their sensorineural counterparts (8/15 cases). Approximately 50% of children with AN showed ERPs of normal latency, amplitude and morphology. In all cases, response presence (at normal latencies) was consistent with reasonable speech perception ability, and response absence was consistent with negligible speech perception.

CONCLUSIONS

In approximately 50% of children with auditory neuropathy, the provision of amplification results in significant open-set speech perception improvements. The results confirm the previously published reports that speech perception ability cannot be reliably estimated from the behavioral audiogram in children with AN. Obligatory ERP test results may offer a means of predicting perceptual skills in newly diagnosed youngsters as the presence of ERPs (with age-appropriate latency and morphology) was correlated with significant open set speech perception abilities and amplification benefit. The absence of the ERP in contrast, indicated profound hearing disability evidenced by profound hearing loss and/or extremely poor speech perception.

Lip-reading the BKB sentence lists: corrections for list and practice effects

Two groups of 21 adult subjects with normal hearing viewed the video recordings of the Bamford-Kowal-Bench standard sentence lists issued by the EPI Group in 1986. Each subject viewed all of the 21 lists and attempted to write down the words contained in each sentence. One group lip-read the lists with no sound (the LR:alone condition). The other group also heard a sequence of acoustic pulses which were synchronized to the moments when the talker's vocal folds closed (the LR&Lx condition). Performance was assessed both by loose (KW(L)) and by tight (KW(T)) keyword scoring methods. Both scoring methods produced the same pattern of results: performance was better in the LR&Lx condition; performance in both conditions improved linearly with the logarithm of the list presentation order number; subjects who produced higher overall scores also improved more with experience of the lists. The data were described well by a logistic regression model which provided a formula which can be used to compensate for practice effects and for differences in difficulty between lists. Two simpler, but less accurate, methods for compensating for variation in inter-list difficulty are also described. A figure is provided which can be used to assess the significance of the difference between a pair of scores obtained from a single subject in any pair of presentation conditions.

Optimum side for fitting a monaural hearing aid. 1. Patients' preference

The criteria generally used to decide in which ear to fit a monaural hearing aid are based on theory or anecdote and have not been verified by experimental observation. In this study to determine optimum side of fitting, 58 new hearing aid users were fitted with a hearing aid in one ear for 10 weeks, and then fitted in the other ear for a further 10 weeks. Subsequently, the subjects were asked their preference for side of hearing aid use and their reasons for this preference. 30 (52%) subjects reported better hearing with their aid in one ear than in the other; 24 (80%) of these preferred the ear with the poorer half-peak level elevation on a speech audiogram. The remaining 28 (48%) reported no difference in their aided hearing ability between ears, though 20 preferred one ear for practical reasons, unrelated to audiometric parameters. A patient's preference for side of fitting can be predicted from audiometric data but with only modest reliability. It is, therefore, recommended that bilateral ear moulds should be routinely provided for bilateral mild to moderate hearing impairment (speech frequency average less than 75 dB HL). If it is decided that only one ear mould should be provided, this should be made for the poorer hearing ear. The poorer hearing ear is best identified from the half-peak level elevation on a speech audiogram.

Self-reported disability and handicap in the population in relation to pure-tone threshold, age, sex and type of hearing loss

A self-administered questionnaire concerning auditory disability and handicap was completed by 1691 subjects who were part of a two-stage random sample of the UK adult population. A principal components analysis of questionnaire replies identified four components. They were interpreted as (a) disability for everyday speech, (b) disability for speech-in-quiet, (c) localisation, and (d) hearing handicap. Components (a) and (d) were the strongest, accounting for 68% of the variance. Subjects also performed pure-tone audiometry amongst other tests. Audiometric information was well described by a two-parameter model characterised by low-to-mid-frequency loss and high-frequency slope. All four components increased progressively with increasing low-to-mid-frequency loss, independent of high-frequency slope. They were best correlated with a binaural average over 0.5, 1 and 2 kHz weighted 4:1 in favour of the better ear, out of several audiometric descriptors examined. Sex and socio-economic group did not generally affect disability or handicap, but people of similar hearing impairment reported less disability and handicap as age increased. This is interpreted as over-compensation for the effects of age in self-report. There were three unexpected findings which may entail some changes in current thinking on the relationship between auditory impairment and self-perceived disability/handicap. Hearing losses incorporating a conductive component in the better ear were more disabling and handicapping than sensorineural losses of equal magnitude. Localisation ability and, to a lesser extent, general hearing handicap were more highly correlated with measures of impairment in the worse ear than in the better ear. There was little evidence for the concept of a 'low fence' in the relationship between impairment and either disability or handicap.

Psychoacoustical and audiometric prediction of auditory disability for different frequency responses at listener-adjusted presentation levels

Audiometric prediction of word identification scores has typically used one fixed presentation level for all subjects in the sample, with presentation in quiet and a wide range of hearing impairment among the listeners; under such conditions it is hardly surprising that moderate to good predictions are found. To see if prediction is possible under clinically relevant conditions, that is, on a homogeneous clinical sample of new hearing-aid candidates and to listener-adjusted levels, as would obtain in use of a hearing aid. In addition to audiometric variables, we employed a clinical approximation to the psychoacoustic tuning curve. We tested speech identification (FAAF) performance both with a 'rising'(+9 dB/octave) and with a 'flat' frequency response. Prediction of performance in the 'flat' condition was only good when a full set of audiometric frequencies entered the multiple-regression formula, each with its own weighting. Audiometric prediction for the 'rising' frequency response was particularly poor. Thus, the fairly good predictability from thresholds found traditionally for word identification scores or other disability measures appears to be a special case, depending partly on the wide range of hearing levels employed. Within our clinical sample the predictive power of formulae based on the mean of all thresholds or of mid-frequency thresholds alone (as used in compensation schemes) or on a priori combinations of thresholds (such as slopes) was generally poor. However, a three-parameter model taking account separately of low (0.25 kHz) and high-frequency (greater than 2.0 kHz) thresholds was effective. This and other audiometric descriptions were valuably supplemented by a psychoacoustic measure of frequency resolution at 2 kHz. In particular, such supplementation here allowed a satisfactory level of prediction to be achieved for speech heard with a +9 dB/octave frequency response, which the audiogram alone did not. The limitations of the prediction paradigm are discussed and several conceptual and statistical problems not previously emphasised in the audiological literature are illustrated in relation to the data.

Investigations of the residual hearing capacity of severely hearing-impaired and profoundly deaf subjects

Speech reception functions (maximum discrimination score for phonemes, speech reception threshold) and auditory functions (pure-tone audiogram, difference limens for frequency and intensity, temporal modulation transfer function, critical ratio and temporal integration) have been investigated in a group of severely hearing-impaired and deaf subjects (median Fletcher index: 80 dB), for different frequency regions (250, 1 000 and 2 000/4 000 Hz). The correlations between the different functions were calculated on the basis of characteristic numbers, derived from the originally measured functions, in the indicated frequency regions. The residual hearing capacities could be described best with two factors, one reflecting the distortion term in the speech reception threshold and the other representing the frequency discrimination for high-frequency tones. It was found that residual hearing capacities are present, at least up to a Fletcher index of 105 dB.

Methods of analysis of large numbers of audiograms

The analysis of large numbers of audiograms raises the question if and how we can reduce the amount of data without discarding essential information. The present paper compares two ways of data reduction: principal-component analysis and curve fitting. The methods are tested on the audiograms of a large family suffering from a dominant hereditary, progressive hearing loss, beginning in the high frequencies. It is shown that principal-component analysis rejects information on the shape of the audiogram, as do all methods generally referred to as factor analysis. The information concerned is essential for our understanding of the patient's ability to discriminate speech. Curve-fitting procedures are shown to be effective in data reduction.

Summarizing pure tone audiograms: an extension of Bamford et al. (1980)

This paper extends the findings of a previous report (Bamford et al., 1980) which described a principal components analysis of pure tone audiometric data. Using a similar approach to the analysis of a large number of pure tone audiograms, the present study confirms the previous work. By far the greater part of the the audiogram variance could be ascribed to two components, one associated with the degree of, and the other with the slope of, the hearing loss. Further, it is shown that the proportions of the variance attributed to the two components change in a meaningful way according to the type of hearing loss: middle-ear, inner-ear, and mixed.