Chronic Unilateral Stroke Research Articles

Walking performance of persons with chronic stroke changed when looking down but not in dimly lit environment.

It is common to walk under different conditions, such as looking straight head, looking down at the feet or in dimly lit environment. The purpose of this study was to determine the impact of these different conditions on walking performance in persons with and without stroke. This was a case-control study. Persons with chronic unilateral stroke and age-matched control (n = 29 each) underwent visual acuity test, Mini Mental Status Examination (MMSE) and joint position sense test of the knee and ankle. The participants walked at their preferred speed under three walking conditions, looking ahead (AHD), looking down (DWN), and in dimly lit environment (DIM). A motion analysis system was used for the recording of the limb matching test and walking tasks. Stroke participants differed from the control group in MMSE, but not in age, visual acuity or joint position sense. For the control group, the differences between the three walking conditions were nonsignificant. For the stroke group, DWN had significantly slower walking speed, greater step width and shorter single leg support phase, but not different symmetry index or COM location, compared to AHD. The differences between AHD and DIM were nonsignificant. Healthy adults did not change their gait patterns under the different walking conditions. Persons with chronic stroke walked more cautiously but not more symmetrically when looking down at the feet, but not in dimly lit environment. Ambulatory persons with stroke may need to be advised that looking down at the feet while walking could be more challenging.

Computer-Based Assessment: Dual-Task Outperforms Large-Screen Cancellation Task in Detecting Contralesional Omissions.

Objective: Traditionally, asymmetric spatial processing (i.e., hemispatial neglect) has been assessed with paper-and-pencil tasks, but growing evidence indicates that computer-based methods are a more sensitive assessment modality. It is not known, however, whether simply converting well-established paper-and-pencil methods into a digital format is the best option. The aim of the present study was to compare sensitivity in detecting contralesional omissions of two different computer-based methods: a “digitally converted” cancellation task was compared with a computer-based Visual and Auditory dual-tasking approach, which has already proved to be very sensitive.Methods: Participants included 40 patients with chronic unilateral stroke in either the right hemisphere (RH patients, N = 20) or the left hemisphere (LH patients, N = 20) and 20 age-matched healthy controls. The cancellation task was implemented on a very large format (173 cm × 277 cm) or in a smaller (A4) paper-and-pencil version. The computer-based dual-tasks were implemented on a 15′′ monitor and required the detection of unilateral and bilateral briefly presented lateralized targets.Results: Neither version of the cancellation task was able to show spatial bias in RH patients. In contrast, in the Visual dual-task RH patients missed significantly more left-sided targets than controls in both unilateral and bilateral trials. They also missed significantly more left-sided than right-sided targets only in the bilateral trials of the Auditory dual-task.Conclusion: The dual-task setting outperforms the cancellation task approach even when the latter is implemented on a (large) screen. Attentionally demanding methods are useful for revealing mild forms of contralesional visuospatial deficits.

The Effects and Adverse Effects of tDCS on Motor Learning Process in Chronic Unilateral Stroke Patients

Objectives: It seems that psycho-physical factors of stroke patients undergoing Transcranial direct current stimulation (tDCS) treatment can affect implicit motor learning process in patient with stroke. The aim of this study was to determine the effects and adverse effects of tDCS on motor learning process in chronic unilateral stroke patients. Methods & Materials: This crossover, sham-controlled, randomized, blinded study was conducted in 2020 on 12 patients with chronic unilateral stroke (Mean±SD age, 60.33±1.87 years), (The Mean±SD time elapsed since the onset of the disease, 1.96±1.36 years) referred to Mobasher Kashani clinic in Hamadan, Iran who were selected using a convenience sampling technique. Patients were randomly divided in to 2 groups: experimental (dual tDCS+SRTT) (n=6) and sham (sham tDCS+SRTT) (n=6) groups. After 3 weeks of washing out period, patients in each group were treated in other brain stimulation group again. Data were collected using the record of reaction time and error of sequenced blocks by related software. Also, adverse effects of tDCS, pain or discomfort, attention and fatigue of patients were assessed by visual analogue scale (VAS) questionnaire. The data were analyzed using linear mixed effects. Results: Data analysis showed a considerable improvement in implicit motor learning in both brain stimulation groups. The most reported sensations were itching and tingling, which continued during all stimulation sessions. The pain or discomfort of the patients was negligible during the intervention sessions. Moreover, the type of brain stimulation, the time and their interaction had no significant effect on the fatigue, attention and pain of the patients (P>0.05). Conclusion: Dual-tDCS technique does not cause serious adverse effects in patients with stroke. It can be used as an effective and useful therapeutic strategy for increase in implicit motor learning in chronic stroke patients.

Unilateral Stroke: Computer-based Assessment Uncovers Non-Lateralized and Contralesional Visuoattentive Deficits.

Patients with unilateral stroke commonly show hemispatial neglect or milder contralesional visuoattentive deficits, but spatially non-lateralized visuoattentive deficits have also been reported. The aim of the present study was to compare spatially lateralized (i.e., contralesional) and non-lateralized (i.e., general) visuoattentive deficits in left and right hemisphere stroke patients. Participants included 40 patients with chronic unilateral stroke in either the left hemisphere (LH group, n = 20) or the right hemisphere (RH group, n = 20) and 20 healthy controls. To assess the contralesional deficits, we used a traditional paper-and-pencil cancellation task (the Bells Test) and a Lateralized Targets Computer Task. To assess the non-lateralized deficits, we developed a novel large-screen (173 × 277 cm) computer method, the Ball Rain task, with moving visual stimuli and fast-paced requirements for selective attention. There were no contralesional visuoattentive deficits according to the cancellation task. However, in the Lateralized Targets Computer Task, RH patients missed significantly more left-sided than right-sided targets in bilateral trials. This omission distribution differed significantly from those of the controls and LH patients. In the assessment of non-lateralized attention, RH and LH patients missed significantly more Ball Rain targets than controls in both the left and right hemifields. Computer-based assessment sensitively reveals various aspects of visuoattentive deficits in unilateral stroke. Patients with either right or left hemisphere stroke demonstrate non-lateralized visual inattention. In right hemisphere stroke, these symptoms can be accompanied by subtle contralesional visuoattentive deficits that have remained unnoticed in cancellation task.

Neural Correlates of Passive Position Finger Sense After Stroke

Background. Proprioception of fingers is essential for motor control. Reduced proprioception is common after stroke and is associated with longer hospitalization and reduced quality of life. Neural correlates of proprioception deficits after stroke remain incompletely understood, partly because of weaknesses of clinical proprioception assessments. Objective. To examine the neural basis of finger proprioception deficits after stroke. We hypothesized that a model incorporating both neural injury and neural function of the somatosensory system is necessary for delineating proprioception deficits poststroke. Methods. Finger proprioception was measured using a robot in 27 individuals with chronic unilateral stroke; measures of neural injury (damage to gray and white matter, including corticospinal and thalamocortical sensory tracts), neural function (activation of and connectivity of cortical sensorimotor areas), and clinical status (demographics and behavioral measures) were also assessed. Results. Impairment in finger proprioception was present contralesionally in 67% and bilaterally in 56%. Robotic measures of proprioception deficits were more sensitive than standard scales and were specific to proprioception. Multivariable modeling found that contralesional proprioception deficits were best explained (r2 = 0.63; P = .0006) by a combination of neural function (connectivity between ipsilesional secondary somatosensory cortex and ipsilesional primary motor cortex) and neural injury (total sensory system injury). Conclusions. Impairment of finger proprioception occurs frequently after stroke and is best measured using a quantitative device such as a robot. A model containing a measure of neural function plus a measure of neural injury best explained proprioception performance. These measurements might be useful in the development of novel neurorehabilitation therapies.

Bimanual elbow robotic orthoses: preliminary investigations on an impairment force-feedback rehabilitation method.

Modern rehabilitation practices have begun integrating robots, recognizing their significant role in recovery. New and alternative stroke rehabilitation treatments are essential to enhance efficacy and mitigate associated health costs. Today’s robotic interventions can play a significant role in advancing rehabilitation. In addition, robots have an inherent ability to perform tasks accurately and reliably and are typically well suited to measure and quantify performance. Most rehabilitation strategies predominantly target activation of the paretic arm. However, bimanual upper-limb rehabilitation research suggests potential in enhancing functional recovery. Moreover, studies suggest that limb coordination and synchronization can improve treatment efficacy. In this preliminary study, we aimed to investigate and validate our user-driven bimanual system in a reduced intensity rehab practice. A bimanual wearable robotic device (BWRD) with a Master–Slave configuration for the elbow joint was developed to carry out the investigation. The BWRD incorporates position and force sensors for which respective control loops are implemented, and offers varying modes of operation ranging from passive to active training. The proposed system enables the perception of the movements, as well as the forces applied by the hemiparetic arm, with the non-hemiparetic arm. Eight participants with chronic unilateral stroke were recruited to participate in a total of three 1-h sessions per participant, delivered in a week. Participants underwent pre- and post-training functional assessments along with proprioceptive measures. The post-assessment was performed at the end of the last training session. The protocol was designed to engage the user in an assortment of static and dynamic arm matching and opposing tasks. The training incorporates force-feedback movements, force-feedback positioning, and force matching tasks with same and opposite direction movements. We are able to suggest identification of impairment patterns in the position-force plot results. In addition, we performed a proprioception evaluation with the system. We set out to design innovative and user immersive training tasks that utilize the BWRD capabilities, and we demonstrate that the subjects were able to cooperate and accomplish the protocol. We found that the Fugl–Meyer and Wolf Motor Function Test (pre to post) measured improvements (15 and 19%, respectively). Recognizing the brevity of the training, we focus our report primarily on the proprioception testing (32% significant improvement, pprop = 0.033) and protocol distinctive features and results. This paper presents the electromechanical features and performance of the BWRD, the testing protocol, and the assessments utilized. Outcome measures and results are presented and demonstrate the successful application and operation of the system.

Effect of mirror therapy combined with somatosensory stimulation on motor recovery and daily function in stroke patients: A pilot study

Mirror therapy (MT) has been recommended as a simple, inexpensive approach to treat motor dysfunction. The use of a mesh glove (MG) was suggested to normalize muscle tone that ameliorates motor impairment. Combining two efficient treatment protocols might maximize the benefits from training. This study investigated the effects of MT combined with MG (MG+MT) versus MT alone on motor performance and daily function after stroke. Sixteen patients with chronic unilateral stroke were recruited. A randomized two-group pretest and posttest design was used to randomly assign participants to MG+MT or MT groups. MT involves repetitive bimanual, symmetrical movement practice in which the individual moves the affected limb as much as she/he could while watching the reflective illusion of the unaffected limb's movements from a mirror. The MG+MT group wore a MG on the affected hand during the MT. The Modified Ashworth scale of muscle spasticity (MAS), Action Research Arm Test (ARAT), Box and Block Test (BBT), and Functional Independence Measure (FIM) were administered to evaluate spasticity, and motor and daily function. The results for the BBT (p=0.013), total scores (p=0.031), grasping subscales (p=0.036) of ARAT, and FIM transfer scores (p=0.013) presented significantly large effects in favor of the MG+MT group. Combining MG with MT significantly improves manual dexterity, grasping, and transfer performance. Adding the MG component into the MT likely increased the richness of sensory input and improved the movement performance more than MT alone.

Effects of Sensory Cueing on Voluntary Arm Use for Patients With Chronic Stroke: A Preliminary Study

Fong KN, Lo PC, Yu YS, Cheuk CK, Tsang TH, Po AS, Chan CC. Effects of sensory cueing on voluntary arm use for patients with chronic stroke: a preliminary study. Objective To investigate the effect of a 2-week program of sensory cueing in which vibration induces the use of the paretic upper extremity in participants with chronic stroke in the community. Design A single-group longitudinal study. Setting Self-help organizations. Participants A convenience sample of 16 community residents (N=16) with chronic unilateral stroke and mild to moderate upper-extremity impairment stratified by the severity of their paretic arm function, measured by using the Functional Test for the Hemiplegic Upper Extremity (FTHUE). Interventions Participants engaged in repetitive upper-extremity task practice for 2 weeks while wearing an ambulatory sensory cueing device on their affected hand for 3 hours a day. Main Outcome Measures Evaluations were conducted on the 3 occasions of pretest (1 day before training), posttest (immediately after training), and follow-up test (2 weeks after training) by using the following behavioral measures of paretic upper-extremity performance: the Action Research Arm Test (ARAT), the Box and Block Test, the Fugl-Meyer Assessment (FMA), the FTHUE, power and pinch grips, the Motor Activity Log assessment of arm use, and kinematic data obtained from the device. Results Significant differences were found in ARAT and FMA scores among the pretest, posttest, and follow-up evaluations. The lower functioning group achieved a more significant increase in overall upper-extremity score than in the hand score for the FMA. Conclusion A combination of sensory cueing and movement-based strategies is useful and feasible in improving paretic upper-extremity performance in participants with chronic stroke; however, additional studies with a larger sample size and longer treatment period in a randomized controlled trial would be beneficial.

Utility of the Neuropsychological Assessment Battery in detecting cognitive impairment after unilateral stroke

This study evaluated the clinical utility of the Neuropsychological Assessment Battery (NAB) in a stroke sample by examining the NAB's ability to differentiate a chronic stroke group with radiologically confirmed unilateral damage (n = 42) and a demographically matched healthy control (HC) group (n = 36). The stroke group performed more poorly than the control group across NAB Total score and all five Domain scores. Receiver operator curves (ROC) were derived and area under the curve (AUC) showed moderate diagnostic effectiveness (AUC .70 to .90) for NAB Total score, all five Domain scores, a motor composite, and a Global Deficit Score (GDS) that has been shown to closely approximate clinical ratings of neuropsychological impairment. The NAB Total, GDS, and motor composite had comparable clinical utility, whereas the Attention and Executive domain scores demonstrated better classification utility compared with the Memory domain. Because 90.5% of our stroke sample had middle cerebral artery territory strokes, the comparison of motor and cognitive classification utility may be biased. However, follow-up analyses showed that the NAB accounted for additional variance even when motor composite was included in the model. Sensitivity, specificity, and odds ratios at various clinical cutoffs are provided. These results suggest that the NAB is a useful clinical tool for detection of cognitive deficits in individuals with chronic unilateral stroke, although lenient clinical cutoffs appear warranted to maximize sensitivity.

Gait reveals bilateral adaptation of motor control in patients with chronic unilateral stroke

Functional brain imaging has shown that bilateral brain reorganization may occur after unilateral cerebral damage. The present study searched for evidence of bilateral motor control changes in gait in patients with chronic unilateral stroke. Gait variables (temporal and spatial parameters, footprint peak times (FPPT) and footfall times (FFT)) were recorded in 48 patients with chronic unilateral stroke at their preferred speed, and in 10 healthy volunteers walking from very slowly to very fast on a pressure sensor walkway. The data were divided into 4 groups according to gait velocity. The functional outcome of stroke was measured by the Barthel Index. Patients' gait variables reflected their hemiparetic gait pattern. Slower patients had prolonged stance, FPPT and FFT on the non-affected side (NS), and prolonged swing and shorter FPPT and FFT on the affected side (AS). The magnitude of the asymmetry index of these parameters was inversely associated with velocity performance and, at the same time, it characterized how much the control of the clinically healthy (NS) side was altered during walking. Bilateral changes in kinetic and footfall variables in the chronic stage of unilateral stroke were present. Patients chose their preferred walking velocity using stereotyped, alternative gait patterns, in which the contribution of the NS was larger than that of the AS. Alternative gait patterns may partly demonstrate compensatory behavioral strategies adapted by patients.

Limited dose response to Constraint-Induced Movement Therapy in patients with chronic stroke

Objective: To compare outcomes in motor skill, perceived amount of use and ability of the paretic arm in daily activities between traditional Constraint-Induced Movement Therapy, consisting of 6 hours of in-clinic, therapist-guided task practice, and a shortened Constraint-Induced Movement Therapy, consisting of 1 hour of in clinic, therapist-guided task practice coupled with 5 hours of unsupervised practice at home. Design: A secondary analysis of two previous randomized, controlled, double-blind, parallel group studies. Setting: A research clinic. Participants: Thirty-nine individuals with hemiparesis from a chronic unilateral stroke who were able to extend the wrist 10° and the fingers and thumb 10° from a flexed position and were participants in one of the two studies examining the efficacy of adding neuroplasticity adjuvants to Constraint-Induced Movement Therapy. Main outcome measures: The Wolf Motor Function Test was used to assess motor skill and the Motor Activity Log amount of use and quality of movement scales were used to assess perceived amount of use and ability respectively. Interventions: Constraint-Induced Movement Therapy plus donepezil in the CIMT-6 study (the traditional 6 hours of in-clinic task practice) and Constraint-Induced Movement Therapy plus repetitive transcranial magnetic stimulation in the CIMT-1 study (1 hour of in-clinic task practice). Results: Motor skill gains after two weeks of therapy were equivalent for both groups (n=39; mean difference=2.81, P>0.22), but gains were not maintained six months later with either intervention protocol. Despite this, participants in the CIMT-6 group reported greater use (mean difference=1.52, P<0.001) and movement quality (mean difference=0.95, P<0.004) than those with less therapist-guided practice. Both groups had regressed somewhat in use and ability at the six-month follow-up. Conclusion: These results suggest that 6 hours of therapist-guided practice may not be necessary to facilitate motor skill gains, but may influence patterns of use.

1362 Gait reflects bilateral brain reorganization of motor control in patients with chronic unilateral stroke

1362 Gait reflects bilateral brain reorganization of motor control in patients with chronic unilateral stroke

Gait characteristics and functional ambulation profile in patients with chronic unilateral stroke.

Recent technical progress in gait analysis has resulted in portable walkways with embedded pressure-sensitive sensors. Often claims are made in connection with new equipment of their straightforward clinical use. The purpose of the present study was to assess whether the functional ambulation profile (FAP), calculated from walkway data, is a sensitive measure in the characterization of dissimilar patients with chronic hemiparesis due to stroke. We investigated the relationships between FAP and the type of stroke, patients' functional disability, and spatial and temporal variables of gait obtained with the pressure sensor system walkway. Gait variables and FAP scores were compared in 25 patients with residual hemiparesis due to stroke and in 31 healthy subjects. A prolonged swing phase in the affected side and a prolonged stance phase in the nonaffected side were found in patients. Footprint pressure data revealed reduced peak pressure of the affected-side metatarsal area in patients, probably reflecting foot paresis. Higher Barthel Index score and lower Rankin Scale score were reflected in FAP scores. The FAP scores of patients reflected well their characteristic spatio-temporal gait variations; however, the FAP score seemed a reliable measure of gait normality/abnormality only in rather unhurried gait. Thus, it is useful when a single number is needed.

Relation of cerebral blood flow to motor and cognitive functions in chronic stroke patients.

The aim of this study was to examine the levels of cerebral blood flow in relation to motor and cognitive functions in 300 chronic unilateral stroke patients (age, 64 +/- 12 years; mean +/- SD). Cerebral blood flow was measured by the 133Xe inhalation method, adjusted for age, sex, and PCO2 level. Motor function was scored according to Brunnstrom hemiplegic staging and cognitive function according to the Hasegawa dementia rating scale tested in Japanese. Asymmetries of blood flow between affected and nonaffected hemispheres increased with lesion size and were highest in 11 embolic strokes (20 +/- 9%) and higher in 80 nonembolic cortical infarctions (11 +/- 11%) and 76 hemorrhages (9 +/- 7%) than in the group of 133 subcortical infarctions (2 +/- 6%) or 16 control subjects (1 +/- 2%). Severity of hemiparesis correlated with decreased cerebral blood flow in the affected hemisphere (P < .01) and increased hemispheric asymmetries of blood flow (P < 001). Cognitive impairments, after adjusting for age, correlated with decreased cerebral blood flow in the nonaffected hemisphere (P < .0001), left hemispheric lesions (P < .0005), and embolic stroke (P < .005) but not with asymmetries of blood flow. Among 67 patients having bilateral reductions of cerebral blood flow, 25 patients with left hemispheric lesions showed more severe cognitive impairments than among 42 patients with right hemispheric lesions (P < .05). We confirmed that severity of hemiparesis correlated with the degree of asymmetries of cerebral blood flow, reflecting the extent and location of the lesions. Bilateral reductions of cerebral blood flow in patients with left hemispheric lesions may in part contribute to cognitive impairments, indicating reductions of global neuronal activities in the contralateral hemisphere or diffuse cerebrovascular changes. Further studies of cerebral metabolism and follow-up of cerebral circulation are required to reveal the pathophysiology and clinical consequences.