Topographic quantitative analysis of the intrinsic alpha rhythm in chronic obstructive pulmonary disease.

Twenty-two patients with documented COPD and no other significant illnesses were studied to assess the effect of varying degrees of COPD on the intrinsic alpha rhythm. The severity of COPD was determined by spirometry with assessment of FEV1, FVC, and FEV1/FVC. The alpha frequency for COPD patients was slower than that which characterizes age equated normals and averages 1.6 S.D. below normative data base mean values (range -0.43 S.D. to -1.85 S.D.). Impairment of pulmonary functioning significantly correlated with the degree of alpha frequency slowing over the posterior cortical regions, and the slowest alpha frequencies occurred in those COPD patients with the lowest FEV1/FVC ratios. Impairment of cognitive functioning is thus an important clinical consideration in treatment of patients with COPD but may go unrecognized until late in the course of the disease.