Impacts of Sensation, Perception, and Motor Abilities of the Ipsilesional Upper Limb on Hand Functions in Unilateral Stroke: Quantifications From Biomechanical and Functional Perspectives

Aiming Movement After Stroke: Do Time-Since-Injury and Impairment Severity Influence Ipsilateral Performance?

In this cross-sectional study, we evaluated post-stroke ipsilesional (less affected) upper limb aiming movement in individuals whose strokes were either 2-5 months (n = 16) or >6 months (n = 17) prior to our testing; we also compared both stroke groups to a control group of healthy individuals (n = 14). We evaluated the participants' level of movement impairment in the contralateral upper limb from the site of the cerebrovascular lesion as an indicator of the severity of the participants' impairment. Participants were asked to move a stylus on a tablet with their ipsilesional upper limb according to a visual stimulus seen on a monitor. Those who had experienced more recent strokes showed poorer movement planning and execution, regardless of their impairment level. Since the stroke occurred, the amount of time was significantly associated with the ipsilesional aiming movement, and improvement over time brought performance levels closer to that of healthy controls.

Sensorimotor control of object manipulation following middle cerebral artery (MCA) stroke

Methods for assessing the loss of hand function post-stroke examine limited aspects of motor performance and are not sensitive to subtle changes that can cause deficits in everyday object manipulation tasks. Efficiently lifting an object entails a prediction of required forces based on intrinsic features of the object (sensorimotor integration), short-term updates in the forces required to lift objects that are poorly predicted (sensorimotor memory), as well as the ability to modulate distal fingertip forces, which are not measured by existing assessment tools used in clinics for both diagnostic and rehabilitative purposes. The presented research examined these three components of skilled object manipulation in 60 chronic, unilateral middle cerebral artery stroke participants. Performance was compared to age-matched control participants, and linear regressions were used to predict performance based on clinical scores. Most post-stroke participants performed below control levels in at least one of the tasks. Post-stroke participants presented with combinations of deficits in each of the tasks performed, regardless of the hemisphere damaged by the stroke. Surprisingly, the ability to modulate distal forces was impaired in those patients with damage ipsilateral (right hemisphere) to the hand being used. Sensorimotor integration was also impaired in patients with right hemisphere damage, though they performed at control levels in later lifts, whereas left-hemisphere-damaged patients did not. Lastly, during a task requiring sensorimotor memory, neither patient group performed outside of control ranges on initial lifts, with patients with right hemisphere damage showing impaired performance in later lifts suggesting they were unable to learn the mapping novel mapping of color and mass of the objects. The presented research demonstrates unilateral MCA stroke patients can have deficits in one or more components required for the successful manipulation of hand-held objects and that skillful object lifting requires intact bilateral systems. Further, this information may be used in future studies to aid efforts that target rehabilitation regimens to a stroke survivor's specific pattern of deficits.

Does grip strength of the less-affected side of ischemic stroke survivors influences performance of self-care activities?

Background and aim

Adequate grip strength is needed to execute various self-care activities. This study was aimed to assess the influence of grip strength of the less-affected side of ischemic stroke survivors on performance of self-care activities, and also to determine the reference values of less-affected grip strength needed for independent performance of each of the self-care activities.

Methods

Seventy-three consenting patients with ischemic stroke participated in this cross-sectional study. Handheld dynamometer was used to measure grip strength of the less-affected hand, while functional independence measure was used to evaluate self-care activities (eating, grooming, bathing, dressing of upper body, dressing of lower body and toileting) as independent and dependent. Data was analyzed using inferential statistics of Pearson’s correlation, binomial logistic regression, and receiver operating characteristics. Alpha level was set at p < 0.05.

Results

The mean hand grip strength, functional independence measure and trunk control test scores were 23.8 kg, 29.9 kg, and 68.2 kg respectively. Grip strength was significantly associated with independence in all of the self-care activities (p < 0.05). Less-affected grip strength of 19.5 kg (sensitivity, 80.4%; specificity, 80.1%; area under curve, 0.85), 23.7 kg (sensitivity, 79%; specificity, 72.2%; area under curve, 0.79), 24.8 kg (sensitivity, 70.2%; specificity, 65.2%; area under curve, 0.75), 24.7 kg (sensitivity, 82.1%; specificity, 80.1%; area under curve, 0.84), 23.7 kg (sensitivity, 80.1%; specificity, 76.1%; area under curve, 0.84), and 19.9 kg (sensitivity, 76.9%; specificity, 76.2%; area under curve, 0.79) was needed for independent performance in eating, grooming, bathing, dressing of upper body, dressing of lower body, and toileting respectively.

Conclusion

The less-affected grip strength of patients with ischemic stroke influences their ability to independently perform self-care activities. The reference values of less-affected grip strength in association with other stroke-related characteristics may help clinicians to estimate independence in eating, grooming, bathing, dressing of upper body, dressing of lower body, and toileting among patients with ischemic stroke.

Object-centered sensorimotor bias of torque control in the chronic stage following stroke

When lifting objects whose center of mass (CoM) are not centered below the handle one must compensate for arising external torques already at lift-off to avoid object tilt. Previous studies showed that finger force scaling during object lifting may be impaired at both hands following stroke. However, torque control in object manipulation has not yet been studied in patients with stroke. In this pilot study, thirteen patients with chronic stage left hemispheric stroke (SL), nine patients with right hemispheric stroke (SR) and hand-matched controls had to grasp and lift an object with the fingertips of their ipsilesional hand at a handle while preventing object tilt. Object CoM and therewith the external torque was varied by either relocating a covert weight or the handle. The compensatory torque at lift-off (Tcom) is the sum of the torque resulting from (1) grip force being produced at different vertical finger positions (∆CoP × GF) and (2) different vertical load forces on both sides of the handle (∆Fy × w/2). When having to rely on sensorimotor memories, ∆CoP × GF was elevated when the object CoM was on the ipsilesional-, but decreased when CoM was on the contralesional side in SL, whereas ∆Fy × w/2 was biased in the opposite direction, resulting in normal Tcom. SR patients applied a smaller ∆CoP × GF when the CoM was on the contralesional side. Torques were not altered when geometric cues were available. Our findings provide evidence for an object-centered spatial bias of manual sensorimotor torque control with the ipsilesional hand following stroke reminiscent of premotor neglect. Both intact finger force-to-position coordination and visuomotor control may compensate for the spatial sensorimotor bias in most stroke patients. Future studies will have to confirm the found bias and evaluate the association with premotor neglect.

Measurement of sensory deficiency in fine touch after stroke during textile fabric stimulation by electroencephalography (EEG)

Objective

Sensory deficiency of fine touch limits the restoration of motor functions after stroke, and its evaluation was seldom investigated from a neurological perspective. In this study, we investigated the cortical response measured by electroencephalography (EEG) on the fine touch sensory impairment during textile fabric stimulation after stroke.

Approach

Both participants with chronic stroke (n = 12, stroke group) and those unimpaired (n = 15, control group) were recruited. To investigate fine touch during textile fabric stimulations, full brain EEG recordings (64-channel) were used, as well as the touch sensation questionnaires based on the American Association of Textile Chemists and Colorists (AATCC) Evaluation Procedure 5. During the EEG measurement, relative spectral power (RSP) and EEG topography were used to evaluate the neural responses toward the fabric stimuli. In the subjective questionnaire, the fine touch for fabric stimuli was rated and represented by 13 different sensation parameters. The correlation between the fine touch evaluated by the EEG and the questionnaire was also investigated.

Main results

The neural responses of individuals with fine touch impairments after stroke were characterized by a shifted power spectrum to a higher frequency band, enlarged sensory cortical areas and higher RSP intensity (P < 0.05). Asymmetric neural responses were obtained when stimulating different upper limbs for both unimpaired participants and stroke participants (P < 0.05). The fine touch sensation of the stroke participants was impaired even in the unaffected limb. However, as a result of different neural processes, the correlation between the EEG and the questionnaire was weak (r < 0.2).

Significance

EEG RSP was able to capture the varied cortical responses induced by textile fabric fine touch stimulations related to the fine touch sensory impairment after stroke.

Effectiveness of Motivational Interviewing in Regard to Activities of Daily Living and Motivation for Rehabilitation among Stroke Patients

Background: Stroke patients urgently need rehabilitation to enhance activities of daily living. This study aims to determine whether motivational interviewing (MI) improves the performance of activities of daily living and enhances motivation for rehabilitation among first-stroke patients. Methods: A quasi-experimental design was used in this study. The study recruited 65 patients between March and October 2016. Before the intervention, all patients received routine care. The experimental group (n = 33) received weekly sessions of MI for 6 weeks, whereas the control group (n = 32) received individual attention from a research nurse weekly for 6 weeks. Structured questionnaires were used to collect data, including demographic data, activities of daily living data (Barthel index {BI} and instrumental activities of daily living {IADLs} scale), and rehabilitation motivation data. Results: The BI and IADLs scores significantly improved with time in both the experimental and control groups. The generalized estimating equation approach showed that at 6 weeks and 3 months after the intervention, the rehabilitation motivation scores in the experimental group were respectively 3.10 and 2.54 points higher than those in the control group, with significant differences. Conclusions: MI could effectively enhance motivation for rehabilitation among stroke patients.

Changes in ipsilesional hand motor function differ after unilateral injury to frontal versus frontoparietal cortices in Macaca mulatta

We tested the hypothesis that injury to frontoparietal sensorimotor areas causes greater initial impairments in performance and poorer recovery of ipsilesional dexterous hand/finger movements than lesions limited to frontal motor areas in rhesus monkeys. Reaching and grasping/manipulation of small targets with the ipsilesional hand were assessed for 6-12 months post-injury using two motor tests. Initial post-lesion motor skill and long-term recovery of motor skill were compared in two groups of monkeys: (1) F2 group-five cases with lesions of arm areas of primary motor cortex (M1) and lateral premotor cortex (LPMC) and (2) F2P2 group-five cases with F2 lesions + lesions of arm areas of primary somatosensory cortex and the anterior portion of area 5. Initial post-lesion reach and manipulation skills were similar to or better than pre-lesion skills in most F2 lesion cases in a difficult fine motor task but worse than pre-lesion skill in most F2P2 lesion cases in all tasks. Subsequently, reaching and manipulation skills improved over the post-lesion period to higher than pre-lesion skills in both groups, but improvements were greater in the F2 lesion group, perhaps due to additional task practice and greater ipsilesional limb use for daily activities. Poorer and slower post-lesion improvement of ipsilesional upper limb motor skill in the F2P2 cases may be due to impaired somatosensory processing. The persistent ipsilesional upper limb motor deficits frequently observed in humans after stroke are probably caused by greater subcortical white and gray matter damage than in the localized surgical injuries studied here.

Actigraphic measurement of the upper limbs movements in acute stroke patients

Background

Stroke units provide patients with a multiparametric monitoring of vital functions, while no instruments are actually available for a continuous monitoring of patients motor performance. Our aim was to develop an actigraphic index able both to identify the paretic limb and continuously monitor the motor performance of stroke patients in the stroke unit environment.

Methods

Twenty consecutive acute stroke patients (mean age 69.2 years SD 10.1, 8 males and 12 females) and 17 bed-restrained patients (mean age 70.5 years SD 7.3, 7 males and 10 females) hospitalized for orthopedic diseases of the lower limbs, but not experiencing neurological symptoms, were enrolled. This last group represented our control group. The motor activity of arms was recorded for 24 h using two programmable actigraphic systems showing off as wrist-worn watches. The firmware segmented the acquisition in epochs of 1 minute and for each epoch calculates two motor activity indices: MA_e1 (Epoch-related Motor Activity index) and MA_e2 (Epoch-related Motor Activity index 2). MA_e1 is defined as the standard deviation of the acceleration module and MA_e2 as the module of the standard deviation of acceleration components. To describe the 24 h motor performance of each limb, we calculated the mean value of MA_e1 and MA_e2 (respectively MA_{1_24h} and MA_{2_24h}). Then we obtained two Asymmetry Rate Indices: AR_{1_24h} and AR_{2_24h} to show the motor activity prevalence. AR_{1_24h} refers to the asymmetry index between the values of MA_e1 of both arms and AR_{2_24h} to MA_e2 values.

The stroke patients were clinically evaluated by NIHSS at the beginning (NIHSS_T0) and at the end (NIHSS_T1) of the 24 h actigraphic recordings.

Results

Both MA_{1_24h} and MA_{2_24h} indices were smaller in the paretic than in the unaffected arm (respectively p = 0.004 and p = 0.004). AR_{2_24h} showed a better capability (95% of paretic arms correctly identified, Phi Coefficient: 0.903) to discriminate the laterality of the clinical deficit than AR_{1_24h} (85% of paretic arms correctly identified, Phi Coefficient: 0,698). We also found that AR_{1_24h} did not differ between the two groups of patients while AR_{2_24h} was greater in stroke patients than in controls and positively correlated with NIHSS total scores (r: 0.714, p < 0.001 for NIHSS, IC95%: 0.42–0.90) and with the sub-score relative to the paretic upper limb (r: 0.812, p < 0.001, IC95%: 0.62–0.96).

Conclusions

Our data show that actigraphic monitoring of upper limbs can detect the laterality of the motor deficit and measure the clinical severity. These findings suggest that the above described actigraphic system could implement the existing multiparametric monitoring in stroke units.

Effect of aerobic exercise prior to modified constraint-induced movement therapy outcomes in individuals with chronic hemiparesis: a study protocol for a randomized clinical trial

BACKGROUND

Recovery of upper limb function in individuals after a stroke remains challenging. Modified constraint-induced movement therapy (m-CIMT) has strong evidence for increasing the use and recovery of sensorimotor function of the paretic upper limb. Recent studies have shown that priming with aerobic exercise prior to task-specific training potentiates upper limb recovery in individuals with stroke. This protocol describes a randomized clinical trial designed to determine whether priming with moderate-high intensity aerobic exercise prior to m-CIMT will improve the manual dexterity of the paretic upper limb in individuals with chronic hemiparesis.

METHODS

Sixty-two individuals with chronic hemiparesis will be randomized into two groups: Aerobic exercise + m-CIMT or Stretching + m-CIMT. m-CIMT includes 1) restraint of the nonparetic upper limb for 90% of waking hours, 2) intensive task-oriented training of the paretic upper limb for 3 h/day for 10 days and 3) behavior interventions for improving treatment adherence. Aerobic exercise will be conducted on a stationary bicycle at intervals of moderate to high intensity. Participants will be evaluated at baseline, 3, 30, and 90 days postintervention by the following instruments: Motor Activity Log, Nottingham Sensory Assessment, Wolf Motor Function Test, Box and Block Test, Nine-Hole Peg Test, Stroke Specific Quality of Life Scale and three-dimensional kinematics. The data will be tested for normality and homogeneity. Parametric data will be analyzed by two-way ANOVA with repeated measures and Bonferroni's adjustment. For nonparametric data, the Friedman test followed by the Wilcoxon test with Bonferroni's adjustment will be used to compare the ratings for each group. To compare the groups in each assessment, the Mann-Whitney test will be used.

DISCUSSION

This study will provide valuable information about the effect of motor priming for fine upper limb skill improvement in people with chronic poststroke hemiparesis, bringing new evidence about the association of two therapies commonly used in clinical practice.

TRIAL REGISTRATION

This trial was retrospectively registered (registration number RBR-83pwm3 ) on 07 May 2018.

Classifying hand sensorimotor functions of the chronic kidney disease patients using novel manual tactile test and pinch-holding-up activity

Hand function deterioration brings about inconvenience to the daily lives of the chronic kidney disease patients. However, a full spectrum of hand function examination is absent. Therefore, this study aimed to classify the hand sensorimotor functions of the chronic kidney disease patients using the novel sensorimotor assessment tools, manual tactile test (MTT) and pinch-holding-up activity (PHUA) test, and explore the feasibility in comparison with traditional evaluations in the clinical practice. 68 stage-5 chronic kidney disease patients and 50 healthy subjects were recruited in this study. A series of conventional evaluations and two novel hand function tools, manual tactile test and pinch-holding-up activity test were conducted from the perspective of hand dexterity, sensory input threshold, force generation and sensorimotor control. Independent t-test was used to find out group differences and the receiver operating characteristic curve was used to determine accuracy of the tests. In our results, significant reduction of hand dexterity, sensory input, force generation and sensorimotor control was found in patients from an overall perspective. This trend was discovered to be the same when dividing the subjects into the old and young age group. From the receiver operator characteristic curves, nearly all the areas under the curve of all tests were over 0.8. The novel evaluation tools, the manual tactile test and pinch-holding-up activity, were found to have comparable or even better accuracy than the traditional ones. The shape and weight subtests of the manual tactile test displayed the highest accuracy. To sum up, by incorporating the novel and conventional assessment tests, this study built up the fundamental understanding of the hand functions in multiple dimensions and consolidate the clinical merits of applying the two novel tools, manual tactile test and pinch-holding-up activity, on chronic kidney disease patients.

Closed-Loop Control of the Centre of Pressure in Post-Stroke Patients With Balance Impairments

When a lightly touched surface is moved according to a closed-loop control law, it has been shown in young adults that the centre of pressure (CoP) can be displaced in a controllable way without the conscious cooperation of participants. In this closed-loop paradigm, the surface velocity was continuously adjusted according to the CoP position. Since the closed-loop control of the CoP does not require the participant's voluntary cooperation, it could be of interest for the development of innovative biofeedback devices in balance rehabilitation. Before anticipating the implementation of this closed-loop control paradigm with patients, it is necessary to establish its effects on people suffering from balance impairments. The aim of this paper was to assess the effects of this CoP closed-loop control in post-stroke (PS) patients and aged-matched healthy controls. Efficacy of the closed-loop control for driving the patients' CoP was assessed using the saturation time and two scores computing the error between the predefined and the current CoP trajectories. 68% and 83% of the trials were considered as successful in patients and controls, respectively. The global tracking error of the closed-loop score was similar between the two groups. However, when examining the real CoP displacement from the starting position to the desired one, PS patients responded to the closed-loop control to a lesser extent than controls. These results, obtained in the same conditions for healthy and PS individuals could be improved by tuning the closed-loop parameters according to individual characteristics. This paper paves the road towards the development of involuntary/automatic biofeedback techniques in more ecological conditions.