P59. Evaluation of representational deficits in neglect patients – Visual search patterns in two different bed side tests

Abstract

Early diagnosis of different modalities in neglect after right hemisphere ischemic lesion and subsequent adequate therapy is crucial in regard to the clinical outcome (e.g. Buxbaum et al., 2004). Bed-side tests in the acute phase after stroke usually include only clinical examination and paper based cancellation tests (e.g. Ota search task, Bell‘s Cancellation). Additional testing such as recording of deficit in visual exploration by tracking of eye movements and standardized test for diagnosis of representational neglect have so far been only conducted in as non-bed-side tests in sub-acute or chronic stages (Isihai et al., 1989). The present study thus investigates the visual exploration during two different tasks in the acute phase of neglect, using a mobile eye-tracking device. Altogether, 31 acute stroke patients with right hemisphere lesion were included. Out of these, 28 could tolerate the eye-tracking device. The first task was a modified baking tray task in which the patients had to collect (first trial) and redistribute (second trial) 16 equally on a tray (modified baking tray Task, Fig. 1a and b; Tham, 1996). For diagnosis of representational deficits a second task consisted of enlisting objects presented on a picture board (third trial, Fig. 2a) and to reproduce the named objects while focussing the white back of the board (fourth trial). The eye movements were tracked during all trials (Fig. 2b and c). Additionally, well-established clinical and paper-based evaluation was carried out. Behavioural results of the modified baking tray task confirm a neglect to the left during collection and redistribution of the cookies ( F =14.710, p F =10.458; p =.004). Enlisting of the objects on the picture board also confirmed a neglect to the left ( F =24.238; p F =48.438; p F =30.221; p Both bedside tests for diagnosis of neglect were proved to be applicable in the very acute phase after ischemic stroke: during collection of the cookies as well as naming and recalling of objects on the picture board, the left space was disregarded. We further demonstrate additional representational deficits in these patients that exceed the deficits in visual neglect. For redistribution of the cookies as well as naming the objects from memory – even though all cookies had been collected before and all objects named before - a stronger deficit to the left was found. Representation of the spatial setup thus seems to be even more biased during intrinsically motivated tasks. Tracking of the visual exploration additionally helped to objectify these results and showed to be, at least partly, applicably in acute bed-side tests. Since the diagnosis of the modality of representational deficits has so far not been investigated in the very acute stage of stroke, only little is known about its development and impact on rehabilitation. Further studies will be necessary on this topic.