Changes in Spatial Working Memory in Stable Chronic Obstructive Pulmonary Disease: A Retrospective Study

Abstract

Chronic obstructive pulmonary disease (COPD) is characterized by irreversible airflow limitation and is often accompanied by cognitive impairment. Little is known about the working memory of COPD patients. The aim of the study is to evaluate the spatial working memory of COPD patients using the classical visuospatial working memory neuropsychological paradigms. This was a retrospective study of patients with COPD who were evaluated for neurocognitive functions between February and December 2018 at Hefei Second People’s Hospital. Healthy controls (HC) were included. The neuropsychological tests included the Beijing Version of the Montreal Cognitive Assessment Test (MoCA), digit span test (DS), Chinese Auditory Verbal Learning Test (CAVLT), Stroop test, and Verbal Fluency Test (VFT). The COPD group performed worse in MoCA (22.3±4.5 vs. 26.1±2.9, P<0.001), Stroop interference test (44.2±16.9 vs. 36.8±10.3, P=0.038), and VFT (12.9±2.8 vs. 15.3±4.7, P=0.021) vs. the HC group. Compared with the HC group, COPD patients had statistically significant differences with respect to 0-back RT (657±46 vs. 578±107, P=0.001), 1-back accuracy (41.8±12.1% vs. 81.5±18.1%, P<0.001), 1-back RT (592±75 vs. 431±138, P<0.001), 2-back accuracy (31.4±9.9% vs. 68.1±16.6%, P<0.001), and 2-back RT (563±79 vs. 455±153, P=0.002). Only PaO2 was independently associated with 0-back RT (B=0.992±0.428, P=0.028) and 1-back ACC (B=0.003±0.001, P=0.004). COPD patients exhibit impairment in working memory and executive function, but not in short- or long-term memory. The impairment of working memory in a patient with COPD may be more due to integrate memory information rather than to memory information storage. COPD patients exhibit a frontal-type cognitive decline.