Relation of Mild Traumatic Brain Injury history to abnormalities on a preliminary Neuroendocrine screen; A multicenter LIMBIC-CENC analysis

PRIMARY OBJECTIVES

Determine if an abnormal preliminary neuroendocrine disorder (NED) blood test screen is associated with mild TBI (mTBI) history or post-concussiveclinical features.

RESEARCH DESIGN

Observational.

METHODS

Among 1,520 participants with military combatexposure, we measured randomly timed serum levels of insulin-likegrowth factor-1, thyroid stimulating hormone (TSH), and total testosterone as a preliminary NED screen. Using multivariable models, we analyzed relation of screen results in mTBI group membership and post-concussiveclinical features (fatigue, depression, cognitive symptoms, executive function, processing speed).

RESULTS

None of the mTBI positive groups, including repetitive (≥3 mTBI) and blast-related,differed from the non-TBIcontrols on rates of abnormal lab screen or rates of growth hormone deficiency (GHD), hypothyroidism or male hypogonadism in treatment records. Lab screen findings were also not associated with any clinical feature.

CONCLUSIONS

This study shows no evidence that remote mTBI(s) or implicated post-concussiveclinical features are linked to GHD, hypothyroidism or male hypogonadism. Large case-controlstudies incorporating more definitive neuroendocrine disorder NED testing (TSH plus thyroxine, early morning testosterone, LH, FSH, prolactin and GH provocative testing) are needed to determine whether mTBI(s) alone elevate one's risk for chronic NED and how best to select patients for comprehensive testing.

1155 The Association Between STOPBANG Risk and Sleep Quality in an mTBI Sample

Introduction

Although Obstructive Sleep Apnea (OSA) is prevalent in the military population, traditional scoring/clinical cut-offs of available screening tools may not be appropriate for this younger, slimmer population. We additionally have limited information regarding utility of OSA screening in those with history of mild traumatic brain injury (mTBI). The current study compared multiple STOPBANG scoring methods to determine how well they were associated with self-reported sleep measures in an mTBI sample.

Methods

Secondary analyses were conducted from a large database of evaluations from a multi-center, longitudinal study of mTBI. Participants were included if they had completed the STOPBANG and additional sleep measures. The subsequent sample (N=486) included participants with history of mTBI (n=408) and controls (n=78). The sample was predominantly male (n=421) with a mean age of 39 (IQR = 31/37/47).

Results

Sleep efficiency was not significantly associated with any STOPBANG scoring, in the total sample or when controlling for mTBI. In the total sample, sleep quality was most strongly associated with traditional STOPBANG scoring (STOPBANG ≥ 3, β=0.51). Sleep duration was most strongly associated with Snoring/Tired/Hypertension (STP = 3, β=0.79). When controlling for mTBI, duration was most strongly associated with traditional scoring (β=0.48), while sleep quality was most strongly associated with Snoring/Tired/Hypertension (β=0.78). Follow-up analyses demonstrate a significant difference in correlation between groups for STP/Sleep Quality, with a stronger correlation for those without mTBI.

Conclusion

The STOPBANG measure was significantly associated with self-reported sleep quality/duration measures, but not sleep efficiency. Although traditional clinical cut-offs for OSA predicted sleep measures in this sample, the relationship between risk scores and outcomes became more nuanced when history of mTBI was included. Future studies are needed to understand the relationship between OSA risk and subsequent diagnosis in the mTBI population.

Support

Defense and Veterans Brain Injury Center (GDHS,W91YTZ-13-C-0015), DOD(W81XWH-12-2-0095), VA(I01 CX001135)

Voxel-based analysis of diffusion tensor imaging in mild traumatic brain injury in adolescents

BACKGROUND AND PURPOSE

DTI of normal-appearing WM as evaluated by conventional MR imaging in mTBI has the potential to identify important regional abnormalities that relate to PCS. VBA was used to examine WM changes in acute mTBI.

MATERIALS AND METHODS

WM was assessed between 1 and 6 days postinjury with voxel-based DTI analyses in 10 adolescent patients with mTBI and 10 age-matched control participants. In addition to the voxel-based group, analysis used to identify brain pathology across all patients with mTBI, 2 voxel-based linear regressions were performed. These analyses investigated the relation between 1) the ADC and PCS severity scores, and 2) ADC and scores on the BSI of emotional symptoms associated with mTBI. We hypothesized that frontotemporal WM changes would relate to symptoms associated with PCS and endorsed on the BSI.

RESULTS

Patients with mTBI demonstrated significant reductions in ADC in several WM regions and in the left thalamus. As expected, no increases in ADC were found in any region of interest. All injury-affected regions showed decreased radial diffusivity, unchanged AD, and increased FA, which is consistent with axonal cytotoxic edema, reflective of acute injury.

CONCLUSIONS

Whole-brain WM DTI measures can detect abnormalities in acute mTBI associated with PCS symptoms in adolescents.

Diffusion tensor imaging of acute mild traumatic brain injury in adolescents

BACKGROUND

Despite normal CT imaging and neurologic functioning, many individuals report postconcussion symptoms following mild traumatic brain injury (MTBI). This dissociation has been enigmatic for clinicians and investigators.

METHODS

Diffusion tensor imaging tractography of the corpus callosum was performed in 10 adolescents (14 to 19 years of age) with MTBI 1 to 6 days postinjury with Glasgow Coma Scale score of 15 and negative CT, and 10 age- and gender-equivalent uninjured controls. Subjects were administered the Rivermead Post Concussion Symptoms Questionnaire and the Brief Symptom Inventory to assess self-reported cognitive, affective, and somatic symptoms.

RESULTS

The MTBI group demonstrated increased fractional anisotropy and decreased apparent diffusion coefficient and radial diffusivity, and more intense postconcussion symptoms and emotional distress compared to the control group. Increased fractional anisotropy and decreased radial diffusivity were correlated with severity of postconcussion symptoms in the MTBI group, but not in the control group.

CONCLUSIONS

In adolescents with mild traumatic brain injury (MTBI) with Glasgow Coma Scale score of 15 and negative CT, diffusion tensor imaging (DTI) performed within 6 days postinjury showed increased fractional anisotropy and decreased diffusivity suggestive of cytotoxic edema. Advanced MRI-based DTI methods may enhance our understanding of the neuropathology of TBI, including MTBI. Additionally, DTI may prove more sensitive than conventional imaging methods in detecting subtle, but clinically meaningful, changes following MTBI and may be critical in refining MTBI diagnosis, prognosis, and management.