Evidence of objective memory impairments in deployed gulf war veterans with subjective memory complaints

Abstract

Introduction: Despite the fact that many veterans returned from the 1991 Gulf War (GW) with complaints of memory difficulties, most neuropsychological studies to date have found little evidence of a correspondence between subjective and objective measures of cognitive function in GW veterans. However, if GW veterans complain about memory problems, it is likely that they experience memory problems in their daily lives. In this respect, it is notable that the past studies that have investigated the relationship between subjective and objective measures of cognitive function in GW veterans used composite measures to quantify subjective complaints and batteries of neuropsychological tests that assessed multiple domains to objectively measure cognitive function. The study’s focus on memory was motivated by the suggestive evidence that subjective memory complaint may be a harbinger of further cognitive decline and increased risk for dementia. Materials and Methods: This study examined the association between subjective memory complaint (probed with single question: “Do you have difficulty remembering things?”) and performance on a single objective test of verbal learning and memory (i.e., California Verbal Learning Test, CVLT-II) in a sample of 428 deployed GW veterans. Results: GW veterans who endorsed memory difficulties performed more poorly on CVLT-II measures of total learning, retention, and delayed recall than GW veterans without subjective memory complaints (p < 0.001), even after accounting for demographic (e.g., age, sex, education) and clinical variables (e.g., diagnoses of current post-traumatic stress disorder [PTSD], depressive disorder, and/or anxiety disorder) that could potentially contribute to memory deficits. Among GW veterans who met the Centers for Disease Control and Prevention criteria for chronic multisymptom illness (N = 272), subjective memory complaint significantly predicted CVLT-II retention scores (β = −0.12, p = 0.04) and marginally predicted CVLT-II delayed recall scores (β = −0.11, p = 0.05) over and above potentially confounding demographic and clinical variables. Conclusion: This study suggests that deployed GW veterans with subjective memory complaints have objective memory impairments. In light of the evidence linking subjective memory complaint to increased risk for dementia in the elderly, these findings suggest that aging GW veterans with subjective memory complaints should be closely monitored for further cognitive decline.