Differential fine force control of the upper and lower lips

Area of Science:

• Neuroscience
• Speech Science
• Biomechanics

Background:

• The precise neural control of lip movements is fundamental for speech production.
• Existing literature suggests potential differential control mechanisms for the upper and lower lips.
• Understanding these mechanisms is vital for diagnosing and treating speech disorders.

Purpose of the Study:

• To investigate the hypothesis of differentially controlled neuronal connectivities for the upper and lower lips.
• To establish a normative database for fine force control measures relevant to speech.
• To compare the fine force control capabilities of the upper and lower lips.

Main Methods:

• Literature review to formulate hypotheses.
• Development of a normative database for fine force control measures.
• Analysis of select physiologic measures of lip force control during speech-relevant tasks.

Main Results:

• Fine force control in the lower lip was significantly more stable than in the upper lip.
• Lower lip recruitment rates for fine force control were higher compared to the upper lip.
• The findings indicate differential neural control influencing lip kinematics.

Conclusions:

• The lower lip demonstrates superior fine force control, likely due to distinct neural connectivities.
• These findings provide insights into the neural basis of lip motor control.
• The study highlights the potential utility of these measures in assessing dysarthrias.