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

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.

Which sites better represent the sensory function of hands in convalescent stroke patients? A study based on electrophysiological examination

Background

Assessing hand sensation in stroke patients is necessary; however, current clinical assessments are time-consuming and inaccurate.

Objective

This study aimed to explore the nature of light touch sensation and two-point discrimination (2-PD) of different hand sites in convalescent stroke patients based on somatosensory evoked potentials (SEP).

Methods

Light touch sensation and 2-PD of the thumb, the index finger, the little finger, thenar, and hypothenar were measured (n = 112) using sensory measurement tools. Sensory differences among the hand sites were then compared. The correlation analysis between SEP and the hemiplegic hand function was made. Sensory functions were divided into three levels: sensory intactness, sensory impairment, and sensory loss.

Results

Light touch sensations were mainly associated with sensory impairment in the finger and palm region. The 2-PD of the finger region was mainly sensory loss and that of the palm region was mainly sensory impairment. There was no statistical difference in the light touch sensation among the sites of the hand. The correlation coefficients between the 2-PD and SEP N20 amplitudes differed. The correlation coefficients of the thenar and hypothenar were the smallest, and that of the finger was the largest. Light touch sensation and 2-PD in patients with stroke were related to the hemiplegic hand function.

Conclusion

Any site on the hand could be selected as the measurement site for light touch sensation. The little finger and hypothenar may be appropriate sites when screening for 2-PD. To improve the patient's recovery they could receive more sensory stimulation of the hand.

Mediating Effect of Upper Limb Use on the Relationship Between Upper Limb Performance and Activities of Daily Living: A Longitudinal Mediation Analysis

INTRODUCTION

Upper limb performance, frequency of upper limb use, and psychological factors are associated with activities of daily living (ADLs) after stroke. We performed a mediation analysis to investigate how the frequency of upper limb use and some psychological factors mediate the relationship between upper limb performance and ADLs.

METHODS

Twenty-two patients with stroke were included in this longitudinal study. We utilized the frequency of upper limb use outcome measures (amount of use and quality of motion of the motor activity log), psychological factors outcome measures (General Self-Efficacy Scale), upper limb performance outcome measures (Fugl-Meyer Assessment (FMA)), and ADLs outcome measure (Functional Independence Measure (FIM) motor subscale (M)). Mediation analysis with a bootstrap sampling procedure was used to assess the indirect effects.

RESULTS

Mediation analysis showed that the FMA, as measured by the FIM (M), had significant indirect effects on the amount of use (95% bootstrapped confidence interval (CI): 0.36-2.42) and quality of motion (95% bootstrapped CI: 0.06-1.88). The relationship between upper limb performance and ADLs was mediated by the frequency of upper limb use.

CONCLUSION

Our findings suggest that improving the frequency of upper limb use may accelerate post-stroke recovery.

A novel tablet-based application for assessment of manual dexterity and its components: a reliability and validity study in healthy subjects

BACKGROUND

We developed five tablet-based tasks (applications) to measure multiple components of manual dexterity.

AIM

to test reliability and validity of tablet-based dexterity measures in healthy participants.

METHODS

Tasks included: (1) Finger recognition to assess mental rotation capacity. The subject taps with the finger indicated on a virtual hand in three orientations (reaction time, correct trials). (2) Rhythm tapping to evaluate timing of finger movements performed with, and subsequently without, an auditory cue (inter-stimulus interval). (3) Multi-finger tapping to assess independent finger movements (reaction time, correct trials, unwanted finger movements). (4) Sequence tapping to assess production and memorization of visually cued finger sequences (successful taps). (5) Line-tracking to assess movement speed and accuracy while tracking an unpredictably moving line on the screen with the fingertip (duration, error). To study inter-rater reliability, 34 healthy subjects (mean age 35 years) performed the tablet tasks twice with two raters. Relative reliability (Intra-class correlation, ICC) and absolute reliability (Standard error of measurement, SEM) were established. Task validity was evaluated in 54 healthy subjects (mean age 49 years, range: 20-78 years) by correlating tablet measures with age, clinical dexterity assessments (time taken to pick-up objects in Box and Block Test, BBT and Moberg Pick Up Test, MPUT) and with measures obtained using a finger force-sensor device.

RESULTS

Most timing measures showed excellent reliability. Poor to excellent reliability was found for correct trials across tasks, and reliability was poor for unwanted movements. Inter-session learning occurred in some measures. Age correlated with slower and more variable reaction times in finger recognition, less correct trials in multi-finger tapping, and slower line-tracking. Reaction times correlated with those obtained using a finger force-sensor device. No significant correlations between tablet measures and BBT or MPUT were found. Inter-task correlation among tablet-derived measures was weak.

CONCLUSIONS

Most tablet-based dexterity measures showed good-to-excellent reliability (ICC ≥ 0.60) except for unwanted movements during multi-finger tapping. Age-related decline in performance and association with finger force-sensor measures support validity of tablet measures. Tablet-based components of dexterity complement conventional clinical dexterity assessments. Future work is required to establish measurement properties in patients with neurological and psychiatric disorders.

Decreased Tactile Sensitivity Induced by Disownership: An Observational Study Utilizing the Rubber Hand Illusion

The sense of body ownership, the feeling that one’s own body belongs to oneself, is generated from the integration of visual, tactile, and proprioceptive information. However, long-term non-use of parts of the body due to physical dysfunction caused by trauma or illness may disturb multisensory integration, resulting in a decreased sense of body ownership. The rubber hand illusion (RHI) is an experimental method of manipulating the sense of ownership (SoO). In this illusion, subjects feel as if the rubber hand in front of them were their own hand. The RHI elicits the disownership phenomenon; not only does the rubber hand feels like one’s own hand, but one’s own hand does not feel like one’s own hand. The decrease of ownership of one’s own body induced by the bodily illusion is accompanied by neurophysiological changes, such as attenuation of somatosensory evoked potential and decreases in skin temperature. If the loss of the SoO is associated with decreased neurophysiological function, the dysfunction of patients complaining of the loss of ownership can be exacerbated; appropriate rehabilitation prescriptions are urgently required. The present study attempted to induce a sense of disownership of subjects’ own hands using the RHI and investigated whether the tactile sensitivity threshold was altered by disownership. Via questionnaire, subjects reported a decrease of ownership after the RHI manipulation; at the same time, tactile sensitivity thresholds were shown to increase in tactile evaluation using the Semmes-Weinstein monofilaments test. The tactile detection rate changes before and after the RHI were negatively correlated with the disownership-score changes. These results show that subjects’ sense of disownership, that their own hands did not belong to them, led to decreases in tactile sensitivity. The study findings also suggest that manipulating of illusory ownership can be a tool for estimating the degree of exacerbation of sensory impairment in patients. Consideration of new interventions that optimize the sense of body ownership may contribute to new rehabilitation strategies for post-stroke sensory impairment.

Evolution and prediction of mismatch between observed and perceived upper limb function after stroke: a prospective, longitudinal, observational cohort study

BACKGROUND

A previously shown 'mismatch' group of patients with good observed upper limb (UL) motor function but low perceived UL activity at six months post stroke tends to use the affected UL less in daily life than would be expected based on clinical tests, and this mismatch may also be present at 12 months. We aimed to confirm this group in another cohort, to investigate the evolution of this group from six to 12 months, and to determine factors on admission to inpatient rehabilitation and at 6 months that can discriminate between mismatch and good match groups at 12 months.

METHODS

Persons after stroke were recruited on rehabilitation admission and re-assessed at six and 12 months. Observed UL function was measured with the upper extremity subscale of the Fugl-Meyer Assessment (FMA-UE) and perceived UL activity by the hand subscale of the Stroke Impact Scale 3.0 (SIS-Hand). We defined mismatch as good observed UL function (FMA-UE > 50/66) but low perceived activity (SIS-Hand≤75/100). Potential discriminators at admission and 6 months (demographic characteristics, stroke characteristics, UL somatosensory function, cognitive deficits, mental function and activity) were statistically compared for match and mismatch groups at 12 months.

RESULTS

We included 60 participants (female: 42%) with mean (SD) age of 65 (12) years. We confirmed a mismatch group of 11 (18%) patients at 6 months, which increased to 14 (23%) patients at 12 months. In the mismatch group compared to the good match group at 12 months, patients had a higher stroke severity and more somatosensory impairments on admission and at 6 months.

CONCLUSIONS

We confirmed a group of patients with good observed UL function but low perceived activity both at six and at 12 months post stroke. Assessment of stroke severity and somatosensory impairments on admission into rehabilitation could determine mismatch at 12 months and might warrant intervention. However, large differences in clinical outcomes between patients in the mismatch group indicate the importance of tailoring training to the individual needs.