Changes in Intermuscular Coherence as a Function of Age and Phase of Speech Production During an Overt Reading Task.

PURPOSE The authors evaluated changes in intermuscular coherence (IMC) of orofacial and speech breathing muscles across phase of speech production in healthy younger and older adults. METHOD Sixty adults (30 younger = M: 26.97 year; 30 older = M: 66.37 year) read aloud a list of 40 words. IMC was evaluated across phase: preparation (300 ms before speech onset), initiation (300 ms after onset), and total execution (entire word). RESULTS Orofacial IMC was lowest in the initiation, higher in preparation, and highest for the total execution phase. Chest wall IMC was lowest for the preparation and initiation and highest for the total execution phase. Despite age-related differences in accuracy, neuromuscular modulation for phase was similar between groups. CONCLUSION These results expand our knowledge of speech motor control by demonstrating that IMC is sensitive to phase of speech planning and production.