Prognostic Value of Sensory Defect in Rehabilitation of Hemiplegics

Somatosensory Deficits After Stroke: Insights From MRI Studies

Somatosensory deficits after stroke are a major health problem, which can impair patients' health status and quality of life. With the developments in human brain mapping techniques, particularly magnetic resonance imaging (MRI), many studies have applied those techniques to unravel neural substrates linked to apoplexy sequelae. Multi-parametric MRI is a vital method for the measurement of stroke and has been applied to diagnose stroke severity, predict outcome and visualize changes in activation patterns during stroke recovery. However, relatively little is known about the somatosensory deficits after stroke and their recovery. This review aims to highlight the utility and importance of MRI techniques in the field of somatosensory deficits and synthesizes corresponding articles to elucidate the mechanisms underlying the occurrence and recovery of somatosensory symptoms. Here, we start by reviewing the anatomic and functional features of the somatosensory system. And then, we provide a discussion of MRI techniques and analysis methods. Meanwhile, we present the application of those techniques and methods in clinical studies, focusing on recent research advances and the potential for clinical translation. Finally, we identify some limitations and open questions of current imaging studies that need to be addressed in future research.

Outcome measurement of hand function following mirror therapy for stroke rehabilitation: A systematic review

STUDY DESIGN

Systematic review.

INTRODUCTION

Mirror therapy is a treatment used to address hand function following a stroke. Measurement of outcomes using appropriate assessment tools is crucial; however, many assessment options exist.

PURPOSE OF THE STUDY

The purpose of this study is to systematically review outcome measures that are used to assess hand function following mirror therapy after stroke and, in addition, to identify the psychometric and descriptive properties of the included measures and through the linking process determine if the outcome measures are representative of the International Classification of Functioning, Disability and Health (ICF).

METHODS

Following a comprehensive literature search, outcome measures used in the included studies were linked to the ICF and analyzed based on descriptive information and psychometric properties.

RESULTS

Eleven studies met inclusion criteria and included 24 different assessment tools to measure hand or upper limb function. Most outcome measures used in the selected studies (63%) were rated by the evaluating therapist. Thirteen outcome measures (54%) linked to the ICF body function category and 10 measures (42%) linked to activities and participation. One outcome measure was linked to not defined, and all other ICF categories were not represented. A majority of outcome measures have been assessed for validity, reliability, and responsiveness, but responsiveness was the least investigated psychometric property.

DISCUSSION

Current studies on mirror therapy after stroke are not consistent in the assessment tools used to determine hand function. Understanding of study outcomes requires analysis of the assessment tools. The outcome measures used in the included studies are not representative of personal and environmental factors, but tools linking to body functions and activities and participations provide important information on functional outcome.

CONCLUSIONS

Integrating a combination of measures that are psychometrically sound and reflective of the ICF should be considered for assessment of hand function after mirror therapy after stroke.

Somatosensory Deficits After Ischemic Stroke

Background and Purpose- About 50% to 80% of stroke survivors present with somatosensory deficits. Somatosensory deficits because of an ischemic stroke are determined by the infarct location. However, a detailed understanding of the long-term effect of lesions on somatosensory performance is lacking. Methods- This prospective observational study enrolled 101 ischemic stroke patients. For voxel-based lesion-symptom mapping, magnetic resonance imaging fluid-attenuated inversion recovery imaging infarct lesions were segmented within 5 days after stroke. Standardized tests such as the National Institutes of Health Stroke Scale and the Rivermead Assessment of Somatosensory Performance were performed during acute stage, after 3 and 12 months. This included bilateral testing for multiple tactile and proprioceptive somatosensory modalities (pressure, light touch, sharp-dull discrimination, temperature discrimination, sensory extinction, 2-point discrimination, and joint position and movement sense). We further study the association of acute somatosensory deficit with functional outcome 12 months after stroke assessed by the modified Rankin Scale using univariate and multiple linear regression analysis also including acute motor deficit assessed by the arm research action test. Results- Sixty patients (59.4%) showed impairment in at least one somatosensory modality. Light touch was most frequently affected (38.7%), whereas temperature was least frequently affected (21.8%). After 3 months, significant recovery was observed in all somatosensory modalities, with only minor additional improvements after 12 months. Voxel-based lesion-symptom mapping revealed significant associations of lesions in the primary and secondary somatosensory and insular cortex with somatosensory deficits. Acute somatosensory deficit was associated with functional outcome at 12 months. However, including the acute motor deficit, somatosensory deficit was no longer an independent predictor of functional outcome. Conclusions- Our study confirms that somatosensory deficits are frequent in acute ischemic stroke but largely recover over time. Infarct lesions in the primary and secondary somatosensory cortex and insula show a robust association with somatosensory impairment. Long-term disability is influenced by somatosensory deficits but driven by motor symptoms.

Tactile-STAR: A Novel Tactile STimulator And Recorder System for Evaluating and Improving Tactile Perception

Many neurological diseases impair the motor and somatosensory systems. While several different technologies are used in clinical practice to assess and improve motor functions, somatosensation is evaluated subjectively with qualitative clinical scales. Treatment of somatosensory deficits has received limited attention. To bridge the gap between the assessment and training of motor vs. somatosensory abilities, we designed, developed, and tested a novel, low-cost, two-component (bimanual) mechatronic system targeting tactile somatosensation: the Tactile-STAR-a tactile stimulator and recorder. The stimulator is an actuated pantograph structure driven by two servomotors, with an end-effector covered by a rubber material that can apply two different types of skin stimulation: brush and stretch. The stimulator has a modular design, and can be used to test the tactile perception in different parts of the body such as the hand, arm, leg, big toe, etc. The recorder is a passive pantograph that can measure hand motion using two potentiometers. The recorder can serve multiple purposes: participants can move its handle to match the direction and amplitude of the tactile stimulator, or they can use it as a master manipulator to control the tactile stimulator as a slave. Our ultimate goal is to assess and affect tactile acuity and somatosensory deficits. To demonstrate the feasibility of our novel system, we tested the Tactile-STAR with 16 healthy individuals and with three stroke survivors using the skin-brush stimulation. We verified that the system enables the mapping of tactile perception on the hand in both populations. We also tested the extent to which 30 min of training in healthy individuals led to an improvement of tactile perception. The results provide a first demonstration of the ability of this new system to characterize tactile perception in healthy individuals, as well as a quantification of the magnitude and pattern of tactile impairment in a small cohort of stroke survivors. The finding that short-term training with Tactile-STAR can improve the acuity of tactile perception in healthy individuals suggests that Tactile-STAR may have utility as a therapeutic intervention for somatosensory deficits.

Somatosensory deficits after stroke: a scoping review

In the past years, there have been increasing research activities focusing on somatosensory symptoms following stroke. However, as compared to the large number of clinical and neuroimaging studies on motor symptoms, the number of studies tracing somatosensory symptoms after stroke and their recovery is rather small. It is an ongoing discussion, to which extent somatosensory deficits after stroke influence patient's long-term outcome in motor and sensory performance and functional independence in activities of daily living. Modern brain imaging techniques allow for studying the impact of stroke lesion localization and size on acute and persisting clinical impairment. Here, we review the literature on somatosensory symptoms after stroke. We summarize epidemiological information on frequency and characteristics of somatosensory symptoms affecting all parts of the body in the acute and chronic stage of stroke. We further give an overview of brain imaging studies of stroke affecting the somatosensory system. Finally, we identify open questions which need to be addressed in future research and summarize the implications for clinical practice.

Recovery mechanisms of somatosensory function in stroke patients: implications of brain imaging studies

Somatosensory dysfunction is associated with a high incidence of functional impairment and safety in patients with stroke. With developments in brain mapping techniques, many studies have addressed the recovery of various functions in such patients. However, relatively little is known about the mechanisms of recovery of somatosensory function. Based on the previous human studies, a review of 11 relevant studies on the mechanisms underlying the recovery of somatosensory function in stroke patients was conducted based on the following topics: (1) recovery of an injured somatosensory pathway, (2) peri-lesional reorganization, (3) contribution of the unaffected somatosensory cortex, (4) contribution of the secondary somatosensory cortex, and (5) mechanisms of recovery in patients with thalamic lesions. We believe that further studies in this field using combinations of diffusion tensor imaging, functional neuroimaging, and magnetoencephalography are needed. In addition, the clinical significance, critical period, and facilitatory strategies for each recovery mechanism should be clarified.

Correlation between somatosensory function and cortical activation induced by touch stimulation in patients with intracerebral hemorrhage

OBJECTIVES

The correlation between somatosensory function and cortical activation induced by touch stimulation in patients with intracerebral hemorrhage (ICH) was investigated by functional magnetic resonance imaging (fMRI).

METHODS

Thirty-two chronic ICH patients with somatosensory deficits in tactile sensation were enrolled. For fMRI, touch stimulation was applied on the dorsum of the affected hand (contralateral to the ICH), using a rubber brush at a frequency of 1 Hz. Regions of interests (ROIs) were set at the primary sensory-motor cortex [SM1: Brodmann's area (BA) 1, 2, 3, 4], the posterior parietal cortex (PPC: BA 5, 7) and the secondary somatosensory cortex (S2: BA 43) in both hemispheres. The tactile sensation subscale of the Nottingham Sensory Assessment (NSA) was used to determine somatosensory function.

RESULTS

Significant correlations were found between NSA scores and voxel counts in the contralateral (ipsilesional) SM1 (r = 0.642; p < 0.05), the contralateral PPC (r = 0.507; p < 0.05) and the ipsilateral (contralesional) SM1 (r = 0.466; p < 0.05). However, no correlation was found between NSA scores and the contralateral S2 (r = 0.323; p > 0.05), the ipsilateral PPC (r = 0.252; p > 0.05) or the ipsilateral S2 (r = 0.280; p > 0.05).

CONCLUSIONS

It was found that somatosensory functions were positively correlated with degrees of blood oxygenation level dependent signal change of the following ROIs: the contralateral SM1, the contralateral PPC and the ipsilateral SM1. Opposingly, the S2 showed no correlation on either side of the brain.

Surgery for gliomas involving the left inferior parietal lobule: new insights into the functional anatomy provided by stimulation mapping in awake patients

OBJECT

Surgery in the left dominant inferior parietal lobule (IPL) is challenging because of a high density of somatosensory and language structures, both in the cortex and white matter. In the present study, on the basis of the results provided by direct cerebral stimulation in awake patients, the authors revisit the anatomofunctional aspects of surgery within the left IPL.

METHODS

Fourteen consecutive patients underwent awake craniotomy for a glioma involving the left IPL. Intraoperative motor, sensory, and language mapping was performed before and during the tumor removal, at both the cortical and subcortical levels, to optimize the extent of resection, which was determined based on functional boundaries. Anatomofunctional correlations were performed by combining the results of intraoperative mapping and those provided by pre- and postoperative MR imaging.

RESULTS

At the cortical level, the primary somatosensory area (retrocentral gyrus) limited the resection anteriorly in all cases, at least partially. Less frequently, speech arrest or articulatory problems were observed within the parietal operculum (4 cases). The lateral limit was determined by language sites that were variably distributed. Anomia was the most frequent response (9 cases) at the posterior third of the superior (and/or middle) temporal gyrus. Posteriorly, less reproducible reorganized language sites were seldom observed in the posterior portion of the angular gyrus (2 cases). At the subcortical level, in addition to somatosensory responses due to stimulation of the thalamocortical pathways, articulatory disturbances were induced by stimulation of white matter in the anterior and lateral part of the surgical cavity (11 cases). This tract anatomically corresponds to the horizontal portion of the lateral segment of the superior longitudinal fascicle (SLF III). Deeper and superiorly, phonemic paraphasia was the main language disturbance (12 cases), elicited by stimulation of the posterosuperior portion of the arcuate fascicle. All these eloquent structures were surgically preserved. Despite slight cognitive disorders (working memory, writing, or calculation) in 6 cases, no patient retained a severe or a moderate postoperative deficit (except one with right hemianopia [mean follow-up 41.8 months]). Resection was total or near total in 9 patients and partial in 3 cases.

CONCLUSIONS

To the authors' knowledge, this is the first series dedicated to the surgery of gliomas involving the left IPL. Interestingly, a certain degree of interindividual variability was observed in the distribution of the cortical maps, especially for language. Therefore, it is suggested that no rigid pattern of resection can be considered within the left IPL, and that surgery in this region should be performed in awake patients to adapt the tumor removal to individual functional limits. Nonetheless, several landmarks have been regularly identified, especially at the subcortical levels (SLF III and arcuate fascicle); a better knowledge of these functional tracts could be helpful to optimize functional outcomes.

Identification of spinothalamic tract and its related thalamocortical fibers in human brain

Little is known about the spinothalamic tract (STT) and its related thalamocortical fibers. In the current study, we attempted to identify the STT and related thalamocortical fibers in the human brain, using diffusion tensor tractography (DTT). We recruited 23 healthy volunteers for this study. Diffusion tensor images (DTIs) were scanned using 1.5-T, and the STT and medial lemniscus (ML) were obtained using FMRIB software. Normalized DTI tractography was reconstructed using the Montreal Neurological Institute (MNI) echo-planar imaging (EPI) template supplied with the SPM. The STT began at the posterolateral medulla and ascended to the ventral posterior-lateral (VPL) nucleus of the thalamus, through the pontine tegmentum posterolateral to the ML, and through the mesencephalic tegmentum posterior to the ML. STT-related thalamocortical fibers originated from the VPL nucleus of the thalamus and ascended through the posterior limb of the internal capsule and the posterior portion of the corona radiata, terminating at the primary somatosensory cortex. We identified the STT and its related thalamocortical fibers using DTT. These results would be helpful in the clinical field and also in research on somatosensory function in the human brain.

Sensory dysfunction following stroke: incidence, significance, examination, and intervention

Recent studies have provided evidence of the widespread incidence of sensory dysfunction following stroke. The importance of these findings lies in the association between sensory loss poststroke and poorer outcomes in motor capacity, functional abilities, length of inpatient stay, and quality of life. Since literature suggests that clinicians can use information about clients' sensory status to predict rehabilitation outcomes and select appropriate interventions, the accuracy of somatosensory assessment is extremely clinically relevant. However, many of the clinical tests that are commonly used to examine sensation have not been found to be valid or reliable. Emerging evidence supports the efficacy of several interventions that target the sensory systems. This article reviews the incidence, significance, examination, and interventions for sensory dysfunction following stroke and summarizes the important characteristics of interventions directed at somatosensation.

The stroke rehabilitation paradigm

The matrix of stroke rehabilitation is evolving as we look outside the box of traditional therapy type, timing, and intensity of rehabilitation techniques. For inpatient wards, the goal of medical stability and prompt resolution of complications to maximize participation in therapy remains paramount. In the current medical model, we focus on teaching compensatory strategies and rarely on restorative approaches because of time and financial limitations. Researchers aim to identify new technologic and molecular approaches to improve functional outcomes and more accurately predict disability. This article examines different concepts surrounding the comprehensive rehabilitation paradigm of stroke survivors.

The effect of spasticity, sense and walking aids in falls of people after chronic stroke

OBJECTIVE

To study the effects of spasticity, sensory impairment, and type of walking aid on falls in community dwellers with chronic stroke.

METHODS

Functional Independence Measure (FIM) Instrument, Joint Position Sense Evaluation (JPS), the Rivermead motor assessment scale (RMA), Ashworth Scale, Tinetti Assessment Tool were used to assess 100 cases.

RESULTS

Fifty-three of the cases were grouped as nonfallers, 36 as one-time fallers and 11 as repeat fallers. These 3 groups were found to be different from each other in respect to FIM, Tinetti test and RMA (p < 0.001). In respect to knee JPS, nonfallers and one-time faller groups were found to be different from repeat fallers (p = 0.001). There is a difference among the groups in respect to Ashworth assessment (p < 0.001), use of walking aid (p = 0.01) and type of walking aid (p = 0.01). Some 43% of the cases use a walking aid (58.1% cane, 41.9% high cane). According to Ordinal logistic regression analysis, it was found that the possibility of fall increased (p < 0.01), as the value of spasticity increased while the possibility of the fall of the individuals with stroke decreased (p < 0.00 - 0.01) as Tinetti, RMA and FIM variables increased.

CONCLUSIONS

In respect to falls, spasticity is also an indicator for chronic stroke patients, as is motor impairment, functional situation, impairment of balance and walking. Sensory impairment, using a walking aid and the type were found to be ineffective.

Can vision of the body ameliorate impaired somatosensory function?

Viewing the body is reported to improve tactile acuity [Kennett, S., Taylor-Clarke, M., & Haggard, P. (2001). Non-informative vision improves the spatial resolution of touch in humans. Current Biology, 11, 1188-1191]. The aim of the present study was to investigate whether this effect might be useful in improving somatosensory deficits of brain damaged patients. To support this proposal, we firstly tested the hypothesis that vision might modulate tactile performance when tactile information is limited. Thirty-two healthy subjects performed a two points discrimination task (2PDT) in three conditions: looking at their stimulated forearm, at a neutral object or at a rubber foot. The results showed that the effectiveness of visual enhancement of touch varies as a function of subjects' tactile acuity. Moreover, the accuracy in 2PDT was higher when viewing their arm only in subjects with lower tactile sensitivity. To directly demonstrate that viewing the body might ameliorate tactile deficits, the same experiment was conducted on 10 brain damaged patients suffering a reduced somatosensory sensitivity. An amelioration of the performance was found in viewing arm condition. These findings suggest that the interaction between different sensory modalities might be effective in ameliorating deficits in single modalities.

Rehabilitation of somatic sensation and related deficit of motor control in patients with pure sensory stroke11No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the author(s) or upon any organization with which the author(s) is/are associated

OBJECTIVE

To assess the effectiveness of a rehabilitative training program for deficits in somatic sensation and motor control of the hand in patients with pure sensory stroke.

DESIGN

Multiple baseline and before-after follow-up trial with behavioral analysis of single cases.

SETTING

Rehabilitation unit of a university hospital in Italy.

PARTICIPANTS

Four patients were studied: 2 had a unilateral lesion confined to the parietal lobe (patients 1, 2), and 2 had a unilateral lesion of the thalamus (patients 3, 4) that also lapped the posterior limb of the internal capsule. All 4 patients had chronic deficits in somatic sensation and motor control of the contralesional hand.

INTERVENTION

Behavioral training consisting of exercises aimed at improving somatic sensation and motor control of the affected, contralesional hand. Thirty treatment sessions, each lasting 50 minutes, were performed.

MAIN OUTCOME MEASURES

Somatic deficit was evaluated with 5 tests, and motor control deficit was assessed with 4 tests. One functional test estimated the influence of somatic deficit on daily activities. A visual analog scale (VAS) was also submitted to the patients' relatives to evaluate the amount of use of the affected arm in daily life activities. A baseline was obtained by recording each measure, except for the VAS, 4 times at the first evaluation session. Evaluation sessions were conducted before, after, and 6 months after the end of the experimental treatment.

RESULTS

All patients showed a stable baseline in at least 8 of the outcome measures. Patients 1 and 2 significantly improved in 9 and 7 outcome measures, respectively. Patients 3 and 4 improved in 4 and 7 outcome measures, respectively. With the exception of case 3, all patients considerably increased their use of the affected arm during daily life. The improvement was generally stable over a 6-month period, suggesting that the treatment had a long-term effect.

CONCLUSIONS

Results suggest the possible effectiveness of our training program for treating somatic and motor control deficits of the hand in patients with cortical or subcortical pure sensory stroke.

A Standardized Paediatric Sensory Assessment for the Lower Extremity: Preliminary Results of a Reliability Study in Normal School-Aged Children

The aims of this study were to establish a set of standardized sensory procedures for lower extremity sensory assessment in a paediatric population, to gather preliminary data on normal sensory performance, and to derive preliminary reliability estimates. Three subtests derived from the paediatric upper extremity sensory battery under development by Cooper, Majnemer, Rosenblatt and Birnbaum (1993) were performed bilaterally on 50 healthy, school-aged children: i) pressure sensitivity and ii) directionality, on the plantar surface of the distal phalanx of the hallux, using the Semmes-Weinstein Pressure Aesthesiometer, and iii) proprio-ception at the first metatarsal-phalangeal joint. Neither age nor gender exerted any significant effects on the data, whereas dominance did. Cut-offs were determined separately for the dominant and nondominant halluces. Data analysis revealed good test-retest and inter-rater agreements on all subtests. These sensory subtests show promise as a standardized, reliable and therapeutically useful assessment of lower extremity sensation in children at risk for sensory impairment.

The determination of sensory deficits in children with hemiplegic cerebral palsy

Therapeutic intervention for children with cerebral palsy begins with accurate appraisal of abilities and disabilities. Currently, treatment focuses on the identified motor deficits, with any underlying sensory deficits often being overlooked. Sensory input is an essential component of motor function and motor control. Therefore, the objective of this study was to determine the presence and extent of sensory deficits in school-aged hemiplegic children using a formal clinical sensory battery, as well as somatosensory evoked potentials. A cross-sectional comparative study was performed comparing sensory function in hemiplegic children and healthy controls. Nine hemiplegic children and 41 healthy controls between 4 and 19 years of age were assessed. Hemiplegic children were included if they had a minimum level of receptive language function of 30 to 33 months and expressive language ability of 24 to 27 months, and no severe limitation of joint range of the hand. Significant bilateral sensory deficits (88.8%) were ascertained in hemiplegic children (P < .05), when compared to the performance of the healthy controls. Stereognosis and proprioception were the chief modalities affected bilaterally. The extent of sensory loss did not mirror the severity of motor deficit. Conversely, findings on somatosensory evoked potentials were closely related to motor function. Thus, a clinical sensory evaluation should be an integral part of the assessment of children with cerebral palsy. The likelihood of sensory impairment in one or more modalities on the hemiplegic or nonhemiplegic side is underappreciated and needs to be identified by rehabilitation specialists to maximize the functional potential of these children.

Sensory loss in stroke patients: effective training of tactile and proprioceptive discrimination

Although somatosensory loss following stroke is common, with negative consequences for functional outcome, studies of existing somatosensory retraining programs are limited by theoretical weaknesses, poor methodology, and negative findings. We, therefore, developed a new program for stroke patients and investigated its effect on tactile discrimination in four AB, single-case quasi-experiments and its effect on tactile and proprioceptive discrimination in four multiple-baseline experiments. Training involved specific, graded discrimination tasks, attentive exploration of stimuli with vision occluded, deliberate anticipation, and quantitative feedback. Graphic and statistical interrupted time-series analyses indicated that treatment produced improvements in seven of eight tactile time series and all four proprioceptive time series. Baseline improvement in one tactile time series prevented unequivocal evaluation of treatment effect. Improvements were clinically significant, discrimination in the affected hand becoming comparable to the other hand and normal performance. Therapeutic effects were maintained at 3-month to 5-month follow-up tests.

A controlled trial of the retraining of the sensory function of the hand in stroke patients

A controlled trial of retraining of the sensory function of the hand was undertaken in hemiplegic patients after the period of spontaneous recovery. Twenty hemiplegic patients with sensory deficit in the hand, two or more years after stroke, received systematic retraining three times a week for six weeks. Sensation in the plegic hand was tested before and after this period in these patients and in 19 untreated control patients. The treated group showed large and significant gains on all sensory tests (P < 0.001), while no change occurred in the control group. It is concluded that somatosensory deficit can be alleviated even years after stroke and that rehabilitation for stroke patients should include sensory retraining for those with sensory deficit.

Functional prognosis in stroke: use of somatosensory evoked potentials

Median nerve somatosensory evoked potentials (SEPs) were performed on 35 patients with acute stroke and correlated with functional outcome as measured by placement, length of stay and an activities of daily living index (Barthel Index). There was a statistically significant correlation of both SEP and sensory examination at the 0.05 level to eventual functional outcome. SEPs were better than age, sex and side of CVA in predicting functional outcome as measured by these scores. SEPs and sensory examination are interrelated but SEPs offer the advantages of objectivity, the ability to quantify results and the use in unconscious or dysphasic patients.

Rehabilitation for stroke: a review

Survivors of stroke are often left with severe mental and physical disabilities, which create a major social and economic burden. Many investigators have attempted to assess the role of rehabilitation in reducing such disability. Few controlled studies provide accurate assessment and documentation of benefit. Because of the presence of multiple variables and inadequate measures of outcome, it is difficult to design studies evaluating the effectiveness of rehabilitation for stroke. It is unclear how early rehabilitation should begin and what aspects of rehabilitation are important. Intensive rehabilitation is an expensive and limited resource; thus, the ability to identify the subgroup of patients with stroke who are likely to benefit is a critical issue. Although preliminary guidelines for the selection of patients who are appropriate for rehabilitation are given, no uniform criteria reliably differentiate patients who need rehabilitation from those who will recover spontaneously or do poorly. Controlled studies in the practice of rehabilitation for stroke will provide much useful information for patient management.

Light touch thresholds in normal persons and cerebral vascular disease patient: bilateral deficit after unilateral lesion

Sensory thresholds, using the 2-alternative forced choice technique, were studied in normal subjects and in patients with unilateral cerebral vascular disease, as documented by clinical-radiologic correlation. In normal person the absolute threshold for light touch increased with age. Bilateral impairment of sensation with unilateral cerebral vascular lesions occurred in 30% of the patients. Tactile deficit was always greater on the side contralateral to infarction or hemorrhage. An ipsilateral deficit did not exist independent of contralateral deficity, and was more likely to occur with complete sensory loss contralaterally. There was a tendency for persons with larger lesions as determined clinically and by CAT scan to have ipsilateral as well as contralateral deficit. The incidence or severity of ipsilateral deficit was not related to lesion laterality.

Visual field defects and the prognosis of stroke patients

The prognosis of stroke patients is related to the presence or absence of homonymous hemianopia at time of admission to a stroke center. Two hundred thirty-four patients were followed for an average of 15 months. In patients with nonhemorrhagic strokes in the middle cerebral artery territory the presence of a dense homonymous hemianopia lasting for more than 24 hours, together with any degree of motor, sensory or speech defect, seemed to affect adversely the potential for rehabilitation and survival. Data were insufficient to draw similar conclusions with other types of cerebrovascular lesions. The pertinent literature is briefly reviewed.