Translating the Interplay of Cognition and Physical Performance in COPD and Interstitial Lung Disease: Meeting Report and Literature Review.

TOPIC IMPORTANCE: Cognitive and physical limitations are common in individuals with chronic lung diseases, but their interactions with physical function and activities of daily living are not well characterized. Understanding these interactions and potential contributors may provide insights on disability and enable more tailored rehabilitation strategies. REVIEW FINDINGS: This review summarizes a 2-day meeting of patient partners, clinicians, researchers, and lung associations to discuss the interplay between cognitive and physical function in people with chronic lung diseases. This report covers four areas: (1) cognitive-physical limitations in patients with chronic lung diseases; (2) cognitive assessments; (3) strategies to optimize cognition and motor control; and (4) future research directions. Cognitive and physical impairments have multiple effects on quality of life and daily function. Meeting participants acknowledged the need for a standardized cognitive assessment to complement physical assessments in patients with chronic lung diseases. Dyspnea, fatigue, and age were recognized as important contributors to cognition that can affect motor control and daily physical function. Pulmonary rehabilitation was highlighted as a multidisciplinary strategy that may improve respiratory and limb motor control through neuroplasticity and has the potential to improve physical function and quality of life. SUMMARY: There was consensus that cognitive function and the cognitive interference of dyspnea in people with chronic lung diseases contribute to motor control impairments that can negatively affect daily function, which may be improved with pulmonary rehabilitation. The meeting generated several key research questions related to cognitive-physical interactions in individuals with chronic lung diseases.

Continuous measurements of respiratory muscle blood flow & oxygen consumption using non-invasive FD-NIRS & DCS.

Prior studies of muscle blood flow and muscle specific oxygen consumption have required invasive injection of dye and Magnetic Resonance Imaging, respectively. Such measures have limited utility for continuous monitoring of the respiratory muscles. Frequency domain near-infrared spectroscopy and diffuse correlation spectroscopy (FD-NIRS & DCS) can provide continuous surrogate measures of blood flow index (BFi) and metabolic rate of oxygen consumption (MRO2). This study aimed to validate sternocleidomastoid FD-NIRS & DCS outcomes against electromyography (EMG) and mouth pressure (Pm) during incremental inspiratory threshold loading (ITL). Six females and six male healthy adults (mean±SD; 30±7 years, maximum inspiratory pressure 118±61 cmH2O) performed incremental ITL starting at low loads (8±2 cmH2O) followed by 50g increments every two minutes until task failure. FD-NIRS & DCS continuously measured sternocleidomastoid oxygenated and deoxygenated hemoglobin+myoglobin (oxy/deoxy[Hb+Mb]), tissue saturation of oxygen (StO2), BFi, and MRO2. Ventilatory parameters including inspiratory Pm were also evaluated. Pm increased during incremental ITL (P<0.05), reaching -47[-74 - -34] cmH2O (median[25%-75%IQR] at task failure. Ventilatory parameters were constant throughout ITL (all P>0.05). Sternocleidomastoid BFi and MRO2 increased from the start of the ITL (both P<0.05). Deoxy[Hb+Mb] increased close to task failure, concomitantly with a constant increase in MRO2, and decreased StO2. Sternocleidomastoid deoxy[Hb+Mb], BFi, StO2 and MRO2 obtained during ITL via FD-NIRS & DCS correlated with sternocleidomastoid EMG (all P<0.05). In healthy adults, FD-NIRS & DCS can provide continuous surrogate measures of respiratory BFi and MRO-2. Increasing sternocleidomastoid oxygen consumption near task failure was associated with increased oxygen extraction and reduced tissue saturation.

Impact of cognitive capacity on physical performance in chronic obstructive pulmonary disease patients: A scoping review.

Background: Chronic obstructive pulmonary disease (COPD) is often accompanied by impaired cognitive and physical function. However, the role of cognitive function on motor control and purposeful movement is not well studied. The aim of the review was to determine the impact of cognition on physical performance in COPD. Methods: Scoping review methods were performed including searches of the databases: MEDLINE, EMBASE, Cochrane Systematic Reviews, Cochrane (CENTRAL), APA PsycINFO, and CINAHL. Two reviewers independently assessed articles for inclusion, data abstraction, and quality assessment. Results: Of 11,252 identified articles, 44 met the inclusion criteria. The review included 5743 individuals with COPD (68% male) with the forced expiratory volume in one second range of 24-69% predicted. Cognitive scores correlated with strength, balance, and hand dexterity, while 6-min walk distance (n = 9) was usually similar among COPD patients with and without cognitive impairment. In 2 reports, regression analyses showed that delayed recall and the trail making test were associated with balance and handgrip strength, respectively. Dual task studies (n = 5) reported impaired balance or gait in COPD patients compared to healthy adults. Cognitive or physical Interventions (n = 20) showed variable improvements in cognition and exercise capacity. Conclusions: Cognition in COPD appears to be more related to balance, hand, and dual task function, than exercise capacity.