Residual oculomotor and exploratory deficits in patients with recovered hemineglect.
Several studies on hemineglect have reported that patients recover remarkably well when assessed with neuropsychological screening tests, however, they show deficits on novel or complex tasks. We investigated whether such deficits can be revealed with eye movement analysis, applying two basic oculomotor tasks as well as two exploratory tasks. Eye movements were recorded in eight hemineglect patients at least eleven months after right-hemisphere brain damage had occurred. Sixteen healthy volunteers participated in the control group. Regarding the basic oculomotor tasks, only the overlap task revealed residual deficits in patients, suggesting that a directional deficit in disengaging attention persisted during recovery. Further residual deficits were evident in the exploratory tasks. When everyday scenes were explored, patients showed a bias in early orienting towards the ipsilateral hemispace. In a search task, they demonstrated the same orienting bias as well as a non-directional deficit concerning search times. Moreover, patients preferentially fixated in the contralateral hemispace, but did not benefit from this asymmetry in terms of search times, i.e. they did not detect contralateral targets faster than ipsilateral ones. This suggests a dissociation between oculomotor processes and attentional ones. In conclusion, we have identified behavioural aspects that seem to recover slower than others. A disengagement deficit and biases in early orienting have been the most pronounced residual oculomotor deficits.
Pflugshaupt
Tobias
T
Departments of Neurology and Clinical Research, Perception and Eye Movement Laboratory, University of Berne, Inselspital, Freiburgstrasse 10, 3010 Berne, Switzerland.
Bopp
Stefanie Almoslöchner
SA
Heinemann
Dörthe
D
Mosimann
Urs P
UP
von Wartburg
Roman
R
Nyffeler
Thomas
T
Hess
Christian W
CW
Müri
René M
RM
D000328:Adult; D001288:Attention / Q000502:physiology*; D001925:Brain Damage, Chronic / Q000503:physiopathology; D005106:Exploratory Behavior / Q000502:physiology; D005133:Eye Movements / Q000502:physiology*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D016555:Matched-Pair Analysis; D008875:Middle Aged; D009483:Neuropsychological Tests; D009801:Oculomotor Muscles / Q000503:physiopathology; D010364:Pattern Recognition, Visual / Q000502:physiology; D010468:Perceptual Disorders / Q000175:diagnosis* / Q000503:physiopathology; D020127:Recovery of Function; D012016:Reference Values; D013037:Spatial Behavior / Q000502:physiology; D014796:Visual Perception / Q000502:physiology*