Faculty Bibliography

We seek to elucidate the underlying pathophysiology of injury sustained after mild traumatic brain injury (MTBI) using multi-shell diffusion MRI, deriving compartment-specific WM tract integrity (WMTI) metrics. WMTI allows a more biophysical interpretation of WM changes by describing microstructural characteristics in both intra- and extra-axonal environments. Thirty-two patients with MTBI within 30 days of injury and twenty-one age- and sex-matched controls were imaged on a 3T MR scanner. Multi-shell diffusion acquisition was performed with 5 b-values (250 - 2500 s/mm²) along 6 - 60 diffusion encoding directions. Tract-based spatial statistics (TBSS) was used with family-wise error (FWE) correction for multiple comparisons. TBSS results demonstrate focally lower intra-axonal diffusivity (D_axon) in MTBI patients in the splenium of the corpus callosum (sCC) (p < 0.05, FWE-corrected). The Area Under the Curve (AUC)-value for was 0.76 with low sensitivity of 46.9%, but 100% specificity. These results indicate that D_axon may be a useful imaging biomarker highly specific for MTBI-related WM injury. The observed decrease in D_axon suggests restriction of the diffusion along the axons occurring shortly after injury.

Introduction/Rational Despite the outcomes achieved by the diagnostic, treatment, preventative and other services provided to adults with TBI in inpatient acute and subacute rehabilitation facilities, nursing homes, residential and outpatient programs, of late access to comprehensive rehabilitation has been increasingly limited by third-party payers, not uncommonly with the justification that there is no 'Class I' evidence to support the provision of these needed services. The outcome of this discriminatory process is that individuals with TBI are unable to receive care from which they could benefit, thereby limiting their recovery and increasing the burden of care on their families and society. Method/Approach BIAA is funding the development of guidelines as to what diagnostic, treatment, preventative and other services, whether medical, social, psychological or educational, should be provided and in what settings and/or phases after injury onset. The project utilizes GRADE methodology and incorporates evidence from studies that are less than Class I. Where evidence is lacking, consensus recommendations developed by expert panels are included. The guidelines will be disseminated widely to patients, families, service providers, insurers and policymakers. Guidelines development started with the development of PICOT (Population, Intervention, Comparator, Outcome, Time point) questions to direct the identification of evidence. Results/Effects Five panels of about 11 stakeholders each (persons with TBI, family members, clinicians, researchers) have developed 54 PICOT questions, in five areas: behavioral issues; cognitive rehabilitation; functional issues; chronic medical issues; vocational-community. Many of these questions contain subsidiary questions focused on the subgroups or time points for which treatments are most effective. The chronic medical issues panel will formulate additional questions once the incidence/prevalence of chronic comorbidities has been determined. Screening of over 16,000 abstracts (using the Covidence website) has been completed for most questions, and extracting of data (using the Systematic Review Data Repository) has started. Conclusions/Limitations Conclusion: This presentation will highlight the PICOT questions, and some of the methodological challenges created by the large number of questions and the extensive literature at least potentially relevant to them

After traumatic brain injury (TBI), central autonomic dysfunction might contribute to long-term increased mortality rates. Central autonomic dysfunction might depend on initial trauma severity. This study was performed to evaluate differences in autonomic modulation at rest and upon standing between patients with a history of mild TBI (post-mild-TBI patients), moderate or severe TBI (post-moderate-severe-TBI patients), and healthy controls. In 20 post-mild-TBI patients (6-78 months after TBI), age-matched 20 post-moderate-severe-TBI patients (6-94 months after TBI) and 20 controls, we monitored respiration, RR intervals (RRI) and systolic blood pressure (BPsys) at supine rest and upon standing. We determined mainly sympathetic low (LF) and parasympathetic high (HF) frequency powers of RRI fluctuations, sympathetically mediated LF-BPsys powers, LF/HF-RRI ratios, normalized (nu) LF-RRI and HF-RRI powers, and compared data between groups, at rest and upon standing (ANOVA with post hoc testing). We correlated autonomic parameters with initial Glasgow Coma Scale (GCS) scores (Spearman test; significance: p < 0.05). Supine BPsys and LFnu-RRI powers were higher while HFnu-RRI powers were lower in post-moderate-severe-TBI patients than post-mild-TBI patients and controls. LFnu-RRI powers were higher and HFnu-RRI powers were lower in post-mild-TBI patients than controls. Upon standing, only post-mild-TBI patients and controls increased LF-BPsys powers and BPsys and decreased HF-RRI powers. GCS scores correlated positively with LFnu-RRI powers, LF/HF-RRI ratios, and inversely with HFnu-RRI powers, at standing position. More than 6 months after TBI, there is autonomic dysfunction at rest and upon standing which is more pronounced after moderate-severe than mild TBI and in part correlates with initial trauma severity.

OBJECTIVE: This study investigated the utility of sideline concussion tests, including components of the Sports Concussion Assessment Tool, 3rd Edition (SCAT3) and the King-Devick (K-D), a vision-based test of rapid number naming, in an outpatient, multidisciplinary concussion center treating patients with both sports-related and non-sports related concussions. The ability of these tests to predict clinical outcomes based on the scores at the initial visit was evaluated. METHODS: Scores for components of the SCAT3 and the K-D were fit into regression models accounting for age, gender, and sport/non-sport etiology in order to predict clinical outcome measures including total number of visits to the concussion center, whether the patient reached a SCAT3 symptom severity score