| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 3044682 | Clinical Neurophysiology | 2013 | 10 Pages |
ObjectiveTo explore the galvanic-evoked vestibulospinal reflex in health and disease.MethodsVestibular-evoked whole-body movement was measured in 60 controls and eight patients with bilateral vestibular impairment, using 1 mA × 2 s Galvanic Vestibular Stimulation (GVS). The displacement (s) and velocity (v) of 7 markers placed on the head, neck, shoulders, mid-thorax and hips and ground reaction forces (F) were recorded.ResultsMonaural GVS evoked anterolateral whole-body movement away from the cathode. For controls, peak response magnitudes were 22.3 ± 12.4 mm, 25.9 ± 14.3 mm s−1 and 3.2 ± 1.3 N for s, v and F. Left right asymmetry measured using the Jongkee’s formula was 12.59 ± 8.64%, 11.94 ± 11.09% and 11.68 ± 8.99% for s, v and F. All three measures were symmetrical for left and right mastoid stimulation and showed good to excellent test retest reliability. Patients with bilateral vestibular failure had absent or attenuated responses. For this patient group, the (“R/B”) ratios between the “response period” and baseline body-sway for s, v and F were 2.1 ± 0.8, 1.7 ± 1.1 and 1.3 ± 0.6, which were significantly lower than 5.4 ± 4.2, 4.1 ± 2.5 and 2.3 ± 0.8 for controls, with s and v providing better separation between controls and patients. There were no significant correlations between the amplitudes of galvanic body sway responses and vestibular-evoked myogenic potentials (VEMPs).ConclusionGVS enables non-invasive assessment of the vestibulospinal reflex.SignificanceThis method offers a clinically applicable, test of vestibular contributions to standing balance.
► Low intensity galvanic stimulation evokes a stereotyped anterolateral whole-body sway response that is robust, symmetrical and shows good to excellent test retest reliability. ► There is a small but significant attenuation in galvanic body sway with age and no relationship between sway amplitudes and VEMP amplitudes. ► Bilateral vestibular hypofunction is associated with markedly attenuated galvanic body sway responses confirming their vestibular origin.
