EFFECT OF SEVERITY OF CHRONIC OBSTRUCTIVE PULMONARY DISEASE ON COGNITIVE DYSFUNCTION IN PATIENTS ATTENDING A TERTIARY CARE CENTRE IN KERALA

Cognitive dysfunction is an important systemic effect of COPD affecting various cognitive domains. The mechanisms involved in the impairment of cognition and the relevant factors are complex and not fully understood. Our study aimed to evaluate the impact of disease severity and impairment of respiratory physiology on cognitive impairment in patients with established COPD. In a hospital based cross sectional study, we examined hundred consecutive COPD patients for their lung parameters and further graded them into groups based on severity of disease by a multidimensional staging (BODE) index. All the subjects were then assessed for cognitive skills of orientation, attention, memory, visuo perceptual abilities and executive functions by neuropsychological battery of tests. Out of the respiratory parameters resting oxygen saturation (SpO2), modified Medical Research Council (mMRC) and Chronic obstructive pulmonary disease Assessment Test (CAT) scores correlated well with most of the cognitive domains. There was a significant correlation of resting SpO2 with Mini Mental State Examination (MMSE), orientation, registration, attention, recall, language and Clock Drawing Test (CDT). mMRC correlated significantly with the tasks Trail Making Test (TMT-A and TMT-B), orientation and recall. CAT score correlated significantly with orientation and MMSE and CDT. The decline in pulmonary function is associated with cognitive dysfunction and an impairment of cognition increases significantly with the advancement of the disease. Among the various cognitive domains, memory, attention, symbolic representation and visual processing (CDT), reproduction of numeric sequences, cognition flexibility, and shifting capacity (TMT-A and TMT-B) were the most affected.