Cognitive speed as an objective measure of tinnitus

Abstract

Objectives/hypothesis: Subjective, chronic tinnitus is a common but poorly understood condition. The heterogeneity within tinnitus has hindered the development of functional severity measures and effective treatment. Tinnitus at least partially results from maladaptive cortical processes that are associated with cognitive deficits. This study examined whether cognitive processing speed might serve as a novel objective measure of tinnitus severity, and whether the psychiatric comorbidities of depression and somatization are predictive of self-reported tinnitus severity.

Study design: Cross-sectional study of 92 chronic tinnitus participants.

Methods: The Tinnitus Handicap Inventory (THI) captured the self-reported severity of tinnitus. Cognitive processing speed was objectively measured by the Brain Speed Test (BST), a short computerized test from Posit Science. Somatization and depression were captured by the Whiteley-7 and Patient Health Questionnaire-9 scales. The results of these tests were combined into a Composite Psychiatric State (CPS) variable. The ability of BST z score and CPS level to predict THI was assessed.

Results: There was a significant correlation (r = 0.54, P < .001) between BST z scores and THI in those with bothersome tinnitus (THI ≥ 30). Additionally, BST z score was correlated with the validated neurocognitive tests. Multivariate analysis identified BST z score and CPS level as independent predictors of THI.

Conclusions: In severe tinnitus, BST provides an objective measure of the functional impact of tinnitus. Cognitive processing speed and psychiatric state are independent predictors of self-reported tinnitus severity. These measures help define clinical subgroups within tinnitus: one subgroup whose functional impact is primarily cognitive and another whose functional impact is primarily psychiatric.