Magnitudes of decline on Automated Neuropsychological Assessment Metrics subtest scores relative to predeployment baseline performance among service members evaluated for traumatic brain injury in Iraq

Abstract

Objective: : Identify the proportion of service members demonstrating declines in Automated Neuropsychological Assessment Metrics (ANAM) scores as part of a traumatic brain injury (TBI) evaluation conducted while deployed to Iraq.

Background: : Although TBI has been associated with poorer performance on cognitive test in the general population and military combatants, little is known about the proportion of service members demonstrating declines in ANAM scores after TBI.

Methods: : Military personnel (N = 116) referred to a combat support hospital for TBI evaluation in Iraq underwent a standardized intake evaluation including computerized neurocognitive testing, psychological and physical health questionnaires, a clinical interview, and a physical examination by a physician. Predeployment and postinjury cognitive performance among service members with and without a TBI diagnosis was compared.

Results: : A significantly larger proportion of patients with TBI demonstrated greater declines in speed across all ANAM subtests compared with patients with no TBI. Differences in accuracy scores among patients with TBI relative to patients without TBI were nonsignificant. Patients with TBI also demonstrated greater than minimal declines on throughput Simple Reaction Time, Procedural Reaction Time, Code Substitution-Learning, and Spatial Memory scores, with no significant differences on Code Substitution-Delayed or Mathematical Processing (MATH). A similar pattern was seen among individuals examined within 72 hours of index injury.

Conclusion: : Assessment of cognitive impairment following TBI in a combat zone may assist providers in making treatment recommendations for service members with mild TBI.