Gail D. Chermak

Word identification performance in the presence of competing speech and noise in learning disabled adults.

Eight learning disabled (LD) adults and eight control subjects identified monosyllabic words presented simultaneously in the presence of speech spectrum noise and three types of linguistic maskers. The performance of LD subjects was poorer than that of the control subjects under each masking condition. Word identification was poorest in the presence of speech noise for both groups. No difference in performance was seen as a function of the linguistic content of the competing speech maskers. These results suggest that LD subjects present greater susceptibility to acoustic masking relative to control subjects and may support the view that auditory-language deficits observed in LD individuals may be secondary to an underlying acoustic-phonetic disorder rather than a central phonologic disorder. LD college students may experience S/N ratios in the classroom that perpetuate or exacerbate their listening problems.

Characteristics of pediatric performance on a test battery commonly used in the diagnosis of central auditory processing disorder

BACKGROUND Although central auditory processing disorder (CAPD) test battery performance has been examined in adults with neurologic lesions of the central auditory nervous system (CANS), similar data on children being referred for CAPD evaluations are sparse. PURPOSE This study characterizes CAPD test battery performance in children using tests commonly administered to diagnose the disorder. Specifically, this study describes failure rates for various test combinations, relationships between CAPD tests used in the battery, and the influence of cognitive function on CAPD test performance and CAPD diagnosis. A comparison is also made between the performance of children with CAPD and data from patients with neurologic lesions of the CANS. RESEARCH DESIGN A retrospective study. STUDY SAMPLE Fifty-six pediatric patients were referred for CAPD testing. DATA COLLECTION AND ANALYSIS Participants were administered four CAPD tests, including frequency patterns (FP), low-pass filtered speech (LPFS), dichotic digits (DD), and competing sentences (CS). In addition, they were given the Wechsler Intelligence Scale for Children (WISC). Descriptive analyses examined the failure rates of various test combinations, as well as how often children with CAPD failed certain combinations when compared with adults with CANS lesions. A principal components analysis was performed to examine interrelationships between tests. Correlations and regressions were conducted to determine the relationship between CAPD test performance and the WISC. RESULTS Results showed that the FP and LPFS tests were most commonly failed by children with CAPD. Two-test combinations that included one or both of these two tests and excluded DD tended to be failed more often. Including the DD and CS test in a battery benefited specificity. Tests thought to measure interhemispheric transfer tended to be correlated. Compared with adult patients with neurologic lesions, children with CAPD tended to fail LPFS more frequently and DD less frequently. Both groups failed FP with relatively equal frequency. CONCLUSIONS The two-test combination that showed the highest failure rate for children with CAPD was LPFS-FP. Comparison with adults with CANS lesions, however, suggests that the mechanisms underlying LPFS performance in children need to be better understood. The two-test combination that showed the next highest failure rates among children with CAPD and did not include LPFS was CS-FP. If it is desirable to use a dichotic measure that has a lower linguistic load than CS then DD can be substituted for CS despite the slightly lower failure rate of the DD-FP battery.

Perspectives on the Pure-Tone Audiogram

BACKGROUND The pure-tone audiogram, though fundamental to audiology, presents limitations, especially in the case of central auditory involvement. Advances in auditory neuroscience underscore the considerably larger role of the central auditory nervous system (CANS) in hearing and related disorders. Given the availability of behavioral audiological tests and electrophysiological procedures that can provide better insights as to the function of the various components of the auditory system, this perspective piece reviews the limitations of the pure-tone audiogram and notes some of the advantages of other tests and procedures used in tandem with the pure-tone threshold measurement. PURPOSE To review and synthesize the literature regarding the utility and limitations of the pure-tone audiogram in determining dysfunction of peripheral sensory and neural systems, as well as the CANS, and to identify other tests and procedures that can supplement pure-tone thresholds and provide enhanced diagnostic insight, especially regarding problems of the central auditory system. RESEARCH DESIGN A systematic review and synthesis of the literature. DATA COLLECTION AND ANALYSIS The authors independently searched and reviewed literature (journal articles, book chapters) pertaining to the limitations of the pure-tone audiogram. RESULTS The pure-tone audiogram provides information as to hearing sensitivity across a selected frequency range. Normal or near-normal pure-tone thresholds sometimes are observed despite cochlear damage. There are a surprising number of patients with acoustic neuromas who have essentially normal pure-tone thresholds. In cases of central deafness, depressed pure-tone thresholds may not accurately reflect the status of the peripheral auditory system. Listening difficulties are seen in the presence of normal pure-tone thresholds. Suprathreshold procedures and a variety of other tests can provide information regarding other and often more central functions of the auditory system. CONCLUSIONS The audiogram is a primary tool for determining type, degree, and configuration of hearing loss; however, it provides the clinician with information regarding only hearing sensitivity, and no information about central auditory processing or the auditory processing of real-world signals (i.e., speech, music). The pure-tone audiogram offers limited insight into functional hearing and should be viewed only as a test of hearing sensitivity. Given the limitations of the pure-tone audiogram, a brief overview is provided of available behavioral tests and electrophysiological procedures that are sensitive to the function and integrity of the central auditory system, which provide better diagnostic and rehabilitative information to the clinician and patient.

Auditory Training for Central Auditory Processing Disorder

Auditory training (AT) is an important component of rehabilitation for patients with central auditory processing disorder (CAPD). The present article identifies and describes aspects of AT as they relate to applications in this population. A description of the types of auditory processes along with information on relevant AT protocols that can be used to address these specific deficits is included. Characteristics and principles of effective AT procedures also are detailed in light of research that reflects on their value. Finally, research investigating AT in populations who show CAPD or present with auditory complaints is reported. Although efficacy data in this area are still emerging, current findings support the use of AT for treatment of auditory difficulties.

Psychophysical and behavioral peripheral and central auditory tests

Diagnostic batteries to assess the integrity of the central auditory nervous system (CANS) include behavioral (i.e., psychophysical) tests, electrophysiologic procedures, and to some degree, electroacoustic procedures. In this chapter, we focus on behavioral tests used to identify lesions (including diffuse lesions), abnormalities, or dysfunction of the CANS, as well as identify associated functional deficits (e.g., listening in noise deficits). Following a brief review of several tests considered more peripheral in their application (e.g., pure-tone thresholds, otoacoustic emissions, acoustic reflex), we provide some historic context and a review of tests currently in use which are sensitized by design to measure central auditory function, as well as others which have not been adopted clinically and new tests and procedures which hold promise for clinical diagnosis. Tests reviewed include those of dichotic listening, temporal processing (e.g., temporal resolution and temporal patterning), binaural interaction (e.g., masking level differences), monaural low-redundancy measures (e.g., speech in noise or competition, filtered speech, time-compressed speech), and new paradigms which measure auditory evoked potentials in response to test stimuli typically used in behavioral tests.

Comparison of two tests of auditory temporal resolution in children with central auditory processing disorder, adults with psychosis, and adult professional musicians

Abstract Objective: Evaluate auditory temporal resolution threshold outcomes across three different populations. Design: Two commercially available tests of auditory gap detection (Random gap detection (RGDT) test, and Gaps-in-noise (GIN) test) were administered to all participants. Study sample: Adult professional musicians (APM) (N = 11, age range 28–61 years); children with central auditory processing disorder (CAPD) (N = 22, age range 7.5–17 years); and first episode psychosis patients (FEP) (N = 17, age range 18–48 years). Results: It was not possible to calculate a threshold for the RGDT for 13 of 22 children with CAPD and for 7 of 17 adults with FEP due to response inconsistency. Analysis of variance (ANOVA) excluding cases that produced inconsistent RGDT results showed that only RGDT thresholds differed across groups (F = 8.73, p = 0.001). Three t-tests comparing test means within group revealed statistically significant differences between the gap detection thresholds obtained with the RGDT vs. the GIN for each group. No significant correlations were seen between RGDT and GIN. Conclusion: Lower/better gap detection thresholds and smaller standard deviations were obtained using the GIN in all three groups. Lack of correlation between the two tests suggests that they may measure different processes.

Differential Diagnosis of Speech Sound Disorder (Phonological Disorder): Audiological Assessment beyond the Pure-tone Audiogram

BACKGROUND According to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, diagnosis of speech sound disorder (SSD) requires a determination that it is not the result of other congenital or acquired conditions, including hearing loss or neurological conditions that may present with similar symptomatology. PURPOSE To examine peripheral and central auditory function for the purpose of determining whether a peripheral or central auditory disorder was an underlying factor or contributed to the childs SSD. RESEARCH DESIGN Central auditory processing disorder clinic pediatric case reports. STUDY SAMPLE Three clinical cases are reviewed of children with diagnosed SSD who were referred for audiological evaluation by their speech-language pathologists as a result of slower than expected progress in therapy. RESULTS Audiological testing revealed auditory deficits involving peripheral auditory function or the central auditory nervous system. These cases demonstrate the importance of increasing awareness among professionals of the need to fully evaluate the auditory system to identify auditory deficits that could contribute to a patients speech sound (phonological) disorder. CONCLUSIONS Audiological assessment in cases of suspected SSD should not be limited to pure-tone audiometry given its limitations in revealing the full range of peripheral and central auditory deficits, deficits which can compromise treatment of SSD.

The Use of the Gaps-In-Noise Test as an Index of the Enhanced Left Temporal Cortical Thinning Associated with the Transition between Mild Cognitive Impairment and Alzheimer’s Disease

Background: The known link between auditory perception and cognition is often overlooked when testing for cognition. Purpose: To evaluate auditory perception in a group of older adults diagnosed with mild cognitive impairment (MCI). Research Design: A cross‐sectional study of auditory perception. Study Sample: Adults with MCI and adults with no documented cognitive issues and matched hearing sensitivity and age. Data collection: Auditory perception was evaluated in both groups, assessing for hearing sensitivity, speech in babble (SinB), and temporal resolution. Results: Mann–Whitney test revealed significantly poorer scores for SinB and temporal resolution abilities of MCIs versus normal controls for both ears. The right‐ear gap detection thresholds on the Gaps‐In‐Noise (GIN) Test clearly differentiated between the two groups (p < 0.001), with no overlap of values. The left ear results also differentiated the two groups (p < 0.01); however, there was a small degree of overlap ∼8‐msec threshold values. With the exception of the left‐ear inattentiveness index, which showed a similar distribution between groups, both impulsivity and inattentiveness indexes were higher for the MCIs compared to the control group. Conclusions: The results support central auditory processing evaluation in the elderly population as a promising tool to achieve earlier diagnosis of dementia, while identifying central auditory processing deficits that can contribute to communication deficits in the MCI patient population. A measure of temporal resolution (GIN) may offer an early, albeit indirect, measure reflecting left temporal cortical thinning associated with the transition between MCI and Alzheimer’s disease.

The relationship between central auditory processing, language, and cognition in children being evaluated for central auditory processing disorder

Background: Pediatric central auditory processing disorder (CAPD) is frequently comorbid with other childhood disorders. However, few studies have examined the relationship between commonly used CAPD, language, and cognition tests within the same sample. Purpose: The present study examined the relationship between diagnostic CAPD tests and “gold standard” measures of language and cognitive ability, the Clinical Evaluation of Language Fundamentals (CELF) and the Wechsler Intelligence Scale for Children (WISC). Research Design: A retrospective study. Study Sample: Twenty‐seven patients referred for CAPD testing who scored average or better on the CELF and low average or better on the WISC were initially included. Seven children who scored below the CELF and/or WISC inclusion criteria were then added to the dataset for a second analysis, yielding a sample size of 34. Data Collection and Analysis: Participants were administered a CAPD battery that included at least the following three CAPD tests: Frequency Patterns (FP), Dichotic Digits (DD), and Competing Sentences (CS). In addition, they were administered the CELF and WISC. Relationships between scores on CAPD, language (CELF), and cognition (WISC) tests were examined using correlation analysis. Results: DD and FP showed significant correlations with Full Scale Intelligence Quotient, and the DD left ear and the DD interaural difference measures both showed significant correlations with working memory. However, ∼80% or more of the variance in these CAPD tests was unexplained by language and cognition measures. Language and cognition measures were more strongly correlated with each other than were the CAPD tests with any CELF or WISC scale. Additional correlations with the CAPD tests were revealed when patients who scored in the mild–moderate deficit range on the CELF and/or in the borderline low intellectual functioning range on the WISC were included in the analysis. Conclusions: While both the DD and FP tests showed significant correlations with one or more cognition measures, the majority of the variance in these CAPD measures went unexplained by cognition. Unlike DD and FP, the CS test was not correlated with cognition. Additionally, language measures were not significantly correlated with any of the CAPD tests. Our findings emphasize that the outcomes and interpretation of results vary as a function of the subject inclusion criteria that are applied for the CELF and WISC. Including participants with poorer cognition and/or language scores increased the number of significant correlations observed. For this reason, it is important that studies investigating the relationship between CAPD and other domains or disorders report the specific inclusion criteria used for all tests.

Enhancement of the Auditory Late Response (N1-P2) by Presentation of Stimuli From an Unexpected Location

BACKGROUND Passive electrophysiological protocols, such as the middle latency response and speech auditory brainstem response, are often advocated in the objective assessment of central auditory processing disorder (CAPD). However, few established electrophysiological protocols exist for CAPD assessment that have patients participate in active tasks which more closely approximate real-world listening. To this end, the present study used a discrimination task (i.e., oddball paradigm) to measure an enhancement of the auditory late response (N1-P2) that occurs when participants direct their auditory attention toward speech arising from an unexpected spatial location. PURPOSE To establish whether N1-P2 is enhanced when auditory attention is directed toward an unexpected location during a two-word discrimination task. In addition, it was also investigated whether any enhancements in this response were contingent on the stimulus being counted as part of the oddball paradigm. RESEARCH DESIGN Prospective study with a repeated measures design. STUDY SAMPLE Ten normal hearing adults, with an age range of 18-24 years. DATA COLLECTION AND ANALYSIS The N1 and P2 latencies and peak-to-peak amplitudes were recorded during a P300 paradigm. A series of repeated measures of analysis of variance and a correlation analysis was performed. RESULTS There was a significant effect of stimulus location, in which words arising from the unexpected location showed a larger N1-P2 peak-to-peak amplitude and an earlier N1 latency. This effect was seen regardless of whether or not participants had to count the word total in memory. CONCLUSIONS These findings suggest that spatial enhancement of the N1-P2 is a fairly robust phenomenon in normal hearing adult listeners. Additional studies are needed to determine whether this enhancement is absent or reduced in patients with CAPD.