Clinimetric properties of the pressure biofeedback unit method for estimating respiratory pressures

Reliability and Minimal Detectable Change for Respiratory Muscle Strength Measures in Individuals With Multiple Sclerosis

BACKGROUND AND PURPOSE

The test-retest reliability and minimal detectable changes (MDCs) for respiratory muscle strength measures have not been determined in individuals with multiple sclerosis (MS). This study determined the test-retest reliability and MDCs for specific respiratory muscle strength measures, as well as their associations with health-related quality of life (HRQoL), disability, dyspnea, and physical activity level measures in this population. In addition, the study examined differences in respiratory muscle strength between different degrees of disability.

METHODS

Sixty-one individuals with MS attended 2 appointments separated by 7 to 10 days. Respiratory muscle strength was evaluated by maximal inspiratory and expiratory pressures (MIP/MEP), HRQoL by EuroQol-5D-5L (index and visual analog scale [EQ-VAS]), disability by the Expanded Disability Status Scale, dyspnea by the Medical Research Council scale, and physical activity levels by the International Physical Activity Questionnaire.

RESULTS

Respiratory muscle strength measures had excellent test-retest reliability (ICC ≥ 0.92). The MDC for MIP is 15.42 cmH 2 O and for MEP is 17.84 cmH 2 O. Participants with higher respiratory muscle strength (MIP/MEP cmH 2 O and percentage of predicted values) had higher HRQoL ( r = 0.54-0.62, P < 0.01, EQ-5D-5L index; r = 0.30-0.42, P < 0.05, EQ-VAS); those with higher expiratory muscle strength (cmH 2 O and percentage of predicted values) had lower levels of disability ( r ≤ -0.66) and dyspnea ( r ≤ -0.61). There were differences in respiratory muscle strength between different degrees of disability ( P < 0.01; d ≥ 0.73).

DISCUSSION AND CONCLUSION

Respiratory muscle strength measures provide excellent test-retest reliability in individuals with MS. MDCs can be interpreted and applied in the clinical setting. Low respiratory muscle strength can contribute to a poor HRQoL; specifically, expiratory muscle strength appears to have the strongest influence on disability status and dyspnea.

Mawangdui-Guidance Qigong Exercise for patients with chronic non-specific low back pain: Study protocol of a randomized controlled trial

Introduction

Worldwide, there is a high frequency of chronic non-specific low back pain (CNLBP), which is a significant public health concern. The etiology is complicated and diverse, and it includes a number of risk factors such as diminished stability and weak core muscles. Mawangdui-Guidance Qigong has been employed extensively to bolster the body in China for countless years. However, the effectiveness of treating CNLBP has not been assessed by a randomized controlled trial (RCT). In order to verify the results of the Mawangdui-Guidance Qigong Exercise and examine its biomechanical mechanism, we intend to perform a randomized controlled trial.

Methods and analysis

Over the course of 4 weeks, 84 individuals with CNLBP will be randomly assigned to receive either Mawangdui-Guidance Qigong Exercise, motor control exercise, or medication (celecoxib). Electromyographic data, including muscle activation time, iEMGs, root mean square value (RMS) and median frequency (MF), will be the main outcomes. The Japanese Orthopedic Association (JOA) Score, the Mcgill Pain Questionnaire (MPQ), beta-endorphin, and substance P are examples of secondary outcomes. At the start of treatment and 4 weeks later, all outcomes will be evaluated. SPSS version 20.0 (SPSS Inc., Chicago, IL, USA) will be used for all of the analysis.

Discussion

The prospective findings are anticipated to offer an alternative treatment for CNLBP and provide a possible explanation of the mechanism of Mawangdui-Guidance Qigong Exercise on CNLBP.

Ethics and dissemination

The Sichuan Regional Ethics Review Committee on Traditional Chinese Medicine has given the study approval (Approval No. 2020KL-067). It has also registered at the website of China Clinical Trial Center Registration. The application adheres to the Declaration of Helsinki’s tenets (Version Edinburgh 2000). Peer-reviewed papers will be used to publicize the trial’s findings.

Trial registration number

ClinicalTrials.gov, identifier ChiCTR2000041080.

Maximal inspiratory pressure is associated with health-related quality of life and is a reliable method for evaluation of patients on hemodialysis

OBJECTIVE

To evaluate the association between Maximal Inspiratory Pressure (MIP) and health-related quality of life (HRQoL) and to verify the reliability of the MIP in patients on hemodialysis.

METHODS

In a repeated-measures design, patients on hemodialysis performed MIP and specific HRQoL questionnaire (trial 1). The MIP was repeated after 6 to 8 weeks (trial 2) and reliability was assessed using Intra-class Correlation Coefficient. Standard Error of Measurement and Minimal Detectable Change scores were calculated.

RESULTS

Sixty-one individuals (68.9% men) were evaluated in trial 1. MIP was associated with specific domains "Symptoms" (r = 0.45; R² adjusted = 0.192) and the kidney disease component summary (r = 0.38; R² adjusted = 0.138). Regarding generic domains, the MIP was associated with "Physical Functioning" (r = 0.57; R² adjusted = 0.375) and Physical component summary (r = 0.47; R² adjusted = 0.258). Thirty-three patients were randomly selected to perform a second MIP test (trial 2). The Intra-class Correlation Coefficient was 0.94 (95%CI 0.88-0.97). By Bland-Altman analysis, the bias was 3.2 cmH2O, which represents a difference of 3.7%. The Standard Error of Measurement and Minimal Detectable Change for MIP were 5.9 cmH2O and 13.8 cmH2O, respectively.

CONCLUSION

The MIP is a reliable test, associated with physical domains of HRQoL in patients on hemodialysis. Thus, it is a useful method for respiratory evaluation in this population.

Trunk muscle activity during pressure feedback monitoring among individuals with and without chronic low Back pain

BACKGROUND

Pressure biofeedback unit (PBU) is a widely used non-invasive device to assist core muscle training by providing pressure feedback. The aim this study was to compare the muscle activities of transverse abdominis (TA) and multifidus (MF) at different target pressures (50, 60 and 70 mmHg) of PBU between individuals with and without cLBP.

METHODS

Twenty-two patients with chronic LBP (cLBP) and 24 age matched healthy individuals were recruited. Electromyography (EMG) signals were recorded from the TA and MF muscles while the TA and MF were contracted to achieve PBU pressure value of 50, 60 and 70 mmHg in random order. The average EMG amplitude (AEMG) of 3 replicate trials was used in the analysis after normalization to %MVIC. %MVIC is defined as the mean of the three AEMG divided by the AEMG of MVIC. Two-way ANOVA was performed to assess the effects of groups (healthy and cLBP) and the three different target pressures of PBU. Independent sample t-test was conducted to compare between the two groups. Spearman's correlation analysis was performed in the cLBP group to determine potential correlations between EMG activity, NPRS and ODI.

RESULTS

The %MVIC of the TA and MF in the cLBP group were higher than the control group at each pressure value (P<0.05). During maximal voluntary isometric contraction (MVIC) of TA and MF, compared with healthy groups, cLBP subjects showed a decrease (TA mean = 47.61 μV; MF mean = 42.40 μV) in EMG amplitudes (P ≤ 0.001). The MVIC of MF was negatively correlated with Numerical Pain Rating Scale (r = - 0.48, P = 0.024) and Oswestry Disability Index (r = - 0.59, P = 0.004).

CONCLUSIONS

We measured the trunk muscles activities at different PBU pressure values, which allows the individual to estimate trunk muscle contraction via PBU. Clinicians may be able to confer the data obtained through EMG recordings to adjust the exercise intensity of PBU training accordingly.

Evaluation of Postural Stability and Transverse Abdominal Muscle Activity in Overweight Post-Stroke Patients: A Prospective, Observational Study

PURPOSE

Post-stroke hemiparesis has a significant impact on postural stability. The transversus abdominis (TrA) muscle contributes to the stability of the spine. The aim was to assess both the postural stability and the activity of the TrA muscle in overweight post-stroke patients.

METHODS

A group of 56 participants (61.12 ± 11.5 years) was divided into the study group (n=28 post-stroke patients, 63.7 ± 10.9 years) and control group (n= 23 healthy participants (58.5 ± 12.2 years). The Berg Balance Scale (BBS) and the Timed Up and Go Test (TUG) were used to evaluate postural stability and risk of falls. The Pressure Bio-Feedback Stabilizer (PBFS) device was used to assess functional stability.

RESULTS

Stroke had a significantly negative effect on the BBS (p < 0.001) and TUG (p = 0.001). The older age negatively affected the BBS (p = 0.001), TUG (p = 0.017), and the TrA muscle activity (p = 0.017). Higher values of body mass index (BMI) negatively affected the BBS (p = 0.028), however there were no changes of TUG results (p = 0.141), and the TrA muscle activity (p = 0.808). Also, BBS and TUG results were not associated with TrA muscle activity (p = 0.541 and p = 0.411, respectively). The results of the BBS, TUG, and PBFS did not differ according to gender (p < 0.05). Time from stroke negatively affected the TUG (p = 0.001), but had no effect on the TrA muscle activity (p < 0.05). The side of hemiparesis did not affect the postural stability (p < 0.05).

CONCLUSION

The consequences of a stroke have an essential negative effect on postural stability. Factors such as age, gender, time from stroke, and the side of the hemiparesis have not negatively affected postural stability in overweight post-stroke patients.