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Biomedical subjects

A Sunderland

Publications and source records attributed to A Sunderland.

At least 19 recordsLinked to original sources

The impact of cognitive impairment on upper body dressing difficulties after stroke: a video analysis of patterns of recovery.

OBJECTIVE: to study the underlying cognitive deficits influencing a stroke patient's ability to relearn to dress. The aim was to investigate how recovery had occurred and whether the nature of cognitive impairment was the reason for persistent dressing problems. METHODS: the dressing performance of 30 stroke patients was compared at the sub-acute stage and three months later. Standardised cognitive and physical tests were carried out, together with a video analysis of patients putting on a polo shirt. RESULTS: thirteen patients with preserved power in the upper limb used both arms to put on the shirt. Despite visuospatial impairment or apraxia in some cases, all were successful given sufficient time. Out of 17 patients with arm paresis, 12 were dependent putting on the shirt. Amongst the five who were independent, significantly fewer cases of cognitive impairment were seen on tests for apraxia (p<0.05) and visuospatial perception (p<0.05). Video analysis confirmed the importance of cognitive problems such as neglect or apraxia. Three patients who failed shirt dressing showed neglect or apraxia at follow up and had persistent arm paresis. Test failures also occurred amongst those who were independent. DISCUSSION: cognitive impairment affected patients attempting to relearn to dress with one hand, but did not affect patients who used both hands. The three patients who remained impaired on cognitive tests at follow up were unable to adapt or learn any compensatory strategies. The influence of cognition on a person's ability to learn compensatory strategies has implications for the design of rehabilitation therapies.

Activities of Daily Living↗

A pilot study of event-related functional magnetic resonance imaging of monitored wrist movements in patients with partial recovery.

BACKGROUND AND PURPOSE: Previous functional imaging studies of motor recovery after stroke have investigated cerebral activation during periods of repetitive, often complex, movement. This article reports the use of an event-related approach to study activation associated with isolated simple movements (wrist extension). This allows investigation of the pattern of the motor response and corresponding brain activation on a trial-by-trial basis. Patients with partial recovery can be assessed, and allowance can be made for abnormalities in the shape of hemodynamic responses. METHODS: Functional MRI at 3 T was performed during a series of isolated, near-isometric wrist extension movements. A visual tracking procedure was used to elicit forces of 10% and 20% of maximum voluntary contraction. Force output from both wrists was monitored continuously. A voxel-wise procedure was used to fit the optimum hemodynamic response functions in each case. RESULTS: Three chronic stage patients with partial recovery were successfully scanned and compared with 8 healthy controls. The patients showed well-lateralized motor responses but inaccurate control of force. During movement of the paretic wrist, we observed excessive activation of the ipsilateral primary motor cortex and increased relative activation of the supplementary motor area compared with movement of the nonparetic side. In the primary motor area, hemodynamic responses peaked more quickly on the ipsilateral side in 2 patients for movements of the paretic hand, whereas controls showed the opposite trend. CONCLUSIONS: An event-related approach can be used to study the relationship between motor responses and cerebral activation in patients with partial recovery. These preliminary findings suggest that excessive activation in ipsilateral motor cortex and secondary motor areas remains evident under these tightly controlled conditions and cannot be ascribed to mirror movements or abnormalities in the timing of the blood oxygen level-dependent (BOLD) response. However, close monitoring of motor responses also makes evident continuing impairment in motor skill, which makes comparison with activation in normal controls difficult.

Adult↗

Cerebral activation during a simple force production task: changes in the time course of the haemodynamic response.

An event-related paradigm was used to investigate the fMRI signal from the primary motor cortex (M1) and the supplementary motor area (SMA) during isolated isometric wrist extension at five different force levels. There was only a weak trend towards increased area of activation with increased force output, but there was a force-related increase in percentage change of signal within voxels in M1 (Kendall Tc = 0.48, p < 0.01), which may indicate control of force output by variation of neural firing rate. In SMA there was a correlation between peak force output and time-to-peak of the haemodynamic response in SMA (Kendall Tc = 0.74, p < 0.0001). This unexpected finding of a task-related change in the shape of the haemodynamic response within a single brain area requires further investigation. It may indicate a slower rise time at lower perfusion rates, or may be the result of inhibitory processes in motor control.

Adult↗

Ideomotor apraxia, visuomotor control and the explicit representation of posture.

Ideomotor apraxia is normally viewed as a disorder of the representation or execution of action. However, the evidence from gesture imitation is that apraxic patients are unable to reproduce the final posture of a gesture but may not show abnormality in movement kinematics. This supports a hypothesis that impaired gesture imitation is due to a deficit in a conceptual representation of body posture rather than indicating a disorder specific to action control. The present study evaluated whether other aspects of apraxic behaviour might also be most consistent with a deficit in the representation of posture. Patients with left hemisphere damage and apraxia on gesture imitation had difficulty in reproducing a series of actions due to failure to adopt the required configuration of the hand whereas there was no consistent reduction in speed of response once the actions had been learned. They also tended to use an abnormal, clumsy grasp when using a spoon but this dissociated from accurate performance on other tests of manual dexterity where there was less scope for variation in configuration of the hand. These data suggest that the most common deficit in ideomotor apraxia is impaired ability to perform tasks where the goal is to reproduce or adopt complex hand configurations and that impaired execution of some types of action is secondary to this problem. This is consistent with a role for the human left parietal lobe in providing an explicit representation of posture which is used to guide some actions and to supplement a more primitive system of direct visuomotor control.

Adult↗

Recovery of ipsilateral dexterity after stroke.

UNLABELLED: BACKGROUND AND PURPOSE; Previous work indicated that patients within 1 month of parietal or posterior frontal damage are often abnormally slow or clumsy when using the ipsilateral hand for dexterity tasks. This article reports a 6-month follow-up study to assess recovery and the impact on functional outcome. METHODS: Twenty-four patients (80%) were available for follow-up. They used the ipsilateral hand on a dexterity test that simulated everyday hand function. Weakness and ideomotor apraxia were also assessed. Performance was compared with that of healthy age-matched control subjects using the same hand. Rating scales for self-care and dexterity in everyday life were completed by patients and carers. RESULTS: Significant recovery had occurred on all measures, but patients with left hemisphere damage remained impaired on the dexterity test, with 7 patients (58%) scoring below the normal range. Five of these were apraxic. Reports of everyday functioning did not reflect this impairment, but there were inconsistencies in these reports, which raised doubts as to their accuracy. CONCLUSIONS: Ipsilateral dexterity shows recovery during the first 6 months, but there may be persistent impairment related to apraxia after left hemisphere stroke. It appears that the impact of this on functional outcome is typically small compared with the large effect of severity of contralateral paresis. It may be a significant factor in some cases, however, and direct observation of everyday functioning would be needed to clarify more subtle effects on outcome.

Aged↗

Impaired dexterity of the ipsilateral hand after stroke and the relationship to cognitive deficit.

BACKGROUND AND PURPOSE: Previous research has reported impaired hand function on the "unaffected" side after stroke, but its incidence, origins, and impact on rehabilitation remain unclear. This study investigated whether impairment of ipsilateral dexterity is common early after middle cerebral artery stroke and explored the relationship to cognitive deficit. METHODS: Thirty patients within 1 month of an infarct involving the parietal or posterior frontal lobe (15 left and 15 right hemisphere) used the ipsilateral hand in tests that simulated everyday hand functions. Performance was compared with that of healthy age-matched controls using the same hand. Standardized tests were used to assess apraxia, visuospatial ability, and aphasia. RESULTS: All patients were able to complete the dexterity tests, but video analysis showed that performance was slow and clumsy compared with that of controls (P<0.001). Impairment was most severe after left hemisphere damage, and apraxia was a strong correlate of increased dexterity errors (P<0.01), whereas reduced ipsilateral grip strength correlated with slowing (P<0.05). The pattern of performance was different for patients with right hemisphere damage. Here there was no correlation between grip strength and slowing, while dexterity errors appeared to be due to visuospatial problems. CONCLUSIONS: Subtle impairments in dexterity of the ipsilateral hand are common within 1 month of stroke. Ipsilateral sensorimotor losses may contribute to these impairments, but the major factor appears to be the presence of cognitive deficits affecting perception and control of action. The nature of these deficits varies with side of brain damage. The effect of impaired dexterity on functional outcome is not yet known.

Aged↗

The nature and prevalence of memory disorder late after stroke.

This study aimed to investigate the incidence and nature of memory impairment late after stroke. Out of 193 patients between 12 to 36 months post-cerebrovascular accident contacted in a postal survey, 113 replied that they had experienced memory impairment following the stroke. Seventy of these patients were assessed on an adapted version of the Rivermead Behavioural Memory Test, Warrington's Recognition Memory Test for words and faces, and an every day memory questionnaire. The Token Test and the Benton Facial Recognition Test were also administered as measures of language and visuoperceptual processing. Thirty-five of the patients were impaired on one or more of the memory measures. Of these, 16 showed no evidence of dysphasia or visuoperceptual impairment. The 16 cases of selective memory impairment typically had mild to moderate deficits, and only three were impaired across all three tests. The results suggest that memory impairment following stroke does not necessarily involve general memory impairment. The evidence for material-specific memory deficits was much weaker.

Adult↗

Adaptation to cognitive deficit? An exploration of apparent dissociations between everyday memory and test performance late after stroke.

It is widely believed that spontaneous improvements in functioning late after brain damage are due to processes of adaptation to permanent cognitive deficits. Reports of everyday memory and the pattern of performance on memory tests were investigated in 70 patients more than a year after a stroke. Contrary to the adaptation hypothesis, performance on simulations of everyday tasks (Rivermead Behavioural Memory Test) correlated strongly with performance on a test where there was little scope for compensatory strategies (forced-choice recognition memory for words). In 12 cases, initial assessment with the EMQ20 questionnaire suggested few cognitive failures in everyday life despite poor test performance. However, where further investigation was possible, it seemed that unreliability of measures or subtle everyday effects of non-verbal memory impairment could explain the apparent discrepancies. In addition, patients who did poorly on tests were not reported to make frequent use of memory aids. Adaptation to deficit does not therefore appear to be a major influence on everyday memory performance late after stroke, but it may have subtle effects or may be important in other areas of functioning. Implications for clinical memory assessment are discussed.

Activities of Daily Living↗

Differences in recovery from constructional apraxia after right and left hemisphere stroke?

Previous comparisons of constructional apraxia after right and left hemisphere damage have not investigated the influence of time since onset. This paper reports some preliminary findings from stroke patients in a physical rehabilitation trial. Fifty-five patients with right hemisphere damage and 65 with left hemisphere damage were assessed on the WAIS-R Block Design test at 1 month and 6 months post stroke. The groups were similar at 1 month but the left hemisphere group showed better average recovery by 6 months. There was great variability in amount of recovery within the left hemisphere group, suggesting individual differences in initial reasons for failing Block Design, and corresponding differences in the recovery process. Compensation by the right hemisphere is discussed as one possible process. Future detailed longitudinal studies may be useful in contrasting the cognitive deficits which underlie constructional apraxia after right-sided and left-sided lesions, and would provide evidence on mechanisms of recovery and adaptation.

Adult↗

Enhanced physical therapy for arm function after stroke: a one year follow up study.

Ninety seven patients with stroke who had participated in a randomised trial of conventional physical therapy nu an enhanced therapy for arm function were followed up at one year. Despite the emphasis of the enhanced therapy approach on continued use of the arm in everyday life, the advantage seen for some patients with enhanced therapy at six months after stroke had diminished to a non-significant trend by one year. This was due to some late improvement in the conventional therapy group whereas the enhanced therapy group remained static or fell back slightly. It is recommended that trials should be conducted comparing very intensive therapy for the arm with controls without treatment. This would provide a model of the effects of therapy on intrinsic neural recovery that would be relevant to all areas of neurological rehabilitation.

Aged↗

Development of a weekly support group for caregivers of children with HIV disease.

The authors describe a weekly group for caregivers of children with HIV disease which began in January 1988. Presented are four separate developmental stages: (1) universality; (2) development of cohesion; (3) development of conflict; and (4) separation and growth. This group has reduced the members' depression, anxiety and isolation and has assisted them with anticipatory mourning and the creation of a support network.

Adaptation, Psychological↗

Enhanced physical therapy improves recovery of arm function after stroke. A randomised controlled trial.

Previous research on stroke rehabilitation has not established whether increase in physical therapy lead to better intrinsic recovery from hemiplegia. A detailed study was carried out of recovery of arm function after acute stroke, and compares orthodox physiotherapy with an enhanced therapy regime which increased the amount of treatment as well as using behavioural methods to encourage motor learning. In a single-blind randomised trial, 132 consecutive stroke patients were assigned to orthodox or enhanced therapy groups. At six months after stroke the enhanced therapy group showed a small but statistically significant advantage in recovery of strength, range and speed of movement. This effect seemed concentrated amongst those who had a milder initial impairment. More work is needed to discover the reasons for this improved recovery, and whether further development of this therapeutic approach might offer clinically significant gains for some patients.

Activities of Daily Living↗

The impact of human immunodeficiency virus serostatus on reproductive decisions of women.

Each year in the United States, several thousand women infected with the human immunodeficiency virus (HIV) become pregnant. The scope of the pediatric HIV epidemic will be determined by the reproductive decisions of these women. Although initial studies have not documented an effect of serostatus on reproductive choice, these studies have been limited to single-risk groups (eg, drug users) and have had small numbers of participants. We studied 108 HIV-seronegative women and 98 seropositive women through an index pregnancy and for an average of 1.5 years postpartum. Thirty-four of the seronegative women (31%) and 32 of the seropositive women (33%) learned their serostatus early enough in pregnancy to have the option to undergo abortion. One of the 34 seronegative women (2.9%) and six of the 32 seropositive women (18.8%) chose abortion (P less than .05). During follow-up, we found no significant differences in the numbers of pregnancies or live births between seropositive and seronegative women, or between drug-using and non-drug-using women. Among those who developed AIDS (N = 10), no live births occurred during followup. Although positive HIV status did correlate with the decision to terminate pregnancies, it did not correlate with subsequent fertility.

Abortion, Legal↗

Influence of human immunodeficiency virus infection on reproductive decisions.

This article discusses the role of the practitioner in the pregnancy decision-making process of the HIV-infected woman. Literature on women's decisions is reviewed, and variables that influence decisions are discussed. The author concludes that HIV infection does not have a significant impact on pregnancy decisions. Other cultural and psychosocial variables may have more importance.

Attitude to Health↗

Arm function after stroke. An evaluation of grip strength as a measure of recovery and a prognostic indicator.

The value of strength of voluntary grip as an indicator of recovery of arm function was assessed by testing 38 recent stroke patients using a sensitive electronic dynamometer, and comparing the results with those from five other arm movement and function tests (Motricity Index, Motor Club Assessment, Nine Hole Peg Test, and Frenchay Arm Test). This procedure allowed measurement of grip in a large proportion of patients, and strength correlated highly with performance on the other tests. Measuring grip over a six month follow up period was a sensitive method of charting intrinsic neurological recovery. The presence of voluntary grip at one month indicates that there will be some functional recovery at six months.

Adult↗