Paradoxical heat sensation in patients with multiple sclerosis. Evidence for a supraspinal integration of temperature sensation.

Temperature thresholds were determined in 16 patients with probable or definite multiple sclerosis, in six patients with possible but unconfirmed multiple sclerosis and in 34 healthy subjects, using the method of limits and the thermal sensory limen (TSL) of the MarStock technique. A significant proportion of the patients had thresholds outside the 2.5 SD range for normal subjects, both for warmth detection threshold and TSL. In addition, 10 patients with probable or definite multiple sclerosis and one patient with possible multiple sclerosis reported a paradoxical heat sensation, i.e. a sensation of warmth elicited by a cold stimulus. This illusion was almost exclusively observed with the alternating warm and cold stimuli of the TSL procedure. In contrast to experimental nerve block or peripheral demyelinating neuropathy, where paradoxical heat sensation has been described by various authors, in the patients with multiple sclerosis the demyelination sites were located in the central nervous system. The observation that multiple sclerosis patients had paradoxical heat sensation in addition to threshold abnormalities supports the view that supraspinal sites are important for the integration of temperature sensation.