Clinical Use of the Automated Neuropsychological Assessment Metrics TBI-Mil Expanded Battery in Evaluating Concussion Recovery: A Retrospective Study

Abstract

Abstract Introduction This retrospective study evaluated the use of the Automated Neuropsychological Assessment Metrics (ANAM4) Expanded battery in a clinical setting to determine if the resolution of physiological symptoms, in the absence of neurocognitive assessment, was sufficient data in the return-to-duty (RTD) determination. Materials and Methods In this study, 508 U.S. Naval Academy midshipmen were diagnosed with concussion and prescribed a standard treatment protocol. As directed by the protocol, they were evaluated and tracked by medical providers until determined to have normal balance and to be asymptomatic at rest and with exertion. Upon the resolution of these physiological symptoms, the midshipmen were referred for neurocognitive (ANAM4) testing. When results indicated a return to neurocognitive baseline, a RTD determination was made. Results The analysis of data in this study indicated that RTD determinations based solely on the resolution of physiological symptoms would have resulted in 25.1% of the sample being returned to duty before neurocognitive recovery. Additional analysis of the ANAM4 reliable change index (RCI) data for each of the concussed patients revealed a pattern of scores that correlated with an expected length of recovery. Individuals with at least one RCI greater than or equal to −1.64 returned to neurocognitive baseline in 8.92 days, whereas individuals with 2 or more RCIs greater than or equal to −1.25 (but less than −1.64) returned to baseline in 5.78 days, and those with a difference in measured reaction times that were greater or equal to −1.25 returned to baseline in 3.20 days. Furthermore, findings indicated that female service members required additional time for the resolution of physical symptoms as compared to their male counterparts. The mean number of days from injury to being deemed symptoms free in males was approximately 14, as compared to females who were deemed symptom free in 21 days. This difference is statistically significant. Conclusions Findings of this investigation revealed three specific outcomes. First, a computerized neurocognitive assessment instrument should be used as an adjunct measure in evaluating the resolution of physiological symptoms following a concussive injury. Second, results revealed that based on the RCIs of postinjury ANAM4 assessments, it is possible to estimate the remaining recovery time needed for a return to neurocognitive baseline. Third, results of this analysis revealed that gender appears to be a factor in time between concussive injury and resolution of symptoms.