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

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.

Gait differences between COPD and healthy controls: systematic review and meta-analysis

BACKGROUND

Despite the importance of gait as a determinant of falls, disability and mortality in older people, understanding of gait impairment in COPD is limited. This study aimed to identify differences in gait characteristics during supervised walking tests between people with COPD and healthy controls.

METHODS

We searched 11 electronic databases, supplemented by Google Scholar searches and manual collation of references, in November 2019 and updated the search in July 2021. Record screening and information extraction were performed independently by one reviewer and checked for accuracy by a second. Meta-analyses were performed in studies not considered at a high risk of bias.

RESULTS

Searches yielded 21 085 unique records, of which 25 were included in the systematic review (including 1015 people with COPD and 2229 healthy controls). Gait speed was assessed in 17 studies (usual speed: 12; fast speed: three; both speeds: two), step length in nine, step duration in seven, cadence in six, and step width in five. Five studies were considered at a high risk of bias. Low-quality evidence indicated that people with COPD walk more slowly than healthy controls at their usual speed (mean difference (MD) -19 cm·s-1, 95% CI -28 to -11 cm·s-1) and at a fast speed (MD -30 cm·s-1, 95% CI -47 to -13 cm·s-1). Alterations in other gait characteristics were not statistically significant.

CONCLUSION

Low-quality evidence shows that people with COPD walk more slowly than healthy controls, which could contribute to an increased falls risk. The evidence for alterations in spatial and temporal components of gait was inconclusive. Gait impairment appears to be an important but understudied area in COPD.

Feasibility of a Home-Based Cognitive-Physical Exercise Program in Patients With Chronic Obstructive Pulmonary Disease: Protocol for a Feasibility and Pilot Randomized Controlled Trial

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a progressive condition associated with physical and cognitive impairments contributing to difficulty in performing activities of daily living (ADLs) that require dual tasking (eg, walking and talking). Despite evidence showing that cognitive decline occurs among patients with COPD and may contribute to functional limitations and decreased health-related quality of life (HRQL), pulmonary rehabilitation continues to focus mainly on physical training (ie, aerobic and strength exercises). An integrated cognitive and physical training program compared to physical training alone may be more effective in increasing dual-tasking ability among people living with COPD, leading to greater improvements in performance of ADLs and HRQL.

OBJECTIVE

The aims of this study are to evaluate the feasibility of an 8-week randomized controlled trial of home-based, cognitive-physical training versus physical training for patients with moderate to severe COPD and derive preliminary estimates of cognitive-physical training intervention efficacy on measures of physical and cognitive function, dual task performance, ADLs, and HRQL.

METHODS

A total of 24 participants with moderate to severe COPD will be recruited and randomized into cognitive-physical training or physical training. All participants will be prescribed an individualized home physical exercise program comprising 5 days of moderate-intensity aerobic exercise (30-50 minutes/session) and 2 days of whole-body strength training per week. The cognitive-physical training group will also perform cognitive training for approximately 60 minutes, 5 days per week via the BrainHQ platform (Posit Science Corporation). Participants will meet once weekly with an exercise professional (via videoconference) who will provide support by reviewing the progression of their training and addressing any queries. Feasibility will be assessed through the recruitment rate, program adherence, satisfaction, attrition, and safety. The intervention efficacy regarding dual task performance, physical function, ADLs, and HRQL will be evaluated at baseline and at 4 and 8 weeks. Descriptive statistics will be used to summarize intervention feasibility. Paired 2-tailed t tests and 2-tailed t tests will be used to compare the changes in the outcome measures over the 8-week study period within and between the 2 randomized groups, respectively.

RESULTS

Enrollment started in January 2022. It is estimated that the enrollment period will be 24 months long, with data collection to be completed by December 2023.

CONCLUSIONS

A supervised home-based cognitive-physical training program may be an accessible intervention to improve dual-tasking ability in people living with COPD. Evaluating the feasibility and effect estimates is a critical first step to inform future clinical trials evaluating this approach and its effects on physical and cognitive function, ADL performance, and HRQL.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05140226; https://clinicaltrials.gov/ct2/show/NCT05140226.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/48666.

The prefrontal cortex hemodynamic responses to dual-task paradigms in older adults: A systematic review and meta-analysis

Background

Functional near-infrared spectroscopy (fNIRS) is a method to measure cerebral hemodynamics. Determining the changes in prefrontal cortex (PFC) hemodynamics during dual-task paradigms is essential in explaining alterations in physical activities, especially in older adults.

Aims

To systematically review and meta-analyze the effects of dual-task paradigms on PFC hemodynamics in older adults.

Methods

The search was conducted in PubMed, Scopus, and Web of Science from inception until March 2023 to identify studies on the effects of dual-task paradigms on PFC hemodynamics. The meta-analysis included variables of cerebral hemodynamics, such as oxygenated hemoglobin (HbO₂) and deoxygenated hemoglobin (HbR). The heterogeneity of the included studies was determined using the I² statistic. Additionally, subgroup analysis was conducted to compare the effects of different types of cognitive tasks.

Results

A total of 37 studies were included in the systematic review, 25 studies comprising 2224 older adults were included in the meta-analysis. Our findings showed that inhibitory control and working memory tasks significantly increased HbO₂ in the PFC by 0.53 (p < 0.01, 95% CI = 0.37 to 0.70) and 0.13 (p < 0.01, 95% CI = 0.08 to 0.18) μmol/L, respectively. Overall, HbO₂ was significantly increased during dual-task paradigms by 0.36 μmol/L (P < 0.01, 95% CI = 0.27 to 0.45). Moreover, dual-task paradigms also decreased HbR in the PFC by 0.04 (P < 0.01, 95% CI = -0.07 to -0.01). Specifically, HbR decreased by 0.08 during inhibitory control tasks (p < 0.01, 95% CI = -0.13 to -0.02), but did not change during working memory tasks.

Conclusion

Cognitive tasks related to inhibitory control required greater cognitive demands, indicating higher pfc activation during dual-task paradigms in older adults. for clinical implications, the increase in pfc oxygenated hemoglobin and decrease in pfc deoxygenated hemoglobin may help explain why older adults are more likely to fall during daily activities.

Dyspnea induced by inspiratory loading limits dual-tasking in healthy young adults

OBJECTIVES

Dyspnea is a common and multidimensional experience of healthy adults and those with respiratory disorders. Due to its neural processing, it may limit or interfere with cognition, which may be examined with a dual-task paradigm. The aim of this study was to compare single-task performance of Stroop Colour and Word Test (SCWT) or inspiratory threshold loading (ITL) to their combined dual-task performance. Secondly, whether mood was related to dyspnea or cognitive performance was also evaluated.

MATERIALS & METHODS

A virtual pre-post design examined single (SCWT and ITL) and dual-task (SCWT+ITL) performance. For ITL, a Threshold Trainer™ was used to elicit a "somewhat severe" rating of dyspnea. The SCWT required participants to indicate whether a colour-word was congruent or incongruent with its semantic meaning. The Depression, Anxiety and Stress Scale-21 (DASS-21) was completed to assess mood. Breathing frequency, Borg dyspnea rating, and breathing endurance time were ascertained.

RESULTS

Thirty young healthy adults (15F, 15M; median age = 24, IQR [23-26] years) completed the study. SCWT+ITL had lower SCWT accuracy compared to SCWT alone (98.6%, [97.1-100.0] vs 99.5%, [98.6-100.0]; p = 0.009). Endurance time was not different between ITL and SCWT+ITL (14.5 minutes, [6.9-15.0]) vs 13.7 minutes, [6.1-15.0]; p = 0.59). DASS-21 scores positively correlated with dyspnea scores during ITL (rho = 0.583, p<0.001) and SCWT+ITL (rho = 0.592, p<0.001).

CONCLUSIONS

ITL significantly reduced dual-task performance in healthy young adults. Lower mood was associated with greater perceived dyspnea during single and dual-task ITL. Considering the prevalence of dyspnea in respiratory disorders, the findings of this dual task paradigm warrant further exploration to inform dyspnea management during daily activities.

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.

Loss of Neural Automaticity Contributes to Slower Walking in COPD Patients

The physical impairments (e.g., slower walking speed) in patients with chronic obstructive pulmonary disease (COPD) have been attributed to peripheral characteristics (e.g., muscle atrophy). However, cognitive impairment may compromise motor control including walking automaticity. The objective of this study was to investigate PFC neural activity, evaluated using changes in oxygenated hemoglobin (ΔO₂Hb), during preferred paced walking (PPW) in COPD patients and age-matched controls. The ΔO₂Hb from the left and right dorsolateral PFC was measured using functional near-infrared spectroscopy. Fifteen COPD patients (age: 71 ± 8) and twenty age-matched controls (69 ± 7 years) participated. Two-way mixed ANOVA demonstrated that O₂Hb in both groups decreased during PPW from the start (quintile 1; Q1) to the end (quintile 5; Q5) in the left dorsolateral and medial PFC. Q1 was comprised of the data during the first 20% of the task, while Q5 included data collected in the last 20% of the task duration. PPW duration ranged between 30.0 and 61.4 s in the control group and between 28.6 and 73.0 s in COPD patients. COPD patients demonstrated a higher O₂Hb in Q5 compared to the negative O₂Hb in controls in the right medial and dorsolateral PFC during PPW. PPW velocity was lower in COPD patients compared to controls (1.02 ± 0.22 vs. 1.22 ± 0.14 m/s, p = 0.005). Healthy older controls exhibited automaticity during walking unlike patients with COPD. The lesser decrease in O₂Hb in COPD patients may be attributed to increased executive demands or affect-related cues (e.g., pain or dyspnea) during walking.