Does head extension and flexion increase postural instability in elderly subjects when visual information is kept...

Area of Science:

• Gerontology
• Biomechanics
• Neuroscience

Background:

• Postural stability is crucial for elderly individuals.
• Head position influences sensory input (visual, vestibular, somatosensory) affecting balance.
• Understanding these effects is vital for fall prevention strategies.

Purpose of the Study:

• To investigate the impact of head flexion and extension on postural stability in the elderly.
• To assess changes in the anterior-posterior (A-P) center of mass (CM) position during head tilting.
• To differentiate between vestibular and mechanical contributions to postural control alterations.

Main Methods:

• Twelve healthy elderly subjects (mean age 72.3 years) participated.
• Postural stability was measured using center of pressure (CP) excursions on a force platform.
• Measurements were taken during upright stance with the head erect, flexed, and extended, with controlled visual input.

Main Results:

• Postural stability significantly decreased (P < 0.01) when the head was flexed or extended compared to an erect position.
• A significant shift in the mean A-P CM position was observed only during head flexion (P < 0.05).
• These results indicate that head tilting affects balance control beyond vestibular system disruption.

Conclusions:

• Head flexion and extension impair postural stability in the elderly.
• Mechanical perturbation likely contributes to reduced stability with head tilting.
• Further research should explore head-related mechanical influences on balance in aging populations.