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Biomedical subjects

T P Cassidy

Publications and source records attributed to T P Cassidy.

9 recordsLinked to original sources
PubMed2004

Avoidance of obstacles in the absence of visual awareness.

The spatial character of our reaching movements is extremely sensitive to potential obstacles in the workspace. We recently found that this sensitivity was retained by most patients with left visual neglect when reaching between two objects, despite the fact that they tended to ignore the leftward object when asked to bisect the space between them. This raises the possibility that obstacle avoidance does not require a conscious awareness of the obstacle avoided. We have now tested this hypothesis in a patient with visual extinction following right temporoparietal damage. Extinction is an attentional disorder in which patients fail to report stimuli on the side of space opposite a brain lesion under conditions of bilateral stimulation. Our patient avoided obstacles during reaching, to exactly the same degree, regardless of whether he was able to report their presence. This implicit processing of object location, which may depend on spared superior parietal-lobe pathways, demonstrates that conscious awareness is not necessary for normal obstacle avoidance.

Brain Injuries↗
PubMed1999

The association of visual field deficits and visuo-spatial neglect in acute right-hemisphere stroke patients.

BACKGROUND: Visuo-spatial neglect (VSN) after stroke is associated with a poor prognosis for rehabilitation. The co-existence of a visual field deficit (VFD) with VSN may be associated with impaired visuo-spatial functioning and thereby poor functional outcome. OBJECTIVE: To determine whether the presence of a VFD (i) exacerbates VSN and (ii) influences recovery of VSN. METHODS: A prospective study of consecutive acute (<7 days), right-hemisphere stroke patients who were able to undergo detailed assessment of visuo-spatial functioning and visual fields. Clinical assessment and a standardized neuropsychological test was administered by one observer, followed by independent assessment of visual fields by a second observer. Patients were followed up for 12 weeks with 4-weekly re-assessments. RESULTS: 44 consecutive patients (23 women) with a first in a lifetime, acute hemisphere stroke were recruited. Twenty had VSN and VFD, seven VSN only, one VFD only and 17 had normal visual fields and no neglect. The finding of a VFD was significantly associated with the presence of VSN (P<0.0001). Patients with both VFD and VSN had a significantly lower score on the behavioural inattention test. One month post-stroke, this difference was no longer significant. Recovery of VSN and VFD was maximal in the first month, however VSN recovery continued for up to 12 weeks. Patients with VSN and a VFD on admission had a greater mortality at 1 and 3 months. CONCLUSION: The presence of a VFD does appear to exacerbate neglect in the acute stroke patient; this effect is no longer seen after 1 month. Recovery of VSN continues independent of a VFD. Patients with neglect and a VFD have an increased mortality, probably because of greater neurological impairment.

Acute Disease↗
PubMed1998

Recovery from visuospatial neglect in stroke patients.

OBJECTIVES: To describe the natural recovery of visuospatial neglect in stroke patients and the distribution of errors made on cancellation tests using a standardised neuropsychological test battery. METHOD: A prospective study of acute (< seven days) patients with right hemispheric stroke. Patients identified with visuospatial neglect were followed up for three months with monthly clinical and neuropsychological testing RESULTS: There were 66 patients with acute right hemispheric stroke assessed of whom 27 (40.9%) had evidence of visuospatial neglect. Patients with neglect, on admission, had a mean behavioural inattention test (BIT) score of 56.3, range 10-126 (normal>129). Three of the subtests identified errors being made in both the right and left hemispaces. During follow up, recovery occurred across both hemispaces, maximal in the right hemispace. Recovery from visuospatial neglect was associated with improvement in function as assessed by the Barthel score. At the end of the study period only six (31.5%) patients had persisting evidence of neglect. On admission the best predictor of recovery of visuospatial neglect was the line cancellation test (Spearman's rank correlation r=-0.4217, p=0.028). CONCLUSION: The demonstration of errors in both hemispaces has implications for the theory that neglect is a lateralised attentional problem and is important to recognise in planning the rehabilitation of stroke patients.

Activities of Daily Living↗
PubMed1995

The characteristics of respite patients.

A prospective study of planned respite admissions, comparing them to admissions to continuing care. The characteristics, dependency and CAPE scores of each patient were noted, as was medical intervention during the respite admissions. Twelve month follow-up provided data on long-term prognosis. Fifty three (30 females) respite patients; mean age 80.3 years (range 63-97) were compared with 31 (18 females) continuing care patients; mean age 82.6 (range 74-94). There was no difference in the physical dependency between the two groups, except that continuing care patients were significantly more incontinent of urine and had significantly worse cognitive function. Only eight (15%) respite patients needed medical intervention during their admission and one patient died. One year follow-up revealed that 26% of respite patients had died against 48% of continuing care patients (p < 0.01). A further 33% of respite patients had been admitted to institutional care.

Aged↗
PubMed1993

Computerised tomography and stroke.

To evaluate the utilisation of CT diagnostic imaging in patients admitted to hospital with a clinical diagnosis of stroke, and to identify factors which influence the use of CT imaging in stroke. Two hundred and fifty consecutive (155 females) stroke patients were assessed median age 76 years (range 39-95 y). Ninety-seven patients underwent CT scanning; median time to scan from admission was two days (range 0-43). The time to CT scanning was significantly shorter in patients aged < 65 years (p < 0.001), and in patients with a non-disabling stroke (p < 0.05). The factors (odds ratios and 95% confidence limits) significantly associated with CT scanning were male sex (2.21:1.31-3.74); normal Glasgow coma score (2.48:1.59-3.85); Rankin score 1-3 (6.40:1.74-23.56); age < 65 years (10.23:4.49-23.32) and no previous cerebrovascular event (1.97:1.10-3.51). In this study, those patients who would benefit most from medical intervention with antiplatelet agents to reduce the risk of recurrence were more likely to receive CT diagnostic imaging.

Adult↗
PubMed1992

Aortic stenosis in elderly people: an evaluation of clinical and echocardiographic diagnosis.

In a prospective study to assess the sensitivity and specificity of clinical diagnosis against echocardiographic diagnosis in elderly people, 41 patients were studied in two 6-month periods. Overall clinical and echo diagnosis agreed in 75% of cases, but the clinical diagnosis of aortic stenosis was poor in the initial period. Adapting the lessons which were learnt in this initial period in a repeat of the study, the sensitivity of clinical diagnosis of aortic stenosis improved from 0.38 to 0.75. Additional information was gained in 50% of cases by echocardiography, and enabled the clinician to modify treatment in 50% of cases. Aortic stenosis in elderly people may be without clinical signs. Routine echocardiography increases the sensitivity of the clinical diagnosis, and may have major therapeutic implications for the elderly patient.

Aged↗
PubMed1991

Stroke and the carer.

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Cerebrovascular Disorders↗