Tracy Kretzmer

Cognitive sequelae of blast-related versus other mechanisms of brain trauma.

The use of improvised explosive devices has become the hallmark of modern warfare and has resulted in an ever-increasing number of blast-related traumatic brain injuries (TBIs). Despite this fact, very little is actually known about the cognitive sequelae of blast-related TBIs. The purpose of the current study was to compare patterns of performance on neuropsychological measures in subjects who have sustained TBIs as a result of blast (or explosion) with those who have sustained TBIs from non-blast or blunt force trauma (motor vehicle accident, fall, assault, etc.). Participants were categorized as blast-related TBI or non-blast-related TBI and according to severity of injury (mild or moderate-to-severe). No main effects were observed in analysis of covariance between blast-related TBI participants and non-blast-related TBI participants across any of the neuropsychological variables, although an interaction was observed on a visual memory test showing stronger performance for mild blast-related and poorer performance for moderate-to-severe blast-related participants compared with both non-blast groups. Overall, the results do not provide any strong evidence that blast is categorically different from other TBI mechanisms, at least with regard to cognitive sequelae on select measures. Additional findings included a marginally increased incidence of reported posttraumatic stress disorder symptoms among blast-injured participants. (JINS, 2009, 15, 1-8.).

Symptom Complaints Following Combat-Related Traumatic Brain Injury: Relationship to Traumatic Brain Injury Severity and Posttraumatic Stress Disorder

Patients with a history of mild (n = 134) or moderate-to-severe (n = 91) TBI were asked to complete the Neurobehavioral Symptom Inventory (NSI) and the Posttraumatic Stress Disorder Checklist. Consistent with prior research, significantly more postconcussion symptoms were endorsed by the mild group. After controlling for age, time since injury, and mechanism of injury, TBI severity continued to be significantly related to postconcussion complaints on the NSI. However, after controlling for these same variables, along with posttraumatic stress disorder symptom severity, there no longer were differences between the TBI severity groups. That is, patients with mild TBI did not endorse significantly more complaints (adjusted mean = 22.4) than the moderate-to-severe group (adjusted mean = 21.8). These findings suggest that much of the symptom complaints in mildly injured patients may be due to emotional distress.

Symptom Complaints Following Reports of Blast Versus Non-Blast Mild TBI: Does Mechanism of Injury Matter?

Patients with a reported history of mild traumatic brain injury (mild TBI) due to blast (n = 298) or non-blast (n = 92) mechanisms were asked to complete the Neurobehavioral Symptom Inventory (NSI) and the Post-traumatic Stress Disorder Checklist (PCL). Mechanism of injury did not account for a significant amount of variance in post-concussion symptom reporting overall, nor did severity of mild TBI (i.e., brief loss of consciousness versus only an alteration of consciousness). Symptom reporting was greater in those injured more than 1 month ago compared to those injured less than 1 month ago and in those reporting higher levels versus lower levels of PTSD symptoms. When examining specific symptoms, the only symptom that significantly varied between groups was hearing difficulty (with the blast-injured group reporting more severe difficulty with hearing). Findings suggest that greater symptom reporting is most strongly related to emotional distress.

Prospective Evaluation of the Nature, Course, and Impact of Acute Sleep Abnormality After Traumatic Brain Injury

OBJECTIVE To prospectively characterize the prevalence, course, and impact of acute sleep abnormality among traumatic brain injury (TBI) neurorehabilitation admissions. DESIGN Prospective observational study. SETTING Freestanding rehabilitation hospital. PARTICIPANTS Primarily severe TBI (median emergency department Glasgow Coma Scale [GCS] score=7; N=205) patients who were mostly men (71%) and white (68%) were evaluated during acute neurorehabilitation. INTERVENTIONS None. MAIN OUTCOME MEASURE Delirium Rating Scale-Revised-98 (DelRS-R98) was administered weekly throughout rehabilitation hospitalization. DelRS-R98 item 1 was used to classify severity of sleep-wake cycle disturbance (SWCD) as none, mild, moderate, or severe. SWCD ratings were analyzed both serially and at 1 month postinjury. RESULTS For the entire sample, 66% (mild to severe) had SWCD at 1 month postinjury. The course of the SWCD using a subset (n=152) revealed that 84% had SWCD on rehabilitation admission, with 63% having moderate to severe ratings (median, 24d postinjury). By the third serial exam (median, 35d postinjury), 59% remained with SWCD, and 28% had moderate to severe ratings. Using general linear modeling and adjusting for age, emergency department GCS score, and days postinjury, presence of moderate to severe SWCD at 1 month postinjury made significant contributions in predicting duration of posttraumatic amnesia (P<.01) and rehabilitation hospital length of stay (P<.01). CONCLUSIONS Results suggest that sleep abnormalities after TBI are prevalent and decrease over time. However, a high percent remained with SWCD throughout the course of rehabilitation intervention. Given the brevity of inpatient neurorehabilitation, future studies may explore targeting SWCD to improve early outcomes, such as cognitive functioning and economic impact, after TBI.

Postconcussive Symptom Complaints and Potentially Malleable Positive Predictors

The purpose of this study was to examine the relationship between postconcussion symptom complaint (PCS) severity and positive coping factors (knowledge, self-efficacy, and attributions) in a sample of individuals who have sustained a mild TBI, above and beyond the demographic and psychiatric predictors that have been most commonly examined. Ninety-one people with a history of reported mild TBI were surveyed. Hierarchical regression analyses revealed that demographic variables and psychiatric symptom severity predicted PCS severity. Consistent with our hypotheses, knowledge, self-efficacy, and attributions, when taken together, made an independent and significant contribution to prediction of PCS severity (21% of additional variance). The most potent factor was attribution, or the extent to which one attributes symptoms to mild TBI versus other causes. Those who attribute their symptoms to TBI are more likely to report greater symptom severity overall. Taken together, knowledge, self-efficacy, and attributions contribute independently to PCS severity. Additional research is needed to determine if these factors are amenable to intervention.

Prolonged Exposure Therapy With Veterans and Active Duty Personnel Diagnosed With PTSD and Traumatic Brain Injury

The present study used archival clinical data to analyze the delivery and effectiveness of prolonged exposure (PE) and ancillary services for posttraumatic stress disorder (PTSD) among Operation Enduring Freedom, Operation Iraqi Freedom, and Operation New Dawn veterans (N = 69) with histories of mild to severe traumatic brain injury (TBI). Data from standard clinical assessments of veterans and active duty personnel treated in both inpatient and outpatient programs at 2 Department of Veteran Affairs medical centers were examined. Symptoms were assessed with self-report measures of PTSD (PTSD Checklist) and depression (Beck Depression Inventory-II) before and throughout therapy. Mixed linear models were utilized to determine the slope of reported symptoms throughout treatment, and the effects associated with fixed factors such as site, treatment setting (residential vs. outpatient), and TBI severity were examined. Results demonstrated significant decreases in PTSD, B = -3.00, 95% CI [-3.22, -2.78]; t(210) = -13.5; p < .001, and in depressive symptoms, B = -1.46, 95% CI [-1.64, -1.28]; t(192) = -8.32; p < .001. The effects of PE treatment did not differ by clinical setting and participants with moderate to severe injuries reported more rapid gains than those with a history of mild TBI. The results provide evidence that PE may well be effective for veterans with PTSD and TBI.

Pilot of a novel intervention for postconcussive symptoms in active duty, veterans, and civilians.

PURPOSE/OBJECTIVE The authors present a study aimed at pilot testing a novel delivery method, namely a computer intervention, for postconcussive symptom reduction in active duty, veteran, and civilian patients with acute and chronic complaints. Following a concussion/mild traumatic brain injury (MTBI), most individuals recover completely, but a significant proportion report postconcussive symptoms months to years following the injury. Psychoeducational intervention has shown to be effective in reducing postconcussive symptoms in studies done with acute civilian samples, but the efficacy of psychoeducational interventions with individuals who served in combat or have chronic complaints remains unclear. RESEARCH METHOD/DESIGN Twenty-five active duty, veteran, and civilian participants took part in this study. At baseline, each participant completed a self-run psychoeducational computer-based treatment. Participants were reassessed 1-month postintervention via phone to evaluate postconconcussive symptom severity. RESULTS Participants reported significantly fewer postconcussive symptoms at follow-up than baseline (d = .99). Intervention satisfaction was reported, with feedback related to ease of use and quality. CONCLUSIONS/IMPLICATIONS Extending previous studies, current findings demonstrated that psychoeducational intervention following MTBI was associated with postconcussive symptom complaint reduction in both acute and chronic patients. These data also confirm the feasibility of using computerized psychoeducation and speak to the importance of providing education to both acute and chronic patients across settings. Feedback from participants was generally positive. Further investigation with a control group is warranted.

EEG slow waves in traumatic brain injury: Convergent findings in mouse and man

Objective Evidence from previous studies suggests that greater sleep pressure, in the form of EEG-based slow waves, accumulates in specific brain regions that are more active during prior waking experience. We sought to quantify the number and coherence of EEG slow waves in subjects with mild traumatic brain injury (mTBI). Methods We developed a method to automatically detect individual slow waves in each EEG channel, and validated this method using simulated EEG data. We then used this method to quantify EEG-based slow waves during sleep and wake states in both mouse and human subjects with mTBI. A modified coherence index that accounts for information from multiple channels was calculated as a measure of slow wave synchrony. Results Brain-injured mice showed significantly higher theta:alpha amplitude ratios and significantly more slow waves during spontaneous wakefulness and during prolonged sleep deprivation, compared to sham-injured control mice. Human subjects with mTBI showed significantly higher theta:beta amplitude ratios and significantly more EEG slow waves while awake compared to age-matched control subjects. We then quantified the global coherence index of slow waves across several EEG channels in human subjects. Individuals with mTBI showed significantly less EEG global coherence compared to control subjects while awake, but not during sleep. EEG global coherence was significantly correlated with severity of post-concussive symptoms (as assessed by the Neurobehavioral Symptom Inventory scale). Conclusion and implications Taken together, our data from both mouse and human studies suggest that EEG slow wave quantity and the global coherence index of slow waves may represent a sensitive marker for the diagnosis and prognosis of mTBI and post-concussive symptoms.

Community Reintegration Problems Among Veterans and Active Duty Service Members With Traumatic Brain Injury.

Objectives: To examine community reintegration problems among Veterans and military service members with mild or moderate/severe traumatic brain injury (TBI) at 1 year postinjury and to identify unique predictors that may contribute to these difficulties. Setting: VA Polytrauma Rehabilitation Centers. Participants: Participants were 154 inpatients enrolled in the VA TBI Model Systems Program with available injury severity data (mild = 28.6%; moderate/severe = 71.4%) and 1-year postinjury outcome data. Design: Prospective, longitudinal cohort. Main Measures: Community reintegration outcomes included independent driving, employability, and general community participation. Additional measures assessed depression, posttraumatic stress, and cognitive and motor functioning. Results: In the mild TBI (mTBI) group, posttraumatic stress disorder and depressive symptoms were associated with lower levels of various community reintegration outcomes. In the moderate/severe TBI group, cognition and motor skills were significantly associated with lower levels of community participation, independent driving, and employability. Conclusion: Community reintegration is problematic for Veterans and active duty service members with a history of TBI. Unique comorbidities across injury severity groups inhibit full reintegration into the community. These findings highlight the ongoing rehabilitation needs of persons with TBI, specifically evidence-based mental healthcare, in comprehensive rehabilitation programs consistent with a chronic disease management model.

Web-based psychoeducational intervention for postconcussion symptoms: a randomized trial

The objective of this study was to investigate the effectiveness of a web-based educational intervention for reducing postconcussion symptoms. 158 participants with self-reported symptomatic mild traumatic brain injury were randomized to intervention versus control. There was no effect of intervention on symptom severity or attributions. Subgroup analyses suggested benefit of the web-based intervention in those receiving concurrent mental health treatment and in those participants with the greatest time since injury (>1 year after mild traumatic brain injury). Web-based educational intervention was not effective overall in this sample. However, there is some suggestion of promise in those receiving concurrent mental health treatment and with more chronic symptoms. Findings also suggest potential benefit of interventions targeting self-efficacy.