Speech processing disorder in neural hearing loss.

Joseph P Pillion

doi:10.1155/2012/206716

Abstract

Deficits in central auditory processing may occur in a variety of clinical conditions including traumatic brain injury, neurodegenerative disease, auditory neuropathy/dyssynchrony syndrome, neurological disorders associated with aging, and aphasia. Deficits in central auditory processing of a more subtle nature have also been studied extensively in neurodevelopmental disorders in children with learning disabilities, ADD, and developmental language disorders. Illustrative cases are reviewed demonstrating the use of an audiological test battery in patients with auditory neuropathy/dyssynchrony syndrome, bilateral lesions to the inferior colliculi, and bilateral lesions to the temporal lobes. Electrophysiological tests of auditory function were utilized to define the locus of dysfunction at neural levels ranging from the auditory nerve, midbrain, and cortical levels.

Highlights

Audiological evaluations typically involve assessment of sensitivity for pure tones which is summarized on an audiological record or audiogram
Due to the discrepancy between pure tone sensitivity findings indicating the presence of a severe hearing loss, poorer speech processing than would be expected, and the presence of otoacoustic emissions, measurements of the auditory brainstem response were undertaken
All of the patients reported above had markedly impaired speech perception despite the presence of normal otoacoustic emissions which is indicative of normally functioning outer hair cells [4, 5]

Summary

Introduction

Audiological evaluations typically involve assessment of sensitivity for pure tones which is summarized on an audiological record or audiogram. Patient CF was a 7 year old who was thought to have had normal hearing until he failed a school screening and a subsequent screening in his pediatrician’s office for his left ear He was functioning above grade level academically. Due to the discrepancy between pure tone sensitivity findings indicating the presence of a severe hearing loss, poorer speech processing than would be expected, and the presence of otoacoustic emissions, measurements of the auditory brainstem response were undertaken. Patient CF was a normally functioning middle school age child until he was struck by a motor vehicle while riding on a bicycle He was unresponsive at the scene of the accident with a Glasgow Coma Scale of 3.

Discussion

III 7 9

Findings

III V 8 10