Akira Nakashima

In this scoping review, we aimed to comprehensively clarify the methodology of Mental practice (MP) by systematically mapping studies documenting the application of MP to post-stroke paralytic upper-extremity function. Specifically, when is an MP intervention most commonly applied after stroke onset? What is the corresponding MP load (intervention time, number of intervention days, and intervention period)? What are the most common methods of Motor Imagery (MI) recall and MI tasks used during the application of MP? Is MP often used in conjunction with individual rehabilitation? What are the paralyzed side’s upper-limb and cognitive function levels at the start of an MP intervention? The research questions were identified according to PRISMA-ScR. The PubMed, Scopus, Medline, and Cochrane Library databases were used to screen articles published until 19 July 2022. In total, 694 English-language articles were identified, of which 61 were finally included. Most of the studies were conducted in the chronic phase after stroke onset, with limited interventions in the acute or subacute phase. The most common intervention time was ≤30 min and intervention frequency was 5 times/week in MP. An audio guide was most commonly used to recall MI during MP, and 50 studies examined the effects of MP in combination with individual rehabilitation. The Fugl-Meyer Assessment mean for the 38 studies, determined using the Fugl-Meyer Assessment, was 30.3 ± 11.5. Additional research with the aim of unifying the widely varying MP methodologies identified herein is warranted.

The purpose of this scoping review was to comprehensively clarify the methodology of Mental practice (MP) to date by systematically mapping studies that have performed MP on post-stroke paralytic upper extremity function. Specifically, (1) When is the most common timing of MP in-tervention after stroke onset? (2) What is the MP load (intervention time, number of interven-tion days, and intervention period)? (3) What are the most common methods of Motor Imagery (MI) recall and MI tasks during MP? (4) Is MP often used in conjunction with individual rehabili-tative therapies? (5) What is the paralyzed side's upper limb and cognitive function level at the start of MP intervention? Our scoping review was performed ac-cording to PRISMA-ScR to iden-tify research questions. Then, the PubMed, Scopus, Medline, and Cochrane Library databases were used to screen articles published by July 19, 2022. Eligible articles were selected all study designs were included, including studies involving the use of MP for post-stroke paralytic upper extremity function. Selection of eligible papers was done by two or more independent persons. Data were extracted from the eligible papers for items necessary to identify the research ques-tions. English-language articles identified for this study were 694, of which 62 were accepted. The most common intervention time was 30 minutes or less and the duration of the intervention was 5 times a week in MP. The most common method of recalling MI during MP was using an audio guide. In the future, it will be important to conduct accumulation of research to unify the varied widely MP methodologies identified in this study.

Continuous repetition of motor imagery leads to mental fatigue. This study aimed to examine whether fatigue caused by motor imagery training affects improvement in performance and the change in corticospinal excitability. The participants were divided into “physical practice training” and “motor imagery training” groups, and a visuomotor task (set at 50% of maximal voluntary contraction in participants) was performed to assess the training effect on fatigue. The measurements were recorded before and after training. Corticospinal excitability at rest was measured by transcranial magnetic stimulation according to the Neurophysiological Index. Subjective mental fatigue and muscle fatigue were assessed by using the visual analog scale and by measuring the pinch force, respectively. Additionally, the error area was evaluated and calculated at pre-, mid-, and post-terms after training, using a visuomotor task. After training, muscle fatigue, subjective mental fatigue, and decreased corticospinal excitability were noted in both of the groups. Moreover, the visuomotor task decreased the error area by training; however, there was no difference in the error area between the mid- and post-terms. In conclusion, motor imagery training resulted in central fatigue by continuous repetition, which influenced the improvement in performance in the same manner as physical practice training.

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