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Biomedical subjects

H Ring

Publications and source records attributed to H Ring.

At least 37 records · Page 2Linked to original sources
PubMed1999

Functional correlates with left-right asymmetry of visual evoked potentials in stroke patients: modeling and experimental results.

OBJECTIVE: To determine the correlation between a clinical measure of function in patients after first stroke and left-right scalp amplitude of visual evoked potentials using a theoretical model of the head. DESIGN: A random sample of first-stroke patients underwent routine function measurement and investigation of left-right scalp potential asymmetry. Results of the encephalographic tests were compared with those of a healthy subject. To examine the effect of the conductivity in the damaged area on the potential asymmetry, numerical calculations were performed on a model, with four concentric circular compartments representing the brain, cerebrospinal fluid layer, skull, and scalp. The damaged region was modeled as a circular section. SETTING: Neurologic rehabilitation ward of a major rehabilitation hospital and university-affiliated biomedical engineering laboratory. PATIENTS: Four men aged 58 to 71 years, 3 with brain thrombosis and 1 with hemorrhagic stroke. The patients were admitted for rehabilitation an average of 3 weeks after the stroke and stayed for an average of 137 days. Damage was confined to the right brain in all cases; three of the patients had neglect syndrome and/or sensory disturbances. A healthy subject without stroke was also examined. MEASURES: Function was measured with the Functional Independence Measure (FIM) at 48 to 72 hours from admission and during the last week before discharge. Functional gain was calculated by subtracting the FIM admission score from the discharge score. Left-right scalp visual evoked potential amplitude was studied with flash stimuli according to the 10-20 international system and a theoretical model of the head based on two-dimensional computed tomography images; the volume conductor equation was solved numerically using the finite volume method. Left-right potential asymmetry and the damaged-region-to-brain-area ratio were calculated and correlated with the FIM values by linear regression analysis. Negative asymmetry indicates that the activity in the right damaged hemisphere is lower than in the undamaged one. RESULTS: A negative correlation was noted between the FIM score on admission and the left-right scalp potential amplitude asymmetry, and between the FIM gain and the damaged-region-to-brain-area ratio obtained from the computed tomography image. Asymmetry was negative in the thrombotic patients and positive in the hemorrhagic one. The healthy subject showed nonsignificant asymmetry. CONCLUSION: A relationship might exist between the left-right asymmetry of the scalp visual evoked potential and both the damaged-region-to-brain-area ratio and the functional outcome of rehabilitation in poststroke patients. The modeling study shows that the left-right asymmetry is most likely the result of changes in the conductivity at the damaged area, which, in turn, are probably associated with patient functional status and evolution. Further validation in larger groups of patients and normal subjects is needed before these parameters can serve as useful indices for clinical purposes.

Aged↗
PubMed1999

Functional disability and rehabilitation outcome in right hemisphere damaged patients with and without unilateral spatial neglect.

OBJECTIVE: To evaluate the impact of unilateral spatial neglect (USN) on the rehabilitation outcome and long-term functioning in activities of daily living (ADL) and instrumental ADL (IADL) of right hemisphere damaged (RHD) stroke patients. DESIGN: Assessments of sensory-motor and cognitive impairment and of functional disability were conducted upon admission to rehabilitation, upon discharge from the rehabilitation hospital, and 6 months after discharge, up to a year postonset. SETTING: The Loewenstein Rehabilitation Hospital, which receives patients from all general hospitals in Israel. PATIENTS: Forty consecutive admissions of adult right-handed patients with a first, single, right hemispheric stroke proven by computed tomography. Based on their total score in the Behavioral Inattention Test for neglect, patients were divided into two groups: 19 with neglect (USN+) and 21 without neglect (USN-). OUTCOME MEASURES: Functional Independence Measure, for ADL; The Rabideau Kitchen Evaluation, for IADL. RESULTS: Impairment and disability levels of RHD patients with and without USN were clearly differentiated. Neglect is associated with lower performance on measures of impairment (sensory-motor and cognitive), as well as on measures of disability in ADL and IADL. Differences were significant in all testing periods. The recovery pattern of USN+ patients is slower and more attenuated. In both groups, most improvement occurs in the first 5 months after onset. USN is the major predictor of rehabilitation outcome from admission to follow-up. CONCLUSIONS: The significance of neglect as a major source of stroke-related long-term disability justifies further research efforts to develop appropriate therapeutic modalities for this complex, multifactorial syndrome.

Activities of Daily Living↗
PubMed1999

Isolation of speech area syndrome (ISAS): a follow-up study--a rehabilitative approach.

PURPOSE: In this study we present our findings concerning the dynamics of language modalities in the isolation of the speech area syndrome (ISAS). The aim of the study was to establish: (1) the linguistic characteristic features of this group of patients; (2) the course of dynamics of language of each patient; (3) whether this course of dynamics is common for the whole group; (4) whether the course of dynamics we found matches with the report in the literature. METHOD: Over a period of 5 years, nine patients with ISAS were diagnosed and treated in our department. They received varying lengths of treatment, and four were followed for 2-6 years after discharge. RESULTS: Despite the common belief that the prognosis for language rehabilitation for these patients is poor, we found that some ISAS patients improved, even dramatically, after prolonged language treatment. CONCLUSION: It is hoped that these findings will alter clinicians' attitudes towards these patients, and provide some hope for rehabilitation outcome.

Adult↗
PubMed1997

[Quality of life in younger adults (17-49) after first stroke--a two year follow-up].

To study the effect of stroke on the quality of life in younger adults, 199 patients 17-49 years of age who had sustained a first stroke between 1.11.92 and 31.10.93 were followed up. They were interviewed by telephone at 3, 6, 12 and 24 months after the event. 2 died during the first year of follow-up, and 8 had recurrent strokes. After 2 years, 8 additional patients had died and 4 had sustained recurrent events. Gradual improvement was reported within all age groups and in all areas. During the 3-6 months period, a mean of 4% improvement occurred in functional capability, 15% in social and recreational activity and 8% in return-to-work. The 6-12 month period showed an increase of 3% in improvement in mean functional capability, 10% in social and recreational activity and 2% in return-to-work. 1 year after the stroke 27% remained with moderate to severe disability, but over 86% were functionally independent in their daily living activities. There were no significant changes during the second year of follow-up in these statistics. 67% of those employed prior to their stroke returned to work and approximately 70% reported a return to prestroke social and recreational activity. These results demonstrate that the relatively high recovery rate and functional improvement during a year of follow-up were not accompanied by similar rates of improvement in employment and in social integration. They indicate the need for increased emphasis on long-term psychosocial rehabilitation services within the community.

Adult↗
PubMed1997

Functional measures of first-stroke rehabilitation inpatients: usefulness of the Functional Independence Measure total score with a clinical rationale.

OBJECTIVE: The Functional Independence Measure (FIM) was used to measure function in first-stroke patients on admission to and discharge from a rehabilitation center, and to determine gain; all data were analyzed by a clinically oriented approach. DESIGN: All patients admitted after a first supratentorial stroke to a comprehensive rehabilitation facility over a 2-year period were examined prospectively with the FIM. Diagnosis was determined by neuroimaging. Data were collected continuously and stored in the departmental database. For analysis of data, the patients were divided by side of lesion (right or left hemisphere), main clinical syndrome (presence or absence of neglect or aphasic syndromes in those with damage to the right or left hemisphere, respectively), type of lesion (ischemic, hemorrhagic, etc), and site of lesion (cortical or subcortical). SETTING: Neurological rehabilitation ward. PATIENTS: The study population included 151 patients of average age 60.8 years; 60% were men. All were admitted an average of 28.9 days after stroke and rehabilitated for 109.3 days. MAIN OUTCOME MEASURE: The raw FIM total score was determined at 48 to 72 hours after admission and at discharge. FIM gain was calculated by subtracting the FIM discharge score from the FIM admission score for each individual. Length of stay was also recorded. RESULTS: There was no difference in average total FIM scores when patients were divided by side of damage (right or left hemisphere). Significant findings were obtained for the various parameters when the clinical criterion was applied. Patients with neglect or aphasia syndromes showed significantly higher gains despite their lower FIM admission scores, but they had a much longer in-hospital stay. CONCLUSION: The raw FIM total score is a simple, practical, and efficient measure of function in first-stroke patients on admission for rehabilitation, provided an appropriate clinical approach is used during data analysis. Results can be used for comparison with similar measures, determination of admission and discharge policy, and program evaluation. The presence of neglect and aphasic syndromes has a significant effect on the various measures. Length of stay in rehabilitation is also of paramount importance in stroke patients with special clinical syndromes.

Cerebrovascular Disorders↗
PubMed1997

Visual extinction and cortical connectivity in human vision.

Visual extinction is a common, poorly understood, consequence of unilateral cerebral damage, where a patient fails to detect one of two simultaneously presented stimuli (the one more contralateral to the lesion), despite the fact that each stimulus is correctly detected when presented in isolation. The phenomenon implies a failure of shifting attention from an attended object to an unattended one. We show here that pair detection is improved in conditions where the two stimuli presented to the two halves of the visual field are proximal, co-oriented and co-axial. It is further shown that stimulus properties producing reduced extinction correlate with the selectivity pattern of spatial lateral interactions observed in the primary visual cortex. We suggest that neuronal activity in early stages of cortical visual processing encodes, using long-range lateral interactions, an image description in which visual objects are already segmented and marked. Segmentation seems to function properly even in the presence of significant destruction of the parietal cortex leading to extinction.

Cerebral Cortex↗
PubMed1997

SCIM--spinal cord independence measure: a new disability scale for patients with spinal cord lesions.

The Spinal Cord Independence Measure (SCIM) is a new disability scale developed specifically for patients with spinal cord lesions in order to make the functional assessments of patients with paraplegia or tetraplegia more sensitive to changes. The SCIM includes the following areas of function: self-care (subscore (0-20), respiration and sphincter management (0-40) and mobility (0-40). Each area is scored according to its proportional weight in these patients' general activity. The final score ranges from 0 to 100. This study was performed to evaluate the reliability of the SCIM and its sensitivity to functional changes in spinal cord lesion patients compared with the Functional Independence Measure (FIM). Thirty patients were included. Scores were recorded one week after admission and thereafter every month during hospitalization. Each area of function was assessed by a pair of staff members from the relevant discipline. The comparison of scores between each pair of rates revealed a remarkable consistency (r = 0.91-0.99; P < 0.0001; slope approximately 1; constant approximately 0). The total SCIM score (mean = 51, SD = 21) was lower than the total FIM score (mean = 87, SD = 23) owing to the difference in scale range structure and the relatively high cognitive scores of our patients; however, a relationship was noted between the scores of both scales (r = 0.85, P < 0.01). The SCIM was more sensitive than the FIM to changes in function of spinal cord lesion patients: the SCIM detected all the functional changes detected by the FIM total scoring, but the FIM missed 26% of the changes detected by the SCIM total scoring. The mean difference between consecutive scores was higher for the SCIM (P < 0.01). We conclude that the SCIM is a reliable disability scale and is more sensitive to changes in function in spinal cord lesion patients than the FIM. The SCIM when administered by a multidisciplinary team, may be a useful instrument for assessing changes in everyday performance in patients with spinal cord lesion.

Activities of Daily Living↗
PubMed1996

Depression in multiple system atrophy and in idiopathic Parkinson's disease: a pilot comparative study.

Multiple system atrophy (MSA) is a disease causing parkinsonism in which response to levodopa is classically absent, poor, or transient. Idiopathic Parkinson's disease (IPD) itself, which responds favorably to levodopa, has been associated with the development of disease-related depression. Over and above the clinical and pathological characteristics of IPD, MSA causes additional, more widespread, clinical and pathological deficits. We have compared motor disability and mood in 12 patients with MSA and 12 with IPD. There was more severe motor disability, but no clinical evidence of depression among the MSA patients studied, and their Beck Depression Inventory scores did not differ significantly from the group with IPD. We conclude that depression does not appear to be more common in MSA than in IPD.

Activities of Daily Living↗
PubMed1996

Vigabatrin and behaviour disorders: a retrospective survey.

Vigabatrin is an anticonvulsant drug with a relatively favourable side-effect profile. However, in clinical trials behaviour disorders have been reported, including agitation, depression and psychoses. In this study, 136 cases of behavioural problems that had been reported to the manufacturers, or the authors, were followed up. Satisfactory clinical information could be obtained on 81 patients. Of these, 50 cases met the criteria for either a psychosis (n = 28) or depression (n = 22). These were compared with a group of Queen Square patients, with epilepsy and psychosis, who had never taken vigabatrin (n = 21) and another group, who received vigabatrin without experiencing any behavioural problems (n = 28). The main results from this study suggest that: (1) Psychosis as a treatment emergent effect of vigabatrin is seen in patients with more severe epilepsy, compared with those patients who never develop psychopathology, and those developing an affective disorder. The psychosis is related to a right-sided EEG focus, and suppression of seizures (64% became seizure free). (2) Depression as a treatment emergent effect of vigabatrin is associated with a past history of depressive illness. There was little or no change in seizure frequency is this group. Some suggestions for managing patients who may develop these behaviour disorders are given.

Anticonvulsants↗
PubMed1995

Median nerve conduction tests and Phalen's sign in carpal tunnel syndrome.

Carpal tunnel syndrome (CTS) is associated with sensory and/or motor dysfunction of the hand's fingers. The syndrome is caused by a continuous or intermittent pressure on the median nerve (NM) at the patient's wrist. 82 patients suffering from recent CTS symptoms, and 24 matched asymptomatic controls were tested. In the present study we examined five electrophysiological parameters and their correlations with a most commonly used clinical test--the Phalen test. The Phalen measure is the time from initial provocation until positive sign. The electrophysiological measurements are: NM Onset Sensory Velocity, NM Peak Sensory Velocity, NM Motor Nerve Velocity, NM Distal Motor Velocity, NM Residual Latency. Most of the symptomatic hands exhibited pathological values of their clinical or electrophysiological parameters. Phalen and Residual Latency were the most sensitive parameters. Phalen times were not significantly correlated with any of the five electrophysiological parameters, yet sensory velocity tended to decrease in patients with pathological Phalen values.

Adult↗
PubMed1994

Saccadic responses in patients with hemispheric stroke.

Saccadic characteristics were examined in 15 patients with unilateral hemispheric stroke. Eye movements were measured by a standard electro-oculogram technique. In patients with cortical infarcts, mean gain values were lower than in the control subjects for eye movements directed away from the infarct (contralateral), but higher for eye movements towards the infarct (ipsilateral) (p < 0.025). We suggest that impairment of efferent neural signals from the affected hemisphere of stroke patients may decrease excitation of the contralateral neural circuits and inhibition of the ipsilateral neural circuits of the brainstem saccade generator.

Adult↗
PubMed1994

Recognition of mental state terms. Clinical findings in children with autism and a functional neuroimaging study of normal adults.

BACKGROUND: The mind's ability to think about the mind has attracted substantial research interest in cognitive science in recent decades, as 'theory of mind'. No research has attempted to identify the brain basis of this ability, probably because it involves several separate processes. As a first step, we investigated one component process-the ability to recognise mental state terms. METHOD: In Experiment 1, we tested a group of children with autism (known to have theory of mind deficits) and a control group of children with mental handicap, for their ability to recognise mental state terms in a word list. This was to test if the mental state recognition task was related to traditional theory of mind tests. In Experiment 2, we investigated if in the normal brain, recognition of mental state terms might be localised. The procedure employed single photon emission computerised tomography (SPECT) in normal adult volunteers. We tested the prediction (based on available neurological and animal lesion studies) that there would be increased activation in the orbito-frontal cortex during this task, relative to a control condition, and relative to an adjacent frontal area (frontal-polar cortex). RESULTS: In Experiment 1, the group with autism performed significantly worse than the group without autism. In Experiment 2, there was increased cerebral blood flow during the mental state recognition task in the right orbito-frontal cortex relative to the left frontal-polar region. CONCLUSIONS: This simple mental state recognition task appears to relate to theory of mind, in that both are impaired in autism. The SPECT results implicate the orbito-frontal cortex as the basis of this ability.

Adolescent↗