Cognitive performance, dizziness and tinnitus among adults with unilateral audiovestibular disorders

To investigate cognitive performance in patients with unilateral audiovestibular disorders, specifically hearing loss (UHL), vestibular hypofunction (UVH), and Meniere's Disease (MD) using a visually administered, computerized domain-specific cognitive battery.

58 adults: 28 controls (mean age 59 years, range 41-78) and 30 patients (10 UHL [4Frequency Pure Tone Average <25 dB in better ear; >40 poor ear] mean age 55, range 25-76; 10 unilateral MD, mean age 53, 32-78; 10 UVH, mean age 59, 24-82) completed the cognitive test battery and the Dizziness Handicap Inventory (DHI), Tinnitus Handicap Inventory (THI), Speech, Spatial and Qualities of Hearing scale (SSQ12), Activities Specific Balance Confidence Scale (ABC). Age-standardized scores as well as proportion of patients below average were compared between groups and correlations between cognitive performance and symptom severity were explored in clinical groups.

Only 3 domains differed significantly between groups (verbal memory [H(3) = 9.28, p = 0.026], working memory [H(3) = 7.77, p = 0.05] and sustained attention [H(3) = 9.35, p = 0.03]); and only 2 differences remained significant after Bonferroni correction for multiple comparisons: MD scored significantly lower than controls in verbal memory ( $p_{\text{Bonf}}=0.0174$ ) and patients with UHL group scored significantly lower than controls in sustained attention ( $p_{\text{Bonf}}=0.0391$ ). Proportion of individuals in each group performing "below average" (standardized score < 90) on each domain trended toward lower performance on the domains of verbal memory for UHL and MD groups, executive function for MD, and sustained attention for those with UHL or UVL. The latter 2 maintained significance after Bonferroni correction. Overall, less symptom severity (lower THI and DHI scores) correlated with better cognitive function, especially in patients with MD.

Cognitive effects of unilateral audiovestibular disorders represent an important knowledge gap in our understanding of these disorders. In this exploratory pilot study, UHL, MD and UVH demonstrated differences in cognitive performance compared to controls along domains related to memory and sustained attention that may reflect challenges unique to hearing loss, vestibular loss or a combination. Severity of disease related symptoms, specifically dizziness and tinnitus, may also relate to cognitive performance, especially in patients with MD. Further study exploring the cognitive burden of unilateral audiovestibular disease is warranted.