Vestibular evoked myogenic potentials in definite multiple sclerosis
Patients with definite multiple sclerosis frequently suffer from vestibular disorders due to a vestibulo-oculomotor and vestibulospinal systems involvement.
The vestibulospinal reflexes in these subjects can be well investigated through the vestibular evoked myogenic potentials recording.
These potentials, evoked by the acoustic stimulation of the saccular macula and mediated by vestibulocollic reflex pathway, are recorded using surface electromyographic electrodes from the ipsilateral sternocleidomastoid muscle tonically contracted.
Abnormal findings (e.g. absence of response, prolonged latencies etc.) disclose a lesion anywhere in the pathway.
Vestibular potentials were examined in 19 patients (5 men, 14 women; aged 17-71 years; mean age ± SD: 45 ± 14 years) with definite multiple sclerosis to search for lesions in the vestibulospinal pathways.
The response was found abnormal in 14 subjects, absent ( on the left side only) in one of them, normal in the other 4 ones.
These results suggest that latencies of vestibulospinal reflexes can be remarkably delayed in multiple sclerosis.
The paper, after describing the neurophysiological data on which Vestibular potentials recording is based, underlines the usefulness of the test to evaluate the vestibulospinal system function and for monitoring the evolution of the disease in patients afflicted with definite multiple sclerosis.