Long Term Test-Retest Reliability of Auditory Brainstem Response (ABR) and Middle Latency Response (MLR)

Abstract

Objective: To study the variability of auditory brainstem response (ABR) and middle latency response (MLR) over a long term period. Methods: 50 normal hearing subjects participated in the study. All the subjects were tested at 3 months, 6 months and 12 months of the initial testing. The absolute latencies and interpeak latencies of ABR waves and amplitudes & latencies of waves Na and Pa of MLR were measured. Results: The Repeated measure ANOVA did not reveal any statistically significant difference (p>0.05) between interpeak latencies of wave I-III, III-V and I-V across the four visits. The amplitude of MLR wave Pa showed no significant difference across four visits. However significant difference (p<0.05) across visits was observed for latency of wave Na. Conclusions: The absolute latencies of wave III & V and the interpeak latencies of waves I-III, III-V and I-V have good test retest reliability. Reliability of wave I however has not been established. Amplitude of wave Pa has good test retest reliability. Significance: The ABR and MLR can be used as monitoring tools in a number of cases like neurodegenerative disorders, progressive disorders of the central nervous system.