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Right-left asymmetry in tonic pain perception and its modification by simultaneous contralateral noxious stimulation
R Chandramouli1, B R Kanchan, B Ambadevi
1Department of Physiology, Kempegowda Institute of Medical Sciences, Bangalore, India.
Neuropsychologia
|July 1, 1993
Summary
Healthy subjects show right-hand pain dominance. However, applying a second painful stimulus to the opposite hand reversed this pain perception lateralization in 40% of participants, suggesting altered pain modulation.
Area of Science:
- Neuroscience
- Pain Perception
- Human Physiology
Background:
- The cold pressor test (CPT) is a standard method for inducing pain and assessing pain perception.
- Previous studies suggest a lateralization of pain perception, with the right hand often exhibiting a higher pain threshold and tolerance.
- The influence of concurrent stimuli on this established pain lateralization requires further investigation.
Purpose of the Study:
- To investigate whether the observed lateralization of pain perception in the right hand persists when the contralateral hand is exposed to simultaneous non-noxious or noxious stimuli.
- To explore the mechanisms underlying changes in pain perception lateralization under dual-stimulus conditions.
Main Methods:
- Administration of the cold pressor test (CPT) to healthy subjects.
- Simultaneous application of non-noxious or noxious stimuli to the contralateral hand during the CPT.
- Assessment of pain perception using measures such as pain threshold, pain tolerance, Graphic Rating Scale, Pain Perception Inventory (PPI), and McGill Pain Questionnaire (MPQ).
Main Results:
- In the initial CPT (Test I), subjects demonstrated significant pain lateralization to the right hand, characterized by higher pain threshold and tolerance, and lower pain scores.
- When a noxious stimulus was applied to the contralateral hand during the CPT (Test III), a reversal of pain laterality to the left hand was observed in 40% of subjects for pain threshold.
- Exposure to a non-noxious stimulus on the contralateral hand (Test II) did not result in a significant reversal of laterality.
Conclusions:
- Pain perception lateralization, as assessed by the CPT, is not absolute and can be modulated by concurrent stimuli.
- The observed reversal of laterality in Test III suggests the involvement of diffuse noxious inhibitory controls (DNIC) and attentional focus mechanisms.
- These findings highlight the complex interplay between different sensory inputs in modulating pain perception and lateralization.