Clinical Trial: Body Temperature in Persons With Tetraplegia When Exposed to Cold

Study Status: Completed
Recruit Status: Completed
Study Type: Interventional

Official Title: Core Temperature During Cold Exposure in Persons With Tetraplegia

Brief Summary:

The ability to maintain normal body core temperature (Tcore = 98.6°F) is impaired in persons with tetraplegia. Despite the known challenges to the ability of persons with spinal cord injury (SCI) to maintain Tcore, and the effects of hypothermia to impair mental function in able-bodied (AB) persons, there has been no work to date addressing these issues in persons with tetraplegia.

The aim of this study is to determine if exposure of up to 2 hrs to cool temperatures (64°F) causes body core temperature to decrease in persons with tetraplegia and if that decrease is related to a decrease in mental performance.

After sitting in a cool (64°F) room for up to 2 hours the investigators hypotheses are:

Hypotheses (1): Tcore of most of the persons with tetraplegia will decline approximately 1.8°F (e.g., 98.6 to 96.8°F) while Tcore of controls will not decline at all; (2) Most of the persons with tetraplegia will show a decline in mental performance (memory or clear-headedness) while only some of AB controls will show a decline.

The second aim of this study is to determine if a 10 mg dose of an approved blood pressure raising medicine (midodrine hydrochloride) will (1) reduce the decrease in body core temperature and (2) prevent or delay the decline in mental performance in the group with tetraplegia compared to the exact same procedures performed on the day with no medicine (Visit 1) in the same group.

Hypotheses (3 & 4): The changes in blood flow to the skin caused by taking a one-time dose of midodrine will lessen the decline in Tcore and prevent or delay the decline in mental performance compared to the changes in Tcore and mental performance during coo

Detailed Summary:

This study will investigate the mechanisms contributing to the thermoregulatory fragility in persons with tetraplegia when exposed to cool ambient temperatures that are routinely encountered during activities of daily living (ADL). Subnormal body core temperatures and vulnerability to hypothermia (Tcore<95°F) has been reported in veterans with tetraplegia upon exposure to relatively mild environmental temperatures. The impact that a drift in Tcore will be expected to have on cognitive performance, specifically working memory and executive function, will be demonstrated. These 2 areas of cognitive performance are vital for the ability to optimally care for one's self, which persons with higher cord lesions must excel at to ensure health, as well as to be able to attain the maximal degree of independence possible. Administration of an alpha agonist, midodrine hydrochloride, in an attempt to attenuate the drift in Tcore and prevent or delay the expected decline in cognitive performance to exposure to cool on cognitive function will be investigated as well.

Primary Specific Aim: To determine the change in: (1) Tcore and (2) cognitive performance (attention, working memory, processing speed, and executive function) in persons with tetraplegia after exposure to a cool environment (64°F) for up to 120 min in the seated position.

Primary Hypotheses:(1) 66% of persons with tetraplegia will demonstrate a decline of 1.8°F in Tcore while 0% of controls will demonstrate that same thermal decline; (2) 80% of persons with tetraplegia will have a decline of at least 1 T-score in Stroop Interference scores (executive functioning) while 30% of controls will demonstrate that same magnitude of decline.

Secondary Specific Aims: To determine the change in: (1) the average of di
Sponsor: James J. Peters Veterans Affairs Medical Center

Current Primary Outcome:

• Visit 1: Percent Change in Core Body Temperature [ Time Frame: Baseline, Up to 2 hours ]
  We will test the effects of cool temperature (64°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 persons with tetraplegia through comparing the percent changes in core body temperatures between groups from baseline to after cool exposure.
• Visit 2: Percent Change in Core Body Temperature With Midodrine [ Time Frame: Baseline, Baseline Post-midodrine, Up to 2 hours ]
  We will test the effects of midodrine on the ability to maintain a constant body temperature (e.g., core temperature of 98.6°F) after exposure to cool temperatures (64°F) in persons with tetraplegia through comparing the percent changes in core body temperature during visit 1 to percent changes in core body temperature during visit 2.

Original Primary Outcome: Core body temperature [ Time Frame: 2 hours ]

Current Secondary Outcome:

• Visit 1: Percent Changes in Cognitive Performance - Stroop Interference [ Time Frame: Baseline, Up to 2 hours ]
  Cognitive performance will be evaluated using the Interference T-Scores obtained using the Stroop Color and Word Test. We will measure the change in cognitive performance in persons with tetraplegia after exposure to a cool environment (64°F) of up to 120 min in the seated position. Note: 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.
• Visit 1: Percent Changes in Cognitive Performance - Delayed Recall [ Time Frame: Baseline, Up to 2 hours ]
  Cognitive performance will be evaluated using the Delayed Recall obtained using the Memory section of the Montreal Cognitive Assessment (MoCA). We will measure the change in cognitive performance in persons with tetraplegia after exposure to a cool environment (64°F) of up to 120 min in the seated position. Note: Scores are based on individual performance. All subjects are asked to remember two lists of five words (one list during baseline, and one list during cool Challenge). Lower scores indicate poorer performance, and a positive percent change in indicates improved cognitive performance.

Original Secondary Outcome: Cognitive performance [ Time Frame: 2 hours ]

Dates:
Date Received: March 21, 2013
Date Started: July 2011
Date Completion:
Last Updated: February 5, 2016
Last Verified: February 2016