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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Unilateral neglect may be a multicomponent attentional disorder consisting of an initial automatic orienting of attention toward the ipsilesional side and a subsequent impairment in contralesionally reorienting attention, both of which are superimposed on a generalised reduction in attention resources. It has been hypothesised that patients' ability to reorient attention contralesionally may recover relatively quickly, but that the ipsilesional attention bias may be relatively persistent. This hypothesis was tested by consecutively examining 13 patients who had had a right hemisphere stroke, and who had left unilateral neglect. They were examined once shortly after the stroke and again 12 months later, using a battery of standard clinical and experimental tasks. Patients initially showed a strong and consistent rightward attentional bias in addition to a failure to reorient their attention leftward. After 12 months patients continued to show an abnormal ipsilesional attentional bias, though most were now able to fully reorient their attention toward the contralesional side. These results suggest that restitution of the capacity to reorient attention contralesionally may underlie the apparent recovery from clinical signs of unilateral neglect. The presence of a residual ipsilesional attentional bias in most patients, however, may, at least in part, account for the poor functional outcomes in some apparently "recovered" patients.
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PMID:Residual rightward attentional bias after apparent recovery from right hemisphere damage: implications for a multicomponent model of neglect. 820 32

Unilateral neglect, an attentional deficit in detecting and acting on information coming from one side of space, is a relatively common consequence of right hemisphere stroke. Although neglect has been observed following damage to a variety of brain structures, to date no reports exist of neglect phenomena arising from Huntington's Disease (HD). However, reports in the animal and human literature suggest that neglect is possible following damage to a primary site for Huntington's pathology, the basal ganglia. Here we present a patient (BG) with genetically proven HD who, in the context of the mild intellectual, executive and attentional impairments associated with the disorder, showed a remarkably severe and stable neglect for left space. MRI and electrophysiological results make it unlikely that the spatial bias could be accounted for by basic sensory loss. In addition, behavioural investigation indicated that, although BG's neglect operated in a very striking manner along body-centred co-ordinates (missing almost all information presented to her left), more general limitations in visual attention were apparent to the left-side of information presented entirely to the right of the body midline. Further evidence is presented showing that the neglect was manifest on tactile and auditory tasks as well as those presented in the visual domain. The presence of neglect in HD in this case is novel and somewhat puzzling, particularly as flourodeoyglucose positron emission tomography revealed bilateral caudate hypoperfusion. Reducing the statistical threshold on this analysis revealed a potential frontal hypometabolism that was more marked in the right than left hemisphere. However, as this was only apparent at a threshold below that normally considered acceptable (due to the resulting number of false positives), this possible account of the neglect must be viewed very cautiously.
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PMID:A case of unilateral neglect in Huntington's disease. 1292 32

Patients with left-sided neglect frequently show repetitive behaviour on the ipsilesional side, such as re-markings on cancellation tasks or extensive elaboration on drawings. It is unclear whether these perseverative responses occur as a symptom of hemi-neglect or inattention in general, and/or whether they are related to anatomical brain correlates such as lesion location, lesion side or volume. In a first study, we examined the prevalence and neuropsychological correlates of perseverative responses in 206 subacute stroke patients and 63 healthy controls. Perseverative responses were considered present when there was at least one re-marking on the Star Cancellation, and both the degree and spatial distribution of re-markings were examined. A distinction was made between hemi-neglect and non-lateralized inattention. Spatial and verbal working memory were assessed with the Corsi Block Span and the Digit Span. Verbal and non-verbal executive function was assessed with the Visual Elevator and Letter Fluency. Stroke patients without inattention demonstrated re-markings that were related to executive performance, and the degree of perseveration was equally distributed across the sheet. Hemi-neglect patients but not patients with generalized inattention demonstrated more re-markings than controls, suggesting that a lateralized spatial attention bias triggers the perseverative responses. Patients with left and right hemi-neglect showed the same prevalence of perseveration, but the distribution of re-markings was more lateralized towards the ipsilesional side in patients with right-hemispheric stroke. The degree of perseveration in patients with hemi-neglect was related to the severity of the neglect. The goal of the second study on a subset of patients (n = 127) was to determine the neuroanatomical correlates of perseverative responses in the early phase of stroke. Lesion anatomy was administered by indicating involvement of frontal, parietal, temporal, occipital lobe, caudate nucleus, lenticular nucleus and/or thalamus. Lesion volume was calculated using a manual tracing technique. Lesion analyses indicated that perseverative behaviour is strongly associated with lesions involving the caudate nucleus or the lenticular nucleus, independent of lesion volume. The caudate nucleus was an important correlate of perseveration independent of the presence of hemi-neglect. No association was found between lesion side and perseverative responses, in contrast to previous studies. In conclusion, a stroke involving the basal ganglia and the presence of (left- or right-sided) hemi-neglect are two important associates of perseverative responses in the subacute phase of stroke.
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PMID:Neuropsychological and neuroanatomical correlates of perseverative responses in subacute stroke. 1687 Aug 85

Unilateral neglect is a challenging disorder that pervades a range of behaviours following stroke and hampers recovery. Although a preponderance of clinical studies measure performance on a range of bedside assessments, including line bisection and cancellation tasks, there have been calls for studies to embrace more relevant functional measures. Here, for the first time, we present data from two separate tasks that characterise the performance of seven patients with unilateral neglect when navigating a power wheelchair. The tasks involved negotiating an obstacle course and steering a central path between gaps of different sizes. Results from the obstacle course confirmed the clinical observation and predicted bias of contralesional errors. However, the second task revealed a robust "crossover" effect. Patients deviated to the ipsilesional side for large gaps but deviated increasingly contralesionally when steering through small gaps in behaviour that was analogous to that previously shown on line bisection tasks. Contrary to being seen as an unintuitive finding, further analysis of these errors suggests that patients are giving disproportionate weight to the location of the ipsilesional object when plotting a midline course between two objects. Our results provide a platform for further studies to investigate the modulation and rehabilitation of this important skill.
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PMID:From both sides now: crossover effects influence navigation in patients with unilateral neglect. 1834 87

Unilateral neglect, a lack of awareness for one side of space, is a common and debilitating consequence of stroke. Previous work has identified a relationship between enduring left neglect and diminished general alertness and shown that increasing alertness can temporarily reduce the severity of the spatial bias. In that research, alertness was modulated by loud tones or with pharmacological stimulants. Here we examine whether cognitive, endogenously driven changes can produce similar short-term improvements. Time-pressure is associated with increased subjective arousal and increased activation in cortical regions associated with alertness. Here five patients completed a spatial cancellation task with and without instructions regarding a time limit. Significant reductions in neglect severity were observed when patients believed that they were acting under time-pressure, despite the conditions being equivalent in the actual (unlimited) time available. Functional imaging work has highlighted the secondary effects that damage to networks mediating alertness can have on structurally intact spatial systems. The results here suggest that activation of presumably spared function in these damaged networks can induce moment-by-moment changes in spatial function and, crucially, that this can be achieved using entirely endogenous means.
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PMID:A demonstration of endogenous modulation of unilateral spatial neglect: the impact of apparent time-pressure on spatial bias. 1807 29

Unilateral neglect is usually caused by right hemisphere damage from stroke, leading to difficulties in attending to stimuli in the left perceptual hemifield. As an example, a patient suffering from neglect may read only the right part of a word or the right part of sentences, or eat only from the right side his plate. Neglect is more common, and most often more severe, following infarcts in the right hemisphere than the left. Brain damage leading to neglect usually involves infarcts in the inferior parietal lobe, temporo-parietal junction and/or the superior temporal lobe. Most theories of the nature of neglect assume that neglect involves dysfunctional attentional mechanisms. Increased understanding of neglect has led to the development of several effective therapeutic interventions, where prism adaptation has received the most attention in recent years. This article reviews brain damage in neglect, theories of neglect, therapeutic methods for neglect and their possible future developments.
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PMID:[Unilateral neglect: a review of causes, anatomical localization, theories and interventions]. 1918 12

Neuropsychology includes both the psychiatric manifestations of neurological illness (primary brain-based disorders) and neurobiology of "idiopathic" psychiatric disorders. Neurological primary brain disorders provoke broad spectrum of brain pathophysiology that cause deficit sin human behaviour, and the magnitude of neurobehavioral-related problems is a world wide health concern. Speech disorders of aphasic type, unilateral neglect, anosognosia (deficit disorders), delirium and mood disorders (productive disorders) in urgent neurology, first of all in acute phase of stroke are more frequent disorders then it verified in routine exam, not only in the developed and large neurological departments. Aphasia is common consequence of left hemispheric lesion and most common neuropsychological consequence of stroke, with prevalence of one third of all stroke patients in acute phase although exist reports on greater frequency. Unilateral neglect is a disorder that mostly effects the patient after the lesion of the right hemisphere, mostly caused by a cerebrovascular insult (infarct or haemorrhage affecting a large area - up to two thirds of the right hemisphere), and in general the left-side neglect is the most widespread neuropsychological deficit after the lesion of the right cerebral hemisphere. Reports on the incidence of visual neglect vary and they range from 13 to 85%. Anosognosia is on the second place as neuropsychological syndrome of stroke in right hemisphere, characterized by the denial of the motor, visual or cognitive deficit. This syndrome, defined as denial of hemiparesis or hemianopsia, is a common disorder verified in 17-28% of all patents with acute brain stoke. There are different reports on frequency of delirium in acute stroke, from 24 to 48%, and it is more frequent in hemorrhagic then ischemic stoke. Post stroke depression (PSD) is one of the more frequent consequences on the stroke, and the prevalence of PSD has ranged from 5 to 63% of patients in several cross-sectional studies, peaking three to six months after a stroke.
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PMID:Neuropsychology of acute stroke. 2056 62

This study compared participation following a stroke according to the presence of specific cognitive deficits. Participation is defined as the involvement of a person in daily activities and social roles. Three weeks after being discharged home, 197 older adults (aged 65 years and older) who had a stroke were evaluated using the Assessment of Life Habits, which includes 12 domains of daily activities and social roles. The presence of a cognitive deficit was determined by the scores obtained on tests assessing memory, visual perception, language, unilateral attention, and the inhibition component of executive functions. After adjusting for depressive symptoms, time since stroke, and comorbidities, five of the domains of participation are significantly more restricted by some cognitive deficits. Memory deficits affect the communication (p = .006) and leisure (p = .032) domains. In the presence of visual perception deficits, the nutrition (p = .019), communication (p = .004), and responsibilities (p < .0005) domains are more limited. Language deficits have an impact on several domains of participation, namely communication (p < .0005), responsibilities (p < .0005), community life (p = .001), and leisure (p = .021). Unilateral neglect and deficits in the inhibition component of executive functions are not found to restrict participation. Overall, participation after stroke is related to cognitive function. Looking carefully at individual domains of activities and roles provides essential information in guiding rehabilitation interventions aimed at enhancing participation after discharge.
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PMID:Differences in participation according to specific cognitive deficits following a stroke. 2166 Jul 63

Unilateral neglect has been shown to dissociate into three areas of space: personal, peripersonal, and locomotor. Robertson, Hogg, and McMillan (1998) showed that movement of the contralesional limb (limb activation therapy) reduced neglect in a patient 18 months after brain injury. However, the beneficial effects of treatment were only maintained in peripersonal space. This study replicated and extended the work of Robertson et al. (1998) to evaluate limb activation therapy at a more acute stage of recovery. A single case ABABA design was used with a patient 8 weeks post-stroke. No significant overall treatment effect was observed. However, a significant effect of the first treatment phase was seen in peripersonal and locomotor space. This improvement was maintained in locomotor space, but not in peripersonal space. This study provides tentative support for the efficacy of limb activation therapy at an acute stage of recovery. However, more research is needed to strengthen this conclusion and clarify the generalisability of the observed effects.
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PMID:Rehabilitation of unilateral neglect in the acute recovery stage: The efficacy of limb activation therapy. 2185 20

One of the most devastating cognitive deficits following a stroke is when the patient neglects one half of the body and surroundings (unilateral neglect). Unilateral neglect following a stroke has a high prevalence and is one of the most important predictors of poor functional outcome. Various treatment methods have been studied over the past decades but their effects appear too short-term or task-specific and therefore, difficult to extrapolate to other untrained situations. A possible new intervention is transcranial direct current stimulation (tDCS), which is capable of modulating brain activity by polarizing neurons with the aid of a constant low current. Recent research suggests that inhibiting the intact hemisphere or increasing the neuronal activity in the damaged hemisphere might reduce unilateral neglect. For treating unilateral neglect, tDCS appears to be a promising technique; however, more research is necessary to reveal its therapeutic potential.
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PMID:[Transcranial direct current stimulation; potential new treatment for unilateral neglect]. 2383 1


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