The role of body size in somatosensory testing.

To try to replicate our earlier findings of body size influences in somatosensory testing we measured thresholds of heat pain, warmth, cold and vibration in 66 young, normal-weight women. Our assumption was that true body measure effects have to be demonstrable even in a sample limited with regard to age and sex and without extreme body size variation (which may be linked to pathology). In the present sample, body size (a linear combination of height and weight) did not have a very strong relation with any of the somatosensory thresholds (slightly stronger for the warmth and cold thresholds than for the heat pain and vibration thresholds). Hence, we could not fully replicate our earlier findings of marked body size effects on warmth and cold thresholds obtained in a sample without such limits. A measure of the body fat content seemed to have some explanatory power, but only for the vibration thresholds. We conclude that body measures, age and sex may be confounded in a way that cannot always be sorted out by a posteriori analyses and should therefore be treated a priori as independent variables for purposes such as establishing normal values in somatosensory testing.