Assessing the Comprehensive Soldier Fitness Program: Measuring Startle Response and Prepulse Inhibition

Abstract : Historically, studies on Soldiers returning from combat focus on the potential for negative health outcomes such as posttraumatic stress disorder. However, current research is also assessing potential positive outcomes associated with combat such as resilience and posttraumatic growth. The Comprehensive Soldier Fitness Program is designed to promote psychological fitness by developing strengths in the emotional, spiritual, social and family domains. Though the program has produced some gains in building resilience in Soldiers, additional measures such as startle response and prepulse inhibition may assist in determining the program's effectiveness and/or provide additional metrics to improve it. The startle response occurs when a startling stimulus, such as a loud noise or skin shock, causes a measurable level of constriction in the orbicularis oculi muscle surrounding the eye. Prepulse inhibition (PPI) occurs when a mild stimulus precedes a startling stimulus, resulting in suppression of the startle response. A Soldier with a reduced PPI and increased startle response may be someone who is susceptible to PTSD. Conversely, a Soldier with a robust PPI and decreased startle response effect could typify a resilient individual.