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The current perception thresholds vary between horizontal and 70 degrees tilt-up positions
1Department of Anesthesiology, Kumamoto University School of Medicine. Surgical Center, Kumamoto University Hospital, Japan. shimoda@kaiju.medic.kumamoto-u.ac.jp
Anesthesia and Analgesia
|July 27, 2000
Summary
Posture significantly affects current perception threshold (CPT) measurements. For accurate clinical evaluation of peripheral nerve disorders, CPT should consistently be measured in the horizontal posture.
Area of Science:
- Neuroscience
- Physiology
- Biomedical Engineering
Background:
- Posture influences physiological parameters, including autonomic nervous system activity.
- Current perception threshold (CPT) is a measure of nerve function sensitive to physiological changes.
Purpose of the Study:
- To investigate the effect of body posture on CPT measurements.
- To explore the relationship between CPT, autonomic activity, and blood pressure in different postures.
Main Methods:
- CPT was measured at 5, 250, and 2000 Hz in the middle finger of 20 healthy males in horizontal and 70-degree tilt-up positions (TUP).
- Autonomic nervous activity was assessed using heart rate variability (HRV) and spontaneous baroreflex sensitivity.
- Correlations between CPT, HRV, and mean systolic blood pressure were analyzed.
Main Results:
- CPTs were significantly lower in the 70-degree TUP compared to the horizontal posture across all tested frequencies.
- Tilt-up posture led to decreased parasympathetic tone, indicated by HRV and baroreflex changes.
- CPTs showed significant correlations with mean systolic blood pressure and HRV components, particularly in the TUP.
Conclusions:
- Posture significantly alters CPT values, with lower thresholds observed in the tilt-up position.
- The relationship between CPT and blood pressure suggests a link to mechanisms like hypertension-induced hypoalgesia.
- Standardized posture, preferably horizontal, is crucial for reliable CPT assessment in clinical settings.