Impact of Hearing Loss on Cognitive Abilities in Subjects with Tinnitus

Abstract

Background: This study aimed to delineate the underlying pathophysiology of tinnitus between normal hearing and hearing loss subjects. Objective: The study aimed to characterize the neuropsychological aspects of two types of groups with tinnitus having variable hearing thresholds. Materials and Methods: The study sample comprises 75 subjects in a group with tinnitus and normal hearing, and 100 subjects in the tinnitus and hearing loss group. Subjects were matched to their respective controls for age, gender, and education levels. Subjects underwent verbal learning and memory tasks, visual learning, memory, listening attention, sustained visual attention, work memory, category control, phonemic mastery, response inhibition, and data processing velocity. Results and Conclusions: Subjects having hearing loss with bilateral tinnitus showed significantly reduced performance on total learning capacity (P = 0.02) and recognition (P = 0.05) (Rey's auditory verbal learning test), auditory attention tasks, digit forward span test (DFST) (P = 0.03), digit span test score (P = 0.01), and working memory (P = 0.02) (digit backward span test). For response inhibition tasks and Stroop interference (P = 0.03), subjects with normal hearing with bilateral tinnitus displayed lower performance. This study proves a relationship between poor working memory, auditory memory, total learning capacity, and recognition due to hearing impairment in bilateral Tinnitus subjects. The study has substantial implications for effective assessment and treatment recommendations in hearing loss with bilateral tinnitus subjects.