Effect of Heat Exposure on Cognition in Persons With Tetraplegia

Study Summary

The ability to maintain normal body temperature (Tcore) is impaired in persons with tetraplegia: subnormal Tcore and vulnerability to hypothermia (\<95 F) have been documented in this population after exposure to even mild environmental temperatures. However, no work to date has addressed the effect of subnormal Tcore on cognitive performance in persons with tetraplegia despite studies with able-bodied (AB) individuals that have documented progressive decline in various aspects of cognitive performance associated with the magnitude of the depression in Tcore. The investigators' study will confirm and extend their initial observations in persons with higher cord lesions who have subnormal Tcore to show that cognitive performance will be improved by raising Tcore to euthermic levels. This improvement should be associated with greater function and independence, reintegration into society, and an improved quality of life. Specific Aims: During exposure to 95 F for up to 120 minutes in the seated position, the investigators' aims are: Primary Specific Aim: To determine if a modest rise in Tcore to euthermic levels has a positive effect on cognitive performance (attention, working memory, processing speed, and executive function) in persons with higher-level spinal cord injury (SCI). Primary Hypothesis: Based on the investigators' pilot data: (1) 80% of persons with SCI will demonstrate an increase of 1 F in Tcore, while none of the AB controls will demonstrate such an increase; (2) 80% of persons with SCI will have an improvement of at least one T-score in Stroop Interference scores (a validated measure of executive function), while none of the AB controls will demonstrate a change in cognitive performance. Secondary Specific Aim: To determine changes in: (1) The average of distal skin temperatures; (2) Sweat rate; and (3) Subjective rating of thermal sensitivity. Secondary Hypothesis: Persons with SCI will have less of a percent change in average distal skin temper

Primary Outcome

The investigators measured the effects of warm temperature (95 F) exposure, of up to 120 minutes, on the ability to maintain a constant body temperature (e.g., core temperature of 98.6 F) in both groups of subjects. Core temperature was measured at baseline (thermoneutral) and after 120 minutes of warm temperature exposure (Warm Challenge). The change in core temperature from baseline to 120 minutes of Warm Challenge was calculated.

Interventions

• PROCEDURE Warm Temperature