Trauma, Pain, and Psychological Distress

Posttraumatic stress disorder (PTSD) and chronic musculoskeletal pain (CMP) are highly prevalent ( Breslau, 2002 ) and comorbid disorders ( Otis, Keane, & Kerns, 2003 ). The shared vulnerability model explains this overlap in part through a common attentional bias toward threat ( Asmundson, Coons, Taylor, & Katz, 2002 ). The current study made use of the acoustic startle to assess cognitive bias to threat in participants (n = 106; 64% women) who reported experiencing a motor vehicle accident (MVA). Participants were divided into five groups based on their diagnoses: PTSD, CMP, both PTSD and CMP, any general (i.e., non-PTSD) anxiety disorder with no CMP, and a no-disorder Control group. Self-report measures were used to assess psychological symptoms, trauma response, and pain-related factors. Word stimuli (i.e., trauma, sensory pain, health, pleasant, neutral) were presented visually prior to onset of the acoustic startle probe to assess for diagnosis-congruent attentional biases (e.g., persons with PTSD respond differently to trauma words). Relative to the general anxiety and control group, persons with PTSD or chronic pain demonstrated delayed startle peak and greater startle intensity across all word stimuli types; the results suggest there may be psychophysiologically measurable differences associated with PTSD and pain. The startle probe paradigm remains relatively nascent for such research, but has potential utility for assessment and treatment monitoring. Comprehensive results, discussion, and implications are analyzed.

Time Course of Error-Potentiated Startle and its Relationship to Error-Related Brain Activity

Errors are aversive, motivationally-salient events which prime defensive action. This is reflected in a potentiated startle reflex after the commission of an error. The current study replicates and extends previous work examining the time course of error-potentiated startle as a function of startle lag (i.e., 300 ms or 800 ms following correct and error responses). In addition, the relationship between error-potentiated startle and error-related brain activity in both the temporal (error-related negativity, ERN/Ne) and spectral (error-related theta and delta power) domains was investigated. Event-related potentials (ERPs) were recorded from 32 healthy undergraduates while they performed an arrowhead version of a flanker task. Complex Morlet wavelets were applied to compute oscillatory power in the delta- and theta-band range. Consistent with our previous report, startle was larger following errors. Furthermore, this effect was evident at both early and late startle probe times. Increased delta and theta power after an error was associated with larger error-potentiated startle. An association between ERN amplitude and error-potentiated startle was only observed in a subgroup of individuals with relatively large ERN/Ne amplitude. Among these individuals, ERN/Ne magnitude was also related to multiple indices of task performance. This study further supports the notion that errors are aversive events that prime defensive motivation, and that error-potentiated startle is evident beyond the immediate commission of an error and can be predicted from error-related brain activity.