Cognitive and Motor Therapy After Stroke Is Not Superior to Motor and Cognitive Therapy Alone to Improve Cognitive and Motor Outcomes: New Insights From a Meta-analysis.

OBJECTIVE: To evaluate whether cognitive and motor therapy (CMT) is more effective than no therapy, motor therapy, or cognitive therapy on motor and/or cognitive outcomes after stroke. Additionally, this study evaluates whether effects are lasting and which CMT approach is most effective. DATA SOURCES: AMED, EMBASE, MEDLINE/PubMed, and PsycINFO databases were searched in October 2022. STUDY SELECTION: Twenty-six studies fulfilled the inclusion criteria: randomized controlled trials published in peer-reviewed journals since 2010 that investigated adults with stroke, delivered CMT, and included at least 1 motor, cognitive, or cognitive-motor outcome. Two CMT approaches exist: CMT dual-task ("classical" dual-task where the secondary cognitive task has a distinct goal) and CMT integrated (where cognitive components of the task are integrated into the motor task). DATA EXTRACTION: Data on study design, participant characteristics, interventions, outcome measures (cognitive/motor/cognitive-motor), results and statistical analysis were extracted. Multilevel random effects meta-analysis was conducted. DATA SYNTHESIS: CMT demonstrated positive effects compared with no therapy on motor outcomes (g=0.49; 95% confidence interval [CI], 0.10, 0.88) and cognitive-motor outcomes (g=0.29; 95% CI, 0.03, 0.54). CMT showed no significant effects compared with motor therapy on motor, cognitive, and cognitive-motor outcomes. A small positive effect of CMT compared with cognitive therapy on cognitive outcomes (g=0.18; 95% CI, 0.01, 0.36) was found. CMT demonstrated no follow-up effect compared with motor therapy (g=0.07; 95% CI, -0.04, 0.18). Comparison of CMT dual-task and integrated revealed no significant difference for motor (F1,141=0.80; P=.371) or cognitive outcomes (F1,72=0.61, P=.439). CONCLUSIONS: CMT was not superior to monotherapies in improved outcomes after stroke. CMT approaches were equally effective, suggesting that training that enlists a cognitive load per se may benefit outcomes.

Limb apparent motion perception: Modification by tDCS, and clinically or experimentally altered bodily states.

Limb apparent motion perception (LAMP) refers to the illusory visual perception of a moving limb upon observing two rapidly alternating photographs depicting the same limb in two different postures. Fast stimulus onset asynchronies (SOAs) induce the more visually guided perception of physically impossible movements. Slow SOAs induce the perception of physically possible movements. According to the motor theory of LAMP, the latter perception depends upon the observer's sensorimotor representations. Here, we tested this theory in two independent studies by performing a central (study 1) and peripheral (study 2) manipulation of the body's sensorimotor states during two LAMP tasks. In the first sham-controlled transcranial direct current stimulation between-subject designed study, we observed that the dampening of left sensorimotor cortex activity through cathodal stimulation biased LAMP towards the more visually guided perception of physically impossible movements for stimulus pairs at slow SOAs. In the second, online within-subject designed study, we tested three participant groups twice: (1) individuals with an acquired lower limb amputation, either while wearing or not wearing their prosthesis (2) individuals with body integrity dysphoria (i.e., with a desire for amputation of a healthy leg) while sitting in a regular position or binding up the undesired leg (to simulate the desired amputation); (3) able-bodied individuals while sitting in a normal position or sitting on one of their legs. We found that the momentary sensorimotor state crucially impacted LAMP in individuals with an amputation and able-bodied participants, but not in BID individuals. Taken together, the results of these two studies substantiate the motor theory of LAMP.

Electrocorticographic dissociation of alpha and beta rhythmic activity in the human sensorimotor system.

This study uses electrocorticography in humans to assess how alpha- and beta-band rhythms modulate excitability of the sensorimotor cortex during psychophysically-controlled movement imagery. Both rhythms displayed effector-specific modulations, tracked spectral markers of action potentials in the local neuronal population, and showed spatially systematic phase relationships (traveling waves). Yet, alpha- and beta-band rhythms differed in their anatomical and functional properties, were weakly correlated, and traveled along opposite directions across the sensorimotor cortex. Increased alpha-band power in the somatosensory cortex ipsilateral to the selected arm was associated with spatially-unspecific inhibition. Decreased beta-band power over contralateral motor cortex was associated with a focal shift from relative inhibition to excitation. These observations indicate the relevance of both inhibition and disinhibition mechanisms for precise spatiotemporal coordination of movement-related neuronal populations, and illustrate how those mechanisms are implemented through the substantially different neurophysiological properties of sensorimotor alpha- and beta-band rhythms.