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Tonic Neuromuscular Processing Affects Postural Adaptation Differently in Aging and Parkinson's Disease
1Neuromotor Sciences Program, College of Public Health, Temple University, Philadelphia, PA, United States.
Frontiers in Neurology
|February 6, 2019
Summary
Postural after-effects, crucial for balance, are altered by aging and Parkinson's disease (PD). Healthy older adults and individuals with PD exhibit impaired postural control adaptation compared to young adults.
Area of Science:
- Neurology
- Biomechanics
- Gerontology
Background:
- Upright posture relies on phasic and tonic neuromuscular control.
- Tonic dysfunction, seen in Parkinson's Disease (PD) and aging, impacts postural stability.
- Postural lean after-effects reflect long-term tonic responses to altered somatosensory input.
Purpose of the Study:
- To investigate how aging and PD affect long-term tonic postural responses (after-effects).
- To examine the influence of support surface orientation on postural after-effects in different age groups and PD patients.
Main Methods:
- Forty-one participants (young, older, PD) underwent quiet stance (QS) and sway-referenced (SR) surface conditions.
- Adaptation involved 120s of toes-up static or sinusoidal tilt.
- Post-adaptation involved 120s of QS or SR to measure postural lean after-effects.
Main Results:
- Young and older adults showed significant anterior center of pressure (COP) shifts during post-adaptation QS, unlike PD patients.
- Older adults exhibited longer decay constants for postural after-effects compared to young adults.
- PD patients demonstrated delayed adaptation to surface changes, with less significant after-effects on SR surfaces.
Conclusions:
- Postural after-effects are retained and amplified on unstable surfaces, differing between healthy aging and PD.
- Tonic neuromuscular processes are vital for adapting postural control to changing conditions.
- Age-related changes and basal ganglia function significantly influence postural adaptability.
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