Vestibular Evoked Myogenic Potentials in Patients With Low Vitamin B12 Levels

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.

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.

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).

Increased rates of absent VEMPs and decreased amplitudes with normal latencies are attributed to peripheral vestibular hypofunction in patients with vitamin B12 deficiency.