Faculty Bibliography

Brain-derived neurotrophic factor (BDNF) plays a key role in energy balance. In population studies, SNPs of the BDNF locus have been linked to obesity, but the mechanism by which these variants cause weight gain is unknown. Here, we examined human hypothalamic BDNF expression in association with 44 BDNF SNPs. We observed that the minor C allele of rs12291063 is associated with lower human ventromedial hypothalamic BDNF expression (p < 0.001) and greater adiposity in both adult and pediatric cohorts (p values < 0.05). We further demonstrated that the major T allele for rs12291063 possesses a binding capacity for the transcriptional regulator, heterogeneous nuclear ribonucleoprotein D0B, knockdown of which disrupts transactivation by the T allele. Binding and transactivation functions are both disrupted by substituting C for T. These findings provide a rationale for BDNF augmentation as a targeted treatment for obesity in individuals who have the rs12291063 CC genotype.

Although the experience of vicarious sensations when observing another in pain have been described postamputation, the underlying mechanisms are unknown. We investigated whether vicarious sensations are related to posttraumatic stress disorder (PTSD) symptoms and chronic pain. In Study 1, 236 amputees completed questionnaires about phantom limb phenomena and vicarious sensations to both innocuous and painful sensory experiences of others. There was a 10.2% incidence of vicarious sensations, which was significantly more prevalent in amputees reporting PTSD-like experiences, particularly increased arousal and reexperiencing the event that led to amputation (φ = .16). In Study 2, 63 amputees completed the Empathy for Pain Scale and PTSD Checklist-Civilian Version. Cluster analyses revealed 3 groups: 1 group did not experience vicarious pain or PTSD symptoms, and 2 groups were vicarious pain responders, but only 1 had increased PTSD symptoms. Only the latter group showed increased chronic pain severity compared with the nonresponder group (p = .025) with a moderate effect size (r = .35). The findings from both studies implicated an overlap, but also divergence, between PTSD symptoms and vicarious pain reactivity postamputation. Maladaptive mechanisms implicated in severe chronic pain and physical reactivity posttrauma may increase the incidence of vicarious reactivity to the pain of others.

Worldwide prevalence of amputation has created an increasing demand for improved upper and lower extremity prostheses. Current prosthetics are often uncomfortable and difficult to control and provide limited functional restoration. Moreover, the inability to normalize anthropomorphic biomechanics with a prosthesis increases one's risk of developing long-term health risks such as arthritis, skin breakdown, and pain. Recent advances in bionic prosthetic development hold great promise for rehabilitation and improving quality of life with limb loss. This brief review discusses the current state of advanced prostheses, the integration of robotics in the care of individuals with major limb amputation, and some innovative surgical techniques that are being explored for clinical feasibility.

The authors describe the mechanisms of traumatic brain injury (TBI), examining in depth the characteristics of closed head, penetrating, and blast-related TBI. Events on a structural as well as cellular level are reviewed. Blast-related brain injury, in particular, affects military service members preferentially, but is also relevant in cases of industrial accidents as well as terrorist events.

This study describes the psychometric investigation of an 11-item symptom checklist, the Abbreviated Concussion Symptom Inventory (ACSI). The ACSI is a dichotomously scored list of postconcussive symptoms associated with mild traumatic brain injury. The ACSI was administered to Marines (N = 1,435) within the 1st month of their return from combat deployments to Afghanistan. Psychometric analyses based upon nonparametric item response theory supported scoring the ACSI via simple summation of symptom endorsements; doing so produced a total score with good reliability (α = .802). Total scores were also found to significantly differentiate between different levels of head injury complexity during deployment, F(3, 1,431) = 100.75, p < .001. The findings support the use of the ASCI in research settings requiring a psychometrically reliable measure of postconcussion symptoms.

Controversy exists as to whether the lingering effects of concussion on emotional, physical, and cognitive symptoms is because of the effects of brain trauma or purely to emotional factors such as post-traumatic stress disorder or depression. This study examines the independent effects of concussion on persistent symptoms. The Defense Automated Neurobehavioral Assessment, a clinical decision support tool, was used to assess neurobehavioral functioning in 646 United States Marines, all of whom were fit for duty. Marines were assessed for concussion history, post-concussive symptoms, emotional distress, neurocognitive functioning, and deployment history. Results showed that a recent concussion or ever having experienced a concussion was associated with an increase in emotional distress, but not with persistent post-concussive symptoms (PPCS) or neurocognitive functioning. Having had multiple lifetime concussions, however, was associated with greater emotional distress, PPCS, and reduced neurocognitive functioning that needs attention and rapid discrimination, but not for memory-based tasks. These results are independent of deployment history, combat exposure, and symptoms of post-traumatic stress disorder and depression. Results supported earlier findings that a previous concussion is not generally associated with post-concussive symptoms independent of covariates. In contrast with other studies that failed to find a unique contribution for concussion to PPCS, however, evidence of recent and multiple concussion was seen across a range of emotional distress, post-concussive symptoms, and neurocognitive functioning in this study population. Results are discussed in terms of implications for assessing concussion on return from combat.

Combat-related concussions are significant sources of injury and morbidity among deployed military service members. Musculoskeletal injury also is one of the most prevalent battle and nonbattle-related deployed injury types. Both injuries threaten the service member's physical condition as well as unit and mission readiness due to reduced duty status or evacuation from military theater of operations. In August 2010, the Concussion Restoration Care Center (CRCC) was established at Camp Leatherneck, Afghanistan, to address the need for consistent and specialized evaluation and care of concussion and musculoskeletal injury. This performance improvement effort examined evaluation and treatment of concussion and musculoskeletal injury at the CRCC. Among 4,947 military personnel evaluated at the CRCC between August 2010 and May 2013, 97.9% were returned to duty and retained in theater. Members averaged 10 to 12 days of limited duty status to achieve complete recovery. Concussion injury was secondary to blast injury in 90% of cases. Sport/recreation, occupational, and other accidental injuries each represented 30% of the musculoskeletal injuries with only 10% reported as result of combat. The utilization patterns and outcome measures demonstrate the success and utility of a multidisciplinary clinical model of care for these two types of injuries in the far-forward deployed setting.