Disruption of thermal perception in a multiple sclerosis patient with central pain

Objective: To investigate integrative thermal perception in a patient with multiple sclerosis. Design: Quantitative thermosensory testing was used to evaluate pain and other sensations produced by heat, cold, and the thermal grill pain illusion. Patient: The authors report on a 43-year-old patient with central pain manifest most strongly in her left arm and hand, contralateral to an upper cervical spinothalamic lesion due to multiple sclerosis. Outcome Measures and Results: Quantitative thermosensory testing showed that the patient had heat hypalgesia (no pain with stimuli of 45-50degreesC) and cold allodynia (pain with innocuous cool temperatures, 25-10degreesC). Whereas healthy subjects rated 20 and 40degreesC as nonpainful, but the thermal grill (intermixed 20 and 40degreesC stimuli) as painful, the patient rated the thermal grill as less painful than 20degreesC. Conclusions: The absence of thermal grill-evoked pain is consistent with the hypothesis that in some cases of central pain the loss of the thermosensory pathway results in disruption of the normal cold inhibition of burning pain.