Computerized Dynamic Posturography does not detect measured CVEMP and OVEMP abnormalities

Computerized Dynamic Posturography (CDP)was developed by the American space program to assess imbalance in astronauts, and eventually evolved into a clinical diagnostic tool. However it is not a specific measure of vestibular function. Vestibular Evoked Myogenic Potential testing (VEMPs) is a new clinical tool which is sensitive and specific for measuring otolithic pathology, especially in the atypical vestibular patient.

As posturography measures ability to maintain balance, and VEMP testing measures the structures responsible for this, we wondered if CDP results would correlate with VEMP abnormalities in the clinical setting.

We analysed 180 patients sequentially referred to our unit for vestibular complaints. All patients had a full battery of vestibular assessments. We correlated VEMP results with CDP results to look for abnormality patterns and correlations. An occasional patient's only abnormality was on CDP RESULTS: There was a high rate of VEMP abnormalities seen, which correlates with the fact that our referral base consists of patients with chronic vestibular complaints. The rate of VEMP abnormalities was the same in patients with normal CDP and those with abnormal CDP.

Our results do not suggest that CDP is unnecessary, but we feel that they emphasize the idea that these tests are measuring two different aspects of balance control. In some patients, all assessments are abnormal, but in some patients only one assessment is abnormal, suggesting that these modalities measure different things and are all important in the diagnostic armamentarium. Hopefully in the near future, the use of virtual reality will reduce the cost of CDP to the point where it can be made widely accessible to patients and clinicians.