Cooling and multiple sclerosis: Cognitive and sensory effects

Abstract

The effects of cooling on sensory and cognitive processes were investigated in heat- sensitive multiple sclerosis (MS) patients and healthy control (HC) subjects. The Life- Support cooling jacket was used to lower core body temperature by one degree or more. Auditory event-related potentials and neuropsychological test performance were examined in both the cooled and the normal states. Eight MS patients and eight HC subjects underwent two hours of cooling on one day and two hours of sham cooling on another day (order counterbalanced across subjects). Cooling significantly slowed conduction speed in the auditory brainstem pathway of both groups. Cooling also delayed a longer latency sensory ERP (N100) in the MS patients, but not in the healthy controls. A cognitive evoked related potential measure (P300) was delayed in the MS patients but was not affected by cooling in either group. The MS patients had significantly poorer neuropsychological performance than HC subjects but performance on most of these tests was not affected by cooling. Since the electrophysiological and neuropsychological measures tapped a broad range of CNS functions and brain areas, the data suggest that the marked clinical improvement seen with cooling in heat-sensitive MS patients is not accounted for by facilitation of the sensory and cognitive processes of the CNS. © 1996 Demos Vermande.