Multiregion thermal sensitivity mapping of the hand

Area of Science:

• Neuroscience
• Human Sensory Physiology

Background:

• Previous studies indicated the hand dorsum might be more sensitive to temperature than the palm.
• However, a comprehensive comparison across multiple corresponding dorsal and palmar regions was lacking.

Purpose of the Study:

• To investigate if the hand dorsum exhibits greater sensitivity to temperature variations compared to the palm.
• To compare thermal detection and pain thresholds between dorsal and palmar hand regions.

Main Methods:

• Utilized the Method of Limits to measure cold and warmth detection thresholds in 15 healthy volunteers.
• Employed a 2.56 cm(2) thermode across 10 defined hand areas with a 32°C baseline and 1°C/s rate of change.
• Assessed cold-pain and heat-pain thresholds in a subset of participants.

Main Results:

• All tested dorsal hand regions demonstrated significantly higher sensitivity to cold stimuli than corresponding palmar areas.
• While warmth detection differences were less uniform, overall dorsal sensitivity to warmth was also significantly greater.
• The dorsum showed heightened sensitivity to painful thermal stimuli compared to the palm.

Conclusions:

• The dorsal aspect of the hand is demonstrably more sensitive to temperature changes than the palmar surface.
• This increased sensitivity extends to both detection and pain perception of thermal stimuli.
• Findings suggest distinct regional differences in somatosensory processing within the human hand.