Cross-correlation evaluated muscle co-ordination for speech production.

Abstract In this investigation the jaw-mouth-lip (JML) co-ordination is quantified using cross-correlation (CC) between facial electromyography (EMG) while speaking words 'zero to nine'. The facial EMG data of four prominent facial muscles, namely Zygomaticus Major (ZM) from the mouth region, Levator Labii Superioris (LLS), Orbicularis Oris Inferioris (OOI) from the lip region and Anterior Belly of Diagastric (ABD) from the jaw region are collected and analysed. A total of six muscle pairs, (1) ABD-ZM, (2) ZM-LLS, (3) OOI-ZM, (4) ABD-LLS, (5) ABD-OOI and (6) LLS-OOI, are formed based on their position. Based on correlation study, all these muscle pairs show a significantly different co-ordination level (p<0.05). The CC of the ABD-LLS muscle pair is observed with maximum co-ordination level among all spoken words (Tukey's post-hoc, α=0.05). These investigations based on CC in JML co-ordination could be used in designing various biomedical engineering tools such as speech prosthesis, facial lie detectors, etc.