Polar-phase indices of perioral muscle reciprocity during syllable production in Parkinson’s disease

Shin Ying Chu, Steven M. Barlow, Jaehoon Lee, Jingyan Wang

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Purpose: This research characterised perioral muscle reciprocity and amplitude ratio in lower lip during bilabial syllable production [pa] at three rates to understand the neuromotor dynamics and scaling of motor speech patterns in individuals with Parkinson’s disease (PD). Method: Electromyographic (EMG) signals of the orbicularis oris superior [OOS], orbicularis oris inferior [OOI] and depressor labii inferioris [DLI] were recorded during syllable production and expressed as polar-phase notations. Result: PD participants exhibited the general features of reciprocity between OOS, OOI and DLI muscles as reflected in the EMG during syllable production. The control group showed significantly higher integrated EMG amplitude ratio in the DLI:OOS muscle pairs than PD participants. No speech rate effects were found in EMG muscle reciprocity and amplitude magnitude across all muscle pairs. Conclusion: Similar patterns of muscle reciprocity in PD and controls suggest that corticomotoneuronal output to the facial nucleus and respective perioral muscles is relatively well-preserved in our cohort of mild idiopathic PD participants. Reduction of EMG amplitude ratio among PD participants is consistent with the putative reduction in the thalamocortical activation characteristic of this disease which limits motor cortex drive from generating appropriate commands which contributes to bradykinesia and hypokinesia of the orofacial mechanism.

Original languageEnglish (US)
Pages (from-to)616-627
Number of pages12
JournalInternational Journal of Speech-Language Pathology
Issue number6
StatePublished - Nov 2 2017


  • Electromyography
  • Parkinson’s disease
  • perioral muscle
  • reciprocity
  • speech rate

ASJC Scopus subject areas

  • Research and Theory
  • Otorhinolaryngology
  • Language and Linguistics
  • LPN and LVN
  • Speech and Hearing


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