Availability of vestibular myogenic evoked potential (VEMP) and blink reflex study in evaluating vestibular pathways of patients with cerebellar and brain stem lesion

Abstract

Patients with cerebellar and brain stem lesions present symptoms of vestibular dysfunction, due to involvement of vestibular pathways. To investigate the relationship and availability of the VEMP and blink reflex study with vestibular pathways, we evaluated patients with cerebellar and brain stem lesion, analyzed the results of VEMP and blink reflex studies, which reflects vestibular dysfunction and vestibular nerve pathways. Sixteen Patients with cerebellar or brain stem stroke diagnosed by MRI were enrolled. VEMP and blink reflex study was performed using Nicolet.Viking IV D ® and DantecKeypointMedtronics ® . Clinical evaluation to check vestibular function and Berg balance scale was conducted. Participants were divided into normal and abnormal groups by comparing P13, N13 latency and amplitude of VEMP and latency difference of R1 and R2 of blink reflex, of the affected side against the sound side. McNemar and Wilcoxon rank sum test was done to confirm the correlation of abnormal VEMP, blink reflex studies and Berg balance test scores. ( P < 0.05). Participants with abnormal blink reflex, 37.5% (3/8) revealed abnormal VEMP results. 50% (3/6) of participants with abnormal VEMP, also revealed abnormal blink reflex results. Among the patients with brain stem lesion, 53.8% (7/13) showed abnormal blink reflex, while 46.2% (6/13) showed abnormal VEMP. There was no statistical correlation with the results of abnormal VEMP and abnormal blink reflex, but tendency of positive correlation was present. Brainstem stroke patients with abnormal blink reflex showed average of 6 in berg balance score, indicating very severe balance impairment, respectively. The tendency of positive correlation of abnormal blink reflex and VEMP suggests the overlap of vestibular pathway and brainstem pathway. This infers the possibility of utilizing VEMP instead of blink reflex as an evaluation tool for brain stem lesion, since the VEMP is more painless and simply conducted than blink reflex. Further study with more participants is needed.