Nicholas J. Pastorek

Postconcussive symptoms after blast and nonblast-related mild traumatic brain injuries in Afghanistan and Iraq war veterans.

Blast injury is common in current warfare, but little is known about the effects of blast-related mild traumatic brain injury (mTBI). Profile analyses were conducted investigating differences in self-reported postconcussive (PC) symptoms in 339 veteran outpatients with mTBI histories reporting current symptoms based on mechanism of injury (blast only, nonblast only, or both blast and nonblast), number of blast injuries, and distance from the blast. Veterans with any blast-related mTBI history were younger and reported higher posttraumatic stress symptoms than veterans with nonblast-related mTBI histories, with a marginally significant difference in posttraumatic stress symptom report between veterans reporting blast-related mTBI only and those reporting nonblast-related mTBI. The groups did not differ in terms of PC symptom severity or PC symptom cluster profiles. Among veterans with blast-related mTBI histories, PC symptom report did not vary by number of blast-related mTBIs or proximity to blast. Overall, posttraumatic stress symptoms accounted for a substantial portion of variance in PC symptom report. In veteran outpatients with remote mTBI histories who have enduring symptom complaints related to the mTBI, mechanism of injury did not clearly contribute to differential PC symptom severity or PC symptom cluster profile. Proximal rather than distal factors may be important intervention targets in returning symptomatic veterans with mTBI histories.

Associations among Pain, PTSD, mTBI, and Heart Rate Variability in Veterans of Operation Enduring and Iraqi Freedom: A Pilot Study

OBJECTIVE The objective of the study was to determine if there is dysregulated autonomic nervous system activity as manifested by depressed heart rate variability (HRV) among veterans of Operations Enduring and Iraqi Freedom (OEF/OIF). PARTICIPANTS AND SETTING The study used a convenience sample of OEF/OIF veterans (n = 28) seen at a Level II Polytrauma Network Site at the Michael E. DeBakey VA Medical Center. Participants were similar to other OEF/OIF veterans who received care at this site. DESIGN Cross sectional study. MEASURES Time domain analysis (standard deviation of beat-to-beat intervals [SDNN]) of HRV, diagnoses of mild traumatic brain injury and post-traumatic stress disorder (PTSD), and pain ratings from medical records. RESULTS As a group, the sample evidenced markedly depressed HRV (as reflected by SDNN) as compared with available age and gender corrected normative data. Pain (71%), PTSD (57%), and mild traumatic brain injury (mTBI) (64%) were prevalent. Thirty-six percent had all three measures (P3). Pain and P3 were significantly and negatively associated with SDNN (r = -0.460, P = 0.014; r = -0.373, P = 0.05, respectively). CONCLUSIONS These preliminary findings support the high prevalence of depressed HRV and P3 among veterans seen in a level II Polytrauma Center. The findings also suggest a possible synergistic effect of pain, PTSD, and mTBI on depressed HRV. The nature and implications of these relationships require additional research to elucidate.

Postconcussive symptoms in OEF-OIF veterans: factor structure and impact of posttraumatic stress.

PURPOSE Veterans with a history of mild traumatic brain injury (mTBI) are reporting postconcussive symptoms (PCSx) in addition to experiencing postdeployment physical and emotional comorbidities. The Veterans Health Administration has mandated specialized evaluation and treatment for veterans with a history of mTBI and has suggested widespread use of the Neurobehavioral Symptom Inventory (NSI) as a measure of PCSx. This study evaluated the NSIs factor structure and assessed the impact of posttraumatic stress (PTS) on the scale at the item and factor levels. RESEARCH METHOD Five hundred twenty-nine charts of returning veterans who screened positive for traumatic brain injury were reviewed, and 345 who met criteria for mTBI were included in the study. RESULTS Results of factor analysis on the NSI revealed a difficult-to-interpret factor structure that was inconsistent with the results of civilian studies. PTS explained 5%-38% of the variance in individual PCSx, and after controlling for this variance, the factor structure more closely paralleled findings from the civilian literature. CONCLUSION PTS is an important variable to account for when evaluating PCSx in veterans. Research and clinical implications for the measurement and interpretation of self-reported PCSx are discussed.

The dangers of failing one or more performance validity tests in individuals claiming mild traumatic brain injury-related postconcussive symptoms

Evaluating performance validity is important in any neuropsychological assessment, and prior research recommends a threshold for invalid performance of two or more performance validity test (PVT) failures. However, extant findings also indicate that failing a single PVT is associated with significant changes in neuropsychological performance. The current study sought to determine if there is an appreciable difference in neuropsychological testing results between individuals failing different numbers of PVTs. In a sample of veterans with reported histories of mild traumatic brain injury (mTBI; N =178), analyses revealed that individuals failing only one PVT performed significantly worse than individuals failing no PVTs on measures of verbal learning and memory, processing speed, and cognitive flexibility. Additionally, individuals failing one versus two PVTs significantly differed only on delayed free recall scores. The current findings suggest that failure of even one PVT should elicit consideration of performance invalidity, particularly in individuals with histories of mTBI.

PTSD and Cognitive Functioning: Importance of Including Performance Validity Testing

Many studies have observed an association between post-traumatic stress disorder (PTSD) and cognitive deficits across several domains including memory, attention, and executive functioning. The inclusion of response bias measures in these studies, however, remains largely unaddressed. The purpose of this study was to identify possible cognitive impairments correlated with PTSD in returning OEF/OIF/OND veterans after excluding individuals failing a well-validated performance validity test. Participants included 126 men and 8 women with a history of mild traumatic brain injury (TBI) referred for a comprehensive neuropsychological evaluation as part of a consortium of five Veterans Affairs hospitals. The PTSD CheckList (PCL) and Word Memory Test (WMT) were used to establish symptoms of PTSD and invalid performance, respectively. Groups were categorized as follows: Control (PCL < 50, pass WMT), PTSD-pass (PCL ≥ 50, pass WMT), and PTSD-fail (PCL ≥ 50, fail WMT). As hypothesized, failure on the WMT was associated with significantly poorer performance on almost all cognitive tests administered; however, no significant differences were detected between individuals with and without PTSD symptoms after separating out veterans failing the WMT. These findings highlight the importance of assessing respondent validity in future research examining cognitive functioning in psychiatric illness and warrant further consideration of prior studies reporting PTSD-associated cognitive deficits.

Effect of clinical characteristics on cognitive performance in service members and veterans with histories of blast-related mild traumatic brain injury

Abstract Objective: To examine the relationship between clinical characteristics and cognitive performance in service members and veterans with histories of blast-related mild traumatic brain injury (mTBI). Design: This study consisted of 40 Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF) service members and veterans; 20 participants reported blast exposure and alteration of mental status consistent with mTBI and 20 participants denied blast exposure and had no history of traumatic brain injury (TBI), but could have experienced extra-cranial injuries. Measures of simple reaction time, processing speed, visual attention, working memory and mathematical processing were used to assess long-term effects of mTBI. Measures of post-traumatic stress symptom severity, pain intensity, sleep difficulty and subjective appraisal of cognition at time of testing were also obtained. Multivariate analyses were conducted with clinical characteristics and mTBI history as predictors of cognitive performance. Results: There was no evidence of an effect of mTBI history on cognitive performance in this sample. However, post-traumatic stress symptom severity was significantly related to two measures of cognitive performance. Conclusions: This study demonstrated the importance of considering the effects of current clinical symptoms (e.g. post-traumatic stress) as possibly having greater influence on current cognitive functioning than the effects of a remote history of mTBI.

Combat Exposure, PTSD Symptoms, and Cognition Following Blast-Related Traumatic Brain Injury in OEF/OIF/OND Service Members and Veterans

Traumatic brain injury (TBI) and post-traumatic stress disorder (PTSD) are frequently documented among the Operation Enduring Freedom/Operation Iraqi Freedom/Operation New Dawn (OEF/OIF/OND) veterans. This study will investigate both combat exposure and PTSD as factors that may influence objective cognitive outcomes following blast-related mild TBI (mTBI). Participants included 54 OEF/OIF/OND veterans who had been exposed to blast and reported symptoms consistent with mTBI and 43 combat-deployed control participants who had no history of blast exposure or TBI. Raw scores from the Controlled Oral Word Association Test, Trail Making Test, Color-Word Interference Test, and Verbal Selective Reminding Test were used to measure cognitive functioning. All participants demonstrated adequate effort on the Word Memory Test. Demographics, injury characteristics, overall intellectual functioning, and total scores from the PTSD Checklist-Civilian Version (PCL-C) and Combat Exposure Scale (CES) were used as the predictors for each cognitive measure. History of mTBI was significantly associated with higher PCL-C and CES scores. Multivariable linear regression, however, showed no significant differences in cognitive performance between groups. The absence of effect of mTBI, PTSD, and combat exposure on cognitive functioning noted in this study may be partially explained by the inclusion of only those participants who passed performance validity testing.

Prognostic Importance of Self-Reported Traits/Problems/Strengths and Environmental Barriers/Facilitators for Predicting Participation Outcomes in Persons With Traumatic Brain Injury: A Systematic Review

OBJECTIVE To conduct a systematic review of the prognostic value of self-reported traits/problems/strengths and environmental barriers/facilitators for participation outcomes in persons with traumatic brain injury (TBI). DATA SOURCES Articles published through August 15, 2013, obtained by conducting electronic searches of PubMed, PsycINFO, and Cumulative Index to Nursing and Allied Health Literature databases and a review of reference lists of reviewed articles. STUDY SELECTION Reviewed articles were written in English and presented findings on adult humans with TBI, participation outcomes, and ≥ 1 self-reported trait/problem/strength (eg, depression, pain, coping style) and/or ≥ 1 environment barrier/facilitator (eg, social support, family functioning, access to services). DATA EXTRACTION Each of the 996 abstracts was examined by 2 reviewers, and those failing to meet all inclusion criteria were excluded. Data were extracted from the 63 retained articles by 2 independent reviewers, who met to resolve any differences in study quality rating or evidence recorded. Study quality was determined using American Academy of Neurology (AAN) criteria. DATA SYNTHESIS Conclusions regarding prognostic importance of self-report and environmental barrier/facilitator variables were made using AAN criteria. Conclusions regarding barrier/facilitator variables indicated that access to transportation, access to services, and participation in social interaction were possibly predictive of employment outcome, whereas living arrangements and social support were possibly not predictive of employment outcome. Conclusions regarding self-report variables indicated that the number of postconcussive symptoms, fatigue, and physical competence were probably predictive of employment and need for supervision, whereas self-efficacy was probably not predictive of employment. Subjective well-being, pain, and social interaction were possibly predictive of employment, whereas coping style was possibly not predictive. CONCLUSIONS Although additional investigation is needed, self-report variables are likely to make important contributions to predicting participation outcomes. Future research should be guided by coherent conceptual models and use a consistent set of assessment instruments to facilitate comparisons between studies.

A retrospective review of digit span-related effort indicators in probable Alzheimer's disease patients.

There has been extensive research on the use of both stand-alone and embedded measures of effort in neuropsychological testing; however, relatively few studies have reported on their utility in the context of dementia. Previous studies that have examined the specificity of traditionally used cut-scores on embedded measures of effort with dementia samples have largely found high rates of false positive errors. The present study examined the specificity of several Digit Span derived embedded measures of effort in a large clinical sample of patients with probable Alzheimers disease stratified by level of dementia severity. Of the measures that were examined, only the Vocabulary – Digit Span score demonstrated promising specificity through the moderate level of dementia severity. All of the remaining indices, including Reliable Digit Span, Digit Span Age-Corrected Scaled Score, and Longest Digits Forward (1 & 2 Trials), yielded unacceptable rates of false positive errors as dementia severity increased. The implications for these findings are discussed, including the limitations of importing methods of assessing effort from one sample to another.

Mild traumatic brain injury and pain in Operation Iraqi Freedom/Operation Enduring Freedom veterans.

The purpose of this study was to describe the pain experience in Operation Iraqi Freedom/Operation Enduring Freedom veterans with and without a history of mild traumatic brain injury (mTBI) who present to polytrauma clinics for evaluation and management. We sought to evaluate the relationship between a veterans history of mTBI and posttraumatic stress (PTS) on axial pain, head/headache pain, and pain interference. We performed retrospective chart reviews of 529 Iraq/Afghanistan veterans referred for evaluation at two Department of Veterans Affairs medical centers. Problems with head/headache, low back, and neck pain were frequently endorsed. Subjective pain interference was reported in 21% of patients without a history of mTBI, 31.9% of patients with a history of mTBI with disorientation only, and 36.1% of patients with a history of mTBI with loss of consciousness. Statistically significant differences existed between the mTBI groups on PTS symptom endorsement, and PTS was predictive of pain experience and interference. A history of mTBI with loss of consciousness predicted head/headache pain, but otherwise did not predict pain or pain interference. PTS was strongly related to the pain experience. Pain is common in polytrauma patients. PTS severity is strongly associated with both pain report and pain interference, with head/headache pain showing a unique association with a history of mTBI. Implications for evaluation and management of pain in this complex population are discussed.