Evaluation of VEMP Findings in Parkinson’s Patients

Objective: Parkinson’s disease is a progressive neurodegenerative disease characterized by tremor and bradycardia. Parkinson’s, caused by dopamine deficiency, is the second most common neurodegenerative dis ease, affecting 2-3% of the population over 65 years of age. Gender, age and some environmental factors are reported as risk factors for Parkinson’s disease. Vestibular evoked myogenic potentials (VEMP) is an electrophysiological method used to evaluate the integration of otolithic organs and vestibular nerves with the brainstem and musculature. cVEMP evaluates vestibulocolic reflex from saccular afferents to brainstem vestibular nuclei via inferior vestibular nerve, oVEMP evaluates vestibulo-ocular reflex function from the utricle to brainstem vestibular nuclei via the superior vestibular nerve and medial longitudinal fascicle. Abnormalities in VEMP responses have been reported in patients with Parkinson’s in the literature. The aim of this study is to evaluate the results of VEMP in Parkinson’s patients by compiling the literature examining VEMP findings in Parkinson’s patients and to raise awareness on this issue. Materials and Methods: In this study, 24 studies investigating vestibular-evoked myogenic potential findings in Parkinson’s patients, published in PubMed, Web of Science, and Scopus electronic databases between 2009 and 2024, were examined. “Parkinson’s disease, cervical vestibular evoked myogenic potential, ocular vestibular evoked myogenic potential” was used as a key word, and the information obtained from the relevant publications was compiled. Discussion: Although there are studies reporting that there is no difference in VEMP responses between Parkinson’s patients and healthy controls, many studies have reported significantly more abnormalities in vestibular evoked myogenic potential measurements in Parkinson’s patients compared to the control group. In some studies, the rate of not obtaining VEMP responses (cVEMP and oVEMP) was found to be higher in Parkinson’s patients compared to the healthy control group. Many studies have indicated that the latencies of P13 and N23 waves were significantly prolonged in cVEMP measurements in Parkinson’s patients compared to the control group. In patients with Parkinson’s, the mean amplitudes of P13 and N23 were significantly lower in cVEMP measurements than in the control group, and in oVEMP measurement, it was reported that the n1-p1 amplitude was significantly reduced bilaterally in the contralateral of the clinically affected side. Conclusion: When the studies in the literature are examined, it is seen that Parkinson’s disease affects both cervical vestibular evoked myogenic potential and ocular vestibular evoked myogenic potential measurements. These measurements are thought to provide important information in Parkinson’s patients as they evaluate the vestibulocolic and vestibulo-ocular reflex pathways.