Objectives: To explore the usefulness of vestibular tests including "vestibular evoked myogenic potentials" (VEMPs) and the video head impulse test (vHIT) in the early diagnosis of "idiopathic Parkinson's disease" (PD).
Materials and methods: The study involved 80 participants including 40 patients (24 males, 16 females; age average 63.20 ± 7.94 years) with PD and 40 healthy individuals (18 males and 22 females; age average of 60.36 ± 7.68 years). The Modified Hoehn and Yahr (H&Y) scale was used to measure how Parkinson's symptoms progress and the level of disability. Patients with PD underwent cVEMPs, oVEMPs, and vHIT and the results were compared with those of 40 age-matched healthy control (HC) subjects. vHIT results and VEMP responses were registered in all patients and HCs.
Results: One-sided absent cVEMP responses were found in 6 (15%) patients with PD and 8 (20%) patients had bilaterally absent responses. Five (12.5%) patients had 1-sided absent oVEMP responses and it was bilateral in 6 (15%). Patients with PD had significantly shorter cVEMP P1, N1 latency, lower cVEMP amplitudes, and oVEMP amplitudes than the HC group. The cVEMP and oVEMP amplitude asymmetry ratio was significantly higher in the PD group (P < .05). Evaluation of vHIT results and vestibular-ocular reflex (VOR) gain between the groups revealed that anterior canal and posterior canal VOR gains results were remarkably lower in the PD group than in the HCs (P < .05). There was no difference in right and left lateral canal VOR gains between the groups (P > .05).
Conclusion: The results of this study suggest that cVEMP and vHIT can be used to evaluate the vestibular system in patients with early-stage Parkinson's disease.
Keywords: Parkinson’s disease; cervical vestibular evoked myogenic potential; ocular vestibular evoked myogenic potential; video head impulse test.