Neuropsychologic effects of continuous oxygen therapy in chronic obstructive pulmonary disease.

Continuous ambulatory oxygen therapy was administered at 2 liters per minute by nasal cannula to a study group of ten hypoxemic patients with chronic obstructive pulmonary disease (COPD). Prior to therapy, a battery of neuropsychologic and psychologic tests was administered. These were repeated after hypoxemia had been relieved for four weeks. The results were compared to similar testing performed in a less severely hypoxemic comparison group of 12 patients with an equal degree of COPD. The comparison group was tested before and after four weeks, with no change in therapy. The hypoxemic treatment group initially scored significantly lower than the comparison group in five neuropsychologic tests. With oxygen therapy, significant improvement occurred in eight of ten neurophychologic test results and in four psychologic test results. No improvement was noted in the comparison group. After oxygen therapy, the previously noted differences between the treatment and comparison groups were no longer evident. These data suggest that hypoxemia is associated with depression in neuropsychologic and psychologic functioning which can be improved with relief of hypoxemia.