Task Complexity and Image Clarity Facilitate Motor and Visuo-Motor Activities in Mirror Therapy in Post-stroke Patients

So write this up as a specific stroke rehab protocol and deliver it to all 10 million yearly stroke survivors  now and into the future.

Your responsibility since we have fucking failures of stroke associations that can't accomplish that simple task for all stroke researchers.

Task Complexity and Image Clarity Facilitate Motor and Visuo-Motor Activities in Mirror Therapy in Post-stroke Patients

Umar Muhammad Bello^1,2, Chetwyn C. H. Chan^3* and Stanley John Winser¹

• ¹Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Kowloon, Hong Kong, SAR China
• ²Department of Physiotherapy, Yobe State University Teaching Hospital, Damaturu, Nigeria
• ³Department of Psychology, The Education University of Hong Kong, Tai Po, Hong Kong, SAR China

Introduction: Mirror therapy is effective in the recovery of upper-limb function among post-stroke patients. An important component of mirror therapy is imagining finger movements. This study aimed to determine the influence of finger movement complexity and mirror image clarity on facilitating motor and visuo-motor activities in post-stroke patients.

Methods: Fifteen post-stroke patients and 18 right-handed healthy participants performed simple or complex finger tapping while viewing mirror images of these movements at varying levels of clarity. The physical setup was identical to typical mirror therapy. Functional near infrared spectroscopy (fNIRS) was used to capture the brain activities elicited in the bilateral primary motor cortices (M1) and the precuneus using a block experimental design.

Results: In both study groups, the “complex finger-tapping task with blurred mirror image” condition resulted in lower intensity (p < 0.01) and authenticity (p < 0.01) of the kinesthetic mirror illusion, and higher levels of perceived effort in generating the illusion (p < 0.01), relative to the “simple finger-tapping with clear mirror image” condition. Greater changes in the oxygenated hemoglobin (HbO) concentration were recorded at the ipsilesional and ipsilateral M1 in the “complex finger-tapping task with blurred mirror image” condition relative to that recorded in the “simple finger-tapping task with clear mirror image” condition (p = 0.03). These HbO concentration changes were not significant in the precuneus. Post-stroke patients showed greater changes than their healthy counterparts at the ipsilesional M1 (F = 5.08; p = 0.03; partial eta squared = 0.14) and the precuneus (F = 7.71; p < 0.01; partial eta squared = 0.20).

Conclusion: The complexity and image clarity of the finger movements increased the neural activities in the ipsilesional motor cortex in the post-stroke patients. These findings suggest plausible roles for top-down attention and working memory in the treatment effects of mirror therapy. Future research can aim to corroborate these findings by using a longitudinal design to examine the use of mirror therapy to promote upper limb motor recovery in post-stroke patients.

Introduction

A plane mirror is a simple tool used daily to provide instant visual feedback on body appearance, thereby influencing self-recognition (1). Due to these properties, the plane mirror has been used in rehabilitation clinics as a biofeedback apparatus for balance and postural training (2). Advanced therapeutic application of a plane mirror is an essential element of Ramachandran's mirror therapy or the mirror-induced visual illusion (MVI) paradigm (3).

Mirror therapy has been widely used as a rehabilitative intervention to enhance motor performance in post-stroke patients (4, 5). Moderate evidence supports the effect of mirror therapy for the regain of motor function of upper and lower limbs in this population (5–7). The key feature of mirror therapy is viewing images of motor activity of the unaffected limb to generate an illusion of moving the hidden, affected limb. The generation of the mirror illusion has been associated with activations in the primary motor cortex (M1), precuneus, premotor cortex, primary somatosensory cortex, cerebellum, dorsolateral pre-frontal cortex, superior temporal gyrus and posterior cingulate cortex (8–11), which subserve motor, cognitive and perceptual processes (8, 12). Long-term training using mirror therapy leads to upward regulation of activity in the ipsilesional M1 in post-stroke patients (13), which contributes to post-stroke patients' upper-limb functional regain (14).

Recent studies conducted by our research team highlighted mental imagery as one potential explanation for the useful changes in upper limb function during mirror therapy due to consistent overlap of neural activity reported in the M1, precuneus, primary somatosensory cortex, and cerebellum (10, 11). Another theory explaining the mental processes of mirror therapy in the literature is the mirror neuron system theory (15, 16). However, the theory is limited in substantiating some of the basic neural mechanisms of the mirror therapy paradigm [see Bello et al. (10) and Bello et al. (11)]. For example, lack of significant number of neural substrates of the mirror neuron system, found sub-serving the mirror therapy mental procesess (8), and the activation of ipsilateral M1 in the mirror therapy paradigm, while viewing an immobile image of a hand holding a pencil (17, 18). On the other hand, “Mental imagery” which denotes the rehearsal of limb movement without actual execution (19, 20), shares overlapping neural substrates and associated mental processes with mirror therapy. It can further be classified into kinesthetic motor imagery and visual motor imagery, with the former yielding greater activity in the motor areas and inferior parietal lobule (21, 22).

Briefly, mental imagery theory postulates that the mirror therapy paradigm generates visual image of an “imagined action” of the hidden static limb, owing to the similarities between the hidden limb and the mirror inverted image (23, 24). Kinaesthetic motor imagery, as a modality of mental imagery is associated with the internal generation of sensory components of movement (for example kinesthesia, muscle stretching and joint mobility), associated with the execution of similar movement (20, 22). Existing literature indicated that kinaesthetic motor imagery evokes activation of the motor system without visible mobility of the imagined body part (22, 25, 26). This could serves as the basis for the presence of kinaesthetic mirror illusion (27, 28) in the mirror therapy paradigm (10).

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