Carl C. Crandell

Classroom Acoustics for Children With Normal Hearing and With Hearing Impairment

Past investigations demonstrate that the acoustical environment of a classroom is a critical factor in the academic, psychoeducational, and psychosocial achievement of children with normal hearing and with hearing impairment. This article examines several acoustical variables, such as noise, reverberation, and speaker-listener distance, which can deleteriously affect speech perception in classrooms. Moreover, the discussion examines the effects of these variables on the speech perception abilities of both children with normal hearing and children with hearing loss. Finally, appropriate acoustical criteria are suggested for children in educational settings.

Speech recognition in noise by children with minimal degrees of sensorineural hearing loss

It is well recognized that the acoustical environment in a classroom is an important variable in the psychoeducational achievement of hearing-impaired children. To date, however, there remains a paucity of information concerning the importance of classroom acoustics for children with minimal degrees of sensorineural hearing loss (SNHL). The present investigation examined the effects of commonly reported classroom signal to noise ratios (+6, +3, 0, -3, and -6 dB) on the sentence recognition of 20 normal-hearing children and 20 children with minimal degrees of SNHL (i.e., pure-tone averages of 15-30 dB HL through the speech frequency range). Results indicated that children with minimal degrees of SNHL obtained poorer recognition scores than normal-hearing children across most listening conditions. Moreover, the performance decrement between the two groups increased as the listening environment became more adverse. Educational implications of these data, such as acoustical modification of the classroom and/or the utilization of frequency modulation sound field amplification systems, are discussed.

Speech Perception in Noise by Children for Whom English Is a Second Language

Appropriate classroom acoustics and academic achievement of children is known to be correlated. To date, however, there remains a lack of research concerning the importance of classroom acoustics f...

Comorbid auditory processing disorder in developmental dyslexia

Objective The primary objective of this study was to investigate the extent of comorbid auditory processing disorder (APD) in a group of adults with developmental dyslexia. An additional objective was to compare performance on auditory tasks to results from standardized tests of reading in an attempt to generate a clinically useful profile of developmental dyslexics with comorbid APD. Design A group of eleven persons with developmental dyslexia and 14 age- and intelligence-matched controls participated in the study. Behavioral audiograms, 226-Hz tympanograms, and word recognition scores were obtained binaurally from all subjects. Both groups were administered the frequency-pattern test (FPT) and duration-pattern test (DPT) monaurally (30 items per ear) in both the left and right ear. Gap detection results were obtained in both groups (binaural presentation) using narrowband noise centered at 1 kHz in an adaptive two-alternative forced-choice (2-AFC) paradigm. The FPT, DPT, and gap detection results were analyzed for interaural (where applicable), intergroup, and intragroup differences. Correlations between performance on the auditory tasks and the standardized tests of reading were examined. Additive logistic regression models were fit to the data to determine which auditory tests proved to be the best predictors of group membership. Results The persons with developmental dyslexia as a group performed significantly poorer than controls on both the FPT and DPT. Furthermore, the group differences were significant in both monaural conditions. On the FPT and DPT, five of the eleven participants with dyslexia performed below the widely used clinical criterion for APD of 70% correct in either ear. All five of these participants performed below criterion on the FPT, whereas four of the five additionally performed below 70% on the DPT. The data also were analyzed by fitting a series of stepwise logistic regression models, which indicated that gap detection did not significantly predict group membership, whereas the FPT and DPT were significant predictors. The addition of the FPT score after the DPT did not result in a significant change in the residual deviance. Conclusions Approximately half of the participants with developmental dyslexia showed clinically significant diminished performance on the FPT and DPT indicative of APD. These results indicate that the percentage of persons with developmental dyslexia and comorbid APD may be substantial enough to warrant serious clinical considerations.

Multiple benefits of personal FM system use by children with auditory processing disorder (APD)

Children with auditory processing disorders (APD) were fitted with Phonak EduLink FM devices for home and classroom use. Baseline measures of the children with APD, prior to FM use, documented significantly lower speech-perception scores, evidence of decreased academic performance, and psychosocial problems in comparison to an age- and gender-matched control group. Repeated measures during the school year demonstrated speech-perception improvement in noisy classroom environments as well as significant academic and psychosocial benefits. Compared with the control group, the children with APD showed greater speech-perception advantage with FM technology. Notably, after prolonged FM use, even unaided (no FM device) speech-perception performance was improved in the children with APD, suggesting the possibility of fundamentally enhanced auditory system function.

Effects of sound-field frequency modulation amplification on reducing teachers' sound pressure level in the classroom

Voice problems are a frequent difficulty that teachers experience. Common complaints by teachers include vocal fatigue and hoarseness. One possible explanation for these symptoms is prolonged elevations in vocal loudness within the classroom. This investigation examined the effectiveness of sound-field frequency modulation (FM) amplification on reducing the sound pressure level (SPL) of the teachers voice during classroom instruction. Specifically, SPL was examined during speech produced in a classroom lecture by 10 teachers with and without the use of sound-field amplification. Results indicated a significant 2.42-dB decrease in SPL with the use of sound-field FM amplification. These data support the use of sound-field amplification in the vocal hygiene regimen recommended to teachers by speech-language pathologists.

Individual differences in speech recognition ability: implications for hearing aid selection.

Hearing-impaired listeners with similar audiometric configurations often demonstrate varying abilities to understand speech in the presence of noise and/or reverberation. To date, however, it is unclear which auditory mechanisms are responsible for these perceptual deficits. This lack of information is unfortunate, as individual susceptibility to noise and reverberation may explain why hearing-impaired listeners receive varying degrees of benefit from rehabilitative strategies. The present discussion will examine: (1) individual speech recognition susceptibility to noise and reverberation in hearing-impaired listeners and (2) auditory and cognitive hypotheses to explain individual differences in speech recognition performance. Theoretical and clinical implications for hearing aid selection procedures will be discussed.

Classroom Amplification Technology: Theory and Practice

Many children are struggling to listen and learn in noisy and reverberant classrooms. Some of these children have hearing loss; others have essentially normal hearing but are at risk for accurate speech perception. Hearing aid fitting protocols and technology can be effective for children with hearing loss, but the aids must be selected and adjusted for classroom environments. For many children, personal amplification may not provide enough benefit for listening and learning to occur. For children who require more than a hearing aid and for at-risk children who have difficulty separating the teachers message from background noise, technology that is specifically designed to improve the classroom signal-to-noise ratio (SNR) may be required. In addition to the use of technology, children must learn to listen effectively in order for a meaningful signal to be received and used.

Classroom acoustics for hearing‐impaired children

The present investigation examined ambient noise levels, reverberation times (RT), and noise/reverberation reduction treatments in 32 classrooms utilized for hearing‐impaired pediatric listeners. Unoccupied classroom noise levels were measured with a precision sound‐level meter (Bruel & Kjaer model 2209) equipped with a 1‐in. condenser microphone. Noise measurements were obtained on A‐, C‐, and linear‐weighting networks. Room reverberation was measured at 500, 1000, and 2000 Hz. Noise/reverberation reduction treatments, such as carpeting, draperies, acoustic tile, and furniture treatments, were documented in each room. Results indicated mean ambient noise levels of 50.2 dBA, 65.9 dBC, and 74.4 dB linear. The mean RT was 0.52 s. None of the classrooms met recommended acoustical criteria for ambient noise levels (30–35 dBA), while only 9 rooms (28%) complied with recommended standards for reverberation (RT=0.4 s). Moreover, few of the classrooms exhibited adequate acoustical treatments. These data will be d...

Psychosocial status of children with auditory processing disorder.

BACKGROUND Children with hearing loss often exhibit reduced psychosocial status compared to children with normal hearing. It is reasonable to assume that psychosocial function may also be affected in children diagnosed with auditory processing disorder (APD). However, there are no published studies specifically addressing the psychosocial health of children with APD. PURPOSE This investigation examined relationships between APD and psychosocial status, with an aim to examine nonauditory factors that may influence quality of life of children diagnosed with APD. RESEARCH DESIGN A two-matched group design was employed. Participants and their mothers completed appropriate versions of the Dartmouth Primary Care Cooperative Information Project Charts for Adolescents (COOP-A), the Behavioral Assessment System for Children, Second Edition (BASC-2), and the Social Skills Rating System (SSRS). STUDY SAMPLE Participants consisted of 19 children (aged 9.5-17.8 yr; mean = 11.9) diagnosed with APD and 20 gender- and age-matched (mean = 12.8 yr) children with no evidence of APD by history or audiological assessment. Primary caretakers (mothers) of the participants also completed psychosocial questionnaires according to their perception of their participating childs function. DATA COLLECTION AND ANALYSIS Data were collected at a single visit, following APD diagnosis. Data from each questionnaire were analyzed using appropriate statistical methods for two-group comparisons. RESULTS Analysis of child reports revealed significantly greater psychosocial difficulty in the APD group on subscales of the COOP-A and BASC-2. Increased problems in the APD group were also reported by parents on subscales of the COOP-A, BASC-2, and SSRS. Eta-squared values for all significant findings indicated moderate to large effect sizes, suggesting findings may be generalized to other children in this age group. No between-group differences were found on any subscale for APD children with or without a confirmed or suspected language disorder. CONCLUSION We found that children with APD exhibit increased psychosocial difficulty in several areas compared to children without APD.