Analysis of Post-Deployment Cognitive Performance and Symptom Recovery in U.S. Marines

Abstract

BackgroundComputerized neurocognitive testing (NCAT) has been proposed to be useful as a screening tool for post-deployment cognitive deficits in the setting of mild traumatic brain injury (mTBI). We assessed the clinical utility of post-injury/post-deployment Automated Neurocognitive Assessment Metric (ANAM) testing, using a longitudinal design to compare baseline ANAM tests with two post-deployment ANAM tests in a group of Marines who experienced combat during deployment.Methods and FindingsPost-deployment cognitive performance and symptom recovery were compared in a subsample of 1324 U.S. Marines with high rates of combat exposure during deployment. Of the sample, 169 Marines had available baseline and twice repeated post-deployment ANAM results. A retrospective analysis of the ANAM data, which consisted of a self-report questionnaire about deployment-related blast exposure, recent history of mTBI, current clinical symptoms, and cognitive performance. Self-reported concussion sustained anytime during deployment was associated with a decrease in cognitive performance measured between 2–8 weeks post-deployment. At the second post-deployment test conducted on average eight months later, performance on the second simple reaction time test, in particular, remained impaired and was the most consistent and sensitive indicator of the cognitive decrements. Additionally, post-concussive symptoms were shown to persist in injured Marines with a self-reported history of concussion for an additional five months after most cognitive deficits resolved. Results of this study showed a measurable deployment effect on cognitive performance, although this effect appears to resolve without lasting clinical sequelae in those without history of deployment-related concussion.ConclusionsThese results highlight the need for a detailed clinical examination for service members with history of concussion and persistent clinical symptoms. Reliance solely upon computerized neurocognitive testing as a method for identifying service members requiring clinical follow-up post-concussion is not recommended, as cognitive functioning only slowly returned to baseline levels in the setting of persistent clinical symptoms.

Reliable Change Estimates for Assessing Recovery From Concussion Using the ANAM4 TBI-MIL

“…The group analyses (ie, between-and within-group differences) revealed results, not surprisingly, that were similar to previous reports. 21,23 Both groups performed similarly at T 1 (ie, between; mean effect was g = 0.05), and both groups had statistically significant decreases in scoring at T 2 when compared with their own group baseline at T 1 (ie, within) with effects of 0.32 and 0.56 (slightly below and above the RMPE of 0.41 for group differences) for the NCG and CNG, respectively. When performance was compared at T 2 , the CNG had significantly lower scores than the NCG (ie, between) for 5 of the 7 subtests; however, the mean effect (g = 0.27) for these significant differences was below the RMPE for group differences, suggesting that there were no meaningful differences between the groups.…”

“…These studies reported conflicting results, possibly due to study design and methodological differences, which suggest that further research is warranted. [21][22][23] Haran et al 21 used traditional hypothesis testing to determine whether there were statistically significant different changes in pre-(ie, baseline) to postdeployment performance between SMs with self-reported concussion during deployment and nonconcussed controls. The results of the study revealed that the group with concussion had significant decreases in performance 2 to 8 weeks postdeployment (ie, during the chronic phase), which returned to baseline levels after 7 months postdeployment for all subtests, except for Simple Reaction Time Repeated (SRT2).…”

“…This may need to be given additional interpretive weighting, as a growing body of literature has indicated that ANAM reaction time-based subtests may be the most sensitive indicators for determining postinjury changes in neurocognitive functioning. 16,18,20,21,[28][29][30][31] This study was designed using the strengths of each of the aforementioned studies. The primary aim of this study was to estimate RC parameters from a sample of healthy SMs that could be used by clinicians for postdeployment screening purposes.…”

Volumetric and shape analyses of subcortical structures in United States service members with mild traumatic brain injury

“…A diagnosis of a mild TBI (mTBI) suggests that most Service Members and Veterans will experience full cognitive and functional recovery [29, 69]. However, there are a number of individuals (~20 %) who continue to experience residual symptoms that could impact unit readiness, return to duty, safety of troop operations, and troop retention [13, 27, 67]. Thus, there is significant interest in improving diagnosis, prognostic accuracy, monitoring recovery or decline, and assessing treatment effects, especially for those experiencing persistent symptoms.…”

Stress-Related Mental Health Symptoms in Coast Guard: Incidence, Vulnerability, and Neurocognitive Performance

“…Beyond the development and expression of mental health difficulties, there is growing concern that stress may degrade neurocognitive performance and adversely affect operational performance. Neurocognitive deficits have been reported after repetitive military environmental exposures (e.g., blasts; Luethcke et al, 2011 ), stress-related mental disorders (Marx et al, 2009 ; Luethcke et al, 2011 ; Haran et al, 2013 ), or mild traumatic brain injury (mTBI; Spira et al, 2014 ; Dretsch et al, 2015 ). The Defense Automated Neurobehavioral Assessment (DANA) battery, developed as a clinical decision support tool, consists of a battery of neurocognitive tests as well as psychological assessments for field screening of PTSD and MDD (Lathan et al, 2013 ; Spira et al, 2014 ).…”