Related Experiment Videos
Physiological tremor of the upper limb segments.
1Department of Systems Engineering, University of Electro-Communications, 1-5-1 Chofugaoka, Chofu-shi, Tokyo 182-8585, Japan.
European Journal of Applied Physiology
|September 19, 2001
Summary
Physiological tremor in upper limbs has two components: one supraspinal (8-12 Hz) and one spinal, dependent on limb mass. This finding aids in evaluating neuromuscular function in healthy individuals and patients with neurological diseases.
Area of Science:
- Biomechanics
- Neuroscience
- Human Physiology
Background:
- Physiological tremor is a rhythmic, oscillatory movement present in all limbs.
- Understanding the origin and characteristics of tremor is crucial for diagnosing neurological disorders.
- Previous research has identified various factors influencing tremor, but a comprehensive model is lacking.
Purpose of the Study:
- To analyze the frequency components of physiological tremor in different upper limb segments.
- To develop a model that explains the underlying mechanisms of tremor.
- To investigate the potential clinical applications of tremor analysis.
Main Methods:
- Acceleration sensors were used to measure tremor in the finger, hand, forearm, and upper limb during a holding posture.
- Power spectrum analysis was employed to identify dominant tremor frequencies.
- A mathematical model incorporating spinal and supraspinal reflex pathways was developed and validated against experimental data.
Main Results:
- Two distinct frequency peaks were observed in the tremor's power spectrum across all measured limb segments.
- One peak remained constant at 8-12 Hz across segments, suggesting a supraspinal origin.
- The second peak's frequency varied with limb segment mass, indicating a spinal reflex pathway influence.
Conclusions:
- Physiological tremor comprises two components: a supraspinal component (8-12 Hz) and a spinal component influenced by limb mass.
- The developed model accurately predicts tremor frequency and amplitude, supporting the proposed reflex pathways.
- Tremor analysis offers a potential method for assessing neuromuscular function changes due to prolonged work or neurological conditions like Parkinson's disease and muscular dystrophy.