Adrienne Rubinstein

Combined Effects of Noise and Reverberation on Speech Recognition Performance of Normal-hearing Children and Adults

Objectives: The purpose of this study is to determine how combinations of noise levels and reverberation typical of ranges found in current classrooms will affect speech recognition performance of typically developing children with normal speech, language, and hearing and to compare their performance with that of adults with normal hearing. Speech recognition performance was measured using the Bamford-Kowal-Bench Speech in Noise test. A virtual test paradigm represented the signal reaching a student seated in the back of a classroom with a volume of 228 m3 and with varied reverberation time (0.3, 0.6, and 0.8 sec). The signal to noise ratios required for 50% performance (SNR-50) and for 95% performance were determined for groups of children aged 6 to 12 yrs and a group of young adults with normal hearing. Design: This is a cross-sectional developmental study incorporating a repeated measures design. Experimental variables included age and reverberation time. A total of 63 children with normal hearing and typically developing speech and language and nine adults with normal hearing were tested. Nine children were included in each age group (6, 7, 8, 9, 10, 11, and 12 yrs). Results: The SNR-50 increased significantly with increased reverberation and decreased significantly with increasing age. On average, children required positive SNRs for 50% performance, whereas thresholds for adults were close to 0 dB or <0 dB for the conditions tested. When reverberant SNR-50 was compared with adult SNR-50 without reverberation, adults did not exhibit an SNR loss, but children aged 6 to 8 yrs exhibited a moderate SNR loss and children aged 9 to 12 yrs exhibited a mild SNR loss. To obtain average speech recognition scores of 95% at the back of the classroom, an SNR ≥10 dB is required for all children at the lowest reverberation time, of ≥12 dB for children up to age 11 yrs at the 0.6-sec reverberant condition, and of ≥15 dB for children aged 7 to 11 yrs at the 0.8-sec condition. The youngest children require even higher SNRs in the 0.8-sec condition. Conclusions: Results highlight changes in speech recognition performance with age in elementary school children listening to speech in noisy, reverberant classrooms. The more reverberant the environment, the better the SNR required. The younger the child, the better the SNR required. Results support the importance of attention to classroom acoustics and emphasize the need for maximizing SNR in classrooms, especially in classrooms designed for early childhood grades.

The effect of telephone intervention on success with amplification.

The purpose of this study was to determine whether periodic clinician-initiated telephone contact would reduce the number of unresolved complaints and increase satisfaction, use, and perceived benefit at 4 mo postfitting. Thirty subjects were contacted at 6, 9, and 12 wk postfitting to address questions and to encourage them to return to the clinic to resolve hearing aid-related problems. A control group of 30 subjects was encouraged to contact the center if problems arose at the time of dispensing only. All subjects were interviewed at 4 mo following receipt of the aids, and were sent the Hearing Handicap Inventory for the Elderly at the same time as well as at the time of dispensing. Results revealed a significant reduction in perceived handicap in general, but no significant difference between groups on measures of satisfaction, use, or benefit. There was no significant difference between groups in the number of unresolved complaints at the time of the interview; however, a trend toward fewer complaints in the experimental group was noted. A significantly greater number of complaints were raised for the first time in the control group than in the experimental group at the time of the interview, indicating that more problems remained unaddressed in the absence of clinician-initiated intervention. Therefore, the continued investigation of aggressive, and efficient, postfitting management schemes is warranted.

The Long-term Effect of Early Telephone Intervention on Hearing Aid Success

The purpose of the study was to determine if subjects who were contacted by telephone periodically during the first 3 months following hearing-aid dispensing would report greater satisfaction, more frequent hearing aid use, and fewer complaints at one year postdispensing than subjects who were not contacted frequently. Subjects were 55 hearing-impaired adults who purchased aids, 27 of whom were contacted periodically by phone. Results revealed that frequent telephone contact in the period soon after dispensing does not appear to be an effective mass management tool in this population, although its value cannot be ruled out for some types of clients.

Speech Recognition in Nonnative versus Native English-Speaking College Students in a Virtual Classroom

Background: Limited attention has been given to the effects of classroom acoustics at the college level. Many studies have reported that nonnative speakers of English are more likely to be affected by poor room acoustics than native speakers. An important question is how classroom acoustics affect speech perception of nonnative college students. Purpose: The combined effect of noise and reverberation on the speech recognition performance of college students who differ in age of English acquisition was evaluated under conditions simulating classrooms with reverberation times (RTs) close to ANSI recommended RTs. Research Design: A mixed design was used in this study. Study Sample: Thirty‐six native and nonnative English‐speaking college students with normal hearing, ages 18–28 yr, participated. Intervention: Two groups of nine native participants (native monolingual [NM] and native bilingual) and two groups of nine nonnative participants (nonnative early and nonnative late) were evaluated in noise under three reverberant conditions (0.03, 0.06, and 0.08 sec). Data Collection and Analysis: A virtual test paradigm was used, which represented a signal reaching a student at the back of a classroom. Speech recognition in noise was measured using the Bamford–Kowal–Bench Speech‐in‐Noise (BKB‐SIN) test and signal‐to‐noise ratio required for correct repetition of 50% of the key words in the stimulus sentences (SNR‐50) was obtained for each group in each reverberant condition. A mixed‐design analysis of variance was used to determine statistical significance as a function of listener group and RT. Results: SNR‐50 was significantly higher for nonnative listeners as compared to native listeners, and a more favorable SNR‐50 was needed as RT increased. The most dramatic effect on SNR‐50 was found in the group with later acquisition of English, whereas the impact of early introduction of a second language was subtler. At the ANSI standard’s maximum recommended RT (0.6 sec), all groups except the NM group exhibited a mild signal‐to‐noise ratio (SNR) loss. At the 0.8 sec RT, all groups exhibited a mild SNR loss. Conclusion: Acoustics in the classroom are an important consideration for nonnative speakers who are proficient in English and enrolled in college. To address the need for a clearer speech signal by nonnative students (and for all students), universities should follow ANSI recommendations, as well as minimize background noise in occupied classrooms. Behavioral/instructional strategies should be considered to address factors that cannot be compensated for through acoustic design.

Accounting for the Occlusion Effect with Insert Earphones

BACKGROUND There are clinical implications associated with knowing when the occlusion effect (OE) must be accounted for during bone conduction (BC) testing because spurious results can occur when errors are made in this regard. The amount of OE produced when insert earphones (IEs) are used varies in the literature; thus, further investigation is warranted. PURPOSE The purpose of this project was to determine the OE during BC threshold measurements under the following occluding conditions used clinically: when using partial insertion (PI) versus full insertion (FI) depth and when occluding one versus both ears. RESEARCH DESIGN A descriptive within-subjects design was used in this study. STUDY SAMPLE Twenty-two adults with mean four-frequency pure tone averages of 24 dB HL, aged 40-83 yr, participated. INTERVENTION BC thresholds were obtained at 250, 500, and 1000 Hz under seven conditions: (1) both ears unoccluded, (2) left ear occluded with PI, (3) right ear occluded with PI, (4) both ears occluded with PI, (5) left ear occluded with FI, (6) right ear occluded with FI, (7) both ears occluded with FI. For PI, one half of the length of the IE was beyond the opening of the ear canal. For FI, the lateral edge of the foam insert was flush with the entrance to the ear canal. DATA COLLECTION AND ANALYSIS Mean OEs were compared with previously published data. In addition, variability in the data was examined using frequency distribution plots as well as cumulative frequency and percentile values. RESULTS Mean OEs of 5-13 dB were present in all but the FI condition at 1000 Hz where the OE was <3 dB. Differences between PI and FI conditions were present at each frequency measured, irrespective of whether one or both ears were occluded. The shifts in threshold were consistently more prevalent and greater for the PI than the FI conditions overall. Mean differences between the one-ear and both-ears conditions were not clinically significant. Clinically significant variability in the data was noted, except when comparing the one-ear versus both-ears conditions. CONCLUSIONS Occluding the ear during initial BC measurements may artificially improve the thresholds and create or exaggerate an air-bone gap. Thus, initial BC testing should be performed unoccluded at 250, 500, and 1000 Hz. There is a need to account for the OE even when the IE is flush with the ear canal to avoid insufficient masking.

Effect of Direction of Pressure Change on Obtaining Airtight Seals in Tympanometry

To determine the effect of change in pressure direction on obtaining a seal during tympanometry, an ascending approach (-/+) was attempted when the traditional, descending approach (+/-) was unsuccessful in maintaining an airtight seal. Results revealed that a seal was achieved using the ascending direction in twelve ears when the descending method failed; in only four ears, neither method was successful.

Response of hearing‐impaired adults to a structured program of auditory training

Twenty adults with mild to moderate sensorineural hearing impairments were given three tests of auditory perception: The CUNY Nonsense Syllable Test (NST), the low predictability items of the Speech in Noise (SPIN) test, and the high predictability items of the SPIN test. The tests were administered at a signal‐to‐noise ratio giving a score of approximately 50%, as determined with an adaptive procedure at the beginning of the study. They were tested on four occasions: (1) at the beginning of the study, (2) after one month of “no treatment,” (3) after a month of intensive auditory training, and (4) after a further month of “no treatment.” During the treatment period, ten of the subjects spent all of the time on global tasks (i.e., activities involving sentence perception and perceptual strategy) while the other 10 spent part of the time on analytic tasks (i.e., activities involving consonant recognition). The results showed: (a) that performance improved only during the treatment period, and (b) that the i...