Body Temperature in Persons With Tetraplegia When Exposed to Heat

Completed

Brief Summary: The deleterious effects of hyperthermia are well appreciated in able-bodied persons. However, the consequences of impaired regulation of normal body temperature on cognitive performance of persons with tetraplegia is not known. This study will provide the preliminary findings necessary for future work to design and explore physical and medical interventions to improve temperature regulation in those with tetraplegia with the goal of improved clinical care, health, and quality of life.

The proposed study consists of 1 visit during which 20 subjects (10 with tetraplegia, 10 controls) will be exposed to 81°F for 40 minutes and then 95° F for up to 2 hours. Physiological as well as psychological processes will be monitored in all subjects during the study for safety and to determine differences in responses to exposure to hot ambient temperatures

Detailed Description: After a cervical spinal cord injury (SCI) the motor, sensory and autonomic deficits cause, among other detriments, a blunted ability to maintain a constant core temperature. Impaired thermoregulation leaves persons with tetraplegia more susceptible to hyperthermia than able-bodied persons (AB). There has been a paucity of work addressing the thermoregulatory responses of persons with SCI to hot ambient temperatures, and even less study addressing the effect of these temperatures on cognitive performance. The goals of this pilot study are: to improve our understanding of the thermoregulatory mechanisms of individuals with tetraplegia when exposed to heat and to determine the effect of impaired thermoregulatory mechanisms on cognitive performance during exposure to 35°C for up to 2 hours. In order to address our goals we have designed a study methodology which consists of comparing the physiological and psychological responses of the two study groups (tetraplegia versus AB controls) from thermoneutral (27°C) to hot (35°C) environments.

Recruitment & Eligibility

Inclusion Criteria

Between 18 and 65 years of age;
Duration of injury ≥ 1 year;
Level of SCI C4-T1;
Euhydration (Subjects will be instructed to avoid caffeine and alcohol, maintain normal salt and water intake, and avoid strenuous exercise for 24 hours prior to study); and
Age (± 5 years) and gender matched AB control group.

Exclusion Criteria

Arm && Interventions

Group	Intervention	Description
Control	Heat Exposure	Age and gender-matched able-bodied controls. Ages 18-65 years old.
Tetraplegia	Heat Exposure	Persons with spinal cord injury, level of injury C4-T1, American Spinal Injury Association (ASIA) impairment levels A-B and duration of injury greater than 1 year. Ages 18-65 years old.

Primary Outcome Measures

Name	Time	Method
Core Body Temperature	2 hours	To determine the change in core body temperature in the seated position from 79 degrees F for 30 minutes to 95 degrees F for up to 2 hours. Hypotheses: Persons with tetraplegia will have a greater increase in core body temperature than able-bodied (AB) control subjects. Core body temperature in AB persons will be maintained.

Secondary Outcome Measures

Name	Time	Method
Cognitive Performance - Stroop Interference T-Scores	2 hours	To determine the change in cognitive performance as measured by the Stroop Color and Word Interference T-Scores, measured after 30 min at 79 degrees F and after up to 2 hours at 95 degrees F. Interference T-Scores are derived from the difference between the raw Color-Word score and the projected Color-Word score (which is, in turn, based on the raw scores obtained in the Word and Color portions of the Test). Lower scores indicate poorer performance, and a positive percent change in T-scores indicates improved performance. Hypothesis: Persons with tetraplegia compared with AB will have a greater change in cognitive performance from baseline (79 degrees) to warm exposure (95 degrees).