[PEER REVIEWED] Motor-Cognitive Analysis of Dual Task Walking in Chronic Obstructive Pulmonary Disease Patients: An Analysis Using Functional Near Infrared Spectroscopy v1

Chronic Obstructive Pulmonary Disease (COPD), characterized by airflow limitation, commonly manifests cognitive and physical impairments. Although the interplay of cognitive-motor function is required for many daily activities, these impairments are often managed separately. Our protocol applied a dual task experimental paradigm to assess the interaction and potential decrements of simultaneously performing cognitive and motor tasks. This protocol also utilized functional near infrared spectroscopy (fNIRS) to monitor neural correlates (changes in oxygenated hemoglobin, ΔO2Hb). Two single tasks and a dual task were applied in random order: (1) single task walking evaluated by OPAL sensors to measure gait speed; (2) a cognitive task of determining the number of 5-letter words accurately spelled backwards; (3) dual task walking combined with spelling words backwards. The decrements of performance were evaluated by examining the differences from single to dual task performance as well as normalizing the decrement to the single task performance by the following equation: Dual task cost = [(dual task – single task)/single task] x 100%. The ΔO2Hb monitored over the prefrontal cortex (participant’s forehead) provided neural correlates of the cognitive demands of the single and dual tasks and sample data are provided. Sample data showed that both a COPD patient and older adult (control) walked slower and spelled fewer words with lower accuracy during dual task walking compared to the respective single task. The ΔO2Hb over the right dorsolateral prefrontal cortex is consistent with greater cognitive demands of both single tasks and the dual task in the COPD patient compared to the older adult. This protocol may be informative to healthcare researchers evaluating the functional state of patients with COPD who are capable of independent ambulation because it can provide insights of dual task deficits, and consequently, highlight strategies to mitigate cognitive and physical deficits required for daily activities.