VERBAL MEMORY IMPAIRMENT IN COPD - ITS MECHANISMS AND CLINICAL RELEVANCE

Study objectives: Identification of mechanisms accounting for verbal m emory impairment in patients with severe COPD; assessing the relations hip between verbal memory and the overall cognitive performance; verif ying if verbal memory impairment affects medication adherence. Design: Case-comparison study. Setting: Outpatient Departments of Pneumology and Neurology, Day Hospital of General Surgery. Patients: Forty-two CO PD ambulatory patients, age 70+/-9.7 years, with hypoxemia and hyperca rbia (group A); 27 normal subjects of comparable age and educational l evel (group B); 31 patients with Alzheimer's disease (group C); and 26 older normal subjects (group D). Measurements and results: The overal l cognitive function and verbal memory were evaluated by the Mental De terioration Battery and 14 indexes of verbal memory. Defective retriev al and recognition mechanisms distinguished group A from group B. Acco rding to discriminant analysis, verbal memory profile of COPD patients was group specific in 38.1% of cases and conformed to that of group B , C, and D in 19%, 16.7%, and 26.2% of cases, respectively. In COPD pa tients, both immediate and delayed recall, the strongest determinants of the discriminant function, were significantly correlated with the o verall cognitive performance (rho=0.64, p=0.001; rho=0.61, p=0.001, re spectively). Poor adherence to medication regimen was significantly as sociated with abnormal delayed recall score (82.3% vs 36% in subjects with normal delayed recall, p<0.008). Conclusions: Decline of verbal m emory parallels that of the overall cognitive function in COPD patient s and is due to the impairment of both active recall and passive recog nition of learned material. It could be an important determinant of th e level of medication adherence.