When touch elicits cold: functional imaging of an abnormal sensation

The authors report a 58-year-old man who presented with touch induced cold sensations and loss of pain and normal temperature sensation in the left leg and trunk. He was found to have syringomyelia at the level of the third thoracic vertebrae. A functional magnetic resonance imaging (fMRI) study was performed to evaluate the underlying cortical processing of the touch induced cold sensations. BOLD responses were measured in response to light tonic pressure stimuli and to cold stimuli applied to both the symptomatic area on the left leg and to the unaffected contralateral side. Tonic pressure applied on the unaff…