Effects of mirror training on motor performance in healthy individuals: a systematic review and meta-analysis

Abstract

ObjectiveMirror training (MTr) is a rehabilitation technique for patients with neurological diseases. There is no consensus on its effects on motor function in healthy individuals. This systematic review and meta-analysis considers the effects of MTr on motor function in healthy individuals.DesignThis is a systematic review and meta-analysis.Data sourcesWe searched six databases for studies assessing the effects of MTr on motor function in healthy individuals, published between January 1995 and December 2018. The Cochrane risk of bias was used to assess the quality of the studies. A meta-analysis was conducted with narrative synthesis.Eligibility criteria for selecting studiesEnglish-language randomised controlled trials reporting the behavioural results in healthy individuals were included.ResultsFourteen randomised controlled trials involving 538 healthy individuals were eligible. Two short-term studies showed MTr was inferior to passive vision pattern (standardised mean difference 0.57 (95% CI 0.06 to 1.08), I2=0%, p=0.03). The methods varied and there is limited evidence supporting the effectiveness of MTr compared with three alternative training patterns, with insufficient evidence to support analyses of age, skill level or hand dominance.ConclusionThe limited evidence that MTr affects motor performance in healthy individuals is weak and inconsistent among studies. It is unclear whether the effects of MTr on motor performance are more pronounced than the direct vision pattern, passive vision pattern or action observation. Further studies are needed to explore the short-term and long-term benefits of MTr and its effects on motor learning in healthy individuals.PROSPERO registration numberCRD42019128881.

Immediate effect of adding mirror visual feedback to lateral weight-shifting training on the standing balance control of the unilateral spatial neglect model

“…The MVF can enhance the neurophysiological response and increase cognitive activation to be helpful in neuro-rehabilitation and stroke recovery 37,[52][53][54] . However, our results corroborate a review showing weak evidence and inconsistent studies that mirror training affects healthy individuals' motor performance 14,39) . These outcomes may be due to participants, unlike patients with neglect who do not use the same clues and cannot modify their procedures to recalibrate their spatial representations 20) .…”

“…On the other hand, head-mounted display (HMD) device modifications and adjustments were introduced as an instrument for clinical evaluation and can be a potential treatment strategy for USN patients [34][35][36] . In addition, healthy participants have been involved in determining the physiological effects of the training developed [37][38][39] . Moreover, an increase of postural sway during the eye-opened quiet upright standing task was affected by wearing the HMD for virtual reality (VR) [40][41][42] .…”

Demystifying the mirror taboo: A neurocognitive model of viewing self in the mirror

“…Moving the unaffected limb retrains the affected limb via mirror neuron pathways in the brain (Thieme et al, 2018). The use of mirror training to improve limb strength and performance in healthy individuals is inconclusive (Chen, Wang, Bai, & Wang, 2019). Psychologists have used guided mirror image exposure for individuals with eating disorders and body image disturbances.…”

The Modulatory Effects of Intermittent Theta Burst Stimulation in Combination With Mirror Hand Motor Training on Functional Connectivity: A Proof-of-Concept Study

“…Mirror training (MT), in which participants are required to move one side of their hand while simultaneously observing the mirror visual feedback (MVF) from a mirror placed in the mid-sagittal plane, has been investigated with healthy adults to study the process of observation-based motor learning ( Zult et al, 2016 ; Chen et al, 2019 ) and also applied in stroke rehabilitation to improve the upper extremity motor relearning in patients with hemiplegia ( Fong et al, 2019 ). The neural correlates underlying the MT are still under exploration, and there has been evidence that MVF can activate the parietal–frontal areas across bilateral hemispheres as well as the ipsilateral sensorimotor area (ipsilateral to the training hand and contralateral to the static hand behind the mirror) ( Zhang et al, 2018 ).…”