Association between vestibular evoked myogenic potentials and different dizziness status in Parkinson's disease: A controlled study.

Objective: This study compared ocular and cervical vestibular evoked myogenic potentials (oVEMP and cVEMP) among individuals with Parkinson's disease (PD) without dizziness, with nonspecific dizziness (dizziness without orthostatic hypotension), or with dizziness combined with orthostatic hypotension.

Materials And Methods: We prospectively analyzed 30 of each of the three types of individuals who were admitted to Yongchuan Hospital of Chongqing Medical University (Chongqing, China) between June 2022 and April 2023. The three groups received oVEMP and cVEMP measurements using an electromyography-evoked potential system. For oVEMP, the N10 latency, P16 latency, and amplitude were compared between the three groups and the reference values. For cVEMP, the P13 latency, N23 latency, and amplitude were compared between the three groups and the reference values. Overall characteristics of oVEMP and cVEMP were also assessed using a previously published scoring scale originally developed for individuals with multiple sclerosis between the three groups included. The correlation between VEMP parameters (the latency and amplitude) and VEMP scores were simultaneously analyzed using Pearson's bivariate correlation analysis.

Results: When compared with reference values, the oVEMP and cVEMP parameters of all three groups were found to be slightly different from the reference values. When the three groups included were compared with each other, in terms of oVEMP, the average amplitude in the left eye was significantly higher in those with nonspecific dizziness than in the other two groups. In terms of cVEMP, the average N23 latency on both the right and left sides of the neck and average amplitude on the right side of the neck were significantly higher in those with nonspecific dizziness than in the other two groups. Scores for oVEMP and cVEMP were also significantly higher for those with nonspecific dizziness than for the other two groups. There were no significant differences in oVEMP and cVEMP parameters, and scores for oVEMP and cVEMP between patients with dizziness combined with orthostatic hypotension and those without dizziness. In terms of correlation analysis, the N23 latency of left neck (r = 0.509, p < 0.001), the N23 latency of right neck (r = 0.495, p < 0.001), and the amplitude of right neck (r = 0.304, p = 0.004) correlated positively with cVEMP score.

Conclusions: Patients with PD without dizziness, with dizziness attributable to orthostatic hypotension, and with nonspecific dizziness may be all associated with vestibular dysfunction. The VEMP scores were highest in patients with nonspecific dizziness, so vestibular function is more severely affected in patients with nonspecific dizziness. The VEMP especially cVEMP may be useful for early diagnosis of nonspecific dizziness in PD.