BRIDGING ACTIVITIES AS A MODE OF STRESS TESTING FOR THE HEMIPLEGICS
Tetsuya Tsuji, Meigen Liu, Kazuto Tsujiuchi, Youichiro Aoyagi, Naoichi Chino
Saitama Prefecture General Rehabilitation Center and Keio University, Saitama & Tokyo, Japan
[Objectives] The objectives are to establish a stress testing protocol for the hemiplegics using bridging activities (BA), and to compare their cardiopulmonary responses to normal controls.
[Methods] 1) Preliminary study: 5 hemiplegics performed BA at the rate of 3 repetitions per min. (RPM) for 4 min., and the rate was increased to 6, 12, 18, 24 and 30 RPM every 4 min. Oxygen uptake (VO2) and heart rate (HR) were continuously measured with a Benchmark Exercise System-TM. 2) Comparison to controls: 15 hemiplegics (58.3±7.4 yrs), 5 young healthy controls (27.6±2.3 yrs) and 5 middle-aged controls (55.2±12.3 yrs) performed the BA protocol, and their cardiopulmonary responses were compared. 3) Reproducibility: We repeated the testing twice within a week in 5 hemiplegics and 10 controls, and calculated intracorrelation coefficients (ICC) of VO2. HR and slope of the regression line between VO2. and HR (HR-O2. coefficient). 4) Longitudinal changes: We compared the exercise responses to BA at the start and the end of 3-to 4-months of rehabilitation programs in 10 hemiplegics.
[Results] 1) The BA protocol was applicable to most hemiplegics. 2) The relationship between HR and VO2, were linear, and HR-O2. coefficient were significantly lower in the hemiplegics. 3) The ICCs were over 0.8 for the exercise parameters, indicating satisfactory reproducibility. 4) HR decreased for the same stress level and I-tR-O2. coefficient increased, indicating improved fitness level.
[Conclusion] The BA protocol is a useful mode of stressing the hemiplegics. The linearity between HR and VO2 with this protocol allows us to use the indices of fitness obtained from this relationship.
USE OF CRUTCH FORCE AND PCI TO ASSESS ENERGY COST OF PARAPLEGIC GAIT
M.J. IJzerman, G. Baardman, M.A. van't Hof, H.J. Hermens, P.H. Veltink
Purpose: Determination of validity, reproducibility and responsiveness of physiological cost index (PCI) and crutch forces to predict energy expenditure during paraplegic walking.
Methods: Crutch Forces (peak force and force time integral) as well as PCI were measured in order to determine whether these parameters can be used to estimate oxygen uptake during paraplegic walking. Sensitivity to change (ability to detect longitudinal changes) as well as cross-sectional validity (ability to discriminate between patients) were studied. Reproducibility and responsiveness were assessed to determine the usefulness of the parameters in evaluative studies.
Results: None of the variables were found to be cross-sectionally valid. PCI appeared to be sensitive to detect small differences in oxygen cost (ml.m-1.kg-1). Correlation with the gold standard was approximately 0.86 (95 % CI: [0.43, 0.98]]). Smallest detectable difference (i.e. difference exceeds measurement error) was approximately 30 % and 40 % for oxygen cost and PCI respectively. In order to detect a clinically relevant difference of 20 % in PCI and oxygen cost, 14 and 8 subjects respectively should be included in such a comparative trial.
Conclusions: PCI is an efficient and sensitive method to detect small differences in oxygen cost during paraplegic walking. However, oxygen cost is more responsive to detect clinically relevant differences.