Funder: Department of Defense

Principal Investigator: James Bjork, Ph.D.

Project Period: 10/1/18 to 3/31/20

Funding Amount: $295,932

Pressure ulcers (PU, or bedsores) cause a substantial psychosocial and health burden to spinal cord injury (SCI) patients and result in significant healthcare costs. These costs are higher in individuals who exhibit poor preventative PU self-care. Paralyzed individuals have an unrelenting requirement of proactive action to prevent or heal a PU. They must exert certain effort in the present, such as by frequently shifting positions and visually inspecting skin, in order to prevent an uncertain negative outcome in the future (a new PU or a current PU failing to heal). Therefore, having an impulsive “live in the now” cognitive style could be especially problematic for individuals with SCI to stay on top of their PU prevention and self-care.

Impulsivity is defined as “acting without thinking” on short timescales, as excessive risk-taking or as a myopic preference for small but immediate rewards over larger but delayed rewards. Elevated impulsivity has been shown to increase risk for addictions, obesity, poor medication compliance and other treatment adherence in other health areas. However, the role of impulsivity in SCI health outcomes is not well-known. For example, while doctors assume that smoking increases risk of PU because smoking impairs circulation, it is not known whether some of the relationship between smoking and poor PU outcomes is because a core mental under-appreciation of the future and of penalties underlies both decisions to keep on smoking as well as to give minimal effort on PU self-care.

In response to the Peer Reviewed Medical Research Program (PRMRP) Topic Area on pressure ulcer (prevention), this study will administer iPad tasks to objectively measure several kinds of impulsivity in SCI outpatients who either smoke, binge drink or use cannabis. These tests will determine whether cognitive preferences revealed in brief decision-making and behavioral inhibition tasks are prognostic of poor PU prevention and self-care, and whether these tasks show differences between SCI patients who do versus do not regularly smoke, drink, or use cannabis. Collecting impulsivity information along with substance use information may also provide initial evidence that part of the linkage between poor health outcomes in SCI patients who use substances is due to a core personality trait of impulsivity - either as an early trait that led to the drug use (or to the event that caused the SCI) or as a consequence of chronic drug use damaging the brain.

At veteran and civilian medical centers, we will use medical records to identify paraplegic outpatients age 18-50 with a trauma-induced SCI who have full use of hands with a minimum six months since injury. Patients will be interviewed by phone about substance use. Thirty will be selected for never having regular tobacco or illicit drug use, or binge alcohol use (controls), 30 will be selected for smoking > 10 cigarettes per day with no histories of regular illicit drug use or problematic alcohol use, 30 will be selected for current smoking plus binge drinking with no histories of other regular substance use, and 30 will be selected for current smoking plus cannabis use, but no history of regular use of other drugs.

We will conduct a baseline behavioral assessment in the patient’s home or in the clinic following an outpatient appointment. First, study group membership will be verified with saliva drug screen, breath carbon monoxide and alcohol readings. Using an iPad, a research assistant (RA) will administer mental tasks. The stop-signal and emotional-face go-no-go tasks are like a “Simon says” task of self-control. The delay-discounting and probability-discounting tasks measure how severely the patient de-values hypothetical rewards that are delayed in time or are uncertain, and the Iowa Gambling Task (IGT) will measure risk-taking. The RA will then interview the patient about Spinal Cord Injury Quality of Life (SCI-QoL) using the PROMIS item bank (including PU subdomain). Other assessments include frequency of self-care preventative behavior and mindfulness. Six months after the baseline assessment, the participant will be re-administered (by phone) the same SCI-QoL PROMIS and substance use items, to assess changes in QoL.

We expect to find the following in SCI patients: (1) smokers will show elevated questionnaire and performance-based impulsivity (especially those who also binge-drink or use CAN) compared to non-substance-users. (2) More severe devaluing of delayed rewards and reduced sensitivity to losses during decision-making will be found in patients with poor SCI-QoL and in those with poor SCI self-care behavior. (3A) Baseline decision-based impulsivity will have a significant negative effect on the change of SCI-related QoL PROMIS items over time from baseline to 6-month follow-up. (3B) Among participants with a PU, baseline decision-based impulsivity will have a significant negative effect with the change of PU item bank of the SCI-QoL over time from baseline to 6-month follow-up. Finding elevated impulsivity in those patients with poor SCI self-care will set the stage for future trials of targeted cognitive intervention in these patients. Training better future-oriented thinking may have broader SCI benefits compared to a smoking cessation program alone, for example.