Formal Auditory Training with Individuals after Traumatic Brain Injury

Andréa Tortosa Marangoni,Ana Karina Lima Buriti,Ítalo Capraro Suriano,Daniela Gil

doi:10.4236/health.2017.96070

Abstract

Purpose: Establishing the effects of a formal auditory training program on individuals, after a traumatic brain injury by means of behavioral and electrophysiological tests. Study Design: Longitudinal study. Setting: Study conducted at the electrophysiology clinic of the Federal University of Sao Paulo. Patients: Nine individuals with normal hearing, 20 to 37 years old, who were exposed to severe traumatic brain injury (score of 3 - 8 on the Glasgow Coma Scale upon hospital admission), 6 - 24 months earlier (11 months on average) and had imaging tests showing diffuse axonal injury with or without associated focal lesion. Intervention(s): subjected to a formal auditory training program in an acoustic booth involving eight 45-minute sessions aiming at training the auditory temporal order judgment (frequency and duration of sounds), auditory closure, and figure-ground separation skills for verbal and nonverbal sounds in monotic and dichotic listening tasks. The sessions and activities, in each session, were organized in increasing order of complexity to challenge the auditory system. In order to establish the efficacy of the auditory training, all participants were subjected to behavioral and electrophysiological assessments of the auditory processing, before and after the formal auditory training. Results: On the electrophysiological assessment, the absolute latencies of waves III and V, and of interpeak interval I-V decreased after the auditory training. However, the P300 did not exhibit a significant difference in either the latency or the amplitude parameters. Regarding the behavioral assessment of the auditory processing, it was verified that adequacy of the auditory figure-ground skills for verbal sounds, and the temporal order judging skills. Conclusions: individuals with diffuse axonal injury following a severe traumatic brain injury exhibited an improvement of central auditory processing after formal auditory training, as manifested on electrophysiological and behavioral assessments.

Highlights

Traumatic brain injury (TBI) essentially consists in the result of physical aggression on the skull and its contents caused by impact and acceleration/deceleration of the brain inside the skull
Conclusions: individuals with diffuse axonal injury following a severe traumatic brain injury exhibited an improvement of central auditory processing after formal auditory training, as manifested on electrophysiological and behavioral assessments
Many TBI patients exhibit Central Auditory Processing Disorder (CAPD) which can only be identified by means of electrophysiological techniques and tests for central auditory function [2]

Summary

Introduction

Traumatic brain injury (TBI) essentially consists in the result of physical aggression on the skull and its contents caused by impact and acceleration/deceleration of the brain inside the skull. The lesions caused in the brain during such events can be primary or secondary [1]. Primary injuries refer to those that occur at the moment of trauma and include extradural and subdural hematomas, contusions and diffuse axonal injury. Brain deformation caused by extreme acceleration and deceleration affects nerve fibers, including the neural substrate responsible for hearing, resulting in central auditory deficits, the case in diffuse axonal injury, which involves several areas such the cortical and subcortical auditory regions [2]. Due to the high frequency of brainstem and cortical lesions in TBI patients [3], the performance of long and short-latency auditory evoked potentials (AEP) and behavioral assessment of Central Auditory Processing (CAP) are important in the evaluation of the auditory function at the brainstem and in the subcortical and cortical regions. Many TBI patients exhibit Central Auditory Processing Disorder (CAPD) which can only be identified by means of electrophysiological techniques and tests for central auditory function [2]

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