Cognitive Measures of Vietnam-Era Prisoners of War

To the Editor: Although some studies have found decreased cognitive performance in repatriated prisoners of war (POWS),^1,2 other studies have not found such deficits.^3,4 Many of the studies that have found an intellectual decrement in POWs have methodological limitations, including failure to control for concurrent depression, posttraumatic stress disorder, or other mental illness; nonrandom selection of participants who were unmotivated to malinger; lack of a control group; and insufficient matching between POWs and controls.⁴ In contrast, the largest investigation,³ which studied more than 2500 World War II and Korean War POWs, noted that evidence of organic brain syndrome was "conspicuously absent" from the diagnoses differentiating POWs from controls. More recently, no cognitive differences were found on any cognitive test or on the computed axial tomography scans of POWs and controls.⁴ We assessed the relative cognitive status of US Navy Vietnam-era POWs using data gathered by the Naval Operational Medicine Institute's ongoing POW research program.