PP503 - A Test-Retest Reliability Study of New Generation Auditory Steady-State Response

Abstract:
We examined the test-retest reliability of New Generation Auditory Steady-State Response (ASSR) as implemented in the Interacoustics Eclipse system using the air conduction (AC) and bone-conduction (BC) multiple ASSR techniques among normal-hearing adults. Variables considered are ASSR thresholds and residual noise levels. Results revealed strong test-rest reliability for AC at 500, 1000, 2000, and 4000 Hz. BC test-rest reliability was strong at 1000 Hz and 4000 Hz and low at 2000 Hz. No significant correlation was measured between changes in residual noise levels at threshold and difference in thresholds across two sessions at all tested frequencies.

Summary

Learning Objective: To understand the test-retest reliability of the New Generation multiple ASSR system and its contribution in audiologic clinical settings.

Rationale/

Purpose: ASSR provides objective and ear-specific information essential for early and appropriate intervention. Test-retest reliability is essential for audiologic monitoring. The test-retest reliability of the ASSR has received limited attention. Three studies were found in the literature investigating the test-retest reliability of old generation ASSR. However, to our knowledge, no published reports have specifically examined the test-retest reliability of New Generation ASSR as implemented in the Interacoustics Eclipse system. In addition, no data currently exist in the literature for BC ASSR using the new bone oscillator B-81. This study investigated a) the test-retest reliability of AC and BC ASSR thresholds across two test sessions and b) the relationship between differences in AC and BC ASSR thresholds across two sessions to the residual noise levels in normal hearing adults.

Methods: The study recruited 15 normal-hearing adults (12 Females) with a mean age of 28 years from the department of communication disorders, California State University, and the local population. A two-channel recording montage was utilized. Four surface electrodes were used to record the responses. The non-inverting electrode was placed at the forehead at the hairline, two inverting electrodes were placed on each ear lobe, and the ground electrode was placed on the forehead underneath the non-inverting electrode. ASSR recordings were completed while the subject relaxed or, in most cases, slept on a recliner. Stimuli were presented separately through insert earphones and the B-81 bone transducer, which was placed on the mastoid of the right ear and held in place with a headband. The modified Michel and Jorgensen (2017) procedure is used for threshold determination.

Results: Test-rest reliability for AC ASSR was strong at 500 Hz, 1000Hz, 2000 Hz, and 4000 Hz. Test-retest reliability for BC ASSR was strong at 1000 Hz and 4000Hz, and low at 2000 Hz. Overall, the study found the strongest test-retest reliability at 500 Hz, which is distinct compared to previous studies, which investigated test-retest reliability with old generation ASSR. For AC and BC testing, no significant correlation was measured between the difference in residual noise levels at the threshold and the difference in thresholds at all tested frequencies across test sessions.

Conclusion: The New Generation ASSR showed strong test-retest reliability for normal-hearing adults. The ASSR New Generation system presents improved test-retest reliability at 500 Hz for AC compared to old generation ASSR. The observed improvement might be attributed to using Narrow-band CE-chirp stimuli generating large amplitude responses and the improved detection paradigm utilizing multiple harmonics spectral and phase analysis. The differences in residual noise are not related to changes in threshold across sessions for both AC and BC. The study only examined adults with normal hearing, and future studies need to investigate a larger number of normal and hearing-impaired subjects and the pediatric population.