(PP1001) Auditory Processing and Listening Effort in Normal Hearing Adults with Mild Traumatic Brain Injury

Abstract: Individuals with a history of traumatic brain injury (TBI) have a higher rate of auditory-related complaints, yet clinically these individuals present with normal detection abilities. The proposed study aims to quantify the differences in subjective hearing difficulty and behavioral auditory processing in adults with near-normal detection abilities with and without a history of mild TBI. Two groups, a group with history of mTBI and auditory complaints and a control group, ages 18-59 years old, participated. Results are anticipated to characterize differences in the auditory domain of the mTBI population and potentially lead to better management strategies for this population.

Summary: Objectives

The proposed study aims to quantify the differences in subjective hearing difficulty and behavioral auditory processing in adults with normal to near normal detection abilities with and without a history of mild traumatic brain injury (mTBI).

Rationale

There is a high incidence of traumatic TBI in the U.S. population, with data from the Centers for Disease Control and Prevention indicating there were approximately 2.87 million emergency department visits, hospitalizations, and deaths related to TBI. TBI is differentiated by status from mild to severe. In mild cases of TBI, there is no clear or measurable site of lesion. Despite no clear site of lesion, physiologic changes can occur from mTBI including axonal shearing, swelling, and stretching. This type of diffuse damage to neuronal pathways in the brain leads to less effective transmission of information across multiple sensory domains, including auditory processing. Further, individuals with a history of TBI experience many ongoing auditory and cognitive symptoms that negatively impact their quality of life including sensory impairments (e.g., hearing difficulties or dizziness), and cognitive deficits (e.g., easy fatigue, concentration difficulties, memory loss).

Individuals with TBI report hearing-related difficulties at a higher rate than the normal population. The prevalence of hearing-related difficulties to be as high as 58% in adults with a history of TBI. In structured environments, individuals with a history of TBI often present with normal auditory and cognitive behaviors. However, when the listening and/or cognitive load of the task is increased (e.g., listening in a noisy environment) deficits in auditory and cognitive functioning begin to emerge. Common hearing-related difficulties include difficulty hearing in background noise, difficulty hearing in groups, difficulty understanding rapid speech, challenges remembering spoken information or instructions, and auditory fatigue.

Design

Twenty-four adults 18-59 years old participated. Measurements of subjective hearing difficulty and listening effort via questionnaires including the Hearing Handicap Inventory for Adults (HHIA), the Adult Auditory Processing Scale (AAPS), and the National Aeronautics and Space Administration Task Load Index (NASA-TLX). Behavioral binaural processing measures include tests designed to tax the auditory system and cognitive processing, including dichotic listening, speech recognition in noise and spatialized noise, and auditory working memory.

Results

Preliminary data analysis suggests that the adults with mTBI perceive greater hearing difficulties and listening effort, exhibit poorer binaural processing performance and poorer auditory working memory than the control group. These results provide support for the subjective hearing difficulties often described in the mTBI population and more importantly, may lead to appropriate treatment strategies and an improvement in the quality of life for these individuals.

Conclusions

Patients with a history or mTBI and subjective hearing complaints are likely to be evaluated at audiology clinics. Unfortunately, conventional behavioral testing is not sensitive to detecting the type of problems these patients are experiencing. The identification of measures that are sensitive to the auditory processing abilities of patients with mTBI will allow the field of audiology to better evaluate and treat these individuals.