Proprioception deficits in chronic stroke-Upper extremity function and daily living

The effects of trunk repositioning errors on trunk and extremity functions in stroke

AIM

The aim of this study was to analyze the TRE in three directions including forward flexion, lateral flexion to the hemiparetic side, and rotation to the hemiparetic side in patients with stroke and to compare the errors with age- and sex-matched healthy subjects. In addition, it was investigated which functional outcomes were explanatory for TRE in patients with stroke.

METHODS

Forty-one patients with subacute/chronic stroke (age 59 ± 14.5 years) and 41 healthy subjects (age 57 ± 12.8 years) were included in the study. Demographic and clinical data were collected. TREs were measured using an inclinometer. The Trunk Impairment Scale (TIS), Fugl-Meyer Assessment (FMA), Wolf Motor Function Test (WMFT), Timed Up and Go Test, and 10-m walk test (10MWT) were also used to assess trunk control, motor impairment, upper extremity function, and lower extremity function, respectively, in patients with stroke.

RESULTS

TRE scores in three directions were higher in patients with stroke than in healthy subjects (p < 0.001). TREs in three directions were significantly strongly correlated with all functional outcomes (ρ > 0.60, r < 0.001). Multiple regression analysis determined 10MWT, WMFT-Performance, TIS, and FMA-Upper Extremity as explanatory factors for TRE.

CONCLUSION

The model presented in this study could help clinicians and researchers to predict the TRE in patients with stroke. Gait speed, upper extremity motor ability, upper extremity motor impairment, and trunk control should be considered for TRE after a stroke.

Sensory training combined with motor training improves trunk proprioception in stroke patients: a single-blinded randomized controlled trial

OBJECTIVES

Inadequate trunk function is the underlying cause of many problems such as impaired balance and mobility. Although there have been trunk-based physiotherapy approaches in recent years, almost all of these approaches focus on motor problems. This study aims to investigate the effects of sensory training combined with trunk-centered Bobath exercises on trunk control and proprioception, balance, gait, and the activity of daily living (ADL).

MATERIALS AND METHODS

This study is a randomized controlled trial included with twenty-seven stroke patients. Participants were separated into two groups, Group 1; 'sensory training combined with trunk-centered Bobath exercises' and Group 2; 'trunk-centered Bobath exercises'. Trunk-centered Bobath exercises were used for motor training. Sensory training included transcutaneous electric nerve stimulation and a set of exercises that provide tactile and proprioceptive stimulation. Trunk Impairment Scale, Trunk Reposition Error, Berg Balance Scale, 2-minute walk test, and Barthel Index were used to assess trunk control, trunk proprioception, balance, gait, and ADL respectively.

RESULTS

Intra-group analysis results showed that trunk control, trunk proprioception, balance, gait, and ADL improved in both groups after treatment (p < 0.05). The changes in the Trunk Reposition Error values of the participants in Group 1 before and after treatment was found to be significantly higher than Group 2 (p < 0.05).

CONCLUSIONS

The findings indicated that the application of trunk-centered motor training is effective in improving trunk proprioception and trunk control, balance, gait, and ADL in stroke patients. Also, sensory training combined with trunk-centered motor training was found more effective in improving trunk proprioception than solely motor training.

U-Rate-UE; Measuring Perceived Recovery of the Affected Upper Extremity in Adults Post-stroke

OBJECTIVE

To establish initial validity of "U-Rate-UE", a single-question scale regarding perceived recovery of the stroke affected upper extremity (UE).

DESIGN

A retrospective longitudinal study of data collected at rehabilitation admission, 6 weeks, and 6 months since stroke.

SETTING

Stroke rehabilitation and community-based.

PARTICIPANTS

A convenience sample of 87 individuals, median (interquartile range) age 71.5 (65-80) years, 15.0 (12-20) days post-stroke.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

The affected UE was assessed using the Fugl-Meyer Motor Assessment, grip strength, Action Research Arm Test, the Box and Block Test (BBT), and The Rating of Everyday Arm-Use in the Community and Home. Participants also rated how much they perceive that their affected UE recovered from the stroke using U-Rate-UE; 0-100 (no to full recovery). Longitudinal changes in U-Rate-UE ratings were assessed. In addition, at 6 weeks and 6 months post-stroke, the change in BBT was calculated and participants were grouped into achieved/did not achieve the minimal detectable change (MDC). Correlations between U-Rate-UE to the other UE assessments were assessed at all 3 timepoints.

RESULTS

Significant changes in U-Rate-UE were seen over time (P<.05). At 6 weeks and 6 months, participants who achieved BBT-MDC rated their recovery significantly higher than participants who did not. U-Rate-UE was moderately-strongly significantly correlated to UE assessments (rho=.61-.85, P<.001).

CONCLUSIONS

The U-Rate-UE is supported for use with UE assessments contributing to comprehensive clinical understanding of the recovery of the affected UE in adults post-stroke.

Influence of compression garments on proprioception: A systematic review and meta-analysis

Compression garments (CGs) are commonly used in rehabilitation and sports contexts to enhance performance and speed up recovery. Despite the growing use of CGs in recent decades, there is no unanimous consensus on their overall influence on joint proprioception. In this current meta-analysis, we aim to fill this knowledge gap by assessing the impact of CGs on joint proprioception. We conducted a literature search across seven databases and one registry. Ultimately, we included 27 studies with 671 participants. The meta-analysis revealed that wearing CGs resulted in a significant reduction in absolute error during joint position sensing (Hedges' g: -0.64, p = 0.006) as compared to no CGs. However, further analyses of variables such as constant error (p = 0.308), variable error (p = 0.541) during joint position sense tests, threshold to detect passive motion (p = 0.757), and active movement extent discrimination (p = 0.842) did not show a significant impact of CGs. The review also identified gaps in the reporting of certain outcomes, such as parameters of CGs, reporting of performance, individual-reported outcomes, and lack of placebo comparators. Consequently, this review provides guidelines for future studies that may facilitate evidence-based synthesis and ultimately contribute to a better understanding of the overall influence of CGs on joint proprioception.

An emerging target for male contraception

An inhibitor of a nonhormonal target is identified using a DNA-encoded chemical library.

An update on tests used for intraoperative monitoring of cognition during awake craniotomy

PURPOSE

Mapping higher-order cognitive functions during awake brain surgery is important for cognitive preservation which is related to postoperative quality of life. A systematic review from 2018 about neuropsychological tests used during awake craniotomy made clear that until 2017 language was most often monitored and that the other cognitive domains were underexposed (Ruis, J Clin Exp Neuropsychol 40(10):1081-1104, 218). The field of awake craniotomy and cognitive monitoring is however developing rapidly. The aim of the current review is therefore, to investigate whether there is a change in the field towards incorporation of new tests and more complete mapping of (higher-order) cognitive functions.

METHODS

We replicated the systematic search of the study from 2018 in PubMed and Embase from February 2017 to November 2023, yielding 5130 potentially relevant articles. We used the artificial machine learning tool ASReview for screening and included 272 papers that gave a detailed description of the neuropsychological tests used during awake craniotomy.

RESULTS

Comparable to the previous study of 2018, the majority of studies (90.4%) reported tests for assessing language functions (Ruis, J Clin Exp Neuropsychol 40(10):1081-1104, 218). Nevertheless, an increasing number of studies now also describe tests for monitoring visuospatial functions, social cognition, and executive functions.

CONCLUSIONS

Language remains the most extensively tested cognitive domain. However, a broader range of tests are now implemented during awake craniotomy and there are (new developed) tests which received more attention. The rapid development in the field is reflected in the included studies in this review. Nevertheless, for some cognitive domains (e.g., executive functions and memory), there is still a need for developing tests that can be used during awake surgery.

Post-Stroke Impairments of Manual Dexterity and Finger Proprioception: Their Contribution to Upper Limb Activity Capacity

BACKGROUND

Knowing how impaired manual dexterity and finger proprioception affect upper limb activity capacity is important for delineating targeted post-stroke interventions for upper limb recovery.

OBJECTIVES

To investigate whether impaired manual dexterity and finger proprioception explain variance in post-stroke activity capacity, and whether they explain more variance than conventional clinical assessments of upper limb sensorimotor impairments.

METHODS

Activity capacity and hand sensorimotor impairments were assessed using clinical measures in N = 42 late subacute/chronic hemiparetic stroke patients. Dexterity was evaluated using the Dextrain Manipulandum to quantify accuracy of visuomotor finger force-tracking (N = 36), timing of rhythmic tapping (N = 36), and finger individuation (N = 24), as well as proprioception (N = 27). Stepwise multivariate and hierarchical linear regression models were used to identify impairments best explaining activity capacity.

RESULTS

Dexterity and proprioceptive components significantly increased the variance explained in activity capacity: (i) Box and Block Test was best explained by baseline tonic force during force-tracking and tapping frequency (adjusted R2 = .51); (ii) Motor Activity Log was best explained by success rate in finger individuation (adjusted R2 = .46); (iii) Action Research Arm Test was best explained by release of finger force and proprioceptive measures (improved reaction time related to use of proprioception; adjusted R2 = .52); and (iv) Moberg Pick-Up test was best explained by proprioceptive function (adjusted R2 = .18). Models excluding dexterity and proprioception variables explained up to 19% less variance.

CONCLUSIONS

Manual dexterity and finger proprioception explain unique variance in activity capacity not captured by conventional impairment measures and should be assessed when considering the underlying causes of post-stroke activity capacity limitations.URL: https://www.clinicaltrials.gov. Unique identifier: NCT03934073.

Impaired proprioception and magnified scaling of proprioceptive error responses in chronic stroke

BACKGROUND

Previous work has shown that ~ 50-60% of individuals have impaired proprioception after stroke. Typically, these studies have identified proprioceptive impairments using a narrow range of reference movements. While this has been important for identifying the prevalence of proprioceptive impairments, it is unknown whether these error responses are consistent for a broad range of reference movements. The objective of this study was to characterize proprioceptive accuracy as function of movement speed and distance in stroke.

METHODS

Stroke (N = 25) and controls (N = 21) completed a robotic proprioception test that varied movement speed and distance. Participants mirror-matched various reference movement speeds (0.1-0.4 m/s) and distances (7.5-17.5 cm). Spatial and temporal parameters known to quantify proprioception were used to determine group differences in proprioceptive accuracy, and whether patterns of proprioceptive error were consistent across testing conditions within and across groups.

RESULTS

Overall, we found that stroke participants had impaired proprioception compared to controls. Proprioceptive errors related to tested reference movement scaled similarly to controls, but some errors showed amplified scaling (e.g., significantly overshooting or undershooting reference speed). Further, interaction effects were present for speed and distance reference combinations at the extremes of the testing distribution.

CONCLUSIONS

We found that stroke participants have impaired proprioception and that some proprioceptive errors were dependent on characteristics of the movement (e.g., speed) and that reference movements at the extremes of the testing distribution resulted in significantly larger proprioceptive errors for the stroke group. Understanding how sensory information is utilized across a broad spectrum of movements after stroke may aid design of rehabilitation programs.

Sensory deficits of the paretic and non-paretic upper limbs relate with the motor recovery of the poststroke subjects

BACKGROUND

Post stroke, motor paresis has usually been considered to be a crucial factor responsible for the disability; other impairments such as somatosensory deficits may also play a role.

OBJECTIVE

To determine the relation between the sensory deficits (paretic and non-paretic upper limbs) and the motor recovery of the paretic upper limb and to predict the potential of motor recovery based on the sensory deficits among stroke subjects.

METHODS

The study was a cross-sectional study conducted in a rehabilitation institute. Ninety-five poststroke hemiparetic subjects having sensory impairment in any of the modalities were considered for this study. Sensory deficits were assessed on both the upper limbs (paretic and non-paretic) primarily using Erasmus MC modification of the revised version of Nottingham Sensory Assessment (Em-NSA) and Nottingham Sensory Assessment (Stereognosis) (NSA-S). The motor recovery was assessed using the Fugl-Meyer assessment (FMA).

RESULTS

The measures of sensory deficits exhibited weak but significant correlation [the paretic (Em-NSA and NSA; r = .38 to .58; p < .001) and the non-paretic (Em-NSA and NSA; r = .24 to .38; p = .03 to .001)] with the motor recovery of the paretic upper limb as measured by FMA. The potential of favorable recovery of the paretic upper limb may be predicted using the cutoff scores of Em-NSA (30, 21, and 24) and NSA-S (5, 8, and 5) of the paretic side.

CONCLUSION

In stroke, sensory deficits relate weakly with the recovery of the paretic upper limb and can predict recovery potential of the paretic upper limb.

Neural correlates of bilateral proprioception and adaptation with training

Bilateral proprioception includes the ability to sense the position and motion of one hand relative to the other, without looking. This sensory ability allows us to perform daily activities seamlessly, and its impairment is observed in various neurological disorders such as cerebral palsy and stroke. It can undergo experience-dependent plasticity, as seen in trained piano players. If its neural correlates were better understood, it would provide a useful assay and target for neurorehabilitation for people with impaired proprioception. We designed a non-invasive electroencephalography-based paradigm to assess the neural features relevant to proprioception, especially focusing on bilateral proprioception, i.e., assessing the limb distance from the body with the other limb. We compared it with a movement-only task, with and without the visibility of the target hand. Additionally, we explored proprioceptive accuracy during the tasks. We tested eleven Controls and nine Skilled musicians to assess whether sensorimotor event-related spectral perturbations in μ (8-12Hz) and low-β (12-18Hz) rhythms differ in people with musical instrument training, which intrinsically involves a bilateral proprioceptive component, or when new sensor modalities are added to the task. The Skilled group showed significantly reduced μ and low-β suppression in bilateral tasks compared to movement-only, a significative difference relative to Controls. This may be explained by reduced top-down control due to intensive training, despite this, proprioceptive errors were not smaller for this group. Target visibility significantly reduced proprioceptive error in Controls, while no change was observed in the Skilled group. During visual tasks, Controls exhibited significant μ and low-β power reversals, with significant differences relative to proprioceptive-only tasks compared to the Skilled group-possibly due to reduced uncertainty and top-down control. These results provide support for sensorimotor μ and low-β suppression as potential neuromarkers for assessing proprioceptive ability. The identification of these features is significant as they could be used to quantify altered proprioceptive neural processing in skill and movement disorders. This in turn can be useful as an assay for pre and post sensory-motor intervention research.

Comparison of Upper Extremity Function and Daily Use in Individuals with and without Post Stroke Depression

BACKGROUND

Post-stroke depression (PSD) is a frequent psychiatric complication, however very few studies have investigated its relation to the affected upper extremity (UE) post-stroke. Objective. To compare the affected UE in terms of motor impairment, functional ability, and daily-use in individuals with and without PSD during the first 6 months post-stroke.

METHODS

This study analyzed data from a previous cohort; participants were assessed at rehabilitation admission (T1), 6 weeks (T2), and 6 months (T3) post-stroke. At each time point we compared between participants with and without PSD (Geriatric Depression Scale score ≥ 5). The Fugl-Meyer Motor Assessment assessed motor impairment, Action Research Arm Test assessed functional ability, and the Rating of Everyday Arm-Use in the Community and Home assessed daily-use. Independence in daily activities and cognition were also assessed.

RESULTS

A total of 116 participants were recruited, 38% had PSD at T1. No significant differences were found between groups at T1 and T2. However, significant differences (z = -5.23 to -2.66, p < .01) were found between groups for all UE measures at T3; participants with PSD had lower motor and functional ability and less daily hand-use than participants without PSD. At T3 participants with PSD were also less independent in daily-living.

CONCLUSIONS

PSD is associated with greater UE motor, functional, and daily-use disability at 6 months post-stroke. Our findings underscore the negative impact of PSD on UE during the crucial transition period when individuals return home and integrate back into the community. Further research is needed to delineate the effect of change in PSD status on UE outcomes post stroke.

The Effectiveness of Goal-Oriented Dual Task Proprioceptive Training in Subacute Stroke: A Retrospective Observational Study

OBJECTIVE

To show the effectiveness of goal-oriented proprioceptive training in subacute stroke for balance, autonomy, and fall risk.

METHODS

Out a total of 35 patients, consistent in age (75.31±8.65 years), type of stroke (ischemic, 3 to 11 weeks before), and motor impairment, 18 patients underwent solely proprioceptive rehabilitation, the other 17 dual task exercises. The study assessed autonomy using Barthel Index, fall risk with Timed Up and Go Test (TUG), balance through Berg Balance Scale (BBS) and Tinetti test.

RESULTS

After two months, significant improvements were recorded in Barthel Index, BBS (p<0.0001), Tinetti test (p<0.0001 in dual task group, p=0.0029 in single task group), and TUG (p=0.0052 in dual task group, p=0.0020 in single task group) in both groups. Comparing the two groups, dual task group showed a significant difference in Tinetti balance assessment (p=0.0052), between the total score of Tinetti test and TUG in single (p=0.0271), and dual task (p=0.0235). Likewise, Tinetti gait test was significantly related to TUG in single (p=0.0536), and dual task (p=0.0466), while Tinetti balance test to Barthel Index (p=0.0394), BBS (p<0.0001), and TUG in single (p=0.0219), and dual task (p=0.0196). Lastly, there is a positive correlation of the use of aids with BBS (p=0.0074), and total score of Tinetti test (p=0.0160).

CONCLUSION

In subacute stroke, goal-oriented proprioceptive training improved balance, but only partially autonomy. Furthermore, the use of aids after dual-task exercises improved recovery of balance, but did not reduced falls.

Limitations in utilization and prioritization of standardized somatosensory assessments after stroke: A cross-sectional survey of neurorehabilitation clinicians

BACKGROUND AND PURPOSE

Somatosensory impairments are common after stroke, but receive limited evaluation and intervention during neurorehabilitation, despite negatively impacting functional movement and recovery.

OBJECTIVES

Our objective was to understand the scope of somatosensory assessments used by clinicians in stroke rehabilitation, and barriers to increasing use in clinical practice.

METHODS

An electronic survey was distributed to clinicians (physical therapists, occupational therapists, physicians, and nurses) who assessed at least one individual with stroke in the past 6 months. The survey included questions on evaluation procedures, type, and use of somatosensory assessments, as well as barriers and facilitators in clinical practice.

RESULTS

Clinicians (N = 431) indicated greater familiarity with non-standardized assessments, and greater utilization compared to standardized assessments (p < 0.0001). Components of tactile sensation were the most commonly assessed modality of somatosensation (25%), while proprioception was rarely assessed (1%). Overall, assessments of motor function were prioritized over assessments of somatosensory function (p < 0.0001).

DISCUSSION

Respondents reported assessing somatosensation less frequently than motor function and demonstrated a reliance on rapid and coarse non-standardized assessments that ineffectively capture multi-modal somatosensory impairments, particularly for proprioceptive deficits common post-stroke. In general, clinicians were not familiar with standardized somatosensory assessments, and this knowledge gap likely contributes to lack of translation of these assessments into practice.

CONCLUSIONS

Clinicians utilize somatosensory assessments that inadequately capture the multi-modal nature of somatosensory impairments in stroke survivors. Addressing barriers to clinical translation has the potential to increase utilization of standardized assessments to improve the characterization of somatosensory deficits that inform clinical decision-making toward enhancing stroke rehabilitation outcomes.

Robotic exoskeleton embodiment in post-stroke hemiparetic patients: an experimental study about the integration of the assistance provided by the REFLEX knee exoskeleton

Hemiparetic gait is the most common motor-disorder after stroke and, in spite of rehabilitation efforts, it is persistent in 50% of community dwelling stroke-survivors. Robotic exoskeletons have been proposed as assistive devices to support impaired joints. An example of these devices is the REFLEX knee exoskeleton, which assists the gait of hemiparetic subjects and whose action seems to be properly embodied by stroke survivors, who were able to adapt the motion of their non-assisted limbs and, therefore, reduce their compensation mechanisms. This paper presents an experimental validation carried out to deepen into the effects of REFLEX's assistance in hemiparetic subjects. Special attention was paid to the effect produced in the muscular activity as a metric to evaluate the embodiment of this technology. Significant differences were obtained at the subject level due to the assistance; however, the high dispersion of the measured outcomes avoided extracting global effects at the group level. These results highlight the need of individually tailoring the action of the robot to the individual needs of each patient to maximize the beneficial outcomes. Extra research effort should be done to elucidate the neural mechanisms involved in the embodiment of external devices by stroke survivors.

Elastic Resistance and Shoulder Movement Patterns: An Analysis of Reaching Tasks Based on Proprioception

This study departs from the conventional research on horizontal plane reach movements by examining human motor control strategies in vertical plane elastic load reach movements conducted without visual feedback. Here, participants performed shoulder presses with elastic resistances at low, moderate, and high intensities without access to visual information about their hand position, relying exclusively on proprioceptive feedback and synchronizing their movements with a metronome set at a 3 s interval. The results revealed consistent performance symmetry across different intensities in terms of the reach speed (p = 0.254-0.736), return speed (p = 0.205-0.882), and movement distance (p = 0.480-0.919). This discovery underscores the human capacity to uphold bilateral symmetry in movement execution when relying solely on proprioception. Furthermore, this study observed an asymmetric velocity profile where the reach duration remained consistent irrespective of the load (1.15 s), whereas the return duration increased with higher loads (1.39 s-1.45 s). These findings suggest that, in the absence of visual feedback, the asymmetric velocity profile does not result from the execution of the action but rather represents a deliberate deceleration post-reach aimed at achieving the target position as generated by the brain's internal model. These findings hold significant implications for interpreting rehabilitation approaches under settings devoid of visual feedback.

Combining FES and Exoskeletons in a Hybrid Haptic System for Enhancing VR Experience

Robotic technology and functional electrical stimulation (FES) have emerged as highly effective rehabilitative techniques for individuals with neuromuscular diseases, showcasting their ability to restore motor functions. Within the proposed study, we developed and tested a new hybrid controller combining an upper-limb exoskeleton with FES to enhance haptic feedback when performing task-oriented and bimanual movement, like pick-and-place, in a virtual environment. We investigated the performance of the proposed approach on eight unimpaired participants providing haptic feedback either only by the exoskeleton or by the hybrid system. The hybrid control presents two different modalities, assistive and resistive, to modulate the perception of the load. FES intensity is calibrated to the subjects' biomechanical properties and it is adjusted in real-time according to the real-time motion of the upper limbs. Experimental results highlighted the ability of the hybrid control to improve kinematic performance: in both hybrid modalities subjects reduced the target matching error(values between 0.048±0.007 m and 0.06±0.006 m) without affecting the normal motion smoothness (SPARC values in the hybrid conditions range from -2.58±0.12 to -3.30±0.13). Moreover, the resistive approach resulted in greater metabolic consumption (1.04±0.03 W/kg), indicating a more realistic experience of lifting a virtual object through FES that increased the perceived weight. The innovation in our hybrid control relies on the modulation of muscular activation during manipulation tasks, which could be a promising approach in the clinical treatment of neuromuscular diseases.

Perceptual-Cognitive Integration for Goal-Directed Action in Naturalistic Environments

Real-world actions require one to simultaneously perceive, think, and act on the surrounding world, requiring the integration of (bottom-up) sensory information and (top-down) cognitive and motor signals. Studying these processes involves the intellectual challenge of cutting across traditional neuroscience silos, and the technical challenge of recording data in uncontrolled natural environments. However, recent advances in techniques, such as neuroimaging, virtual reality, and motion tracking, allow one to address these issues in naturalistic environments for both healthy participants and clinical populations. In this review, we survey six topics in which naturalistic approaches have advanced both our fundamental understanding of brain function and how neurologic deficits influence goal-directed, coordinated action in naturalistic environments. The first part conveys fundamental neuroscience mechanisms related to visuospatial coding for action, adaptive eye-hand coordination, and visuomotor integration for manual interception. The second part discusses applications of such knowledge to neurologic deficits, specifically, steering in the presence of cortical blindness, impact of stroke on visual-proprioceptive integration, and impact of visual search and working memory deficits. This translational approach-extending knowledge from lab to rehab-provides new insights into the complex interplay between perceptual, motor, and cognitive control in naturalistic tasks that are relevant for both basic and clinical research.

The locations of stroke lesions next to the posterior internal capsule may predict the recovery of the related proprioceptive deficits

Background

Somatosensory deficits after stroke correlate with functional disabilities and impact everyday-life. In particular, the interaction of proprioception and motor dysfunctions affects the recovery. While corticospinal tract (CST) damage is linked to poor motor outcome, much less is known on proprioceptive recovery. Identifying a predictor for such a recovery could help to gain insights in the complex functional recovery processes thereby reshaping rehabilitation strategies.

Methods

50 patients with subacute stroke were tested before and after neurological rehabilitation. Proprioceptive and motor impairments were quantified with three clinical assessments and four hand movement and proprioception measures using a robotic device. Somatosensory evoked potentials (SSEP) to median nerve stimulation and structural imaging data (MRI) were also collected. Voxel-based lesion-symptom mapping (VLSM) along with a region of interest (ROI) analysis were performed for the corticospinal tract (CST) and for cortical areas.

Results

Before rehabilitation, the VLSM revealed lesion correlates for all clinical and three robotic measures. The identified voxels were located in the white matter within or near the CST. These regions associated with proprioception were located posterior compared to those associated with motor performance. After rehabilitation the patients showed an improvement of all clinical and three robotic assessments. Improvement in the box and block test was associated with an area in anterior CST. Poor recovery of proprioception was correlated with a high lesion load in fibers towards primary sensorymotor cortex (S1 and M1 tract). Patients with loss of SSEP showed higher lesion loads in these tracts and somewhat poorer recovery of proprioception. The VSLM analysis for SSEP loss revealed a region within and dorsal of internal capsule next to the posterior part of CST, the posterior part of insula and the rolandic operculum.

Conclusion

Lesions dorsal to internal capsule next to the posterior CST were associated with proprioceptive deficits and may have predictive value. Higher lesion load was correlated with poorer restoration of proprioceptive function. Furthermore, patients with SSEP loss trended towards poor recovery of proprioception, the corresponding lesions were also located in the same location. These findings suggest that structural imaging of the internal capsule and CST could serve as a recovery predictor of proprioceptive function.

The effect of local vibration applied to the forearm extensor muscles on hand function and muscle activation in stroke patients: a randomized controlled study

OBJECTIVE

This study aims to reveal the effect of low-frequency local vibration applied to the forearm extensor muscles on stroke patients' muscle activation and hand functions.

METHODS

Twenty-four stroke patients were randomized to the vibration group (n = 12) or control group (n = 12). The vibration was applied at a 30 Hz frequency to the forearm extensor muscles with a local vibration device three days a week after the routine, conventional physical therapy sessions for four weeks. Six vibration sets were applied, including one vibration for one minute and a rest for 2 min. Routine, traditional physical therapy was used for the control group in 60-min sessions for 4 weeks. Patients were assessed for muscle activation with surface electromyography (MVC) and The Wolf Motor Function Test (WMFT), Functional Independent Test (FIM) was applied to all patients before and after treatment.

RESULTS

As a result of our study, MVC measurement, WMFT and FIM scores of the vibration group showed more improvement than the control group. Measurement results of vibration group; While MVC measurement increased from 10.21 to 13.79, WMFT-Functional Ability score increased from 42 to 50, WMFT-Performance Time duration increased from 68.78 to 61.83, and FIM score increased from 74.5 to 83. and the measurement results of the control group; MVC measurement increased from 12.28 to 12.22, WMFT-Functional Ability score increased from 48.5 to 51, WMFT-Performance Time duration increased from 70.39 to 70.61, and FIM score increased from 72.5 to 80.5.

CONCLUSION

It was concluded that low-frequency local vibration applied to the forearm extensor muscles improve forearm extensor muscle activation and hand motor function.

CLINICAL TRIAL REGISTRATION

NCT04562220.

Facilitation of imitative movement in patients with chronic hemiplegia triggered by illusory ownership

The sense of body ownership, the feeling that one's body belongs to oneself, is a crucial subjective conscious experience of one's body. Recent methodological advances regarding crossmodal illusions have provided novel insights into how multisensory interactions shape human perception and cognition, underpinning conscious experience, particularly alteration of body ownership. Moreover, in post-stroke rehabilitation, encouraging the use of the paretic limb in daily life is considered vital, as a settled sense of ownership and attentional engagement toward the paralyzed body part may promote increased frequency of its use and prevent learned nonuse. Therefore, in addition to traditional methods, novel interventions using neurorehabilitation techniques that induce self-body recognition are needed. This study investigated whether the illusory experience of a patient's ownership alterations of their paretic hand facilitates the enhancement in the range of motion of succeeding imitation movements. An experiment combining a modified version of the rubber hand illusion with imitation training was conducted with chronic hemiplegia. A larger imitation movement of the paretic hand was observed in the illusion-induced condition, indicating that the feeling of ownership toward the observed limb promotes the induction of intrinsic potential for motor performance. This training, using subjective experience, may help develop new post-stroke rehabilitation interventions.

Effects of joint mobilization combined with acupuncture on pain, physical function, and depression in stroke patients with chronic neuropathic pain: A randomized controlled trial

OBJECTIVE

To investigate the effectiveness of joint mobilization (JM) combined with acupuncture (AC) for the treatment of pain, physical function and depression in poststroke patients.

METHODS

A total of 69 poststroke patients were randomly assigned to the JM+AC group (n = 23), the JM group (n = 23), and the control group (n = 23). Patients in the JM+AC group and the JM group received JM for 30 minutes, twice a week for 12 weeks, and the JM+AC group received AC for 30 minutes separately once a week. The control group did not receive JM or AC. Pain (visual analog scale, shoulder pain and disability index, Western Ontario and McMaster universities osteoarthritis index), physical function (range of motion, 10-m walking speed test, functional gait assessment, manual function test, activities of daily living scale, instrumental activities of daily living scale), and depression (center for epidemiologic studies depression scale, Beck depression inventory) were assessed for each patient before and after the 12 weeks of intervention.

RESULTS

Pain and physical function were improved significantly in the JM+AC group compared with the JM and control groups. Physical function and depression were improved significantly in the JM+AC and JM groups compared with the control group.

CONCLUSION

The treatment of JM combined with AC improved pain, depression, and physical function of poststroke patients with chronic neuropathic pain in this study. This valuable finding provides empirical evidence for the designing therapeutic interventions and identifying potential therapeutic targets.

Clinical, Neuroimaging and Robotic Measures Predict Long-Term Proprioceptive Impairments following Stroke

Proprioceptive impairments occur in ~50% of stroke survivors, with 20-40% still impaired six months post-stroke. Early identification of those likely to have persistent impairments is key to personalizing rehabilitation strategies and reducing long-term proprioceptive impairments. In this study, clinical, neuroimaging and robotic measures were used to predict proprioceptive impairments at six months post-stroke on a robotic assessment of proprioception. Clinical assessments, neuroimaging, and a robotic arm position matching (APM) task were performed for 133 stroke participants two weeks post-stroke (12.4 ± 8.4 days). The APM task was also performed six months post-stroke (191.2 ± 18.0 days). Robotics allow more precise measurements of proprioception than clinical assessments. Consequently, an overall APM Task Score was used as ground truth to classify proprioceptive impairments at six months post-stroke. Other APM performance parameters from the two-week assessment were used as predictive features. Clinical assessments included the Thumb Localisation Test (TLT), Behavioural Inattention Test (BIT), Functional Independence Measure (FIM) and demographic information (age, sex and affected arm). Logistic regression classifiers were trained to predict proprioceptive impairments at six months post-stroke using data collected two weeks post-stroke. Models containing robotic features, either alone or in conjunction with clinical and neuroimaging features, had a greater area under the curve (AUC) and lower Akaike Information Criterion (AIC) than models which only contained clinical or neuroimaging features. All models performed similarly with regard to accuracy and F1-score (>70% accuracy). Robotic features were also among the most important when all features were combined into a single model. Predicting long-term proprioceptive impairments, using data collected as early as two weeks post-stroke, is feasible. Identifying those at risk of long-term impairments is an important step towards improving proprioceptive rehabilitation after a stroke.

The Effects of Trunk and Extremity Functions on Activities of Daily Living, Balance, and Gait in Stroke

OBJECTIVES

The primary aim is to investigate the effect of the trunk, upper extremity, and lower extremity functions on activities of daily living (ADL), balance, and gait. The second aim is to investigate the effect of trunk position sense on trunk control.

METHODS

Thirty-six patients with chronic stroke were included in the study. The Trunk Impairment Scale (TIS), Barthel Index (BI), Berg Balance Scale (BBS), and 2-minute walking test (2MWT) were used for the assessment of trunk function, ADL, balance, and gait respectively. The Stroke Rehabilitation Assessment of Movement upper extremity (STREAM-UE) and lower extremity (STREAM-LE) sub-scales were used to evaluate extremity functions. The trunk position sense was measured with a digital inclinometer.

RESULTS

The mean age of the participants was 58.8 ± 12.6 years. In multiple regression analysis, TIS values were found to have a positive effect on BI and BBS (p < 0.05), and STREAM-LE values have a positive effect on BBS and 2MWT (p < 0.05). STREAM-UE values were no significant effect on BI, BBS, or 2MWT (p > 0.05). Trunk position sense was found to have a positive effect on TIS (p < 0.05).

DISCUSSION

The results of this study showed that trunk functions are more related to ADL and balance than extremity functions. Therefore, trunk training should be included as a basic application in physiotherapy programs for stroke patients.

Proprioceptive Neuromuscular Facilitation Protocol for Thumb Osteoarthritis: A Pilot Study

BACKGROUND

Osteoarthritis (OA) of the thumb carpometacarpal (CMC) joint often presents with joint instability and proprioceptive deficits. Proprioception has been found to play an important role in the rehabilitative process. The purpose of this study was to evaluate the effectiveness of a proprioceptive training program on pain and function in individuals with early-stage thumb Carpometacarpal joint OA.

METHODS

A double-blind experimental trial using a 2-group pretest/posttest design was used in this pilot study. Participants had a diagnosis of grade I and II thumb CMC joint OA in their dominant hand and a pain rating of >4/10 on Visual Analogue Scale. Participants received either standard treatment (control group) or standard treatment plus a proprioceptive training program (experimental group). Outcome measures were lateral pinch strength, pain intensity during activities, and proprioceptive response via joint position sense (JPS) testing.

RESULTS

Twelve individuals (average age of 66.25 years) participated. Both groups had a statistically significant decrease in pain and increase in lateral pinch strength, all occurring with a large effect size but no statistically significant difference between groups. The experimental group experienced a large effect size for JPS testing, whereas the control group experienced a trivial effect size, and there was a statistically significant difference between groups for JPS testing.

CONCLUSIONS

Individuals who completed the proprioceptive training program in this study had an improvement in proprioceptive functioning. This program shows potential for routine inclusion in hand therapy for thumb CMC joint OA; however, additional high-level studies with larger sample sizes are required.

Acuity of Proprioceptive Localization Varies with Body Region

We accurately sense locations of objects touching various points on the body and, if they are irritants, make accurate rapid movements to remove them. Such movements require accurate proprioception of orientation and motion of the reaching limb and of the target. However, it is unknown whether acuity of these sensations is similar for different points on the body. We investigated accuracy of comfortable speed reaching movements of the right index-tip by 10 subjects (five females) to touch 12 different body locations with and without vision with the body part stationary in different locations and moving in different directions. Reaching movements to points on the face/head and trunk had mean errors averaging less than 0.2 cm greater than under vision conditions. Mean errors for reaches to touch points on the left arm and digits were less accurate (p < 0.05), but average less than 1 cm relative to vision conditions. Mean errors for reaches to touch points on the left lower limb were least accurate (p < 0.05), with mean errors averaging 1.5-3.1 cm relative to movements made with vision. We conclude that there is high proprioceptive acuity for locations of points on axial structures and the left upper limb including the digits, which contrasts with previous reports of greatly distorted proprioceptive maps of the face/head and hand. Apparently low proprioceptive acuity for points on the leg may be task sensitive as many lower limb motor tasks can be performed accurately without vision.

Does higher knee hyperextension in patients with hemiplegia affect lateral and medial meniscus volume in the paretic leg? A cross-sectional study

BACKGROUND

After stroke, an abnormal gait pattern gradually leads to knee pain and joint lesions, resulting the gait instability. However, the correlation between the knee hyperextension and gait pattern, the meniscus volume, and the water content of meniscus in paretic and non-paretic legs has not been fully investigated. Moreover, most of physicians tend to ignore this knee hyperextension. This study attempted to emphasize the importance of knee hyperextension using gait analysis and Magnetic resonance imaging (Trial registration number ChiCTR2000039641, date of registration 04/11/2020).

METHODS

Eight patients with chronic hemiplegic (6 male, 2 female) volunteered to participate in this study. Participants was recruited if they had a hemiplegia following a stroke occurring more than 6 months, had an ability to walk 10 m without aids, had a Function Ambulation Category level at least 3 and above, and had a hemiplegic lower extremity identified as Brunnstrom state III or above identification. The spatial-temporal gait parameters and kinematic parameters in the paretic and the non-paretic legs and the percentage of free water content in deep and shallow layers.

RESULTS

Longer time since hemiplegia led to larger angles of knee hyperextension (R = 0.56, p = 0.016), larger angles of knee hyperextension led to more tears in meniscus (R =  - 0.53, - 0,57 and - 0.70), and larger angles of knee hyperextension decreased water content of the lateral meniscus in the non-paretic leg (R =  - 0.91) but increased water content of the medial meniscus (R = 0.53 and 0.63).

CONCLUSIONS

The knee hyperextension could not be ignored by physicians and needed to be diagnosed and treated as early as possible, the time since hemiplegia could be an indicator of sign of knee hyperextension.

Wrist Proprioception in Adults with and without Subacute Stroke

Proprioception is critical to motor control and functional status but has received limited study early after stroke. Patients admitted to an inpatient rehabilitation facility for stroke (n = 18, mean(±SD) 12.5 ± 6.6 days from stroke) and older healthy controls (n = 19) completed the Wrist Position Sense Test (WPST), a validated, quantitative measure of wrist proprioception, as well as motor and cognitive testing. Patients were serially tested when available (n = 12, mean 11 days between assessments). In controls, mean(±SD) WPST error was 9.7 ± 3.5° in the dominant wrist and 8.8 ± 3.8° in the nondominant wrist (p = 0.31). In patients with stroke, WPST error was 18.6 ± 9° in the more-affected wrist, with abnormal values present in 88.2%; and 11.5 ± 5.6° in the less-affected wrist, with abnormal values present in 72.2%. Error in the more-affected wrist was higher than in the less-affected wrist (p = 0.003) or in the dominant (p = 0.001) and nondominant (p < 0.001) wrist of controls. Age and BBT performance correlated with dominant hand WPST error in controls. WPST error in either wrist after stroke was not related to age, BBT, MoCA, or Fugl-Meyer scores. WPST error did not significantly change in retested patients. Wrist proprioception deficits are common, bilateral, and persistent in subacute stroke and not explained by cognitive or motor deficits.

Beyond the Dorsal Column Medial Lemniscus in Proprioception and Stroke: A White Matter Investigation

Proprioceptive deficits are common following stroke, yet the white matter involved in proprioception is poorly understood. Evidence suggests that multiple cortical regions are involved in proprioception, each connected by major white matter tracts, namely: Superior Longitudinal Fasciculus (branches I, II and III), Arcuate Fasciculus and Middle Longitudinal Fasciculus (SLF I, SLF II, SLF III, AF and MdLF respectively). However, direct evidence on the involvement of these tracts in proprioception is lacking. Diffusion imaging was used to investigate the proprioceptive role of the SLF I, SLF II, SLF III, AF and MdLF in 26 participants with stroke, and seven control participants without stroke. Proprioception was assessed using a robotic Arm Position Matching (APM) task, performed in a Kinarm Exoskeleton robotic device. Lesions impacting each tract resulted in worse APM task performance. Lower Fractional Anisotropy (FA) was also associated with poorer APM task performance for the SLF II, III, AF and MdLF. Finally, connectivity data surrounding the cortical regions connected by each tract accurately predicted APM task impairments post-stroke. This study highlights the importance of major cortico-cortical white matter tracts, particularly the SLF III and AF, for accurate proprioception after stroke. It advances our understanding of the white matter tracts responsible for proprioception.

Where Are We on Proprioception Assessment Tests Among Poststroke Individuals? A Systematic Review of Psychometric Properties

BACKGROUND AND PURPOSE

Proprioception is often impaired in poststroke individuals. This is a significant issue since altered proprioception is associated with poorer physical function outcomes poststroke. However, there is limited consensus on the best tools for assessing proprioception and support for their widespread use by clinicians. The objective is to appraise the psychometric properties of each test used to assess proprioception in poststroke individuals.

METHODS

A systematic search was performed according to PRISMA guidelines using the databases MEDLINE, Cochrane Library, PEDro, DiTa, and BioMedicalCentral for articles published up to January 2021.

RESULTS

Sixteen studies of low methodological quality were included. Sixteen different proprioception assessment tests were extracted. The proprioception portion of the Fugl-Meyer Assessment Scale was found to be the most valid and reliable tool for screening patients in clinical settings. Although no real gold standard exists, the technological devices demonstrated better responsiveness and measurement accuracy than clinical tests. Technological devices might be more appropriate for assessing proprioception recovery or better suited for research purposes.

DISCUSSION AND CONCLUSIONS

This review revealed low-quality articles and a paucity of tests with good psychometric properties available to clinicians to properly screen and assess all subcomponents of proprioception. In perspective, technological devices, such as robotic orthoses or muscle vibration, may provide the best potential for assessing the different subcomponents of proprioception. Further studies should be conducted to develop and investigate such approaches.Video, Supplemental Digital Content 1, available at:http://links.lww.com/JNPT/A388.

Proprioceptive based training or modified constraint-induced movement therapy on upper extremity motor functions in chronic stroke patients: A randomized controlled study

BACKGROUND: The Modified Constraint-Induced Movement Therapy (mCIMT) method is a unilateral training that respectively avoids and activates less affected and affected sides of upper extremities; however, the selected options are not typically ideal. Proprioceptive based training (PT) includes bilateral training methods and influencing proprioceptive receptors. OBJECTIVE: The primary purpose was to determine if conventional therapy and PT or conventional therapy and mCIMT therapy show similar improvement in patients with chronic stroke. The secondary purpose was to investigate the effectiveness of conventional therapy and PT or mCIMT therapy in patients with chronic stroke and to compare which of the two interventions is more effective. METHODS: Forty patients with chronic stroke were randomly allocated to only conventional therapy (PTR, n = 14), conventional therapy plus proprioception training (PTR-PT, n = 13), and mCIMT (PTR-mCIMT, n = 13) groups. Evaluations were assessed before and 6 weeks after treatment. RESULTS: Intragroup evaluations revealeda significant improvement in the all scores in the PTR-PT and PTR-mCMIT groups (p = 0.006 < 0.001). Intergroup comparisons demonstrated that the PTR-mCIMT group had a significant improvement in spasticity and motor function scores compared to the PTR (p < 0.001) and the PTR-PT groups (p = 0.006–0.015). CONCLUSIONS: PT and mCMIT applied in addition to conventional therapy in patients with chronic stroke were more effective than only conventional therapy. Additionally, mCMIT showed greater improvement in spasticity and motor function scales than PT.

Development and Validation of a Novel Robot-Based Assessment of Upper Limb Sensory Processing in Chronic Stroke

Upper limb sensory processing deficits are common in the chronic phase after stroke and are associated with decreased functional performance. Yet, current clinical assessments show suboptimal psychometric properties. Our aim was to develop and validate a novel robot-based assessment of sensory processing. We assessed 60 healthy participants and 20 participants with chronic stroke using existing clinical and robot-based assessments of sensorimotor function. In addition, sensory processing was evaluated with a new evaluation protocol, using a bimanual planar robot, through passive or active exploration, reproduction and identification of 15 geometrical shapes. The discriminative validity of this novel assessment was evaluated by comparing the performance between healthy participants and participants with stroke, and the convergent validity was evaluated by calculating the correlation coefficients with existing assessments for people with stroke. The results showed that participants with stroke showed a significantly worse sensory processing ability than healthy participants (passive condition: p = 0.028, Hedges’ g = 0.58; active condition: p = 0.012, Hedges’ g = 0.73), as shown by the less accurate reproduction and identification of shapes. The novel assessment showed moderate to high correlations with the tactile discrimination test: a sensitive clinical assessment of sensory processing (r = 0.52–0.71). We conclude that the novel robot-based sensory processing assessment shows good discriminant and convergent validity for use in participants with chronic stroke.

Sensorimotor performance after high-definition transcranial direct current stimulation over the primary somatosensory or motor cortices in men versus women

The primary somatosensory (S1) cortex is a central structure in motor performance. However, transcranial direct current stimulation (tDCS) research aimed at improving motor performance usually targets the primary motor cortex (M1). Recently, sex was found to mediate tDCS response. Thus, we investigated whether tDCS with an anodal electrode placed over S1 improves motor performance and sensation perception in men versus women. Forty-five participants randomly received 15-min high-definition tDCS (HD-tDCS) at 1 mA to S1, M1, or sham stimulation. Reaching performance was tested before and immediately following stimulation. Two-point orientation discrimination (TPOD) of fingers and proprioception of a reaching movement were also tested. Although motor performance did not differ between groups, reaching reaction time improved in the M1 group men. Reaching movement time and endpoint error improved in women and men, respectively. Correct trials percentage for TPOD task was higher in the S1 compared to the M1 group in the posttest and improved only in the S1 group. Reaching movement time for the proprioception task improved, overall, and endpoint error did not change. Despite the reciprocal connections between S1 and M1, effects of active tDCS over S1 and M1 may specifically influence sensation perception and motor performance, respectively. Also, sex may mediate effects of HD-tDCS on motor performance.

Upper extremity self-efficacy correlates with daily hand-use of individuals with high functional capacity post-stroke

PURPOSE

To understand the role of affected upper extremity (UE) self-efficacy for explaining daily-hand-use in individuals post-stroke. Specifically, to describe UE self-efficacy and to assess the associations between UE self-efficacy to UE motor and functional capacity and daily hand-use.

MATERIALS AND METHODS

This cross-sectional study included individuals post-stroke receiving rehabilitation with high UE functional capacity [Action Research Arm Test (ARAT) > 50]. The Rating of Everyday Arm-Use in the Community and Home (REACH) assessed perceived UE daily use and the Confidence in Arm and Hand Movement scale (CAHM) assessed UE self-efficacy. Functional capacity was assessed by the ARAT and the Fugl-Meyer-motor-assessment assessed motor impairment. Correlations between measures were assessed.

RESULTS

Twenty-two individuals, aged 19-80, with high UE functional capacity [median (IQR) ARAT-56.5 (54-57)] and varying UE self-efficacy [median (IQR) CAHM-76.7 (58-84.4)], were included. UE self-efficacy was significantly correlated with the ARAT (r_s = 0.53, p < 0.01) and REACH (r_s = 0.51, p < 0.01) but ARAT was not significantly correlated with REACH.

CONCLUSIONS

UE self-efficacy is correlated with perceived daily hand-use in individuals with high functional capacity. Further research and a deeper understanding of the clinical implications of UE self-efficacy are warranted. UE self-efficacy should perhaps be assessed during rehabilitation. IMPLICATIONS FOR REHABILITATIONIndividuals with stroke with high affected upper extremity functional capacity do not necessarily use this hand for daily living.Upper extremity self-efficacy is correlated with perceived daily hand-use in individuals with high functional capacity; participants with higher upper extremity self-efficacy also reported more daily hand-use.Upper extremity self-efficacy seems to be upper extremity task or situation-specific.Upper extremity self-efficacy should be assessed during rehabilitation and the clinical implications of (low) upper extremity self-efficacy should be further researched.

Moving toward Appropriate Motor Assessment Tools in People Affected by Severe Acquired Brain Injury: A Scoping Review with Clinical Advices

Severe acquired brain injury (SABI) is among the leading causes of death and disability worldwide. Patients following SABI may develop motor, sensory and cognitive disorders, alone or in combination. This review aims to point out the most used scales to assess motor function in SABI patients, also attempting to give some indications on their applicability in clinical practice. Studies were identified by searching on PubMed, Web of Science, PeDro and Cochrane databases between January and March 2022. We found that motor assessment tools are currently used by researchers/clinicians either in the acute/post-acute phase (for prognosis and rehabilitation purposes) or in the chronic phase (when functional items may also be considered). Moreover, specific scales exist only for patients with disorders of consciousness, whereas regarding motor function, SABI is mainly assessed by adapting the tools commonly used for stroke. Although some doubts remain about the validity of some of these assessment tools in SABI, to investigate motor outcomes is fundamental to establish a correct prognosis and plan a tailored rehabilitation training in these very frail and vulnerable patients.

Active Sensory Therapies Enhancing Upper Limb Recovery Among Poststroke Subjects: A Systematic Review

BACKGROUND

In stroke, sensory deficits may affect the motor recovery of the subjects. The evidence for the active sensory intervention to enhance motor recovery is sparsely available.

PURPOSE

To systematically review the available evidence from the studies on active sensory therapies augmenting upper limb recovery among poststroke subjects.

METHODS

The following databases were searched for the desired articles: PubMed, the Cochrane Central Register of Trials (CENTRAL), DORIS, PEDro, and OTseeker. The primary search keywords were stroke, sensory, and motor. The articles published in English up to August 2021 were considered for the review. Only investigations that studied active sensory interventions to enhance motor recovery were considered for the review. The studies of robotic training, virtual reality, electrical stimulation, and acupuncture were excluded. Motor recovery and sensory recovery were considered as primary and secondary measures, respectively.

RESULTS

Out of 3528 screened studies, eight studies were found eligible for the present systematic review. Active sensory interventions in the form of sensory discrimination, mirror therapy, motor imagery, and specific somatosensory training were utilized in the selected studies. The interventions through mirror therapy and mental imaging have some promising roles in enhancing upper limb recovery. However, there is a lack of strong evidence for the effectiveness of the intervention enhancing motor improvement among the stroke subjects.

CONCLUSION

A comprehensive active sensory protocol should be developed having components of cognitive, sensory, motor, and functional demand. There is a need to conduct good quality randomized trials to support the existing active sensory therapies.

Cancer survivors post-chemotherapy exhibit unique proprioceptive deficits in proximal limbs

BACKGROUND

Oxaliplatin (OX) chemotherapy for colorectal cancer is associated with adverse neurotoxic effects that can contribute to long-term sensorimotor impairments in cancer survivors. It is often thought that the sensorimotor impairments are dominated by OX-induced dying-back sensory neuropathy that primarily affects the distal regions of the limb. Recent preclinical studies have identified encoding dysfunction of muscle proprioceptors as an alternative mechanism. Unlike the dying-back sensory neuropathy affecting distal limbs, dysfunction of muscle proprioceptors could have more widespread effects. Most investigations of chemotherapy-induced sensorimotor impairments have considered only the effects of distal changes in sensory processing; none have evaluated proximal changes or their influence on function. Our study fills this gap by evaluating the functional use of proprioception in the shoulder and elbow joints of cancer survivors post OX chemotherapy. We implemented three multidirectional sensorimotor tasks: force matching, target reaching, and postural stability tasks to evaluate various aspects of proprioception and their use. Force and kinematic data of the sensorimotor tasks were collected in 13 cancer survivors treated with OX and 13 age-matched healthy controls.

RESULTS

Cancer survivors exhibited less accuracy and precision than an age-matched control group when they had to rely only on proprioceptive information to match force, even for forces that required only torques about the shoulder. There were also small differences in the ability to maintain arm posture but no significant differences in reaching. The force deficits in cancer survivors were significantly correlated with self-reported motor dysfunction.

CONCLUSIONS

These results suggest that cancer survivors post OX chemotherapy exhibit proximal proprioceptive deficits, and that the deficits in producing accurate and precise forces are larger than those for producing unloaded movements. Current clinical assessments of chemotherapy-related sensorimotor dysfunction are largely limited to distal symptoms. Our study suggests that we also need to consider changes in proximal function. Force matching tasks similar to those used here could provide a clinically meaningful approach to quantifying OX-related movement dysfunction during and after chemotherapy.

Proprioceptive Training with Visual Feedback Improves Upper Limb Function in Stroke Patients: A Pilot Study

Proprioceptive deficit is one of the common sensory impairments following stroke and has a negative impact on motor performance. However, evidence-based training procedures and cost-efficient training setups for patients with poststroke are still limited. We compared the effects of proprioceptive training versus nonspecific sensory stimulation on upper limb proprioception and motor function rehabilitation. In this multicenter, single-blind, randomized controlled trial, 40 participants with poststroke hemiparesis were enrolled from 3 hospitals in China. Participants were assigned randomly to receive proprioceptive training involving passive and active movements with visual feedback (proprioceptive training group [PG]; n = 20) or nonspecific sensory stimulation (control group [CG]; n = 20) 20 times in four weeks. Each session lasted 30 minutes. A clinical assessor blinded to group assignment evaluated patients before and after the intervention. The primary outcome was the change in the motor subscale of the Fugl-Meyer assessment for upper extremity (FMA-UE-M). Secondary outcomes were changes in box and block test (BBT), thumb localization test (TLT), the sensory subscale of the Fugl-Meyer assessment for upper extremity (FMA-UE-S), and Barthel Index (BI). The results showed that the mean change scores of FMA-UE were significantly greater in the PG than in the CG (p = 0.010 for FMA-UE-M, p = 0.033 for FMA-UE-S). The PG group was improved significantly in TLT (p = 0.010) and BBT (p = 0.027), while there was no significant improvement in TLT (p = 0.083) and BBT (p = 0.107) for the CG group. The results showed that proprioceptive training was effective in improving proprioception and motor function of the upper extremity in patients with poststroke. This trial is registered in the Chinese Clinical Trial Registry (ChiCTR2000037808).

Correlation Between Proprioceptive Impairment and Motor Deficits After Stroke: A Meta-Analysis Review

Introduction: Proprioceptive impairment is a common symptom after stroke. Clarifying how proprioception correlates with motor function after stroke may be helpful in optimizing proprioception-augmented movement training. Previous studies have shown inconsistent findings. A meta-analysis is an optimal method to explore the correlation and identify the factors contributing to these inconsistencies.

Objective: To explore the correlation between proprioception and motor function after stroke through a meta-analysis, taking into account characteristics of the measurements used in these studies.

Methods: We searched multiple databases until November 2021 for eligible studies that measured both proprioception and motor functions in persons with stroke and reported their correlation or data for correlation analysis. A meta-analysis of the correlations was performed. The subgroup analysis and meta-regression were further conducted to investigate potential factors contributing to the heterogeneity of correlation strength, based on the participants' characteristics, proprioception, and motor function measures.

Results: In total, 28 studies comprising of 1,829 participants with stroke were included in the meta-analysis. The overall correlation between proprioception and motor function was significant (r = 0.267, p < 0.05), but there was heterogeneity across studies (I² = 45%, p < 0.05). The results of the subgroup analysis showed proprioception of the axial segment in weight-bearing conditions (r = 0.443, p < 0.05) and upper limb without weight-bearing (r = 0.292, p < 0.05) had a stronger correlation with motor function than proprioception of the lower limb without weight-bearing. The proprioception measured through ipsilateral matching (r = 0.412, p < 0.05) showed a stronger correlation with motor function than through contralateral matching. The International Classification of Functioning, Disability, and Health (ICF) domains of motor function, movement function (r = 0.338, p < 0.05), activity performance (r = 0.239, p < 0.05), and independence (r = 0.319, p < 0.05) showed a stronger correlation with proprioception than with other domains.

Conclusion: There is a significant correlation between proprioception and motor dysfunction after stroke. The proprioception measured in the axial segment under weight-bearing conditions or measured with ipsilateral matching, and motor function, specifically in the ICF domains of movement function, activity performance, and independence showed a positive contribution to the association between proprioception and motor function. The correlation does not imply causation and might be underestimated by attributes of current tests for proprioception and motor function. Further studies are needed to clarify the cause-effect relationship.

Effects of proprioceptive training for people with stroke: A meta-analysis of randomized controlled trials

OBJECTIVE

To evaluate the effectiveness of proprioceptive training on balance performance, trunk control, and gait speed in people with stroke.

METHODS

We searched PubMed, Science Direct, Cochrane, Embase, and Medline for randomized controlled trials that evaluated the effects of proprioceptive training for patients with stroke from the date of each database's inception to July 26, 2021. Two reviewers independently screened the titles and abstracts of potentially eligible articles that were identified on the basis of the search criteria. Methodological quality was determined using version 2 of the Cochrane risk of bias tool for randomized trials. Data were analyzed using Comprehensive Meta-Analysis software. The treatment effect was estimated by calculating Hedges' g and 95% confidence intervals (CIs) using a random-effects model. Statistical heterogeneity was assessed according to the I² value. The primary outcome was balance performance and secondary outcomes were trunk control, gait speed, and basic functional mobility.

RESULTS

In total, 17 trials involving 447 people with stroke were included. Proprioceptive training had a significant effect on balance performance (Hedges' g = 0.69, 95% CI = 0.36-1.01), gait speed (Hedges' g = 0.57, 95% CI = 0.19-0.94), trunk control (Hedges' g = 0.75, 95% CI = 0.33-1.17), and basic functional mobility (Hedges' g = 0.63, 95% CI = 0.31-0.94) among people with stroke.

CONCLUSION

Proprioceptive training may be effective in improving balance performance, gait speed, trunk control, and basic functional mobility among people with stroke.

Zakaria H, M. Ragab W, Al Awaji NN, Y. Elzanaty M, R. Elserougy H. Therapeutic Efficacy of Transcutaneous Electrical Nerve Stimulation Acupoints on Motor and Neural Recovery of the Affected Upper Extremity in Chronic Stroke: A Sham-Controlled Randomized Clinical Trial

Inability to use the affected upper extremity (UE) in daily activities is a common complaint in stroke patients. The somatosensory system (central and peripheral) is essential for brain reorganization and plasticity. Neuromuscular electrical stimulation is considered an effective modality for improving UE function in stroke patients. The aim of the current study was to determine the therapeutic effects of transcutaneous electrical nerve stimulation (TENS) acupoints on cortical activity and the motor function of the affected UE in chronic stroke patients. Forty male and female patients diagnosed with stroke agreed to join the study. They were randomly assigned to group 1 (G1) and group 2 (G2). G1 received task-specific training (TST) and sham electrical stimulation while G2 received TST in addition to TENS acupoints. Session duration was 80 min. Both groups received 18 sessions for 6 successive weeks, 3 sessions per week. Evaluation was carried out before and after completion of the treatment program. Outcome measures used were the Fugl-Meyer Assessment of the upper extremity (FMA-UE) and the box and block test (BBT) as measures of the motor function of the affected UE. Brain activity of the motor area (C3) in the ipsilesional hemisphere was measured using a quantitative electroencephalogram (QEEG). The measured parameter was peak frequency. It was noted that the motor function of the affected UE improved significantly post-treatment in both groups, while no significant change was reported in the FMA-UE and BBT scores post-treatment in either G1 or G2. On the other hand, the activity of the motor area C3 improved significantly in G2 only, post-treatment, while G1 showed no significant improvement. There was also significant improvement in the activity of the motor area (C3) in G2 compared to G1 post-treatment. The results of the current study indicate that TST only or combined with TENS acupoints can be considered an effective method for improving motor function of the affected UE in chronic stroke patients, both being equally effective. However, TST combined with TENS acupoints proved better in improving brain plasticity in chronic stroke patients.

Multisensory Integration in Stroke Patients: A Theoretical Approach to Reinterpret Upper-Limb Proprioceptive Deficits and Visual Compensation

For reaching and grasping, as well as for manipulating objects, optimal hand motor control arises from the integration of multiple sources of sensory information, such as proprioception and vision. For this reason, proprioceptive deficits often observed in stroke patients have a significant impact on the integrity of motor functions. The present targeted review attempts to reanalyze previous findings about proprioceptive upper-limb deficits in stroke patients, as well as their ability to compensate for these deficits using vision. Our theoretical approach is based on two concepts: first, the description of multi-sensory integration using statistical optimization models; second, on the insight that sensory information is not only encoded in the reference frame of origin (e.g., retinal and joint space for vision and proprioception, respectively), but also in higher-order sensory spaces. Combining these two concepts within a single framework appears to account for the heterogeneity of experimental findings reported in the literature. The present analysis suggests that functional upper limb post-stroke deficits could not only be due to an impairment of the proprioceptive system per se, but also due to deficiencies of cross-references processing; that is of the ability to encode proprioceptive information in a non-joint space. The distinction between purely proprioceptive or cross-reference-related deficits can account for two experimental observations: first, one and the same patient can perform differently depending on specific proprioceptive assessments; and a given behavioral assessment results in large variability across patients. The distinction between sensory and cross-reference deficits is also supported by a targeted literature review on the relation between cerebral structure and proprioceptive function. This theoretical framework has the potential to lead to a new stratification of patients with proprioceptive deficits, and may offer a novel approach to post-stroke rehabilitation.

Factors related to daily use of the paretic upper limb in patients with chronic hemiparetic stroke-A retrospective cross-sectional study

AIMS

The present study aimed to determine factors associated with the frequency of paralyzed upper extremity (UE) use in chronic stroke patients with severe UE functional deficiency.

METHODS

We retrospectively reviewed the medical records of 138 consecutive patients, and 117 was analyzed (median age, 55 [range, 18-85] years; median stroke duration, 24.5 [range, 7-302] months) with chronic hemiparetic stroke who were admitted to our hospital for intensive upper extremity rehabilitation. The mean Fugl-Meyer Assessment (FMA) UE score was 28.6. All of them are independent in their activity of daily living (ADL) and without remarkable cognitive deficits. Amount-of-use score of Motor Activity Log-14 (MAL-AOU) was applied as the index of daily use of affected UE. The following parameters were examined as the explanatory variables: demographics, proximal and distal sub-scores of FMA UE, Modified Ashworth Scale (MAS), and sensory function scores in the Stroke Impairment Assessment Set (SIAS).

RESULTS

The median MAL-AOU score was 0.57 [range, 0.28-0.80]. Ordinal regression analysis revealed that FMA proximal, FMA distal, and SIAS sensory function (touch) were associated with AOU score of MAL-14 (Pseudo R-square = 0.460).

CONCLUSION

Not only motor but also sensory function, especially tactile sensation, play a crucial role in the daily use of affected UE in chronic stroke patients with severe UE hemiparesis.

Additional Effects of Xbox Kinect Training on Upper Limb Function in Chronic Stroke Patients: A Randomized Control Trial

Background: Xbox Kinect-based virtual reality, being a novel approach, has therapeutic benefits in rehabilitation and its use is encouraged in stroke rehabilitation of upper extremities. Objective: Primary aim of the current study is to investigate the additional effects of Xbox Kinect training in combination with routine physiotherapy exercises based on each component of Fugl-Meyer Assessment Scale for Upper Extremity (FMA-UE). Moreover, effect of upper limb rehabilitation on cognitive functions was also assessed. Methods: This study was a parallel arm randomized control trial. Fifty-six participants were recruited and randomly allocated to either an Xbox Kinect training group (XKGT) or exercise training group (ETG). Measures of concern were recorded using FMA-UE, Box and Block Test (BBT), and Montreal Cognitive Assessment (MOCA). Evaluation was conducted at baseline and after completion of intervention at the sixth week. Results: There were significant differences from pre- to post-intervention scores of FMA-UE and BBT (p < 0.001) in both groups, whereas no difference was observed for MOCA (XKTG p value 0.417, ETG p value 0.113). At six-week follow-up there were significant differences between both groups in FMA-UE total score (p < 0.001), volitional movement within synergies (p < 0.001), wrist (p = 0.021), hand (p = 0.047), grasp (p = 0.006) and coordination/speed (p = 0.004), favoring the Xbox Kinect training group. Conclusion: To conclude, results indicate repetitive use of the hemiparetic upper extremity by Xbox Kinect-based upper limb rehabilitation training in addition to conventional therapy has a promising potential to enhance upper limb motor function for stroke patients.

Robot-assisted rehabilitation of hand function after stroke: Development of prediction models for reference to therapy

BACKGROUND

Recovery of hand function after stroke represents the hardest target for clinicians. Robot-assisted therapy has been proved to be effective for hand recovery. Nevertheless, studies aimed to refer patients to the best therapy are missing.

METHODS

With the aim to identify which clinical features are predictive for referring to robot-assisted hand therapy, 174 stroke patients were assessed with: Fugl-Meyer Assessment (FMA), Functional Independence Measure (FIM), Reaching Performance Scale (RPS), Box and Block Test (BBT), Modified Ashworth Scale (MAS), Nine Hole Pegboard Test (NHPT). Moreover, patients ability to control the robot with residual force and surface EMG (sEMG) independently, was checked. ROC curves were calculated to determine which of the measures were the predictors of the event.

RESULTS

sEMG control (AUC = 0.925) was significantly determined by FMA upper extremity (FMUE) (>24/66) and sensation (>23/24) sections, MAS at Flexor Carpi (<3/4) and total MAS (>4/20). Force control (AUC = 0.928) was correlated only with FMUE (>24/66).

CONCLUSIONS

FMUE and MAS were the best predictors of preserved ability to control the device by two different modalities. This finding opens the possibility to plan specific therapies aimed at maximizing the highest functional outcome achievable after stroke.

Validity and Reliability of the Semmes-Weinstein Monofilament Test and the Thumb Localizing Test in Patients With Stroke

Background: Somatosensory impairment is common in patients who have had a stroke and can affect their motor function and activities of daily living (ADL). Therefore, detecting and treating somatosensory impairments properly is considered to be very important, and various examinations have been developed. However, the reliability and validity of few of them have been verified due to differences in the procedure of each examiner or poor quantification by the examination itself.

Objective: We hypothesized that, with fixed procedures two convenient clinical examinations, the Semmes-Weinstein Monofilament Test (SWMT) and the Thumb Localizing Test (TLT), could provide reliable assessments of light touch sensation and proprioception. The purpose of this study was to verify the reliability and validity of these two examinations as indices of somatosensory impairment of the upper extremity (UE) in patients with chronic post-stroke hemiparesis.

Methods: Fifty patients with chronic stroke (median time after onset of stroke, 848 [474–1708] days, mean age 57 [standard deviation 14] years) were enrolled at Keio University Hospital from 2017 to 2018. Examiners learned the original method of the SWMT and the TLT rigorously and shared it with each other. The TLT procedure was partially modified by dividing the location of the patient's thumb into four spaces. Two examiners evaluated the SWMT and the TLT for 2 days, and intra-rater and inter-rater reliabilities were calculated using weighted kappa statistics. In addition to this, the evaluator size score of the SWMT was assessed with Bland-Altman analysis to evaluate systematic bias. The Stroke Impairment Assessment Set (SIAS) sensory items were used to assess validity, and Spearman's rank correlation coefficients were calculated.

Results: Intra/inter-rater agreements of the SWMT grade score were 0.89 (thumb, 95%CI: 0.83–0.95)/ 0.75 (0.60–0.91) and 0.80 (index finger, 0.67–0.93)/0.79 (0.66–0.92), and of the TLT they were 0.83 (navel level proximal space, 0.71–0.95)/ 0.83 (0.73–0.92), 0.90 (navel level distal space, 0.85–0.96)/ 0.80 (0.69–0.90), 0.80 (shoulder level proximal space, 0.68–0.92)/ 0.77 (0.65–0.89), and 0.87 (shoulder level distal space, 0.80–0.93)/ 0.80 (0.68–0.92) (P < 0.001, each item). All of them showed substantial agreement, but the MDC of the SWMT evaluator size was 1.28 to 1.79 in the inter-rater test and 1.94–2.06 in the intra-rater test. The SWMT grade score showed a strong correlation with the SIAS light touch sensation item (r = 0.65, p < 0.001), as did the TLT with the SIAS position sense item (r = −0.70–0.62, p < 0.001 each space).

Conclusions: The reliability and validity of the SWMT and the TLT were verified. These tests can be used as reliable sensory examinations of the UE in patients with chronic stroke, and especially for the SWMT, it is more reliable for screening.

Improvement of the Upper Extremity at the Subacute Stage Poststroke: Does Hand Dominance Play a Role?

BACKGROUND

The impact of hand dominance on the expected (motor and functional ability and daily use) improvement of the affected upper extremity (UE) in subacute stroke has not yet been investigated.

OBJECTIVES

To compare between the affected dominant and affected nondominant UE (1) on rehabilitation admission (T1) for motor and sensory abilities, functional ability, and daily use and (2) 6 weeks poststroke onset (T2) and the UE recovery between T1 and T2 regarding percent change, improvement effect size, and percent of participants achieving minimal clinical important difference (MCID).

METHODS

Multicenter longitudinal study.

RESULTS

Thirty-eight participants with affected dominant and 51 participants with affected nondominant UE were recruited. On T1 and T2, between-group differences were not seen for all UE variables. Significant improvement in the motor and functional ability, daily use, and perceived recovery between T1 and T2 were seen for the affected dominant (z = -3.01 to -4.13, P < .01) and nondominant UEs (z = -4.59 to -5.32, P < .01). Effect size improvement values were moderate and large in the affected dominant and nondominant UE (respectively). In addition, 14% to 40% of the participants in both UEs achieved MCID.

CONCLUSIONS

Significant and similar clinical meaningfulness in UE improvement can be expected during subacute rehabilitation; however, improvement magnitude and percent improvement is different for the UE domains of the affected dominant and the affected nondominant UEs. These findings highlight the distinct roles of the dominant and nondominant hands during bimanual daily activities, which can guide clinicians during stroke rehabilitation.

Does Upper Extremity Proprioceptive Training Have an Impact on Functional Outcomes in Chronic Stroke Patients?

Objective

We aimed to investigate the effect of upper extremity proprioceptive training on spasticity and functional motor skills in patients with chronic hemiplegia occurring after stroke.

Method

Thirty chronic hemiplegic patients (17 females, mean age: 66.47±12.55 years) admitted to the Research Center with a diagnosis of chronic hemiplegia developed after stroke were included in the study. Patients were divided into two groups. The first group received a conventional physiotherapy program (PTR) for 5 days a week and the second group additionally received a proprioceptive training program (PTR-PT) for 5 days a week. Before and 6 weeks after the treatment modified Ashworth scale (MAS), Fugl-Meyer upper extremity motor evaluation scale (FMA) and action-research-arm-test (ARAT) and motor activity log-28 scale (MAL-28) were applied. SSPS-22.0 program was used for statistical evaluation and p <0.05 was considered as the level of statistical significance.

Results

There was no difference in MAS scores before and after treatment in the groups (p>0.05). There was a statistically significant improvement in both PTR (p<0.05) and PTR-PT groups (p<0.001) for the FMA, ARAT and MAL-28. scale scores. Although the results obtained in the PTR, and PT groups were more improved, there was a significant result in favor of PTR-PT only regarding the MAL-28 scale scores (p<0.05). It was determined that adding proprioception-based exercises had the greatest effect on FMA, ARAT and MAL-28 in the evaluation of the effect size (>0.3).

Conclusion

It was observed that upper extremity proprioceptive training yielded better results in patients with chronic hemiplegia developed after stroke than conventional therapy in increasing the frequency and quality of movement in upper extremity. This result shows that proprioceptive training programs should be added to stroke rehabilitation methods.

Characteristics Associated with the Differential Activity of Nondominant and Dominant Affected Hands in Patients with Poststroke Right Hemiparesis

Objectives

Spontaneous arm use in patients with poststroke hemiparesis is crucial to the recovery of functional interaction. Patients with stroke and subsequent right hemiparesis have more difficulty adapting to a right-handed environment. The aim of this study was to use wearable devices to assess the asymmetry and difference in the amount of activity of the nondominant and dominant affected hands among patients with stroke and right hemiparesis. The real activity of both hands was measured to assess the correlation with various aspects of the International Classification of Functioning, Disability and Health (ICF). Subjects and Methods. Patients with stroke and right hemiparesis were recruited. They were divided into two groups according to the affected hand. Groups A and B comprised patients with affected nondominant and dominant hands, respectively. The Fugl-Meyer assessment-Upper Extremity (FM-UE) scores, Motor Activity Log (MAL), and hand function domain scores on the Stroke Impact Scale (SIS) were used for assessment. Patients were asked to wear smart wearable devices on both hands 24 hours a day for a month. The amount of activity in both hands was recorded and analyzed.

Results

A total of 29 patients with stroke were divided into group A (n = 14) and group B (n = 15). FM-UE scores were significantly and strongly correlated with the amount of use (AOU) in the MAL. The recorded differential real activity of both hands in group B was significantly lower than that in group A. The asymmetry index of hand use was significantly less favorable in group B. However, no significant differences in AOU in the MAL, FM-UE, and hand function domain in the SIS were identified between the nondominant and dominant affected hands.

Conclusions

The asymmetry and differential activity of both hands were worse in the patients with poststroke right hemiparesis, whose dominant hand was affected. However, no differences of three aspects of the ICF were found between dominant and nondominant affected hands.

Transcutaneous Auricular Vagus Nerve Stimulation with Upper Limb Repetitive Task Practice May Improve Sensory Recovery in Chronic Stroke

BACKGROUND

Sensory impairment is associated with reduced functional recovery in stroke survivors. Invasive vagus nerve stimulation (VNS) paired with rehabilitative interventions improves motor recovery in chronic stroke. Noninvasive approaches, for example, transcutaneous auricular VNS (taVNS) are safe, well-tolerated and may also improve motor function in those with residual weakness. We report the impact of taVNS paired with a motor intervention, repetitive task practice, on sensory recovery in a cohort of patients with chronic stroke.

METHODS

Twelve participants who were more than 3 months postischemic stroke with residual upper limb weakness received 18 × 1 hour sessions over 6 weeks with an average of at least 300 repetitions of functional arm movements per session concurrently with taVNS at maximum tolerated intensity. Light touch and proprioception were scored as part of the Upper Limb Fugl-Meyer (UFM) assessment at baseline and postintervention (score range for sensation 0-12).

RESULTS

Eleven participants (92%) had sensory impairment at baseline of whom 7 (64%) regained some sensation (proprioception n = 6 participants, light touch n = 2, both modalities n = 1) postintervention. The maximal increase in UFM sensation score (3 points) was seen in the patient with the greatest improvement in motor function.

CONCLUSIONS

taVNS paired with motor rehabilitation may improve sensory recovery in chronic stroke patients. The relative contribution of motor and sensory rehabilitation to overall functional recovery in chronic stroke needs further characterization in a larger, phase 2 study.

Anodal Transcranial Direct Current Stimulation Over S1 Differentially Modulates Proprioceptive Accuracy in Young and Old Adults

Background

Proprioception is a prerequisite for successful motor control but declines throughout the lifespan. Brain stimulation techniques such as anodal transcranial direct current stimulation (a-tDCS) are capable of enhancing sensorimotor performance across different tasks and age groups. Despite such growing evidence for a restorative potential of tDCS, its impact on proprioceptive accuracy has not been studied in detail yet.

Objective

This study investigated online effects of a-tDCS over S1 on proprioceptive accuracy in young (YA) and old healthy adults (OA).

Methods

The effect of 15 min of a-tDCS vs. sham on proprioceptive accuracy was assessed in a cross-over, double blind experiment in both age groups. Performance changes were tested using an arm position matching task in a robotic environment. Electrical field (EF) strengths in the target area S1 and control areas were assessed based on individualized simulations.

Results

a-tDCS elicited differential changes in proprioceptive accuracy and EF strengths in the two groups: while YA showed a slight improvement, OA exhibited a decrease in performance during a-tDCS. Stronger EF were induced in target S1 and control areas in the YA group. However, no relationship between EF strength and performance change was found.

Conclusion

a-tDCS over S1 elicits opposing effects on proprioceptive accuracy as a function of age, a result that is important for future studies investigating the restorative potential of a-tDCS in healthy aging and in the rehabilitation of neurological diseases that occur at advanced age. Modeling approaches could help elucidate the relationship between tDCS protocols, brain structure and performance modulation.