Energy cost of obstacle crossing in stroke patients

Does Accelerometry at the Centre of Mass Accurately Predict the Gait Energy Expenditure in Patients with Hemiparesis?

BACKGROUND

The aim of this study was to compare energy expenditure (EE) predicted by accelerometery (EEAcc) with indirect calorimetry (EEMETA) in individuals with hemiparesis.

METHODS

Twenty-four participants (12 with stroke and 12 healthy controls) performed a six-minute walk test (6MWT) during which EEMETA was measured using a portable indirect calorimetry system and EEACC was calculated using Bouten's equation (1993) with data from a three-axis accelerometer positioned between L3 and L4.

RESULTS

The median EEMETA was 9.85 [8.18;11.89] W·kg-1 in the stroke group and 5.0 [4.56;5.46] W·kg-1 in the control group. The median EEACC was 8.57 [7.86;11.24] W·kg-1 in the control group and 8.2 [7.05;9.56] W·kg-1 in the stroke group. The EEACC and EEMETA were not significantly correlated in either the control (p = 0.8) or the stroke groups (p = 0.06). The Bland-Altman method showed a mean difference of 1.77 ± 3.65 W·kg-1 between the EEACC and EEMETA in the stroke group and -2.08 ± 1.59 W·kg-1 in the controls.

CONCLUSIONS

The accuracy of the predicted EE, based on the accelerometer and the equations proposed by Bouten et al., was low in individuals with hemiparesis and impaired gait. This combination (sensor and Bouten's equation) is not yet suitable for use as a stand-alone measure in clinical practice for the evaluation of hemiparetic patients.

Shape of an obstacle affects the mediolateral trajectory of the lower limb during the crossing process

In previous studies involving obstacle crossing, vertical foot clearance has been used as an indicator of the risk of contact. Under normal circumstances, individuals do not always cross over obstacles with the same height on both sides, and depending on the shape of the obstacle, the risk of contact may differ depending on the foot elevation position. Therefore, we investigated whether task-related control of the mediolateral foot position is adapted to the shape of the obstacle. Sixteen healthy young adults performed a task in which they crossed over two obstacles with different shapes while walking: a trapezoidal obstacle and a rectangular obstacle, as viewed from the frontal plane. It was shown that when crossing over a trapezoidal obstacle, the participants maintained foot clearance by controlling the mediolateral direction, which chose the height that needed to be cleared. The results of this study suggest that the lower limb movements that occur during obstacle crossing are controlled not only in the vertical direction but also in the mediolateral direction by adjusting the foot trajectory to reduce the risk of contact. It was demonstrated that control was not only based on the height of the obstacle directly under the foot but also in the foot mediolateral direction, considering the shape of the entire obstacle, including the opposite limb.

Identify the Alteration of Balance Control and Risk of Falling in Stroke Survivors During Obstacle Crossing Based on Kinematic Analysis

This study aims to compare the differences in the kinematic characteristics of crossing obstacles of different heights between stroke survivors and age-matched healthy controls and to identify the changes of balance control strategy and risk of falling. Twelve stroke survivors and twelve aged-matched healthy controls were recruited. A three-dimensional motion analysis system and two force plates were used to measure the kinematic and kinetic data during crossing obstacles with heights of 10, 20, and 30% leg length. The results showed that during leading and trailing limb clearance, (AP) center of mass (COM) velocities of the stroke group were smaller than those of the healthy controls for all heights. The decreased distances between COM and center of pressure (COP) in the AP direction during the both trailing and leading limb support period were also found between stroke survivors and healthy controls for all heights. The COM velocity and COM-COP distance significantly correlated with the lower limb muscle strength. In addition, stroke survivors showed greater lateral pelvic tilt, greater hip abduction, and larger peak velocity in the medio-lateral (ML) direction. There was a positive correlation between the COM-COP distance in the AP direction and the clinical scales. These results might identify that the stroke survivors used a conservative strategy to negotiate the obstacles and control balance due to a lack of muscle strength. However, the abnormal patterns during obstacle crossing might increase the risk of falling. The findings could be used to design specific rehabilitation training programs to enhance body stability, reduce energy cost, and improve motion efficiency.

Botulinum Toxin Type A for the Treatment of Lower Limb Spasticity after Stroke

Post-stroke lower limb spasticity impairs balance and gait leading to reduced walking speed, often increasing wheelchair use and caregiver burden. Several studies have shown that appropriate treatments for lower limb spasticity after stroke include injections of botulinum toxin type A (BoNT-A), phenol or alcohol, surgical correction and a rehabilitation program. In the present article, we review the safety and effectiveness of BoNT-A for the treatment of lower limb spasticity after stroke, with a focus on higher doses of BoNT-A. The cumulative body of evidence coming from the randomized clinical trials and open-label studies selected in the article suggest BoNT-A to be safe and efficacious in reducing lower limb spasticity after stroke. Studies of high doses of BoNT-A also showed a greater reduction of severe post-stroke spasticity. In stroke survivors with spasticity of the ankle plantar-flexor muscles, a combined approach between surgery and BoNT-A can be indicated. However, controversy remains about improvement in motor function relative to post-stroke spasticity reduction after BoNT-A treatment.

Effects of a 6-month self-rehabilitation programme in addition to botulinum toxin injections and conventional physiotherapy on limitations of patients with spastic hemiparesis following stroke (ADJU-TOX): protocol study for a randomised controlled, investigator blinded study

INTRODUCTION

Home-based self-rehabilitation programmes combined with botulinum toxin injections (BTIs) appear to be a relevant approach to increase the recommended intensive rehabilitation of patients with spasticity following a stroke. The literature highlights a lack of evidence of beneficial effects of this adjuvant therapy to reduce limitations of patients with stroke. The aim of this study is to assess the effects of a 6-month self-rehabilitation programme in adjunction to BTI, in comparison with BTI alone, to reduce limitations of patients with spasticity following a stroke.

METHODS AND ANALYSIS

220 chronic patients will participate to this multicentre, prospective, randomised, controlled, assessor blinded study. All patients will benefit from two successive BTI (3 months apart), and patients randomised in the self-rehabilitation group will perform in adjunction 6 months of self-rehabilitation at home. All patients continue their conventional physiotherapy. The main outcome is the primary treatment goal (PTG), which will be determined jointly by the patient and the medical doctor using Goal Attainment Scaling. Impairments and functions, quality of life, mood and fatigue will be assessed. Botulinum toxin will be injected into the relevant muscles according to the PTG. Patients in the self-rehab group will be taught the self-rehabilitation programme involving respectively 10 min of stretching, 10 min of strengthening and 10 min of task-oriented exercises, corresponding to their PTG. Compliance to the self-rehabilitation programme will be monitored.

ETHICS AND DISSEMINATION

Patients will sign written informed consent. Ethical approval was obtained from ethics committee. The results will be disseminated in a peer-reviewed journal and presented at international congresses. The results will also be disseminated to patients.

TRIAL REGISTRATION NUMBER

NCT02944929.

Oxygen uptake during functional activities after stroke-Reliability and validity of a portable ergospirometry system

Background

People with stroke have a low peak aerobic capacity and experience increased effort during performance of daily activities. The purpose of this study was to examine test-retest reliability of a portable ergospirometry system in people with stroke during performance of functional activities in a field-test. Secondary aims were to examine the proportion of oxygen consumed during the field-test in relation to the peak-test and to analyse the correlation between the oxygen uptake during the field-test and peak-test in order to support the validity of the field-test.

Methods

With simultaneous measurement of oxygen consumption, participants performed a standardized field-test consisting of five activities; walking over ground, stair walking, stepping over obstacles, walking slalom between cones and from a standing position lifting objects from one height to another. All activities were performed in self-selected speed. Prior to the field-test, a peak aerobic capacity test was performed. The field-test was repeated minimum 2 and maximum 14 days between the tests. ICC_2,1 and Bland Altman tests (Limits of Agreement, LoA) were used to analyse test-retest reliability.

Results

In total 31 participants (39% women, mean (SD) age 54.5 (12.7) years and 21.1 (14.3) months’ post-stroke) were included. The ICC_2,1 was ≥ 0.80 for absolute V̇O₂, relative V̇O₂, minute ventilation, CO₂, respiratory exchange ratio, heart rate and Borgs rating of perceived exertion. ICC_2,1 for total time to complete the field-test was 0.99. Mean difference in steady state V̇O₂ during Test 1 and Test 2 was -0.40 (2.12) The LoAs were -3.75 and 4.51. Participants spent 60.7% of their V̇O₂peak performing functional activities. Correlation between field-test and peak-test was 0.689, p = 0.001 for absolute and 0.733, p = 0.001 for relative V̇O₂.

Conclusions

This study presents first evidence on reliability of oxygen uptake during performance of functional activities after stroke, showing very good test-retest reliability. The secondary analysis showed that the amount of energy spent during the field-test relative to the peak-test was high and the correlation between the two test was good, supporting the validity of this method.