Dysphagia Evaluation by Using Cross-correlation coefficient of Surface Electromyography

Swallowing disorder, also called dysphagia, is a common complication caused by strokes. The dysphagic patients usually have clinical problems such as choking, malnutrition, significant weight loss, and aspiration pneumonia. Surface electromyography(EMG) provides a simple, non-radioactive, and non-invasive method to measure the muscle activity patterns during swallowing to describe physiology of swallowing behavior. Most of previous studies described the swallowing behavior by the terms of amplitude and latency. However, there is no objective and precise approach to evaluate swallowing coordination. In order to evaluate swallowing coordination more precisely, surface EMG of bilateral muscles involving in swallowing were recorded and the cross-correlation analysis was used. The variations of the cross correlation coefficients were defined as the discoordination index (DI), which reflects the difference between the surface EMG patterns of the bilateral muscle groups. Dysphagia stroke patients and healthy subjects were recruited for sEMG recording. The result shows that the discoordination indexes for dysphagic patients were significantly larger than those for healthy subjects in submental muscles and can be used as an effective way for quantification of the coordination between bilateral swallowing muscles in future studies.