Changes in Oxyhemoglobin Concentration in the Prefrontal Cortex during Cognitive-Motor Dual Tasks in People with Chronic Obstructive Pulmonary Disease.

Cognitive and motor impairment are well documented in chronic obstructive pulmonary disease (COPD) patients, but their relationship has not been studied. This study evaluated and compared cognitive and motor performance during dual tasks and related dorsolateral prefrontal cortex (PFC) changes in oxygenated hemoglobin (Delta O(2)Hb), a proxy measure of neural activity, in patients with COPD and age-matched healthy individuals. Participants performed three single tasks: (1) backwards spelling cognitive task; (2) 30 m preferred paced walk; (3) 30 m fast walk, and two dual tasks: (4) preferred paced walk + backwards spelling; (5) fast paced walk + backwards spelling. The Delta O(2)Hb from left and right dorsolateral PFC were measured using functional near-infrared spectroscopy. Gait velocity was measured using a Zeno walkway. Compared to healthy adults (n = 20), patients with COPD (n = 15) had higher Delta O(2)Hb during single preferred (-0.344 +/- 0.185 vs. 0.325 +/- 0.208 mu M;p = 0.011) and fast paced walk (-0.249 +/- 0.120 vs. 0.486 +/- 0.182 mu M;p = 0.001) in right PFC. Among healthy adults, Delta O(2)Hb were higher bilaterally during preferred paced walking dual versus single task (right: 0.096 +/- 0.159 vs. -0.344 +/- 0.185 mu M,p = 0.013; left: 0.114 +/- 0.150 vs. -0.257 +/- 0.175 mu M,p = 0.049) and in right PFC during fast walking dual versus single task (0.102 +/- 0.228 vs. -0.249 +/- 0.120,p = 0.021). Patients with COPD did not increase O(2)Hb during dual versus single tasks. Patients with COPD exhibited slower velocity than older adults during all walking tasks. The lack of further increase in O(2)Hb from single to dual tasks in patients with COPD, may indicate reduced cognitive-motor capacity and contribute to poorer motor performance limiting safe ambulation. Dual tasking rehabilitation may improve neural efficiency to offset these risks.