Survivors of Chronic Stroke Experience Continued Impairment of Dexterity But Not Strength in the Nonparetic Upper Limb

Cortical activity in patients with high-functioning ischemic stroke during the Purdue Pegboard Test: insights into bimanual coordinated fine motor skills with functional near-infrared spectroscopy

After stroke, even high-functioning individuals may experience compromised bimanual coordination and fine motor dexterity, leading to reduced functional independence. Bilateral arm training has been proposed as a promising intervention to address these deficits. However, the neural basis of the impairment of functional fine motor skills and their relationship to bimanual coordination performance in stroke patients remains unclear, limiting the development of more targeted interventions. To address this gap, our study employed functional near-infrared spectroscopy to investigate cortical responses in patients after stroke as they perform functional tasks that engage fine motor control and coordination. Twenty-four high-functioning patients with ischemic stroke (7 women, 17 men; mean age 64.75 ± 10.84 years) participated in this cross-sectional observational study and completed four subtasks from the Purdue Pegboard Test, which measures unimanual and bimanual finger and hand dexterity. We found significant bilateral activation of the sensorimotor cortices during all Purdue Pegboard Test subtasks, with bimanual tasks inducing higher cortical activation than the assembly subtask. Importantly, patients with better bimanual coordination exhibited lower cortical activation during the other three Purdue Pegboard Test subtasks. Notably, the observed neural response patterns varied depending on the specific subtask. In the unaffected hand task, the differences were primarily observed in the ipsilesional hemisphere. In contrast, the bilateral sensorimotor cortices and the contralesional hemisphere played a more prominent role in the bimanual task and assembly task, respectively. While significant correlations were found between cortical activation and unimanual tasks, no significant correlations were observed with bimanual tasks. This study provides insights into the neural basis of bimanual coordination and fine motor skills in high-functioning patients after stroke, highlighting task-dependent neural responses. The findings also suggest that patients who exhibit better bimanual performance demonstrate more efficient cortical activation. Therefore, incorporating bilateral arm training in post-stroke rehabilitation is important for better outcomes. The combination of functional near-infrared spectroscopy with functional motor paradigms is valuable for assessing skills and developing targeted interventions in stroke rehabilitation.

Roles of Handedness and Hemispheric Lateralization: Implications for Rehabilitation of the Central and Peripheral Nervous Systems: A Rapid Review

IMPORTANCE

Handedness and motor asymmetry are important features of occupational performance. With an increased understanding of the basic neural mechanisms surrounding handedness, clinicians will be better able to implement targeted, evidence-based neurorehabilitation interventions to promote functional independence.

OBJECTIVE

To review the basic neural mechanisms behind handedness and their implications for central and peripheral nervous system injury.

DATA SOURCES

Relevant published literature obtained via MEDLINE.

FINDINGS

Handedness, along with performance asymmetries observed between the dominant and nondominant hands, may be due to hemispheric specializations for motor control. These specializations contribute to predictable motor control deficits that are dependent on which hemisphere or limb has been affected. Clinical practice recommendations for occupational therapists and other rehabilitation specialists are presented.

CONCLUSIONS AND RELEVANCE

It is vital that occupational therapists and other rehabilitation specialists consider handedness and hemispheric lateralization during evaluation and treatment. With an increased understanding of the basic neural mechanisms surrounding handedness, clinicians will be better able to implement targeted, evidence-based neurorehabilitation interventions to promote functional independence. Plain-Language Summary: The goal of this narrative review is to increase clinicians' understanding of the basic neural mechanisms related to handedness (the tendency to select one hand over the other for specific tasks) and their implications for central and peripheral nervous system injury and rehabilitation. An enhanced understanding of these mechanisms may allow clinicians to better tailor neurorehabilitation interventions to address motor deficits and promote functional independence.

[Modern view on upper limb physical rehabilitation after stroke. Literature review]

Stroke is the world's second leading cause of death and the first cause of disability among all diseases. The most common complication of a stroke is a violation of the motor function of the limbs, which significantly worsens the quality of life and the level of self-care and independence of patients. Restoring the function of the upper limb is one of the priority tasks of rehabilitation after a stroke. A large number of factors, such as the location and size of the primary brain lesion, the presence of complications in the form of spasticity, impaired skin and proprioceptive sensitivity, and comorbidities, determine the patient's rehabilitation potential and the prognosis of ongoing rehabilitation measures. Of particular note are the timing of the start of rehabilitation measures, the duration and regularity of the treatment methods. A number of authors propose scales for assessing the rehabilitation prognosis, as well as algorithms for compiling rehabilitation programs for restoring the function of the upper limb. A fairly large number of rehabilitation methods and their combinations have been proposed, including special methods of kinesitherapy, robotic mechanotherapy with biofeedback, the use of physiotherapeutic factors, manual and reflex effects, as well as ready-made programs that include sequential and combined use of various methods. Dozens of studies have been devoted to comparative analysis and evaluation of the effectiveness of these methods. The purpose of this work is to review current research on a given topic and draw up our own conclusion on the appropriateness of using and combining these methods at various stages of rehabilitation in stroke patients.

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.

Less-Affected Hand Function Is Associated With Independence in Daily Living: A Longitudinal Study Poststroke

BACKGROUND AND PURPOSE

The upper extremity (UE) ipsilateral to the brain lesion is mildly affected poststroke. It is unclear whether patients perceive this, and the association between less-affected hand function and independence in activities of daily living (ADL) is unknown. We aimed to (1) assess longitudinal changes in function, dexterity, grip strength, and self-perception of the less-affected UE, (2) compare them to the normative data, and (3) determine the association of both UEs to ADL during the first 6 months poststroke.

METHODS

Consecutive adults following a first stroke were assessed on rehabilitation admission (T1), 6 weeks (T2), and 6 months (T3) poststroke onset. Box and block test assessed function of both UEs. The functional dexterity test (FDT) and Jamar Dynamometer assessed dexterity and grip strength of the less-affected UE. The functional independence measure assessed ADL, and instrumental ADL was assessed at T3. Spearman correlations and multiple regression models were used.

RESULTS

Participants were assessed at T1 (N=87), T2 (N=82), and T3 (N=68). At T1, less-affected UE deficits were apparent (median [interquartile range] box and block test-45 [35-53] blocks, FDT-44.5 [33.3-60.8] seconds, grip-25.5 [16.2-33.9] kilograms), but only 19.5% of the participants self-perceived this. Less-affected hand function significantly improved with 32% and 33% achieving a minimal clinically important difference for box and block test at T2 and T3, respectively. Dexterity improved significantly between T1 and T2 (P<0.001, no established minimal clinically important difference) and grip strength improved significantly between T2 and T3; 3.4% achieving a minimal clinically important difference (P<0.01). At T3, most participants did not reach the norms (box and block test-67.4 blocks, FDT-32.2 seconds, grip-40.5 kilograms). Both the less- and more-affected UEs explained a large portion of the variance of ADL at all time-points, after controlling for age, days-since-stroke-onset, stroke type, and cognition.

CONCLUSIONS

Despite some improvement, the less-affected UE at 6 months poststroke remained below norms, explaining difficulties in ADL and instrumental ADL. Further research is needed.

Mirror therapy in upper limb motor recovery and activities of daily living, and its neural correlates in stroke individuals: A systematic review and meta-analysis

Available literature indicates that 30-66% of stroke survivors present persistent upper limb impairment. Considering the importance of upper limb function for activities of daily living, it is necessary to investigate neurorehabilitation therapies that could improve the upper limb function. Among stroke complementary therapies, mirror therapy has shown promising results. Thus, the aim of this systematic review and meta-analyses was to review and synthesize clinical evidence on the use of mirror therapy on motor recovery of the upper limb and activities of daily living, and its neural correlates in stroke patients. The literature search was carried out in PubMed, ISI Web of Science, and Scopus databases. Twenty-nine studies met all the inclusion criteria. Two meta-analyses were conducted to compare mirror therapy with sham therapy on two general measures, upper limb assessment and activities of daily living. Results suggest that mirror therapy was better than sham therapy, mainly in the subacute phase, but the meta-analyses were nonsignificant. In addition, mirror therapy and cortical reorganization showed potential neural correlates, such as the primary motor cortex, precuneus, and posterior cingulate cortex.

Motor Deficits in the Ipsilesional Arm of Severely Paretic Stroke Survivors Correlate With Functional Independence in Left, but Not Right Hemisphere Damage

Chronic stroke survivors with severe contralesional arm paresis face numerous challenges to performing activities of daily living, which largely rely on the use of the less-affected ipsilesional arm. While use of the ipsilesional arm is often encouraged as a compensatory strategy in rehabilitation, substantial evidence indicates that motor control deficits in this arm can be functionally limiting, suggesting a role for remediation of this arm. Previous research has indicated that the nature of ipsilesional motor control deficits vary with hemisphere of damage and with the severity of contralesional paresis. Thus, in order to design rehabilitation that accounts for these deficits in promoting function, it is critical to understand the relative contributions of both ipsilesional and contralesional arm motor deficits to functional independence in stroke survivors with severe contralesional paresis. We now examine motor deficits in each arm of severely paretic chronic stroke survivors with unilateral damage (10 left-, 10 right-hemisphere damaged individuals) to determine whether hemisphere-dependent deficits are correlated with functional independence. Clinical evaluation of contralesional, paretic arm impairment was conducted with the upper extremity portion of the Fugl-Meyer assessment (UEFM). Ipsilesional arm motor performance was evaluated using the Jebsen-Taylor Hand Function Test (JTHFT), grip strength, and ipsilesional high-resolution kinematic analysis during a visually targeted reaching task. Functional independence was measured with the Barthel Index. Functional independence was better correlated with ipsilesional than contralesional arm motor performance in the left hemisphere damage group [JTHFT: [r ₍₁₀₎ = -0.73, p = 0.017]; grip strength: [r ₍₁₀₎ = 0.64, p = 0.047]], and by contralesional arm impairment in the right hemisphere damage group [UEFM: [r ₍₁₀₎ = 0.66, p = 0.040]]. Ipsilesional arm kinematics were correlated with functional independence in the left hemisphere damage group only. Examination of hemisphere-dependent motor correlates of functional independence showed that ipsilesional arm deficits were important in determining functional outcomes in individuals with left hemisphere damage only, suggesting that functional independence in right hemisphere damaged participants was affected by other factors.