Efficacy of Action Observation Therapy on Patients with Dysphagia After Stroke: A Randomized Controlled Trial

To investigate the efficacy of Action Observation Therapy (AOT) which is conducted by observing and imitating swallowing videos for post-stroke dysphagia. 36 patients with post-stroke dysphagia were randomly assigned to an observation group or a control group equally. Both groups received routine dysphagia rehabilitation. AOT, was conducted for observation group while control group watched a same-duration landscape video before lunch and dinner．Before and after treatment, Watian Swallowing Test (WST), Eating Assessment Tool (EAT-10), Standard Swallowing Assessment (SSA), Functional Oral Intake Scale (FOIS), surface electromyogram (sEMG) and functional near-infrared spectroscopy (fNIRS) were conducted. After 3 weeks of treatment, WST, EAT-10, SSA, and duration of swallowing muscle groups of both groups significantly decreased (P ＜ 0.05). FOIS and amplitude of swallowing muscle groups of both groups significantly increased (P ＜ 0.05). Except for duration of subhyoid muscles and FOIS, other parameters in observation group were significantly improved compared to those in control group ( P ＜ 0.05). fNIRS showed that overall brain function connection was not significantly enhanced, but significant differences in bilateral primary motor cortex/supplementary motor cortex (PMC/SMC), left dorsolateral prefrontal cortex (DLPFC) and right Broca area were observed. Correlation analysis revealed that changes in amplitude of suprahyoid group muscle had a negative correlation with EAT-10 and SSA scores ( r = -0.332, -0.421, P ＜0.05). AOT based on observation and imitation of swallowing videos can enhance the strength of swallowing related muscles (such as the suprahyoid muscle group), shorten swallowing time, optimize the swallowing process, and ultimately promote the recovery of post-stroke swallowing function. Its mechanism may be related to the activation of brain regions such as PMC/SMC, DLPFC, and Broca area.