Efficacy of home-based visuomotor feedback training in stroke patients with chronic hemispatial neglect.

Hemispatial neglect is a severe cognitive condition frequently observed after a stroke, associated with unawareness of one side of space, disability and poor long-term outcome. Visuomotor feedback training (VFT) is a neglect rehabilitation technique that involves a simple, inexpensive and feasible training of grasping-to-lift rods at the centre. We compared the immediate and long-term effects of VFT vs. a control training when delivered in a home-based setting. Twenty participants were randomly allocated to an intervention (who received VFT) or a control group (n = 10 each). Training was delivered for two sessions by an experimenter and then patients self-administered it for 10 sessions over two weeks. Outcome measures included the Behavioural Inattention Test (BIT), line bisection, Balloons Test, Landmark task, room description task, subjective straight-ahead pointing task and the Stroke Impact Scale. The measures were obtained before, immediately after the training sessions and after four-months post-training. Significantly greater short and long-term improvements were obtained after VFT when compared to control training in line bisection, BIT and spatial bias in cancellation. VFT also produced improvements on activities of daily living. We conclude that VFT is a feasible, effective, home-based rehabilitation method for neglect patients that warrants further investigation with well-designed randomised controlled trials on a large sample of patients.

The neural basis of visuomotor deficits in hemispatial neglect.

We have recently reported that patients with hemispatial neglect demonstrate increased terminal errors when performing delayed leftward reaches and that right-brain damaged patients (irrespective of neglect) take longer to complete their movements [Rossit, S., Muir, K., Reeves, I., Duncan, G., Birschel, P., & Harvey, M. (2009). Immediate and delayed reaching in hemispatial neglect. Neuropsychologiaa 47, 1563-1573]. Here we conducted an initial voxel-based lesion-symptom analysis to examine the neural basis of such deficits in 21 right-brain damaged subjects with 11 patients suffering from hemispatial neglect (2 more than in Rossit et al. [Rossit S., Muir K., Reeves I., Duncan, G., Birschel, P., & Harvey, M. (2009). Immediate and delayed reaching in hemispatial neglect. Neuropsychologia 47, 1563-1573] and 10 control patients without the condition. We found that the accuracy impairments in delayed leftward reaches were associated with damage to occipito-temporal areas. In contrast, the movement time slowing was related to more anterior lesions in the frontal lobe. These findings agree with the view that neglect affects actions thought to depend on the processing carried out by the ventral visual stream. In addition, we suggest that the timing impairments which are not neglect-specific maybe be driven by frontal structures.

Immediate and delayed reaching in hemispatial neglect.

Milner and Goodale (The visual brain in action, Oxford: Oxford University Press, 1995; The visual brain in action, 2nd ed., Oxford: Oxford University Press, 2006) propose a model of vision that makes a distinction between vision for perception and vision for action. One strong claim of the model is that the dorsal stream's control of action is designed for dealing with target stimuli in the 'here and now', yet when time is allowed to pass and a reaction has to be made on the basis of a visual memory, the ventral stream is required for successful performance. Regarding the syndrome of hemispatial neglect, Milner and Goodale further claim that the visual dorsal stream is relatively spared in these patients. In the current study we tested whether neglect patients would indeed be unimpaired in immediate pointing, yet show inaccurate pointing in a condition where a delay is interposed between the presentation of the stimulus and the response signal (in particular in left space). We tested the ability of nine neglect patients (and healthy and right hemisphere no neglect control groups) to perform reaches towards immediate and delayed targets, placed in left, central and right locations. Neglect patients showed no accuracy impairments when asked to perform an immediate action. Conversely, when pointing towards remembered leftward locations, they markedly overshoot the target or failed to initiate a reach altogether. These results confirm that patients with neglect are not specifically impaired when performing 'here and now' actions, but rather present deficits when the visuomotor task taps into more perceptual 'off-line' representations thought to depend on ventral visual stream activation.

Progressing stroke: towards an internationally agreed definition.

BACKGROUND: The study of early neurological deterioration (progression) in acute stroke has been hampered by a lack of standardisation in the terminology or assessment procedures. An international panel was therefore convened, to agree on robust operational definitions for future studies and to validate them in an observational study involving 10 centres from the European Stroke Database Collaboration. METHODS: Standardised neurological assessments were performed daily for the first 3 days on patients with acute stroke, consecutively admitted within 24 h of onset, using the Scandinavian Stroke Scale (SSS) scoring system. An early deterioration episode (EDE) was defined as a >/=2 SSS-point worsening in either conscious level, arm, leg or eye movement scores, and/or a >/=3 SSS-point worsening in speech score, between consecutive neurological assessments. Stroke progression (SP) was defined as a similar neurological worsening comparing the day 3 assessment with the baseline assessment, or death occurring within 72 h of onset. The ability of SP to predict poor outcome (death or a Barthel ADL score <15/20 at 3 months), independently of initial stroke severity or other prognostic factors, was compared with possible alternative definitions, including one based on the Canadian Stroke Scale. RESULTS: The occurrence of EDEs and SP within the first 3 days of admission could be determined in 563 cases. EDEs occurred in 33% and SP in 26% of cases. Both were strong independent predictors of poor outcome. The prognostic efficiency of the European Progressing Stroke Study (EPSS) definition of SP was better than any of the alternatives examined, and clearly better than a definition based on changes in the total SSS score. CONCLUSIONS: The EPSS definitions of EDEs and SP have good construct and prognostic validity. They can be recommended as a standard for future studies on the aetiology and mechanisms of this common and important phenomenon.