Age-related differences in maximum voluntary lip-closing force and ability to control lip-closing force

Area of Science:

• Gerontology
• Oral Physiology
• Biomedical Engineering

Background:

• Lip function deterioration is a key aspect of oral hypofunction in the elderly.
• Understanding age-related changes in lip function is crucial for enhancing oral health and quality of life.
• Lip function impacts essential activities like eating, speaking, and facial expressions.

Purpose of the Study:

• To quantitatively compare maximum lip-closing force (LCF) and LCF control during voluntary lip-pursing movements between elderly and young adults.
• To elucidate the specific influence of aging on lip muscle strength and motor control.
• To establish a baseline for interventions aimed at mitigating age-related oral hypofunction.

Main Methods:

• A multidirectional LCF measurement system was employed to assess six-directional maximum LCFs.
• Participants included 20 healthy elderly men (mean age 69.6 years) and 20 healthy young men (mean age 25.1 years).
• LCF control was evaluated using an accuracy rate metric during voluntary lip-pursing tasks.

Main Results:

• Elderly adults exhibited significantly lower maximum directional LCF compared to young adults in three directions originating from the lower lip.
• The accuracy rate of LCF control was significantly lower in elderly adults than in young adults across five of the six measured directions.
• These findings indicate a dual impact of aging on lip function, affecting both force generation and precise control.

Conclusions:

• Aging affects lip function through decreased muscle strength and, notably, reduced LCF accuracy.
• Age-related hypofunction of the lips may stem from diminished motor control rather than solely reduced muscle strength.
• Further research into the neuromuscular mechanisms underlying age-related lip function decline is warranted.