Short-term memory impairment in vestibular patients can arise independently of psychiatric impairment, fatigue and sleeplessness

Vestibular dysfunction is associated with visual short-term memory impairment, however, it remains unclear if this impairment arises as a direct result of the vestibular dysfunction or is a consequence of comorbid changes in mood, affect, fatigue and/or sleep. To this end, we assessed the concurrence and inter-dependence of these comorbidities in 101 individuals recruited from a tertiary balance clinic with a neuro-otological diagnosis. Over fifty percent of the sample showed reduced visuospatial short-term memory, 60% and 37% exceeded cut-off on the Beck Anxiety and Depression Inventories respectively, 70% exceeded cut-off on the Fatigue Severity Scale, 44% reported daytime sleepiness on the Epworth Sleepiness Scale, and 78% scored above cut-off on the Pittsburg Sleep Quality Index. The high concurrence of these symptoms give reason to infer the existence of a vestibular cognitive affective syndrome. Structural equation modeling indicated that the significant statistical association between general unassisted posture (a marker of chronic vestibular dysfunction and strong predictor of falls risk) and short-term memory was not mediated by mood and wakefulness. Instead, the memory impairment related more directly to vestibular dysfunction. From a rehabilitation perspective, the implication is that if the vestibular disorder is treated successfully then the memory problem will likewise improve.