Hemianopia and neglect influence on straight-ahead perception.

In spatial neglect, the pathological ipsilesional deviation of the subjective straight ahead (SSA) received both 'translational' and 'rotational' interpretations. Furthermore, hemianopia per se could also influence straight-ahead (SA) perception. Here, we aimed at disentangling the relative effects of neglect and hemianopia on the SSA by using a method analyzing translation and rotation in parallel. We included patients with a right hemisphere stroke. Ten had neglect and hemianopia, 6 neglect only, 3 hemianopia only, and 12 neither one nor the other. 15 were controls. Participants had to adjust a bar, movable in translation and rotation, SA of the navel, in darkness. Patients with spatial neglect showed systematic rightward translation, greater when hemianoptic. The rotation component appeared more variable and was influenced by the presence of a visual field defect, as most of the patients with hemianopia showed an anticlockwise rotation and most of the patients without hemianopia a clockwise rotation. Non-neglect patients and control subjects demonstrated a fair performance level. In conclusion, both neglect and hemianopia resulted in a translation error of the SSA to the ipsilesional side. In neglect patients, additional hemianopia resulted in a counterclockwise rotation. Furthermore, rotation and translation errors appeared dissociated, suggesting a different coding of these dimensions by the right posterior hemisphere.

Reducing rightward bias of subjective straight ahead in neglect patients by changes in body orientation.

BACKGROUND: The subjective straight ahead (SSA), a measure of the representation of body orientation, has been shown to be shifted to the lesion side in neglect patients, and to be influenced by stimulation of sensory systems involved in postural control. METHOD: This study investigates the influence of changing body orientation in the sagittal plane on the SSA in 21 patients with a right hemispheric lesion, of whom 12 had neglect, in comparison with six healthy control subjects. In order to quantify both horizontal components of SSA error (ie, yaw rotation and lateral shift), the study used a method requiring the alignment of a luminous rod with SSA. RESULTS: Neglect patients showed a significant rightward shift in the sitting position, which was greatly reduced in the supine position. No shift occurred in patients without neglect or in controls. Yaw rotation did not reach significance in any group. CONCLUSION: The data showed that the body centred frame of reference, mostly translated in neglect, is strongly improved in the supine position. Changing body orientation seems to be a convenient tool to correct the representation of body midline.

Where is the "straight ahead" in spatial neglect?

We investigated the subjective straight-ahead (SSA) projection of body-midline parts (head and trunk) in patients with neglect and patients with nonneglect, using a method disentangling lateral shift and lateral tilt components of the bias. Patients with neglect showed a similar counterclockwise SSA tilt for each body part and an ipsilesional lateral shift, more severe for the trunk than for the head. Thus, neglect results in a tilt of the body midline representation.

Right spatial neglect after left hemisphere stroke: qualitative and quantitative study.

OBJECTIVES: Comparatively little research has been conducted on right neglect after left brain damage. The authors sought to assess contralateral neglect in subacute left hemisphere stroke patients using a comprehensive test battery validated in a large control group after right hemisphere stroke. METHODS: Seventy-eight left hemisphere stroke patients were assessed. The test battery included a preliminary assessment of anosognosia and visual extinction, a clinical assessment of gaze orientation and personal neglect, and paper-and-pencil tests of spatial neglect in the peripersonal space. Only nonverbal tests were used. RESULTS: Drawing and cancellation tasks revealed neglect in 10 to 13% of patients. The combined battery was more sensitive than any single test alone. A total of 43.5% of patients showed some degree of neglect on at least one measure. Anatomic analyses showed that neglect was more common and severe when the posterior association cortex was damaged. CONCLUSIONS: The frequency of occurrence of right neglect was, as expected, much lower than that reported in a study using the same assessment battery in right brain damage stroke patients. Nevertheless, neglect was found in a substantial proportion of patients at a subacute stage, suggesting that it should be considered in the rehabilitation planning of left brain damage stroke patients.

Sensitivity of clinical and behavioural tests of spatial neglect after right hemisphere stroke.

OBJECTIVES: The lack of agreement regarding assessment methods is responsible for the variability in the reported rate of occurrence of spatial neglect after stroke. The aim of this study was to assess the sensitivity of different tests of neglect after right hemisphere stroke. METHODS: Two hundred and six subacute right hemisphere stroke patients were given a test battery including a preliminary assessment of anosognosia and of visual extinction, a clinical assessment of gaze orientation and of personal neglect, and paper and pencil tests of spatial neglect in the peripersonal space. Patients were compared with a previously reported control group. A subgroup of patients (n=69) received a behavioural assessment of neglect in daily life situations. RESULTS: The most sensitive paper and pencil measure was the starting point in the cancellation task. The whole battery was more sensitive than any single test alone. About 85% of patients presented some degree of neglect on at least one measure. An important finding was that behavioural assessment of neglect in daily life was more sensitive than any other single measure of neglect. Behavioural neglect was considered as moderate to severe in 36% of cases. A factorial analysis revealed that paper and pencil tests were related to two underlying factors. Dissociations were found between extrapersonal neglect, personal neglect, anosognosia, and extinction. Anatomical analyses showed that neglect was more common and severe when the posterior association cortex was damaged. CONCLUSIONS: The automatic rightward orientation bias is the most sensitive clinical measure of neglect. Behavioural assessment is more sensitive than any single paper and pencil test. The results also support the assumption that neglect is a heterogeneous disorder.

[Presenting a battery for assessing spatial neglect. Norms and effects of age, educational level, sex, hand and laterality]. / Présentation d'une batterie de dépistage de la négligence spatiale. Normes et effets de l'âge, du niveau d'éducation, du sexe, de la main et de la latéralité.

The aim of this study was to build up a battery for assessing spatial neglect, then to analyse the norms and potential effects of age, education level, sex, hand used, and laterality. It was also to contribute evaluating the pseudoneglect phenomenon described by Heilman, which consists in a tendency of normal subjects to neglect the right peripersonal space. Tasks selected were presented to important groups of normal subjects, most often larger than 450. The battery comprised of a bell cancellation test, scene copy, clock drawing, two line bisection tasks, identification of overlapping figures, text reading, writing task, and the representational task of the France map. For each of them, different variables were selected, especially investigating the difference between performance in the right and the left hemispaces. This study allowed defining the threshold values (percentiles 5 and 95) for deciding of the pathological character of a patient performance. It also showed that the pseudoneglect phenomenon is more obvious in some tasks such as line bisection, and probably also in the representational task of the France map and writing. His importance and at times his side were influenced by the factors we studied, with between tasks differences, but also by the nature of the task to be performed, and especially his verbal component.

[Neuropsychological correlates of cerebral blood flow anomalies and MRI lesions after rupture of anterior communicating artery aneurysms]. / Corrélations neuropsychologiques des anomalies du débit sanguin cérébral et des lésions IRM après rupture des anévrysmes de l'artère communicante antérieure.

The aim of this study was to investigate relations between neuropsychological disorders resulting from rupture of aneurysms of the anterior communicating artery, regional cerebral blood flow anomalies and brain lesions revealed on MRI. Blood flow was analyzed in 22 consecutive patients at least 3 weeks after surgery using single photon emission computed tomography. Flow values were calculated in 10 regions of interest on each side of the brain. Attention, motor control, executive functions, short-term and long-term learning (verbal, visuo-spatial), categorical evocation, general intellectual performances were investigated. Flow drop was observed over frontal areas, which predominated on the right side. The correlation analyses showed that

[Residual deficit of verbal recall after a left internal cerebral vein infarct]. / Déficit résiduel du rappel verbal après un infarctus de la veine cérébrale interne gauche.

A case of unilateral infarct in the territory of the left internal cerebral vein, severely disturbing cognitive processes, and more especially recall in verbal memory, is reported. This 22-year-old patient survived a left thalamic and striato-capsular infarct related to a straight sinus and left internal cerebral vein thrombosis. Motor and functional recovery was fair, despite late dystonia. At the secondary phase post-stroke, cognitive disorders were severe, including increased short-term forgetting and episodic (anterograde and retrograde) and semantic amnesia. One year later, a residual deficit of verbal recall was observed, which participated in the anterograde and retrograde amnesia. Recognition was well preserved. This case showed that: (1) internal cerebral vein thrombosis can have severe consequences on cognition and memory, and that late prognosis is not as fair as has been previously reported in selected patients, and (2) left diencephalic structures are specifically associated with recollection of verbal information from long-term memory.

[Retrograde memory after rupture of aneurysms of the anterior communicating artery]. / La mémoire rétrograde après rupture des anévrysmes de l'artère communicante antérieure.

The aim of this study was to investigate deficits of retrograde memory, semantic, autobiographical, and for famous events, associated with prefrontal, cingulate and subcortical lesions resulting from anterior communicating artery rupture. Analyses were performed during the secondary phase post-stroke in 16 patients, and performances were compared to those of an equivalent number of matched control subjects. Semantic investigations revealed a significant deficit in each task using evocation, more especially categorical and literal evocations, and the verbal subtests of the WAIS-R: vocabulary, information, comprehension, and similarities. Furthermore, the capacity to categories was preserved. The Crovitz paradigm, which evaluated the autobiographical memory showed a severe deficit in the evocation of events associated with a precise context in place and moreover in time, with a clear tendency to produce semantic responses, but without significant increase in confabulations. The questionnaire on famous events (1936-1985) did not document deficit in recognition and recall. Furthermore, the patients disorder was more severe in learning new information. Memory disorders were best explained by the severity of lesions in the medio-basal frontal and cingulate cortices, but also by the subcortical injury. Significant correlations were observed between the retrograde memory performance and "frontal" tasks, more especially the WCST; however, similar relations were also documented between learning new information and "frontal" performance. These data suggest that retrograde amnesia results from a selective impairment in accessing old memory representations, and that cognitive processes more specifically altered have tight relations with the capacity to organize the search and to shift.

[Dysexecutive syndrome and disorders of motor control in prefrontal mediobasal and cingulate lesions]. / Syndrome dysexécutif et troubles du contrôle moteur dans les lésions préfrontales médio-basales et cigulaires.

Disorders of executive function and motor control are considered to be classical consequences of prefrontal lesions. The aim of this study was to investigate these disorders and their evolution in a series of patients presenting with prefrontal and cingulate lesion following rupture of an anterior communicating artery aneurysm. Twenty one subjects were included, and assessed in the secondary and late post stroke phases. We have used the following tests to assess planning and/or execution time and performance: Trail Making test, Wisconsin Card Sorting Test, London Tower Test, Shopping Test of Martin, sequential gestual test and contradictory responses test from Luria. Correlations between these parameters were used to evaluate subjects strategy. In evaluation of execution time, patients were slower than controls, and the difference was more marked using the Trail Making Test (p < 0.01) and the London Tower Test (p < 0.01). Furthermore, the initiation time was increased in the London Tower Test (p < 0.01), this suggesting that they were slower than impulsive. Groups analysis showed that their performance level was most often similar to that of of controls, even in the secondary phase, with the exception of the number of problems solved whatever number of moves in the London Tower test (p < 0.01) and of the percentage of errors in the sequential motor task (p < 0.03). Similar results were observed in the evaluation of single cases. Correlations between execution time and performance were most often significant and negative, in patients and controls. These results suggest that the management of the speed-accuracy compromise was relatively similar, and that impulsivity, which associates reduction of time to poor performance, was absent or mild. Cingulate, and caudate lesions were identified as the source of most cognitive disorders.