Tracey A. Brickell

Using past behaviour and spontaneous implementation intentions to enhance the utility of the theory of planned behaviour in predicting exercise

OBJECTIVES This study examined the utility of the theory of planned behaviour (TPB), past behaviour, and spontaneous implementation intentions in predicting exercise behaviour. The psychological correlates of spontaneous implementation intentions and the moderating effects of intention, perceived behavioural control, past behaviour, and implementation intentions at various time points were also examined. DESIGN Data collection occurred over three phases with a 2- and 3-week interval. The attrition rate was 35.97% leaving a total of 162 participants (63 males, 99 females). In the first wave, participants completed measures of TPB, spontaneous implementation intentions, and past behaviour. Behaviour was assessed in the second and third waves, and a follow-up measure of spontaneous implementation intentions was completed in Phase 3. RESULTS Several regression analyses were conducted. Attitude towards exercise and perceived behavioural control made a significant contribution to the prediction of intention. Intention made a significant contribution to the prediction of implementation intentions. Spontaneous implementation intentions reduced the effect of intention and past behaviour for behaviour at 2 weeks and when indexed over a 5-week period. When behaviour was measured for a 3-week period (following an initial 2-week period), the variance that intention and past behaviour accounted for in exercise behaviour decreased, and spontaneous implementation intentions were no longer a significant predictor of behaviour. Spontaneous implementation intentions were found to interact with past behaviour, such that implementation intentions predicted exercise behaviour only among participants who did not exercise frequently in the past. CONCLUSIONS Implications and future research directions are discussed.

Autonomy and Control Augmenting the Validity of the Theory of Planned Behaviour in Predicting Exercise

This study examined the utility of the theory of planned behaviour (TPB) along with additional constructs in predicting exercise, and explored the motivational antecedents of exercise intentions. Participants included 162 Canadian University College students (61% females). Measures of TPB, autonomous and controlling intention, perceived autonomy support and core autonomous intention were completed during phase 1 of data collection. Two and three weeks later behaviour was assessed. Hierarchical regression analyses revealed that: (a) attitude and perceived behavioural control significantly predicted TPB intention and core autonomous intention; (b) subjective norm predicted controlling intention; and (c) perceived autonomy support predicted autonomous and core autonomous intention. TPB intention significantly predicted behaviour. TPB is a fairly useful model for predicting behaviour and important information can be gained when other measures of intention are explored.

Neuropsychological Outcome from Blast versus Non-blast: Mild Traumatic Brain Injury in U.S. Military Service Members

The purpose of this study was to compare the neuropsychological outcome from blast-related versus non-blast related mild traumatic brain injury (MTBI). Participants were 56 U.S. military service members who sustained an MTBI, divided into two groups based on mechanism of injury: (a) non-blast related (Non-blast; n = 21), and (b) blast plus secondary blunt trauma (Blast Plus; n = 35). All participants had sustained their injury in theatre whilst deployed during Operation Iraqi Freedom or Operation Enduring Freedom. Patients had been seen for neuropsychological evaluation at Walter Reed Army Medical Center on average 4.4 months (SD = 4.1) post-injury. Measures included 14 clinical scales from the Personality Assessment Inventory (PAI) and 12 common neurocognitive measures. For the PAI, there were no significant differences between groups on all scales (p > .05). However, medium effect sizes were found for the Depression (d = .49) and Stress (d = .47) scales (i.e., Blast Plus > Non-blast). On the neurocognitive measures, after controlling for the influence of psychological distress (i.e., Depression, Stress), there were no differences between the Non-blast and Blast Plus groups on all measures. These findings provide little evidence to suggest that blast exposure plus secondary blunt trauma results in worse cognitive or psychological recovery than blunt trauma alone. (JINS, 2012, 18, 595-605).

Risk Factors for Postconcussion Symptom Reporting after Traumatic Brain Injury in U.S. Military Service Members

The purpose of this study was to identify factors that are predictive of, or associated with, postconcussion symptom reporting after traumatic brain injury (TBI) in the U.S. military. Participants were 125 U.S. military service members (age: M=29.6 years, standard deviation [SD]=8.9, range=18-56 years) who sustained a TBI, divided into two groups based on symptom criteria for postconcussional disorder (PCD): PCD-Present (n=65) and PCD-Absent (n=60). Participants completed a neuropsychological evaluation at Walter Reed Army Medical Center (M=9.4 months after injury, SD=9.9; range: 1.1 to 44.8). Factors examined included demographic characteristics, injury-related variables, psychological testing, and effort testing. There were no significant group differences for age, sex, education, race, estimated premorbid intelligence, number of deployments, combat versus non-combat related injury, or mechanism of injury (p>0.098 for all). There were significant main effects for severity of body injury, duration of loss of consciousness, duration of post-traumatic amnesia, intracranial abnormality, time tested post-injury, possible symptom exaggeration, poor effort, depression, and traumatic stress (p<0.044 for all). PCD symptom reporting was most strongly associated with possible symptom exaggeration, poor effort, depression, and traumatic stress. PCD rarely occurred in the absence of depression, traumatic stress, possible symptom exaggeration, or poor effort (n=7, 5.6%). Many factors unrelated to brain injury were influential in self-reported postconcussion symptoms in this sample. Clinicians cannot assume uncritically that endorsement of items on a postconcussion symptom checklist is indicative of residual effects from a brain injury.

Subjective cognitive complaints and neuropsychological test performance following military-related traumatic brain injury

This study examined the relation between neuropsychological test performance and self-reported cognitive complaints following traumatic brain injury (TBI). Participants were 109 servicemembers from the U.S. military who completed a neuropsychological evaluation within the first 2 yr following mild-severe TBI. Measures included the Personality Assessment Inventory (PAI), Posttraumatic Stress Disorder Checklist (PCL-C), Neurobehavioral Symptom Inventory (NSI), and 17 select measures from a larger neurocognitive test battery that corresponded to three self-reported cognitive complaints from the NSI (i.e., memory, attention/concentration, and processing speed/organization). Self-reported cognitive complaints were significantly correlated with psychological distress (PCL-C total: r = 0.50-0.58; half the PAI clinical scales: r = 0.40-0.58). In contrast, self-reported cognitive complaints were not significantly correlated with overall neurocognitive functioning (with the exception of five measures). There was a low rate of agreement between neurocognitive test scores and self-reported cognitive complaints. For the large minority of the sample (38.5%-45.9%), self-reported cognitive complaints were reported in the presence of neurocognitive test scores that fell within normal limits. In sum, self-reported cognitive complaints were not associated with neurocognitive test performance, but rather were associated with psychological distress. These results provide information to contextualize cognitive complaints following TBI.

Neuropsychological Outcome from Uncomplicated Mild, Complicated Mild, and Moderate Traumatic Brain Injury in US Military Personnel

This study compared the neuropsychological outcome in military personnel following mild-to-moderate traumatic brain injury (TBI). Participants were 83 service members divided into three injury severity groups: uncomplicated mild TBI (MTBI; n = 24), complicated MTBI (n = 17), and moderate TBI (n = 42). Participants were evaluated within 6 months following injury (73% within 3 months) using neurocognitive testing and the Personality Assessment Inventory (PAI). There were no significant differences between the three groups on the majority of neurocognitive measures. Similarly, there were no significant differences between the three groups on the majority of PAI clinical scales (all p > .05), with the exception of two scales. The uncomplicated MTBI group had significantly higher scores on the Anxiety-Related Disorders and Aggression scales compared with the complicated MTBI group, but not the moderate TBI group. Overall, these results suggest that within the first 6 months post injury, there were few detectable differences in the neuropsychological outcome following uncomplicated MTBI, complicated MTBI, or moderate TBI in this military sample.

A Multisite Study of the Relationships between Blast Exposures and Symptom Reporting in a Post-Deployment Active Duty Military Population with Mild Traumatic Brain Injury

Explosive devices have been the most frequent cause of traumatic brain injury (TBI) among deployed contemporary U.S. service members. The purpose of this study was to examine the influence of previous cumulative blast exposures (that did or did not result in TBI) on later post-concussion and post-traumatic symptom reporting after sustaining a mild TBI (MTBI). Participants were 573 service members who sustained MTBI divided into four groups by number of blast exposures (1, 2, 3, and 4-10) and a nonblast control group. Post-concussion symptoms were measured using the Neurobehavioral Symptom Inventory (NSI) and post-traumatic stress disorder (PTSD) symptoms using the Post-traumatic Checklist-Civilian version (PCL-C). Results show groups significantly differed on total NSI scores (p<0.001), where symptom endorsement increased as number of reported blast exposures increased. Total NSI scores were significantly higher for the 3- and 4-10 blast groups compared with the 1- and 2-blast groups with effect sizes ranging from small to moderate (d=0.31 to 0.63). After controlling for PTSD symptoms using the PCL-C total score, NSI total score differences remained between the 4-10-blast group and the 1- and 2-blast groups, but were less pronounced (d=0.35 and d=0.24, respectively). Analyses of NSI subscale scores using PCL-C scores as a covariate revealed significant between-blast group differences on cognitive, sensory, and somatic, but not affective symptoms. Regression analyses revealed that cumulative blast exposures accounted for a small but significant amount of the variance in total NSI scores (4.8%; p=0.009) and total PCL-C scores (2.3%; p<0.001). Among service members exposed to blast, post-concussion symptom reporting increased as a function of cumulative blast exposures. Future research will need to determine the relationship between cumulative blast exposures, symptom reporting, and neuropathological changes.

Factors influencing postconcussion and posttraumatic stress symptom reporting following military-related concurrent polytrauma and traumatic brain injury.

The purpose of this study was to identify factors that are predictive of, or associated with, high endorsement of postconcussion and posttraumatic stress symptoms following military-related traumatic brain injury (TBI). Participants were 1,600 U.S. service members (age: M = 27.1, SD = 7.1; 95.4% male) who had sustained a mild-to-moderate TBI and who had been evaluated by the Defense and Veterans Brain Injury Center at one of six military medical centers. Twenty-two factors were examined that included demographic, injury circumstances/severity, treatment/evaluation, and psychological/physical variables. Four factors were statistically and meaningfully associated with clinically elevated postconcussion symptoms: (i) low bodily injury severity, (ii) posttraumatic stress, (iii) depression, and (iv) military operation where wounded (p < .001, 43.2% variance). The combination of depression and posttraumatic stress symptoms accounted for the vast majority of unique variance (41.5%) and were strongly associated with, and predictive of, clinically elevated postconcussion symptoms [range: odds ratios (OR) = 4.24-7.75; relative risk (RR) = 2.28-2.51]. Five factors were statistically and meaningfully associated with clinically elevated posttraumatic stress symptoms: (i) low bodily injury severity, (ii) depression, (iii) a longer time from injury to evaluation, (iv) military operation where wounded, and (v) current auditory deficits (p < .001; 65.6% variance accounted for). Depression alone accounted for the vast majority of unique variance (60.0%) and was strongly associated with, and predictive of, clinically elevated posttraumatic stress symptoms (OR = 38.78; RR = 4.63). There was a very clear, strong, and clinically meaningful association between depression, posttraumatic stress, and postconcussion symptoms in this sample. Brain injury severity, however, was not associated with symptom reporting following TBI.

Examination of the Mild Brain Injury Atypical Symptom Scale and the Validity-10 Scale to detect symptom exaggeration in US military service members

Objective: The purpose of this study was to examine the clinical utility of two validity scales designed for use with the Neurobehavioral Symptom Inventory (NSI) and the PTSD Checklist–Civilian Version (PCL–C); the Mild Brain Injury Atypical Symptoms Scale (mBIAS) and Validity-10 scale. Method: Participants were 63 U.S. military service members (age: M = 31.9 years, SD = 12.5; 90.5% male) who sustained a mild traumatic brain injury (MTBI) and were prospectively enrolled from Walter Reed National Military Medical Center. Participants were divided into two groups based on the validity scales of the Minnesota Multiphasic Personality Inventory–2 Restructured Form (MMPI–2–RF): (a) symptom validity test (SVT)-Fail (n = 24) and (b) SVT-Pass (n = 39). Participants were evaluated on average 19.4 months postinjury (SD = 27.6). Results: Participants in the SVT-Fail group had significantly higher scores (p < .05) on the mBIAS (d = 0.85), Validity-10 (d = 1.89), NSI (d = 2.23), and PCL–C (d = 2.47), and the vast majority of the MMPI–2–RF scales (d = 0.69 to d = 2.47). Sensitivity, specificity, and predictive power values were calculated across the range of mBIAS and Validity-10 scores to determine the optimal cutoff to detect symptom exaggeration. For the mBIAS, a cutoff score of ≥8 was considered optimal, which resulted in low sensitivity (.17), high specificity (1.0), high positive predictive power (1.0), and moderate negative predictive power (.69). For the Validity-10 scale, a cutoff score of ≥13 was considered optimal, which resulted in moderate–high sensitivity (.63), high specificity (.97), and high positive (.93) and negative predictive power (.83). Conclusion: These findings provide strong support for the use of the Validity-10 as a tool to screen for symptom exaggeration when administering the NSI and PCL–C. The mBIAS, however, was not a reliable tool for this purpose and failed to identify the vast majority of people who exaggerated symptoms.

Clinical utility of the Neurobehavioral Symptom Inventory validity scales to screen for symptom exaggeration following traumatic brain injury.

The purpose of this study was to examine the clinical utility of three recently developed validity scales (Validity-10, NIM5, and LOW6) designed to screen for symptom exaggeration using the Neurobehavioral Symptom Inventory (NSI). Participants were 272 U.S. military service members who sustained a mild, moderate, severe, or penetrating traumatic brain injury (TBI) and who were evaluated by the neuropsychology service at Walter Reed Army Medical Center within 199 weeks post injury. Participants were divided into two groups based on the Negative Impression Management scale of the Personality Assessment Inventory: (a) those who failed symptom validity testing (SVT-fail; n = 27) and (b) those who passed symptom validity testing (SVT-pass; n = 245). Participants in the SVT-fail group had significantly higher scores (p<.001) on the Validity-10, NIM5, LOW6, NSI total, and Personality Assessment Inventory (PAI) clinical scales (range: d = 0.76 to 2.34). Similarly high sensitivity, specificity, positive predictive power (PPP), and negative predictive (NPP) values were found when using all three validity scales to differentiate SVT-fail versus SVT-pass groups. However, the Validity-10 scale consistently had the highest overall values. The optimal cutoff score for the Validity-10 scale to identify possible symptom exaggeration was ≥19 (sensitivity = .59, specificity = .89, PPP = .74, NPP = .80). For the majority of people, these findings provide support for the use of the Validity-10 scale as a screening tool for possible symptom exaggeration. When scores on the Validity-10 exceed the cutoff score, it is recommended that (a) researchers and clinicians do not interpret responses on the NSI, and (b) clinicians follow up with a more detailed evaluation, using well-validated symptom validity measures (e.g., Minnesota Multiphasic Personality Inventory–2 Restructured Form, MMPI–2–RF, validity scales), to seek confirmatory evidence to support an hypothesis of symptom exaggeration.