Identification of subclinical cognitive impairment in chronic obstructive pulmonary disease using auditory P300 event related potential.

Abstract

Adequate cognitive functioning in chronic obstructive pulmonary disease (COPD) patients is essential to understand the nature of the disease, adherence to treatment, and for leading a better quality of life. While cognitive impairment in severe forms of COPD have been well documented, identification of subclinical cognitive impairment in stable COPD patients remains crucial for planning prevention strategies. Hence the present study aimed to study and compare the cognitive function between the COPD patients, and normal individuals. The cognitive function was assessed in 42 stable COPD patients and 42 normal individuals with Mini Mental State Examination (MMSE), and auditory P300 event related potentials. Baseline characteristics and the cognitive parameters were compared between the COPD patients and the normal individuals; a p<0.05 was considered statistically significant. The latency of the P300 waves was significantly (p<0.05) prolonged (304.27±20.73 in COPD, 291.11± 24.53 in normal individuals), and the amplitude (4.36±1.56 in COPD, 5.46±3.12 in normal individuals) was significantly reduced in the COPD patients compared to the normal individuals. MMSE scores were also significantly (p<0.001) different between the COPD patients (26.97±0.89), and the normal individuals (27.80±0.83). Cognition may be affected even at the earlier stages of the disease among the COPD patients, as evident by changes in the P300 values. Auditory P300 event related potential may be used as an adjunct to the routine MMSE examination, as it serves as an effective tool in identifying the cognitive impairment in different stages of COPD. This may help the patients to adopt prevention strategies that help to avoid adverse effects on cognition in future.