Galvanic evoked vestibulospinal and vestibulocollic reflexes in stroke.
OBJECTIVE
Following stroke, the startle reflex, mediated via the reticulospinal tract, is often facilitated. Vestibulospinal reflexes are another bulbospinal reflex, abnormalities of which may contribute to impaired body posture and stance following stroke. We recorded galvanic evoked vestibulospinal and vestibulocollic reflexes to assess whether these showed similar changes to those for startle following stroke affecting the pons and above.


METHODS
Twenty-four stroke subjects (aged 40-82) were studied in the vestibulospinal part of the study, 21 stroke subjects (aged 40-81 years) were studied in the vestibulocollic part, including 18 studied in both. Transmastoid galvanic (DC) current was used to stimulate the vestibular nerve. Vestibulocollic responses were recorded from the sternocleidomastoid muscles and vestibulospinal responses from over soleus in standing subjects.


RESULTS
Vestibulocollic reflex amplitudes and latencies showed no significant differences between the two sides. Similarly short latency (SL) and medium latency (ML) vestibulospinal reflexes did not differ significantly in frequency, latency or amplitude between the affected and unaffected legs.


CONCLUSIONS
Vestibular reflexes are not facilitated by stroke at or above the pontine level. The exaggeration of startle by stroke may be specific to this reflex.
Jankelowitz
S K
SK
Department of Neurology, Institute of Neurological Sciences, Prince of Wales Hospital, Sydney 2031, Australia.
Colebatch
J G
JG
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D004558:Electric Stimulation / Q000379:methods; D005260:Female; D005712:Galvanic Skin Response / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013216:Reflex, Startle / Q000502:physiology*; D013116:Spinal Cord / Q000502:physiology*; D020521:Stroke; D014725:Vestibular Nerve / Q000502:physiology*; D014722:Vestibule, Labyrinth / Q000502:physiology*