Faculty Bibliography

Psychiatric disturbance is common and disabling after traumatic brain injury (TBI). Few studies have investigated the trajectory of psychiatric symptoms in the first 6 months postinjury, when monitoring and early treatment might prevent persistent difficulties. The aim of this study was to examine the trajectory of psychiatric symptoms 1-6 months post-TBI, the patient/injury characteristics associated with changes, and characteristics predictive of persisting symptoms. A secondary analysis was performed on data from a clinical trial with three data collection points. Across eight centers, 872 participants with complicated mild to severe TBI were administered the Brief Symptom Inventory (BSI) at 30, 90, and 180 days postinjury. Mixed-effects models were used to assess longitudinal changes in the BSI Global Severity Index (GSI). Multi-variate logistic regression was used to assess predictors of clinically significant GSI elevations persisting to 6 months post-TBI. In general, GSI scores improved over time. Women improved faster than men; race/ethnicity was also significantly associated with rate of change, with Hispanics showing the most and African Americans the least improvement. Clinically significant psychiatric symptoms (caseness) occurred in 42% of the sample at 6 months, and more than one type of symptom was common. Significant predictors of caseness included African American race, age from 30 to 60 years, longer post-traumatic amnesia (PTA) duration, pre-TBI unemployment, and pre-TBI risky alcohol use. Findings indicate that psychiatric symptoms are common in the first 6 months post-TBI and frequently extend beyond the depression and anxiety symptoms that may be most commonly screened. Patients with longer PTA and preinjury alcohol misuse may need more intensive monitoring for symptom persistence.

OBJECTIVES:: (1) Detailed analysis of diffusion tensor imaging (DTI) parameters (fractional anisotropy and radial diffusivity) to evaluate white matter integrity in the corpus callosum (CC), and (2) examine correlations between DTI data and performance on multiple measures of cognitive functioning. PARTICIPANTS:: Twelve individuals with a history of complicated mild, moderate, or severe traumatic brain injury (TBI) who were an average of 1.7 years postinjury and 12 control participants. MAIN MEASURES:: Standardized and experimental neuropsychological tests; detailed analysis of DTI parameters. RESULTS:: The TBI group demonstrated DTI values suggesting decreased white matter integrity and correlations with severity of injury. Both groups showed correlations between DTI parameters and cognitive measures, with more significant correlations observed for the TBI group. White matter changes in the CC were evident chronically and were related to severity of injury. CONCLUSIONS:: Diffusion tensor imaging parameters suggesting disruptions in white matter in the CC may be implicated in impaired performance, both in terms of cognitive tasks and reaction time, after TBI.

CONTEXT: Traumatic brain injury (TBI) is a serious public health problem in the United States, yet no treatment is currently available to improve outcome after TBI. Approved for use in TBI in 59 countries, citicoline is an endogenous substance offering potential neuroprotective properties as well as facilitated neurorepair post injury. OBJECTIVE: To determine the ability of citicoline to positively affect functional and cognitive status in persons with complicated mild, moderate, and severe TBI. DESIGN, SETTING, AND PATIENTS: The Citicoline Brain Injury Treatment Trial (COBRIT), a phase 3, double-blind randomized clinical trial conducted between July 20, 2007, and February 4, 2011, among 1213 patients at 8 US level 1 trauma centers to investigate effects of citicoline vs placebo in patients with TBI classified as complicated mild, moderate, or severe. INTERVENTION: Ninety-day regimen of daily enteral or oral citicoline (2000 mg) or placebo. MAIN OUTCOME MEASURES: Functional and cognitive status, assessed at 90 days using the TBI-Clinical Trials Network Core Battery. A global statistical test was used to analyze the 9 scales of the core battery. Secondary outcomes were functional and cognitive improvement, assessed at 30, 90, and 180 days, and examination of the long-term maintenance of treatment effects. RESULTS: Rates of favorable improvement for the Glasgow Outcome Scale-Extended were 35.4% in the citicoline group and 35.6% in the placebo group. For all other scales the rate of improvement ranged from 37.3% to 86.5% in the citicoline group and from 42.7% to 84.0% in the placebo group. The citicoline and placebo groups did not differ significantly at the 90-day evaluation (global odds ratio [OR], 0.98 [95% CI, 0.83-1.15]); in addition, there was no significant treatment effect in the 2 severity subgroups (global OR, 1.14 [95% CI, 0.88-1.49] and 0.89 [95% CI, 0.72-1.49] for moderate/severe and complicated mild TBI, respectively). At the 180-day evaluation, the citicoline and placebo groups did not differ significantly with respect to the primary outcome (global OR, 0.87 [95% CI, 0.72-1.04]). CONCLUSION: Among patients with traumatic brain injury, the use of citicoline compared with placebo for 90 days did not result in improvement in functional and cognitive status. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00545662.

BACKGROUND: Studies implicate single nucleotide polymorphism (SNP) rs17070145, a common T --> C polymorphism on the KIBRA gene, in mediating differences in episodic memory. In healthy adults, T-allele carriers perform better than non-carriers on episodic memory measures. However, this association is reversed in adults with subjective memory complaints and populations vulnerable to memory deficits, a problem common in traumatic brain injury (TBI). METHODS: This study assessed associations between variation in the KIBRA gene and cognitive function in 129 adults with severe TBI. In addition to other executive functioning and functional/global outcomes, the Buschke Selective Reminding Test (SRT), Rey-Osterrieth Complex Figure Test and California Verbal Learning Test-II (CVLT-II) were administered 6 and 12 months post-injury. RESULTS: T-allele non-carriers performed better than carriers on multiple episodic memory measures. At 6 months, T-allele non-carriers performed better for delayed recall measures on the SRT. At 12 months, T-allele non-carriers performed better on multiple SRT measures and on List-B learning with CVLT-II. No associations occurred with executive function or global outcome measures. CONCLUSION: These results suggest that rs17070145 T-allele effects are specific to episodic memory and support the hypothesis that associations between rs17070145 variation and memory are disparate between healthy and impaired populations.

OBJECTIVE: The purpose of this study was to examine whether minor high-level language deficits found after traumatic brain injury (TBI) might be due to low-level language processing issues or executive control influences. A possible mechanism was also investigated. METHOD: Nineteen age- and education-matched healthy controls (16 M, 3 F) and 19 persons who had experienced a complicated mild, moderate or severe TBI between 1-3 years prior (16 M, 3 F; mean GCS = 9.44) participated in two computerized behavioural experiments utilizing two paradigms standard in the psycholinguistic literature (priming with lexical decision and verb generation), which included trials of greater and lesser executive demand. RESULTS: Response time and accuracy differences were found in both experiments, indicating deficits in single-word processing for the patient group. Disproportionate difficulty was found for trials which included an executive component. Right visual field (left hemisphere) preferences were found to be stronger in the TBI group than in controls. CONCLUSIONS: Results suggest that persons with TBI may have difficulties in processing single words alone, especially under conditions of increased executive demand, and that atypical patterns of hemispheric recruitment may be associated with these difficulties.

OBJECTIVE: Acute hypogonadotropic hypogonadism (AHH) occurs frequently after TBI, as does chronic hypogonadotropic hypogonadism. However, AHH and persistent hypogonadotropic hypogonadism (PHH) after TBI are not well studied. The objective of this study was to characterize longitudinal hormone profiles and the impact of AHH and PHH on outcome. METHODS: In this prospective cohort study, men with severe TBI (n = 38) had serum gonadal and gonadotropic hormones measured during weeks 1-52 post-injury. AHH, PHH and/or early resolving hypogonadotropic hypogonadism (ERHH) were based on temporal hormone assessments. PHH and hormone profiles were then compared to multiple outcome measures 6-12 months post-TBI. RESULTS: AHH affected 100% of the population, while 37% subsequently developed PHH. Acute testosterone (TEST) and estradiol/testosterone (E2/TEST) ratios were associated with PHH and outcome. Over time, post-acute TEST and E2 levels for the ERHH group approached normal range, while levels for the PHH group remained low. Post-acute gonadotrophin levels were within the normal range for both groups. PHH, along with lower post-acute TEST and E2 profiles, was associated with worse functional and cognitive outcomes at 6 and 12 months post-injury. CONCLUSIONS: These results support screening for post-acute secondary hypogonadism and further research to assess the mechanisms underlying PHH and associated functional and cognitive deficits.

Although impairment of episodic memory is common after traumatic brain injury (TBI), the complex nature of human memory suggests the need to study more than recall alone. For this reason, we are presenting an extension with additional analyses of persons reported in a previous publication ( Russell, Arenth, Scanlon, Kessler, & Ricker, 2011 ). We examined both the encoding and recognition components of an episodic memory paradigm containing both word and letter string blocks using functional magnetic resonance imaging (fMRI) and neuropsychological testing. This paradigm was completed by 12 persons with complicated mild, moderate, or severe TBI and 12 matched uninjured controls. Comparisons were made between groups and stimulus types. While task behavioral performance was not significantly different between groups, imaging results showed greater activation for the TBI group during the encoding portion of the task, while the control group exhibited more activation on the recognition portion. Observed areas of activation suggest that the TBI group may have used a less effective, but more automatic verbal strategy for encoding the nonpronounceable letter strings, while controls may have opted for more of a recognition-focused strategy. Group differences in California Verbal Learning Test-Second Edition (CVLT-II) performance supported these ideas, and further neuropsychological testing also suggested limitations in executive functioning in the TBI group that may have influenced performance. Implications for intervention are discussed.

Cognitive impairment is a common sequela in acquired brain injury and one that predicts rehabilitation outcomes. There is emerging evidence that impairments in cognitive functions can be manipulated by both pharmacologic and nonpharmacologic interventions to improve rehabilitation outcomes. By using stroke as a model for acquired brain injury, we review the evidence that links cognitive impairment to poor rehabilitation outcomes and discuss possible mechanisms to explain this association. Furthermore, we examine nascent promising research that suggests that interventions that target cognitive impairments can lead to better rehabilitation outcomes.

Cytidine 5'-diphosphocholine (CDP-choline or citicoline) is a highly bioavailable compound with potential benefits for aiding neural repair and increasing acetylcholine levels in the central and peripheral nervous system. As a result, many researchers have investigated the use of CDP-choline for various types of neurological insult or conditions, including stroke, traumatic brain injury, and Alzheimer disease. Despite the fact that the safety of the compound has been verified across multiple international studies, evidence for efficacy remains less clear. This may be attributable, at least in part, to several issues, including a lack of randomized clinical trials, a lack of availability of the compound in the United States, and statistical power issues in reported trials. In addition, the fact that CDP-choline has multiple potential points of therapeutic impact makes it an exciting treatment option in theory but also complicates the analysis of efficacy in the sense that multiple mechanisms and time points must be evaluated. Although some clinical conditions do not appear to benefit from CDP-choline treatment, the majority of findings to date have suggested at least minor benefits of treatment. In this review we will examine the evidence in the published literature pertaining to use of CDP-choline in rehabilitation populations and briefly consider the work yet to be done.