RT Journal Article
SR Electronic
T1 Adaptive motion processing in bilateral vestibular failure
JF Journal of Neurology, Neurosurgery & Psychiatry
JO J Neurol Neurosurg Psychiatry
FD BMJ Publishing Group Ltd
SP 1212
OP 1216
DO 10.1136/jnnp.2010.235960
VO 82
IS 11
A1 Roger Kalla
A1 Neil Muggleton
A1 Rainer Spiegel
A1 Domenica Bueti
A1 Jens Claassen
A1 Vincent Walsh
A1 Adolfo Bronstein
YR 2011
UL http://jnnp.bmj.com/content/82/11/1212.abstract
AB Background Patients with bilateral vestibular failure (BVF) suffer from oscillopsia during head movements. This is secondary to the loss of the vestibulo-ocular reflex which is responsible for stabilising retinal images during head movements of high frequency or velocity. Previous studies documented decreased visual motion sensitivity in such patients at low velocities. The authors now examine motion coherence tasks, which have two advantages: (1) the task is associated with the functions of the middle temporal area; and (2) it affords testing at low and high motion velocities, as relevant for patients with oscillopsia due to BVF.Methods Nine BVF patients and nine healthy control subjects were examined with a random dot pattern with variable percentages of dots moving in the target direction. Participants were asked to indicate in which of two possible directions they perceived the coherent motion. Horizontal and vertical planes were tested at speeds from 0.156 to 40°/s.Results Motion coherence thresholds were lower at higher speeds in both groups (p<0.0001). BVF patients had raised motion coherence thresholds (p=0.002) across all velocities as compared with the control subject group.Conclusion In a motion coherence paradigm, BVF patients show raised thresholds. This is the first demonstration of diminished visual motion processing at high velocities, supporting the view that the changes allow BVF patients to partly compensate for the oscillopsia. The findings are interpreted as an adaptive process likely to involve the middle temporal visual motion processing areas.