Optimise dosage and effect size in virtual reality-based intervention for post-stroke survivors with coexistence of language and motor dysfunctions

In the last two decades, virtual reality (VR) techniques are emerging in post-stroke rehabilitation. Post-stroke patients suffer from impairments in verbal communication and motor. A wide co-existence of aphasia and motor dysfunction indicates that the two deficits could derive from similar brain lesions, specifically Broca’s and motor cortex (Anderlini, Wallis & Marinovic, 2019). Motor rehabilitation could help the recovery of language function. This study examines the association between dose, intensity, and effect size in randomized controlled studies focusing on interventions aiming to improve language, speech, and motor function respectively, or co-existence impairment. The study adopts the framework suggested by Baker (2012) and Warren et al. (2007) and referred dosage to as the effect size of a study, reports and summarises dosage characteristics. Our analysis shows that “teaching episodes” and “dose form” are rarely reported in the included VR-based intervention studies. Specifically taking co-existing language and motor dysfunctions together, the dosage components are not related to the intervention effects size and the association is not statistically significant. This study concludes that future study needs to be able to relate dosage to outcome, asking questions about the relationship between the different dosage characteristics and the intervention effect size. Furthermore, we propose that post-stroke survivors adopt nonverbal communication (NVC) to play as both a motor rehabilitator and a facilitator of language recovery. NVC is the transmission of messages or signals through nonverbal behaviour such as eye contact, facial expressions, gestures, and posture.