Cognitive function is preserved in episodic vestibular disorders
Reviewed by Victor Osei-Lah

Cognitive deficit in bilateral vestibular failure in particular, but also in unilateral vestibular failure, is well documented. The authors designed this prospective study to determine if deficits in cognition, as well as anxiety and depression, were present in episodic vestibular disorders in the absence of permanent loss of vestibular function. The two episodic disorders studied were vestibular migraine (VM) and Ménière’s disease (MD). Nineteen adult patients with VM and 19 with MD were included in the study, matched by age, sex and level of education, with 21 healthy controls. They were all subjected to a full neurotological examination and bithermal air caloric tests. In the MD group, eight patients were on prophylaxis, four have had transtympanic steroids, two have had gentamicin treatment, and five were not on medications. In the VM group, 12 were on prophylaxis and seven were not. Median attack frequency was 18/year (range: 8–32) in the MD group and 20/year (range: 10–36) in the VM group at the time of testing. Cognitive and emotional testing was done using several well-validated instruments and questionnaires (Mini Mental State Examination, Reading Span Test, Stroop Test, Benton’s Judgment of Line Orientation Test and Trail Making Test – BJLOT and Beck’s anxiety and depression scale). In all patients, bedside head impulse, ocular motor, positional and caloric tests were normal during the interictal period, as they were in the healthy controls. Statistically, there were no differences between the three groups in the cognitive and emotional tests, as well as Beck’s depression scales. However, Beck’s anxiety scores were significantly higher in the VM group compared with healthy controls. The authors concluded that cognitive function is preserved in VM and MD when there is no vestibular dysfunction during the interictal period. High anxiety levels were present in VM patients but not in the MD patients. The authors did not offer any specific reason except to refer to previous cross-sectional studies showing that anxiety levels were highest in VM and vestibular paroxysmia (36%) followed by MD (28%), compared with low levels of anxiety in patients with bilateral vestibular failure. It has been postulated that a functioning peripheral vestibular system is important in the development of anxiety in patients with vertigo. Limitations of the study such as small numbers and the limited use of objective vestibular function tests were discussed.

Cognitive functions in episodic vestibular disorders: Meniere’s disease and vestibular migraine.
Demirhan MA, Celebisoy N.
J VESTIB RES
2022;33(1):63-70.