SUBJECTS AND METHODS: The pure-tone audiometry (PTA) and auditory brainstem responses (ABRs) from 22 patients (44 ears) with diagnosed noise-induced permanent hearing loss were studied. Three indices of PTA were average thresholds of 0.5 kHz/, /1 kHz, and 2 kHz (PTA1); 2 kHz and 4 kHz (PTA2); and 4 kHz (PTA3) were subdivided into 3 thresholds of hearing. Their relationships with ABR results were analysed. The patterns of PTA from various groups of ABR wave patterns were studied.
RESULTS: In this study, the abnormal ABR wave patterns were detected in 72.7% of the ears. The ears with prolonged ABR wave latency, absent early waves, prolong interpeak wave I-V latency was 20.5%, 18.2%, and 21.1%, respectively. Normal ABRs were recorded in 27.3% of the ears despite marked thresholds elevation of the PTA at high frequencies. Other relationships between PTA results and ABR wave results were discussed.
CONCLUSION: There were relationships between severity of noise-induced hearing loss indicated by PTA and the patterns of ABR wave abnormalities among workers with noise-induced permanent hearing loss.
Methods: Twenty-three participants were recruited for this study. The participants were comprised of 11 Huffaz who memorized 30 chapters of the Islamic Scripture (from the Quran) and 12 non-Huffaz as the control group. All participants had normal hearing perception and underwent an ABR test with and without psychological tasks. The ABR was elicited at 70 dB nHL using a 3000 Hz tone burst stimulus with a 2-0-2 cycle at a stimulus repetition rate of 40 Hz. The ABR wave V amplitude and latencies were measured and statistically compared. A forward digit span test was also conducted to determine participants' working memory capacity.
Results: There were no significant differences in the ABR wave V amplitudes and latencies between Huffaz and non-Huffaz in ABR with and without psychological tasks. There were also no significant differences in the ABR wave V amplitudes and latencies in both groups of ABR with and without psychological tasks. In addition, no significant differences were identified in the digit span working memory score between both groups.
Conclusions: In this study, based on the ABR findings, Huffaz showed the same auditory sensory gating capacity as the non-Huffaz group. The ABR result was consistent with the digit span working memory test score. This finding implies that both groups have similar working memory performance. However, the conclusion is limited to the specific assessment method that we used in this study.
SUBJECTS AND METHODS: Eleven normal-hearing adults participated. The ABR test was repeated twice in the same clinical session and conducted again in another session. The ABR was acquired using both the click and LS CE-Chirp® stimuli at 4 presentation levels (80, 60, 40, and 20 dBnHL). Only the right ear was tested using the ipsilateral electrode montage. The reliability of the ABR findings (amplitudes and latencies) to the click and LS CE-Chirp® stimuli within the same clinical session and between the two clinical sessions was calculated using an intra-class correlation coefficient analysis (ICC).
RESULTS: The results showed a significant correlation of the ABR findings (amplitude and latencies) to both stimuli within the same session and between the clinical sessions. The ICC values ranged from moderate to excellent.
CONCLUSIONS: The ABR results from both the LS CE-Chirp® and click stimuli were consistent and reliable over the two clinical sessions suggesting that both stimuli can be used for neurological diagnoses with the same reliability.
OBJECTIVE: The present study aimed to compare the magnitude of gender difference in speech-evoked auditory brainstem response results between monaural and binaural stimulations.
METHODS: A total of 34 healthy Asian adults aged 19-30 years participated in this comparative study. Eighteen of them were females (mean age=23.6±2.3 years) and the remaining sixteen were males (mean age=22.0±2.3 years). For each subject, speech-evoked auditory brainstem response was recorded with the synthesized syllable /da/ presented monaurally and binaurally.
RESULTS: While latencies were not affected (p>0.05), the binaural stimulation produced statistically higher speech-evoked auditory brainstem response amplitudes than the monaural stimulation (p<0.05). As revealed by large effect sizes (d>0.80), substantive gender differences were noted in most of speech-evoked auditory brainstem response peaks for both stimulation modes.
CONCLUSION: The magnitude of gender difference between the two stimulation modes revealed some distinct patterns. Based on these clinically significant results, gender-specific normative data are highly recommended when using speech-evoked auditory brainstem response for clinical and future applications. The preliminary normative data provided in the present study can serve as the reference for future studies on this test among Asian adults.
METHODS: Twenty-nine healthy Malaysian subjects (14 males and 15 females) aged 19 to 30 years participated in this study. After measuring the head circumference, speech-ABR was recorded by using synthesized syllable /da/ from the right ear of each participant. Speech-ABR peaks amplitudes, peaks latencies, and composite onset measures were computed and analyzed.
RESULTS: Significant gender disparities were noted in the transient component but not in the sustained component of speech-ABR. Statistically higher V/A amplitudes and less steeper V/A slopes were found in females. These gender differences were partially affected after controlling for the head size.
CONCLUSIONS: Head size is not the main contributing factor for gender disparities in speech-ABR outcomes. Gender-specific normative data can be useful when recording speech-ABR for clinical purposes.
METHODS: Seventeen healthy children (6 boys, 11 girls) aged from 5 to 9 years (mean = 6.8 ± 3.3 years) were tested in two sessions separated by a 3-month period. The stimulus used was a 40-ms syllable /da/ presented at 30 dB sensation level.
RESULTS: As revealed by pair t-test and intra-class correlation (ICC) analyses, peak latencies, peak amplitudes and composite onset measures of speech-ABR were found to be highly replicable. Compared to other parameters, higher ICC values were noted for peak latencies of speech-ABR.
CONCLUSION: The present study was the first to report the test-retest reliability of speech-ABR recorded at low stimulation levels in healthy children. Due to its good stability, it can be used as an objective indicator for assessing the effectiveness of auditory rehabilitation in hearing-impaired children in future studies.
METHODS: The prospective clinical study was conducted at Selayang Hospital (SH) and Hospital Canselor Tuanku Muhriz (HCTM) within one year. A total of 38 children ranging from 3 to 18 years old underwent hearing evaluation using ABR tests and MSSR under sedation. The duration of both tests were then compared.
RESULTS: The estimated hearing threshold of frequency specific chirp MSSR showed good correlation with ABR especially in higher frequencies such as 2000 Hz and 4000Hz with the value of cronbach alpha of 0.890, 0.933, 0.970 and 0.969 on 500Hz, 1000Hz, 2000Hz and 4000Hz. The sensitivity of MSSR is 0.786, 0.75, 0.957 and 0.889 and specificity is 0.85, 0.882, 0.979 and 0.966 over 500Hz, 1000Hz, 2000Hz and 4000Hz. The duration of MSSR tests were shorter than ABR tests in normal hearing children with an average of 35.3 minutes for MSSR tests and 46.4 minutes for ABR tests. This can also be seen in children with hearing loss where the average duration for MSSR tests is 40.0 minutes and 52.0 minutes for ABR tests.
CONCLUSION: MSSR showed good correlation and reliability in comparison with ABR especially on higher frequencies. Hence, MSSR is a good clinical test to diagnose children with hearing loss.
CASE REPORT: We report audiological tests and auditory brainstem response (ABR) findings in a 5-year old Malay boy with NS. Despite showing the marked signs of NS, the child could only produce a few meaningful words. Audiological tests found him to have bilateral mild conductive hearing loss at low frequencies. In ABR testing, despite having good waveform morphology, the results were atypical. Absolute latency of wave V was normal but interpeak latencies of wave's I-V, I-II, II-III were prolonged. Interestingly, interpeak latency of waves III-V was abnormally shorter.
CONCLUSION: Abnormal ABR results are possibly due to abnormal anatomical condition of brainstem and might contribute to speech delay.