Cervical Vestibular Evoked Myogenic Potentials in Idiopathic Parkinson Disease

Aim: Postural instability is one of the main characteristic of idiopathic Parkinson's disease (iPD) with unknown cause. The aim of this study is to investigate the role of vestibular system in postural instability by using a modality, cervical vestibular evoked myogenic potentials (cVEMP). Methods: iPD group consisted of 20 patients, 11 female and 9 male, mean age 63,9+/- 10(43-84) years and control group 30 healthy volunteers, 16 males and 14 females, mean age 57,5 +/- 10,5(36-78) years, without any neurological or otological diseases. The mean duration of disease was 8,2 +/- 4,5(3-18) years and twelve of them (60 %) were evaluated as Hoehn-Yahr stage II and remaining as stage III (40 %). In both groups, bilateral sVEMP recordings were done in all individuals. Results were evaluated with SPSS program 12.0 version. Results: For all individuals in both control and iPD groups bilateral cVEMP recordings could be performed (100 %). There were no differences between groups in terms of amplitude and positive wave latency; however, a significantly shortened negative wave latency was found in iPD group (p<0.001). When the effect of age was removed with covariance analysis this difference was still significant (p=0.025). Discussion: Our findings indicate that duration of cVEMP responses was shortened in iPD group. The structures which play a role in PD pathogenesis, interacting with the component of vestibulocollic reflex(VCR) formation. cVEMP responses are the manifestation of VCR and they can provide objective data for evaluation of postural instability and severity.