Energy expenditure and cost of walking and stair climbing in individuals with chronic stroke

Oxygen uptake efficiency slope in community-dwelling ambulant stroke survivors during walking and stair climbing: a cross-sectional study

BACKGROUND

Oxygen uptake efficiency slope during submaximal tests has been proposed as a more appropriate measure of aerobic capacity after suffering a stroke, since some individuals cannot tolerate maximal exercise testing. However, it has not yet been investigated whether the oxygen uptake efficiency slope is able to differentiate between healthy individuals and those who have suffered a stroke.

OBJECTIVES

To compare the oxygen uptake efficiency slope during walking and stair climbing between stroke survivors and age- and sex-matched healthy controls.

METHODS

This is a cross-sectional study in which 18 individuals who had suffered a stroke (stroke survivors) and 18 healthy controls matched for sex and age were included. Oxygen consumption and minute ventilation were collected breath-by-breath during walking (6-min Walk Test) and stair climbing. The oxygen uptake efficiency slope was estimated by the slope of the line obtained through linear regression.

RESULTS

The stroke survivors had a lower oxygen uptake efficiency slope during the 6-min Walk Test than the healthy controls (MD 498, 95% CI 122 to 873, p = .01). The between-group difference for the Stair Test was smaller and not statistically significant (MD 349, 95%CI -73 to 772, p = .10).

CONCLUSIONS

Stroke survivors had lower oxygen uptake efficiency slope during the performance of the 6-min Walk Test when compared to sex- and age-matched healthy controls. This suggests that stroke survivors have worse cardiopulmonary capacity.

Habitual walking speed and fatigue explain self-reported functional capacity after stroke

INTRODUCTION

Individuals after stroke present several motor impairments, which reduced the functional capacity. The understanding of modifiable factors which are related to functional capacity in individuals with chronic stroke could better direct clinical practice. However, the mechanisms that could influence functional capacity in individuals with chronic stroke are not fully understood.

OBJECTIVE

This study aimed to determine which modifiable variables would best predict self-reported functional capacity after stroke.

DESIGN

Cross-sectional.

SETTING

Research laboratory setting.

PARTICIPANTS

Ninety two individuals with chronic stroke, who had a mean age of 60 (SD 13) years and a time since the onset of the stroke of 52 (67) months.

MAIN OUTCOME MEASURES

Regression analysis of cross-sectional data was used to investigate whether body mass index, habitual walking speed, physical activity levels, fatigue, motor recovery, walking distance, and residual strength deficits of the lower limb muscles would predict self-reported functional capacity.

RESULTS

Habitual walking speed alone explained 48% of the variance in functional capacity. When fatigue was included in the model, the explained variance increased to 55%.

CONCLUSIONS

Habitual walking speed and fatigue were significant predictors of self-reported functional capacity in individuals with chronic stroke. These individuals may increase their functional capacity with interventions aimed at increasing walking speed and reducing fatigue.

Accuracy of gait and posture classification using movement sensors in individuals with mobility impairment after stroke

Background: Stroke leads to motor impairment which reduces physical activity, negatively affects social participation, and increases the risk of secondary cardiovascular events. Continuous monitoring of physical activity with motion sensors is promising to allow the prescription of tailored treatments in a timely manner. Accurate classification of gait activities and body posture is necessary to extract actionable information for outcome measures from unstructured motion data. We here develop and validate a solution for various sensor configurations specifically for a stroke population.

Methods: Video and movement sensor data (locations: wrists, ankles, and chest) were collected from fourteen stroke survivors with motor impairment who performed real-life activities in their home environment. Video data were labeled for five classes of gait and body postures and three classes of transitions that served as ground truth. We trained support vector machine (SVM), logistic regression (LR), and k-nearest neighbor (kNN) models to identify gait bouts only or gait and posture. Model performance was assessed by the nested leave-one-subject-out protocol and compared across five different sensor placement configurations.

Results: Our method achieved very good performance when predicting real-life gait versus non-gait (Gait classification) with an accuracy between 85% and 93% across sensor configurations, using SVM and LR modeling. On the much more challenging task of discriminating between the body postures lying, sitting, and standing as well as walking, and stair ascent/descent (Gait and postures classification), our method achieves accuracies between 80% and 86% with at least one ankle and wrist sensor attached unilaterally. The Gait and postures classification performance between SVM and LR was equivalent but superior to kNN.

Conclusion: This work presents a comparison of performance when classifying Gait and body postures in post-stroke individuals with different sensor configurations, which provide options for subsequent outcome evaluation. We achieved accurate classification of gait and postures performed in a real-life setting by individuals with a wide range of motor impairments due to stroke. This validated classifier will hopefully prove a useful resource to researchers and clinicians in the increasingly important field of digital health in the form of remote movement monitoring using motion sensors.

Development of a prediction model for ascent and descent staircase independence during the sub-acute rehabilitation phase in individuals post-stroke

BACKGROUND

Nearly half of individuals post-stroke are dependent in their daily activities. The ability to ascend and descend stairs is an important component of independence in the community.

OBJECTIVE

To predict the future ability of post-stroke individuals at the beginning of the sub-acute rehabilitation phase to achieve ascending and descending staircase independence.

METHODS

36 participants were recruited for the study.

OUTCOME MEASURES

independence in ascending and descending stairs up to the end of the sub-acute rehabilitation phase. Predictive measures included the knee extensors Muscles Strength (MS), the seated Modified Functional Reach (MFR) test, and Heart Rate Variability (HRV) measures. Logistic and Cox regression were used.

RESULTS

Twenty-four participants (66.7%) completed the sub-acute rehabilitation phase being independent in ascending and descending stairs. MFR was the best predictor (R2 = 0.18), and with MS the best predictors for the time (days) to achieve this goal during the sub-acute rehabilitation. HRV measure was found to be the main predictor of the staircase ascent model (R2 = 0.32), and MFR the best predictor for the descent model (R2 = 0.24).

CONCLUSIONS

Balance performance is the main predictor of independence in ascending and descending stairs. Improving this component during the sub-acute rehabilitation phase might be reflected in achieving staircase independence.

The Use of Samsung Health and ECG M-Trace Base II Applications for the Assessment of Exercise Tolerance in the Secondary Prevention in Patients after Ischemic Stroke

Background and objectives: The aim of the study was to use the mobile application Samsung Health for the assessment of parameters of exercise tolerance and the ECG (electrocardiogram) M-Trace Base II for the assessment of cardiological parameters. Materials and Methods: The measurements were conducted during rest and after performing SMWT (Six Minute Walk Test) and SCT (Stair Climb Test) in 26 patients after ischemic stroke (IS) and 26 healthy individuals. Results: In the SMWT, the post-stroke group (SG) walked a shorter distance (p < 0.001), achieving lower mean gait velocity (p < 0.001) and lower maximum gait velocity (p = 0.002). In the SCT, SG achieved a lower mean gait velocity (p < 0.001) and lower maximum gait velocity (p < 0.001) when compared to the control group (CG). In SG, myocardial ischemia in ECG was noted in four patients after SMWT and in three patients following SCT. Both in SG and in CG the increase in SBP (systolic blood pressure) value measured after SMWT and SCT compared to at rest (p < 0.001) was observed. In SG, in the compared ratios rest to SMWT and SCT as well as SMWT to SCT, there was an increase in HR (heart rate) (p < 0.001). Conclusions: ECG M-Trace Base II and Samsung Health are mobile applications that can assess cardiological parameters and exercise tolerance parameters in patients after IS, so they can be used to plan the intensity of exercise in rehabilitation programs.

Upper Limb Energy Demand During Unilateral Arm Crank Submaximal Exercise Testing in Individuals With Chronic Stroke

OBJECTIVE

To investigate upper limb (UL) energy demand during unilateral arm crank submaximal exercise testing in individuals with stroke compared with healthy controls and the relationship between UL energy demand and UL activity in individuals with stroke.

DESIGN

Cross-sectional, observational study.

SETTING

Research laboratory.

PARTICIPANTS

Individuals with chronic stroke (n=14) and controls (n=12), matched for age, sex, and body mass index (N=26).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

UL energy demand was measured as peak oxygen consumption (V̇o₂)/peak load during unilateral arm crank submaximal exercise testing. UL activity was measured using the Box and Block Test (BBT) and Grooved Pegboard Test (GPT).

RESULTS

The energy demand of the paretic side compared with the nonparetic side of the stroke group was 0.43 mL/kg/min/W (95% confidence interval, 0.03-0.83, P=.005) greater than the dominant compared with the nondominant side of the control group. The median difference between sides in peak V̇o₂/peak load was 52% for the group with stroke compared with 11% for the control group. Positive correlations between the median percentage difference between the paretic and the nonparetic side of peak V̇o₂/peak load and BBT were 0.72 (P=.004) and of V̇o₂/peak load and GPT was 0.77 (P=.002).

CONCLUSIONS

The higher energy demand of the paretic UL during unilateral arm crank submaximal exercise testing than the nonparetic and both UL of the controls together with the strong relationship between energy demand and UL activity suggest that the energy demand of the paretic UL has the potential to affect real-life UL activity after stroke.

Energy Cost During the 6-Minute Walk Test and Its Relationship to Real-World Walking After Stroke: A Correlational, Cross-Sectional Pilot Study

BACKGROUND

After experiencing stroke, individuals expend more energy walking than people who are healthy. However, among individuals who have experienced stroke, the correlation between the energy cost of walking, as measured by validated tests (such as the 6-minute walk test), and participation in walking, as measured by more sensitive tools (such as an ambulatory activity monitor), remains unknown.

OBJECTIVE

The main objective of this study was to determine whether the energy cost of walking is correlated with participation in walking.

DESIGN

This study was a correlational, cross-sectional pilot study.

METHODS

Data from 23 participants who had experienced chronic stroke were analyzed. On the first day, data on oxygen uptake were collected using a portable metabolic system while participants walked during the 6-minute walk test. Then, the ambulatory activity monitor was placed on the participants' nonparetic ankle and removed 9 days later. The energy cost of walking was calculated by dividing the mean oxygen uptake recorded during the steady state by the walking speed.

RESULTS

The energy cost of walking was correlated with the following: the number of steps (Spearman rank correlation coefficient [rs] = -0.59); the percentage of time spent in inactivity (rs = 0.48), low cadence (rs = 0.67), medium cadence (rs = -0.56), high cadence (rs = -0.65), and the percentages of steps taken at low cadence (rs = 0.65) and high cadence (rs = -0.64).

LIMITATIONS

Individuals who were physically inactive, convenience sampling, and a small sample size were used in this study.

CONCLUSIONS

Higher energy costs of walking were associated with fewer steps per day and lower cadence in real-world walking in individuals who had experienced stroke.

Prevalence of dyspnea after stroke: a telephone-based survey

OBJECTIVE

Dyspnea is a relevant outcome to be taken into consideration during stroke rehabilitation. Prevalence, severity, and effects of this condition on individuals with stroke remain uncertain. This study investigated the prevalence and severity of dyspnea after a stroke, as well the associations between dyspnea, activity limitations, and participation restrictions.

METHODS

A telephone-based survey was conducted with 285 individuals with stroke. The survey included information regarding the onset and severity of the dyspnea, activity limitations, and participation restrictions. Prevalence of dyspnea was reported as percentage of individuals who had the symptom. Chi-square tests were used to investigate the associations between dyspnea, activity limitations, and participation restrictions. Relative risks and respective 95% confidence intervals were calculated.

RESULTS

Out of the 285 participants, 124 (44%) reported having dyspnea after stroke. Severe symptoms were reported by 51% of the participants with dyspnea. In addition, dyspnea limited activity and restricted social participation in 85% and 49% of the participants, respectively. Dyspnea was significantly correlated with activity limitations (r=0.87; 95% CI 0.82-0.92; p<0.01) and participation restrictions (r=0.53; 95% CI 0.46-0.62; p<0.01). The analyses indicated that individuals with dyspnea were more likely to report that it limited their activities (RR: 6.5; 95% CI 4.3-9.9) and restricted social participation (RR: 1.7; 95% CI 1.5-2.0).

CONCLUSIONS

Dyspnea is an important symptom after stroke and showed to be associated with activity limitations and restrictions in community participation. Earlier detection of dyspnea in people with stroke, followed by appropriate management, is strongly recommended and has the potential to improve activity and social participation.

Validity of the accelerometer and smartphone application in estimating energy expenditure in individuals with chronic stroke

OBJECTIVE

To examine the concurrent validity of the GT3X^® ActiGraph accelerometer and Google Fit^® smartphone application in estimating energy expenditure in people who had suffered a stroke, during fast overground walking.

METHODS

Thirty community-dwelling stroke individuals walked on a 10-meter hallway over 5min at their fastest speeds, wearing a Cortex Metamax 3B^® ergoespirometer, a GT3X^® ActiGraph accelerometer, and a smartphone with the Google Fit^® application. Pearson correlation coefficients were calculated to verify the associations between measures of energy expenditure, in kilocalories (kcal), estimated by both devices and those obtained with the Cortex Metamax 3B^® ergoespirometer (gold-standard measure).

RESULTS

Fair association was found between the energy expenditure values estimated from the combined formula of the ActiGraph GT3X^® and those obtained with the gold-standard measure (r=0.37; p=0.04). No significant associations were found between the energy expenditure values estimated by the Google Fit^® application and those provided by the gold-standard measure.

CONCLUSIONS

The findings demonstrated that both the GT3X^®ActiGraph accelerometer and the Google Fit^® smartphone application do not provide valid measures of energy expenditure in chronic stroke individuals during fast overground walking.

Relationship between oxygen cost of walking and level of walking disability after stroke: An experimental study

BACKGROUND AND PURPOSE

Since physical inactivity is the major risk factor for recurrent stroke, it is important to understand how level of disability impacts oxygen uptake by people after stroke. This study investigated the nature of the relationship between level of disability and oxygen cost in people with chronic stroke.

METHODS

Level of walking disability was measured as comfortable walking speed using the 10-m Walk Test reported in m/s with 55 ambulatory people 2 years after stroke. Oxygen cost was measured during 3 walking tasks: overground walking at comfortable speed, overground walking at fast speed, and stair walking at comfortable speed. Oxygen cost was calculated from oxygen uptake divided by distance covered during walking and reported in ml∙kg^-1 ∙m^-1 .

RESULTS

The relationship between level of walking disability and oxygen cost was curvilinear for all 3 walking tasks. One quadratic model accounted for 81% (95% CI [74, 88]) of the variance in oxygen cost during the 3 walking tasks: [Formula: see text] DISCUSSION: The oxygen cost of walking was related the level of walking disability in people with chronic stroke, such that the more disabled the individual, the higher the oxygen cost of walking; with oxygen cost rising sharply as disability became severe. An equation that relates oxygen cost during different walking tasks according to the level of walking disability allows clinicians to determine oxygen cost indirectly without the difficulty of measuring oxygen uptake directly.