Association between Speech Perception Measures and Auditory Brainstem Response to Paired Click Stimulation in Assessing Temporal Processing in Individuals with and without Cochlear Hearing

Abstract

Introduction: Normal auditory processing is required to understand speech in quiet as well as in noise. Individuals with cochlear hearing loss have difficulty understanding speech in noise. Since speech is dynamic, normal temporal resolution abilities are essential for speech perception in noise. Auditory brainstem response (ABR) using paired click stimulation could be used to neurophysiologically assess the temporal resolution. Speech recognition at a higher sensation level also helps in assessing the temporal processing with respect to the low spontaneous rate fibres which is responsible for the speech encoding at higher intensities. Aim of the study: The aim of present study is to assess the temporal processing abilities measured using ABR with paired click stimulation and its relationship with speech perception measures in individuals with normal hearing and cochlear hearing loss. Objectives: The objective of the present study includes comparison of ABR with paired click stimulation, measures of speech perception and temporal processing measures in individuals with normal hearing sensitivity and cochlear hearing loss. This study also assesses the relationship between speech perception measures and temporal processing measures using paired click ABR in individuals with normal hearing sensitivity and cochlear hearing loss. Materials and methods: Paired click ABR, gap detection threshold(GDT), Speech recognition (SIS 90) at higher sensation levels (90dBSPL) and Quick SIN were measured in 30 participants, 15 normal hearing individuals (30 ears) under Group I and 15 individuals (20 ears) with mild to moderate sensorineural hearing loss under Group II, aged between 18 – 40 years. Results: The results showed a statistically significant difference between the recovery threshold of wave V, SIS 90, Quick SIN and GDT between the experimental and the control groups (P<0.05). In the control group, GDT and recovery thresholds showed statistically significant difference (P<0.05). There was a statistically significant difference between ABR wave V and wave I recovery thresholds in control group (P<0.05). The experimental group showed poorer responses in all the tests. In control group there was a statistically significant positive correlation between PTA and Quick SIN (ρ=0.362, p<0.05) and mild negative correlation between PTA and ABR recovery threshold for wave I (ρ= -0.454, p<0.05), all the other parameters do not show statistically significant correlation. In the experimental group there was no such relationship found between any of the parameters. Conclusion: Recovery thresholds of Paired click ABR responses can be used in assessing the auditory nerve integrity. Since the recovery threshold is a relative measure, it might overcome the limitations of the absolute measures in ABR. Paired click ABR a potential tool in assessing the temporal processing abilities in difficult-to-test population, adults as well as paediatric as is an objective measure.