Challenges to be overcome using population-based sampling methods to recruit veterans for a study of post-traumatic stress disorder and traumatic brain injury.

BACKGROUND: Many investigators are interested in recruiting veterans from recent conflicts in Afghanistan and Iraq with Traumatic Brain Injury (TBI) and/or Post Traumatic Stress Disorder (PTSD). Researchers pursuing such studies may experience problems in recruiting sufficient numbers unless effective strategies are used. Currently, there is very little information on recruitment strategies for individuals with TBI and/or PTSD. It is known that groups of patients with medical conditions may be less likely to volunteer for clinical research. This study investigated the feasibility of recruiting veterans returning from recent military conflicts--Operation Enduring Freedom (OEF) and Operation Iraqi Freedom (OIF)--using a population-based sampling method. METHODS: Individuals were sampled from a previous epidemiological study. Three study sites focused on recruiting survey respondents (n = 445) who lived within a 60 mile radius of one of the sites. RESULTS: Overall, the successful recruitment of veterans using a population-based sampling method was dependent on the ability to contact potential participants following mass mailing. Study enrollment of participants with probable TBI and/or PTSD had a recruitment yield (enrolled/total identified) of 5.4%. We were able to contact 146 individuals, representing a contact rate of 33%. Sixty-six of the individuals contacted were screened. The major reasons for not screening included a stated lack of interest in the study (n = 37), a failure to answer screening calls after initial contact (n = 30), and an unwillingness or inability to travel to a study site (n = 10). Based on the phone screening, 36 veterans were eligible for the study. Twenty-four veterans were enrolled, (recruitment yield = 5.4%) and twelve were not enrolled for a variety of reasons. CONCLUSIONS: Our experience with a population-based sampling method for recruitment of recent combat veterans illustrates the challenges encountered, particularly contacting and screening potential participants. The screening and enrollment data will help guide recruitment for future studies using population-based methods.

Instrumenting the balance error scoring system for use with patients reporting persistent balance problems after mild traumatic brain injury.

OBJECTIVE: To determine whether alterations to the Balance Error Scoring System (BESS), such as modified conditions and/or instrumentation, would improve the ability to correctly classify traumatic brain injury (TBI) status in patients with mild TBI with persistent self-reported balance complaints. DESIGN: Cross-sectional study. SETTING: Outpatient clinic. PARTICIPANTS: Subjects (n=13; age, 16.3±2y) with a recent history of concussion (mild TBI group) and demographically matched control subjects (n=13; age, 16.7±2y; control group). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Outcome measures included the BESS, modified BESS, instrumented BESS, and instrumented modified BESS. All subjects were tested on the noninstrumented BESS and modified BESS and were scored by visual observation of instability in 6 and 3 stance conditions, respectively. Instrumentation of these 2 tests used 1 inertial sensor with an accelerometer and gyroscope to quantify bidirectional body sway. RESULTS: Scores from the BESS and the modified BESS tests were similar between groups. However, results from the instrumented measures using the inertial sensor were significantly different between groups. The instrumented modified BESS had superior diagnostic classification and the largest area under the curve when compared with the other balance measures. CONCLUSIONS: A concussion may disrupt the sensory processing required for optimal postural control, which was measured by sway during quiet stance. These results suggest that the use of portable inertial sensors may be useful in the move toward more objective and sensitive measures of balance control postconcussion, but more work is needed to increase sensitivity.

Military traumatic brain injury: a review.

Military mild traumatic brain injury (mTBI) differs from civilian injury in important ways. Although mTBI sustained in both military and civilian settings are likely to be underreported, the combat theater presents additional obstacles to reporting and accessing care. The impact of blast forces on the nervous system may differ from nonblast mechanisms, mTBI although studies comparing the neurologic and cognitive sequelae in mTBI survivors have not provided such evidence. However, emotional distress appears to figure prominently in symptoms following military mTBI. This review evaluates the extant literature with an eye towards future research directions.

Military risk factors for Alzheimer's disease.

Traumatic brain injury (TBI) and post-traumatic stress disorder (PTSD) are signature injuries of the wars in Iraq and Afghanistan and have been linked to an increased risk of Alzheimer's disease (AD) and other dementias. A meeting hosted by the Alzheimer's Association and the Veterans' Health Research Institute (NCIRE) in May 2012 brought together experts from the U.S. military and academic medical centers around the world to discuss current evidence and hypotheses regarding the pathophysiological mechanisms linking TBI, PTSD, and AD. Studies underway in civilian and military populations were highlighted, along with new research initiatives such as a study to extend the Alzheimer's Disease Neuroimaging Initiative (ADNI) to a population of veterans exposed to TBI and PTSD. Greater collaboration and data sharing among diverse research groups is needed to advance an understanding and appropriate interventions in this continuum of military injuries and neurodegenerative disease in the aging veteran.

Screening for mild traumatic brain injury in the presence of psychiatric comorbidities.

OBJECTIVE: To determine whether or not a battery of neurobehavioral tests, the Brief Objective Neurobehavioral Detector (BOND), could detect mild traumatic brain injury (mTBI) among a group of psychiatric inpatients with numerous substance-related and medical comorbidities. The 16-item BOND is comprised of neurologic examination tasks and has been shown to correlate with radiologic and cognitive findings in previous studies. DESIGN: Masked comparison. SETTING: Inpatient psychiatric unit at the Veterans Affairs Medical Center in Washington, DC. PARTICIPANTS: Patients (N=51) sequentially admitted for suicidal ideation in the context of various psychiatric disorders. INTERVENTIONS: No intervention. MAIN OUTCOME MEASURE: BOND total and subtest scores. RESULTS: Forty-three patients were eligible and analyzed. Twenty-seven had sustained an mTBI in the distant past, and 16 had never sustained a traumatic brain injury (TBI) (non-TBI group). On average, the mTBI group demonstrated a significantly greater number of abnormal subtests on the BOND (mean, 7.22) than did the non-TBI group (mean, 4.50; P=.003). Although the BOND significantly correlated with the presence of mTBI, it did not correlate with any of the psychiatric, substance-related, or medical comorbidities. Multiple regressions indicated that the BOND total score was not explained by age, posttraumatic stress disorder diagnosis, or any combination of the psychiatric, substance-related, or medical comorbidities. High rates of sensitivity (70%) and specificity (69%) were found. CONCLUSIONS: The results of this pilot study suggest that the inexpensive, brief, and objective BOND instrument may be a useful screening tool for the detection of subtle neurologic brain abnormalities after mTBI, even in the presence of substantial comorbidities.

Neuropsychologic assessment of a population-based sample of Gulf War veterans.

OBJECTIVE: The objective of this project was to compare neuropsychologic performance and quality of life in a population-based sample of deployed Gulf War (GW) veterans with and without multisymptom complaints. BACKGROUND/METHODS: The study participants were obtained from the 30,000 member population-based National Health Survey of GW-era veterans conducted in 1995. Cases (N=25) were deployed to the year 1990 and 1991 GW and met Center for Disease Control and Prevention criteria for multisymptom GW illness (GWI). Controls (N=16) were deployed to the 1990 and 1991 GW but did not meet Center for Disease Control and Prevention criteria for GWI. RESULTS: There were no significant differences in composite scores on the traditional and computerized neuropsychologic battery (automated neuropsychologic assessment metrics) between GW cases and controls using bivariate techniques. Multiple linear regression analyses controlling for demographic and clinical variables revealed composite automated neuropsychologic assessment metrics scores were associated with age (b=-7.8; P=0.084), and education (b=22.9; P=0.0012), but not GW case or control status (b=-63.9; P=0.22). Compared with controls, GW cases had significantly more impairment on the Personality Assessment Inventory and the short form-36. CONCLUSIONS: Compared with GW controls, GW cases meeting criteria for GWI had preserved cognition function but had significant psychiatric symptoms and lower quality of life.

Sensor-Based Balance Measures Outperform Modified Balance Error Scoring System in Identifying Acute Concussion.

Balance assessment is an integral component of concussion evaluation and management. Although the modified balance error scoring system (mBESS) is the conventional clinical tool, objective metrics derived from wearable inertial sensors during the mBESS may increase sensitivity in detecting subtle balance deficits post-concussion. The aim of this study was to identify which stance condition and postural sway metrics obtained from an inertial sensor placed on the lumbar spine during the mBESS best discriminate athletes with acute concussion. Fifty-two college athletes in the acute phase of concussion and seventy-six controls participated in this study. Inertial sensor-based measures objectively detected group differences in the acutely concussed group of athletes while the clinical mBESS did not (p < 0.001 and p = 0.06, respectively). Mediolateral postural sway during the simplest condition of the mBESS (double stance) best classified those with acute concussion. Inertial sensors provided a sensitive and objective measure of balance in acute concussion. These results may be developed into practical guidelines to improve and simplify postural sway analysis post-concussion.