Vestibular-evoked myogenic potentials and subjective visual vertical testing in patients with vitamin D...

Otolith function in subjects with vitamin D deficiency/insufficiency is investigated through vestibular-evoked myogenic potentials (VEMP) and subjective visual vertical (SVV) testing. The study group included 62 patients with vitamin D deficiency/insufficiency (30 females, 32 males), with age range 24-56 years (40.6 ± 9.1). The control group included 44 healthy volunteers of similar age and gender distribution. The entire study group had: (1) serum level of 25-hydroxyvitamin D <30 ng/ml; (2) normal bone mineral density as indicated by dual-energy X-ray absorptiometry with T-score >-1; (3) normal middle ear function; (4) Age is ≤60 years. All subjects enrolled in the current study underwent audiovestibular evaluation consisting of pure-tone audiometry, immittancemetry, cervical VEMP (cVEMP), ocular VEMP (oVEMP), and SSV. The entire control group had normal cVEMP, two subjects had abnormal oVEMP. Thirty-three subjects (53%) in the study group had abnormal oVEMP and 31 subjects (50%) had abnormal cVEMP. Forty-one (66%) had abnormal VEMP when abnormal VEMP was considered as either abnormal oVEMP or cVEMP. The entire control and study groups had normal SSV test results. Vitamin D deficiency may be associated with development of otolith dysfunction affecting both the utricle and saccule. This was suggested by the high prevalence of abnormal ocular vestibular-evoked myogenic potentials (oVEMP) and cervical vestibular-evoked myogenic potentials (cVEMP) in the study group.