Cognitive functioning and survival among patients with chronic obstructive pulmonary disease.

An earlier study by the authors had demonstrated neuropsychological impairment among 66 clinically stable patients suffering from chronic obstructive pulmonary disease (COPD), and had found that the deficits were directly associated with the amount of oxygen available to body tissue. We were able to follow 62 of the patients for three years when retrospective analyses were performed to determine the relationship of the neuropsychological test scores with the patients' three-year survival status. Patients who survived had scored significantly (p less than 0.01) higher on the neuropsychological tests than those who had died. Individual analyses of variance indicated that the significant relationship between the neuropsychological tests and survival status was attributable primarily to the Benton Visual Motor Retention Test and the digit symbol subtest of the Wechsler Adult Intelligence Scale. The latter test had, in the earlier study, shown the strongest relationship with partial pressure of oxygen and with a pulmonary function test. These findings suggest that certain neuropsychological tests may reflect both the progress of COPD and three-year survival probability among the patients.