Test-retest reliability and four-week changes in cardiopulmonary fitness in stroke patients: evaluation using a robotics-assisted tilt table

Abstract

BackgroundExercise testing devices for evaluating cardiopulmonary fitness in patients with severe disability after stroke are lacking, but we have adapted a robotics-assisted tilt table (RATT) for cardiopulmonary exercise testing (CPET). Using the RATT in a sample of patients after stroke, this study aimed to investigate test-retest reliability and repeatability of CPET and to prospectively investigate changes in cardiopulmonary outcomes over a period of four weeks.MethodsStroke patients with all degrees of disability underwent 3 separate CPET sessions: 2 tests at baseline (TB1 and TB2) and 1 test at follow up (TF). TB1 and TB2 were at least 24 h apart. TB2 and TF were 4 weeks apart. A RATT equipped with force sensors in the thigh cuffs, a work rate estimation algorithm and a real-time visual feedback system was used to guide the patients’ exercise work rate during CPET. Test-retest reliability and repeatability of CPET variables were analysed using paired t-tests, the intraclass correlation coefficient (ICC), the coefficient of variation (CoV), and Bland and Altman limits of agreement. Changes in cardiopulmonary fitness during four weeks were analysed using paired t-tests.ResultsSeventeen sub-acute and chronic stroke patients (age 62.7 ± 10.4 years [mean ± SD]; 8 females) completed the test sessions. The median time post stroke was 350 days. There were 4 severely disabled, 1 moderately disabled and 12 mildly disabled patients. For test-retest, there were no statistically significant differences between TB1 and TB2 for most CPET variables. Peak oxygen uptake, peak heart rate, peak work rate and oxygen uptake at the ventilatory anaerobic threshold (VAT) and respiratory compensation point (RCP) showed good to excellent test-retest reliability (ICC 0.65–0.94). For all CPET variables, CoV was 4.1–14.5 %. The mean difference was close to zero in most of the CPET variables. There were no significant changes in most cardiopulmonary performance parameters during the 4-week period (TB2 vs TF).ConclusionsThese findings provide the first evidence of test-retest reliability and repeatability of the principal CPET variables using the novel RATT system and testing methodology, and high success rates in identification of VAT and RCP: good to excellent test-retest reliability and repeatability were found for all submaximal and maximal CPET variables. Reliability and repeatability of the main CPET parameters in stroke patients on the RATT were comparable to previous findings in stroke patients using standard exercise testing devices. The RATT has potential to be used as an alternative exercise testing device in patients who have limitations for use of standard exercise testing devices.

Measurement properties of maximal cardiopulmonary exercise tests protocols in persons after stroke: A systematic review

“…A recent study has found the determination of VAT to have good reliability (ICC3,2 = 0.87, 95% CI 0.80-0.95) in persons after stroke (52). RCP has been shown to be identifiable in 96% of persons after stroke and to have reasonably good reliability (ICC3,1 = 0.77 (95% CI 0.24, 0.87)) (53).…”

Physiological determinants of the increase in oxygen consumption during exercise in individuals with stroke

“…Second, we used a recumbent cycle ergometer. A treadmill [6], a total-body recumbent steppe [43], a robotics-assisted tilt table [30], and an arm crank ergometer [31] are also used to assess cardiorespiratory fitness in individuals with stroke. Further studies are warranted to examine whether the major physiological determinant of the increase in V̇O 2 during exercise differs with the exercise devices.…”

“…The ventilatory threshold was determined using a combination of the following criteria: (1) the point where the ventilatory equivalent of oxygen reaches its minimum or starts to increase, without an increase in the ventilatory equivalent of carbon dioxide; (2) the point at which the end-tidal oxygen fraction reaches a minimum or starts to increase, without a decline in the end-tidal carbon dioxide fraction; and (3) the point of deflection of carbon dioxide output versus V̇O 2 [29]. The first two methods were prioritized in case the three methods presented different results [30, 31]. The ventilatory threshold was determined as an average based on the values provided by two independent raters (NI and YS), when the difference in the V̇O 2 values of the corresponding points as determined by the two raters was less than 100 mL·min −1 [31, 32].…”

“…The ventilatory threshold was determined as an average based on the values provided by two independent raters (NI and YS), when the difference in the V̇O 2 values of the corresponding points as determined by the two raters was less than 100 mL·min −1 [31, 32]. In case of any discrepancy, a third experienced rater (KO) judged the point, and the ventilatory threshold was taken as the average of the two closest values [30, 31].…”

Early Incremental Mobilization in the Practice of Neurorehabilitation of Ischemic Stroke

“…Як наслідок, стала можливою вертикалізація з перших днів після інсульту. Наступним кроком стала розробка роботизованих тренажерів, в яких вертикалізація поєднується з пасивним або активним тренуванням ходьби [13]. Втім, в умовах обмежених ресурсів системи охорони здоров'я застосування апаратної вертикалізації при ГПМК залишається казуїстикою.…”