Vestibular Evoked Myogenic Potentials in Patients With Low Vitamin B12 Levels.

Objective: Vitamin B12 deficiency-induced hyperhomocysteinemia has been associated with impaired microarterial flow, demyelization, and neuronal damage, resulting in cochlear damage and auditory dysfunction. Therefore, we aimed to evaluate the possible vestibular-evoked myogenic potential (VEMP) abnormalities in patients with vitamin B12 deficiency.
Material and Method: In this prospective study, 37 patients diagnosed with vitamin B12 deficiency (<220 pg/mL) were compared with 31 audiologically healthy participants with normal B12 levels. Burst-evoked cervical VEMP (cVEMP) measurements were performed on all participants. Additionally, cVEMP responses were analyzed for P1-N1 latency, interpeak amplitude, and amplitude asymmetry ratio. The results of audiometric examination and VEMP records as well as absent responses were evaluated and compared between groups.
Results: The rate of absent VEMP responses was twice as high in the patient group than in the healthy control group (12 vs 6 cases, respectively). Moreover, the mean values of interpeak amplitude in both right and left ears were statistically shorter in the patient group than the control group ( P values = .024 and .007, respectively). Similarly, the mean amplitude asymmetry ratio was statistically higher in the patient group than the control group ( P = .050). There were no statistically significant differences in latency responses between groups. Furthermore, positive, statistically significant correlation was detected between values of the left P1-N1 interpeak amplitude and vitamin B12 levels ( r = 0.287, P = .037).
Conclusions: Increased rates of absent VEMPs and decreased amplitudes with normal latencies are attributed to peripheral vestibular hypofunction in patients with vitamin B12 deficiency.