Variability in cross-modal proprioceptive judgements impair upper limb function across the lifespan

Area of Science:

• Gerontology
• Neuroscience
• Rehabilitation Science

Background:

• Age-related decline in upper-limb function is a significant concern.
• Proprioceptive deficits are hypothesized to contribute to this functional decline.
• Understanding the specific role of proprioception across the lifespan is crucial for targeted interventions.

Purpose of the Study:

• To quantify the causal effect of proprioceptive ability on upper-limb function.
• To investigate whether this effect is modulated by age.
• To identify specific aspects of proprioception (low-level vs. high-level) relevant to functional performance.

Main Methods:

• Developed a causal graph to guide analysis and minimize bias.
• Recruited 184 healthy adults aged 18-95.
• Assessed low-level and high-level proprioception using grasp-based tasks.
• Utilized generalized linear models to estimate causal effects.

Main Results:

• Poor high-level proprioception precision was associated with impaired performance on a functional task (buttoning a shirt).
• The negative impact of poor high-level proprioception precision on functional task performance increased with age.
• No significant association was found between low-level proprioception and functional performance.
• Observed effects, while modest, were consistent and demonstrated age-dependent patterns.

Conclusions:

• High-level proprioception plays a critical role in maintaining upper-limb functional performance.
• Age-related decline in high-level proprioception precision contributes to functional limitations.
• Proprioception represents a potential therapeutic target for mitigating age-associated upper-limb functional decline.