Respiratory Muscle Training Improves Strength and Decreases the Risk of Respiratory Complications in Stroke Survivors: A Systematic Review and Meta-analysis

"Effects of threshold respiratory muscle training on respiratory muscle strength, pulmonary function and exercise endurance after stroke: a meta-analysis"

BACKGROUND

Most studies on improvements in respiratory muscle strength, activities of daily living (ADL) and quality of life (QoL) in stroke patients receiving threshold respiratory muscle training (TRMT) have small sample sizes, and some studies have contradictory results.

OBJECTIVES

To evaluate the effectiveness of TRMT on respiratory muscle strength, pulmonary function and exercise endurance in stroke patients.

MATERIALS AND METHODS

PubMed, Cochrane Library, Physical Therapy Evidence Database (PEDro), Embase (via OVID) and Web of Science databases were searched for randomized controlled trial (RCT) from inception to January 17, 2024. The primary outcome was maximum inspiratory pressure (MIP) or maximum expiratory pressure (MEP). Secondary outcomes included pulmonary function measured by forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1) and peak expiratory flow (PEF), and exercise endurance measured by 6-minute walk test (6MWT).

RESULTS

A total of eight randomized controlled trials(RCTs), including 305 persons, were included in this study. The training time ranged from 3 weeks to 10 weeks. Among them, the intervention group in 4 studies used inspiratory muscle training, and the other 4 studies used inspiratory muscle training and expiratory muscle training. For the primary outcome, TRMT significantly improved MIP (mean=14.68 cmH2O, 95 %CI=2.28 to 27.09 cmH2O, P=0.02) and MEP (mean=9.37 cmH2O, 95 %CI=2.89 to 15.84 cmH2O, P=0.005) in stroke patients. Regarding the secondary outcomes, TRMT improved FVC, FEV1 and 6MWT (P<0.05) but did not significantly improve PEF.

CONCLUSION

TRMT improved inspiratory muscle strength and expiratory muscle strength, improved exercise endurance, and improved FVC and FEV1 of pulmonary function but did not significantly improve PEF.

Structured different exercise protocols improve lung function, respiratory muscle strength, and thickness in stroke patients. A randomized controlled trial

BACKGROUND

The effect of core stabilization exercises (CSE) alone, or in combination with neuromuscular electrical stimulation (NMES) and Kinesio taping (KT) on lung function, respiratory muscle strength, and thickness in patients with stroke is not fully known.

OBJECTIVE

To compare the efficacy of NMES and KT applied with CSE on lung functions, respiratory muscle strength, and thickness in patients with stroke.

METHODS

A total of 45 stroke patients were randomly assigned to the core stabilization exercises (CSE) group, CSE+KT group or CSE+NMES group, respectively. All groups received the training protocol for 30-45 minutes, 3 days a week, for 6 weeks. Lung functions were measured using portable spirometry. Respiratory muscle strength was assessed using an analog manometer to measure maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP). Peak cough flow (PCF) was measured with a peak flow meter. Respiratory muscles thickness were determined using ultrasonography.

RESULTS

Except for FVC (%pred) (F=4.432, p=0.018, np2=0.174), FEV1(%pred) (F=3.725, p=0.032, np2=0.151), and MEP (F=3.861, p=0.029, np2=0.155), the overall group by time interaction for rmANOVA showed that there was no statistically significant difference between groups (p>0.05). After post hoc analysis, it was determined that there was no statistically significant difference between the groups in terms of FVC (%pred), FEV1(%pred) and MEP (p>0.025).

CONCLUSIONS

The addition of NMES or KT to core stabilization exercises did not appear to provide additional benefit in improving lung function, respiratory muscle strength, and thickness in stroke patients.

The Effect of Respiratory Muscle Training on Swallowing Function in Patients With Stroke: A Systematic Review and Meta-Analysis

BACKGROUND

The improvement of swallowing function after stroke is a significant challenge faced by patients and health care professionals. However, the current evidence synthesis of the effects of respiratory muscle training (RMT) on swallowing function is limited.

OBJECTIVE

To assess the effectiveness of RMT on swallowing recovery in patients undergoing stroke.

METHODS

The CKNI, WanFang Data, PubMed, CINAHL, Web of Science, Embase, MEDLINE, and Cochrane Library databases were searched for studies evaluating RMT interventions' effect on swallowing outcomes. Risks of bias were evaluated using the approach recommended by the Cochrane Collaboration tool and a summary of findings table was generated using the GRADE approach. Outcomes were synthesized using a random-effects meta-analysis model.

RESULTS

RMT interventions reduced the risk of aspiration (SMD = 1.19; 95% CI, 0.53-1.84), the recovery process of water swallowing function (RR = 1.22; 95% CI, 1.05-1.42), and the activity of the swallowing muscles (SMD = 2.91; 95% CI, 2.22-3.61). However, there was no significant effect of RMT on the functional level of oral intake (SMD = 0.70; 95% CI, -0.03 to 1.42).

CONCLUSIONS

RMT can be regarded as an innovative, auxiliary means in the near future to better manage and improve swallowing function, given its improving effect on work outcomes in this review.

Cough and Swallowing Therapy and Their Effects on Vocal Fold Bowing and Laryngeal Lesions

OBJECTIVE

Expiratory muscle strength training (EMST) and sensorimotor training of airway protection (smTAP) are two exercises intended to improve cough and swallowing in people with Parkinson's Disease (PwPD). The aims of this study were to (1) examine whether EMST or smTAP elicit changes to vocal fold bowing; and (2) describe the safety of EMST and smTAP as it relates to the development of vocal fold lesions.

METHOD(S)

This was a secondary analysis of data from PwPD who completed EMST or smTAP as part of a prospective randomized controlled trial. Vocal fold bowing (BI) and the presence of laryngeal lesions were blindly analyzed from flexible endoscopic evaluation of swallowing (FEES) using ImageJ software and operational definitions. Linear regression was used to examine the influence time (pre- vs. post-therapy) and therapy (EMST vs. smTAP) on vocal fold bowing. Descriptive statistics were used to describe the presence of laryngeal lesions.

RESULT(S)

Overall, 56 participants were included, 28 per group. The median BI scores pre- and post-therapy were 8.2% and 8.3% for the EMST group and 11.3% and 8.4% for the smTAP group, respectively. Statistical analyses revealed insufficient evidence to suggest an effect of time and treatment type on BI (p > 0.05) or on the presence of vocal fold lesions (p > 0.05).

CONCLUSION

Based on these and previous findings, it appears that changes in vocal fold bowing do not drive treatment effects following EMST and smTAP. Also, this study further supports the safety of smTAP and EMST despite the required forceful exhalation and repetitive coughing.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:1127-1132, 2024.

The effects of respiratory muscle training on respiratory function and functional capacity in patients with early stroke: a meta-analysis

BACKGROUND

Respiratory muscle training is a continuous and standardized training of respiratory muscles, but the evidence of the effects on early stroke patients is not clear. This meta-analysis aimed to investigate the effects of respiratory muscle training on respiratory function and functional capacity in patients with early stroke.

METHODS

PubMed, Embase, PEDro, ScienceDirect, AMED, CINAHL, and China National Knowledge Infrastructure databases were searched from inception to December 8, 2023 for articles about studies that 1) stroke patients with age ≥ 18 years old. Early stroke < 3 months at the time of diagnosis, 2) respiratory muscle training, including inspiratory and expiratory muscle training, 3) the following measurements are the outcomes: respiratory muscle strength, respiratory muscle endurance, pulmonary function testing, dyspnea fatigue score, and functional capacity, 4) randomized controlled trials. Studies that met the inclusion criteria were extracted data and appraised the methodological quality and risk of bias using the Physiotherapy Evidence Database scale and the Cochrane Risk of Bias tool by two independent reviewers. RevMan 5.4 with a random effect model was used for data synthesis and analysis. Mean differences (MD) or standard mean differences (SMD), and 95% confidence interval were calculated (95%CI).

RESULTS

Nine studies met inclusion criteria, recruiting 526 participants (mean age 61.6 years). Respiratory muscle training produced a statistically significant effect on improving maximal inspiratory pressure (MD = 10.93, 95%CI: 8.51-13.36), maximal expiratory pressure (MD = 9.01, 95%CI: 5.34-12.69), forced vital capacity (MD = 0.82, 95%CI: 0.54-1.10), peak expiratory flow (MD = 1.28, 95%CI: 0.94-1.63), forced expiratory volume in 1 s (MD = 1.36, 95%CI: 1.13-1.59), functional capacity (SMD = 0.51, 95%CI: 0.05-0.98) in patients with early stroke. Subgroup analysis showed that inspiratory muscle training combined with expiratory muscle training was beneficial to the recovery of maximal inspiratory pressure (MD = 9.78, 95%CI: 5.96-13.60), maximal expiratory pressure (MD = 11.62, 95%CI: 3.80-19.43), forced vital capacity (MD = 0.87, 95%CI: 0.47-1.27), peak expiratory flow (MD = 1.51, 95%CI: 1.22-1.80), forced expiratory volume in 1 s (MD = 0.76, 95%CI: 0.41-1.11), functional capacity (SMD = 0.61, 95%CI: 0.08-1.13), while inspiratory muscle training could improve maximal inspiratory pressure (MD = 11.60, 95%CI: 8.15-15.05), maximal expiratory pressure (MD = 7.06, 95%CI: 3.50-10.62), forced vital capacity (MD = 0.71, 95%CI: 0.21-1.21), peak expiratory flow (MD = 0.84, 95%CI: 0.37-1.31), forced expiratory volume in 1 s (MD = 0.40, 95%CI: 0.08-0.72).

CONCLUSIONS

This study provides good-quality evidence that respiratory muscle training is effective in improving respiratory muscle strength, pulmonary function, and functional capacity for patients with early stroke. Inspiratory muscle training combined with expiratory muscle training seems to promote functional recovery in patients with early stroke more than inspiratory muscle training alone.

TRIAL REGISTRATION

Prospero registration number: CRD42021291918.

Maximal Respiratory Pressure Reference Equations in Healthy Adults and Cut-off Points for Defining Respiratory Muscle Weakness

INTRODUCTION

Maximal inspiratory and expiratory pressures (PImax/PEmax) reference equations obtained in healthy people are needed to correctly interpret respiratory muscle strength. Currently, no clear cut-off points defining respiratory muscle weakness are available. We aimed to establish sex-specific reference equations for PImax/PEmax in a large sample of healthy adults and to objectively determine cut-off points for respiratory muscle weakness.

METHODS

A multicentre cross-sectional study was conducted across 14 Spanish centres. Healthy non-smoking volunteers aged 18-80 years stratified by sex and age were recruited. PImax/PEmax were assessed using uniform methodology according to international standards. Multiple linear regressions were used to obtain reference equations. Cut-off points for respiratory muscle weakness were established by using T-scores.

RESULTS

The final sample consisted of 610 subjects (314 females; 48 [standard deviation, SD: 17] years). Reference equations for PImax/PEmax included body mass index and a squared term of the age as independent variables for both sexes (p<0.01). Cut-off points for respiratory muscle weakness based on T-scores ≥2.5 SD below the peak mean value achieved at a young age were: 62 and 83cmH2O for PImax and 81 and 109cmH2O for PEmax in females and males, respectively.

CONCLUSION

These reference values, based on the largest dataset collected in a European population to date using uniform methodology, help identify cut-off points for respiratory muscle weakness in females and males. These data will help to better identify the presence of respiratory muscle weakness and to determine indications for interventions to improve respiratory muscle function.

The therapeutic role of inspiratory muscle training in the management of asthma: a narrative review

Asthma is a disorder of the airways characterized by chronic airway inflammation, hyperresponsiveness, and variable recurring airway obstruction. Treatment options for asthma include pharmacological strategies, whereas nonpharmacological strategies are limited. Established pharmacological approaches to treating asthma may cause unwanted side effects and do not always afford adequate protection against asthma, possibly because of an individual's variable response to medications. A potential nonpharmacological intervention that is most available and cost effective is inspiratory muscle training (IMT), which is a technique targeted at increasing the strength and endurance of the diaphragm and accessory muscles of inspiration. Studies examining the impact of IMT on asthma have reported increases in inspiratory muscle strength and a reduction in the perception of dyspnea and medication use. However, because of the limited number of studies and discordant methods between studies more evidence is required to elucidate in individuals with asthma the efficacy of IMT on inspiratory muscle endurance, exercise capacity, asthma control, symptoms, and quality of life as well as in adolescents with differing severities of asthma. Large randomized controlled trials would be a significant step forward in clarifying the effectiveness of IMT in individuals with asthma. Although IMT may have favorable effects on inspiratory muscle strength, dyspnea, and medication use, the current evidence that IMT is an effective treatment for asthma is inconclusive.

Pulmonary function in patients with chronic stroke compared with a control group of healthy people matched by age and sex

BACKGROUND

Effects of chronic stroke on pulmonary function are largely unknown.

AIM

To compare lung volumes in people with chronic stroke with a control group of healthy people matched by age and sex, as well as to investigate the relationship between the lung volumes and functional capacity.

METHODS

A cross-sectional study involving people with chronic stroke. Cases were matched to a control group of healthy people. Lung function and the distance walked during the Six-Minute Walk Test (6MWD) were the main outcomes. Independent t-tests were used to compare pulmonary function between groups and the Pearson correlation coefficient was used to assess any relationship between lung volumes and the 6MWD in the stroke group.

RESULTS

Sixty-six participants (24 males in each group; 56.5 ± 15.5 years) were included. People with stroke presented significantly lower lung volumes when compared to the control group. The median of forced vital capacity (FVC) was 79% and peak expiratory flow was 64% of the reference value. The 6MWD was found to be weakly correlated with inspiratory reserve volume (r = 0.39, p = .03) and peak inspiratory flow (r = 0.35, p = .05).

CONCLUSIONS

People with chronic stroke show decreased lung volumes when compared with healthy people and this likely impacts on their functional capacity.

Effect of respiratory muscle training in asthma: A systematic review and meta-analysis

BACKGROUND

The last systematic review about respiratory muscle training (RMT) in people with asthma was published almost 10 years ago. Since then, several works have been published.

OBJECTIVE

To review the effect of RMT in people with asthma.

METHODS

We conducted a systematic review of research included up to September 2021 in PubMed/MEDLINE, PEDro, Scopus, Web of Science, CINAHL, LILACS, Cochrane Central Register of Controlled Trials and ClinicalTrials.gov. We included randomized controlled trials and quasi-experimental studies assessing the effect of RMT on respiratory muscle function, rescue medication, asthma-related symptoms, lung function, exercise capacity, healthcare use, health-related quality of life (HRQoL) and adverse effects in people with asthma. Risk of bias and methodological quality were assessed with the Cochrane Risk of Bias assessment tool and the PEDro scale. Meta-analysis was performed whenever possible; otherwise a qualitative approach was followed.

RESULTS

Eleven studies (270 participants) were included, 10 with only adults and were included in the meta-analysis. Inspiratory muscle training (IMT) had beneficial effects on maximal inspiratory pressure (PImax: mean difference [MD] 21.95 cmH₂O [95% confidence interval [CI] 15.05; 28.85]), with no changes in maximal expiratory pressure (MD 14.97 cmH₂O [95%CI -5.65; 35.59]), lung function (forced expiratory volume in 1 sec: MD 0.06 [95%CI -0.14; 0.26] L; force vital capacity: MD 0.39 [95%CI -0.24; 1.02] L) and exercise capacity (standard mean difference [SMD] 1.73 [95%CI -0.61; 4.08]). Subgroup analysis revealed that IMT load >50% PImax and duration >6 weeks were beneficial for exercise capacity. The qualitative analysis suggested that IMT may have benefits on respiratory muscle endurance, rescue medication and exertional dyspnoea, with no adverse effects.

CONCLUSIONS

This systematic review and meta-analysis showed a significant increase in PImax after IMT in adults with asthma and reinforced the relevance of the dose-response principle of training. More evidence is needed to clarify the effect of IMT in respiratory muscle endurance, rescue medication, exercise capacity, healthcare use and HRQoL.

TRIAL REGISTRATION

PROSPERO International Prospective Register of Systematic Reviews CRD42020221939; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=221939.

Effectiveness of Nonpharmacological Interventions in the Field of Ventilation: An Umbrella Review

This umbrella review aimed to determine the effectiveness of nonpharmacological interventions in pulmonary ventilation and their impact on respiratory function. An individual with impaired ventilation displays visible variations manifested in their respiratory frequency, breathing rhythm ratio (I:E), thoracic symmetry, use of accessory muscles, dyspnea (feeling short of breath), oxygen saturation, diaphragm mobility, minute ventilation, peak flow, walking test, spirometry, Pimax/Pemax, diffusion, and respiratory muscle strength. Any variation in these markers demands the need for interventions in order to duly manage the signs and symptoms and to improve ventilation.

METHOD

Systematic reviews of the literature published in English, Spanish, French, and Portuguese were used, which included studies in which nonpharmacological interventions were used as a response to impaired ventilation in adults in any given context of the clinical practice. The recommendations given by the Joanna Briggs Institute (JBI) for umbrella reviews were followed. This research took place in several databases such as MEDLINE, CINAHL Complete, CINHAL, MedicLatina, ERIC, Cochrane Reviews (Embase), and PubMed. The Joanna Briggs critical analysis verification list was used for the systematic review. The data extraction was performed independently by two investigators based on the data extraction tools of the Joanna Briggs Institute, and the data were presented in a summary table alongside the support text.

RESULTS

Forty-four systematic reviews, thirty randomized clinical essays, and fourteen observational studies were included in this review. The number of participants varied between n = 103 and n = 13,370. Fifteen systematic revisions evaluated the effect of isolated respiratory muscular training; six systematic revisions evaluated, in isolation, breathing control (relaxed breathing, pursed-lip breathing, and diaphragmatic breathing exercises) and thoracic expansion exercises; and one systematic review evaluated, in isolation, the positions that optimize ventilation. Nineteen systematic reviews with combined interventions that reinforced the role of education and capacitation while also aiming for their success were considered. The articles analyzed isolated interventions and presented their efficacy. The interventions based on respiratory exercises and respiratory muscular training were the most common, and one article mentioned the efficacy of positioning in the compromisation of ventilation. Combined interventions in which the educational component was included were found to be effective in improving pulmonary function, diffusion, oxygenation, and functional capacity. The outcomes used in each study were variable, leading to a more difficult analysis of the data.

CONCLUSIONS

The interventions that were the focus of the review were duly mapped. The results suggest that nonpharmacological interventions used to optimize ventilation are effective, with a moderate to high level of evidence. There is a strong foundation for the use of the chosen interventions. The lack of studies on the intervention of "positioning to optimize ventilation" points out the need for a deeper analysis of its effects and for studies with a clear focus. This study supports the decisions and recommendations for the prescription of these interventions to patients with impaired ventilation.

Respiratory sarcopenia: A position paper by four professional organizations

We defined respiratory sarcopenia as a coexistence of respiratory muscle weakness and decreased respiratory muscle mass. Although respiratory muscle function is indispensable for life support, its evaluation has not been included in the regular assessment of respiratory function or adequately evaluated in clinical practice. Considering this situation, we prepared a position paper outlining basic knowledge, diagnostic and assessment methods, mechanisms, involvement in respiratory diseases, intervention and treatment methods, and future perspectives on respiratory sarcopenia, and summarized the current consensus on respiratory sarcopenia. Respiratory sarcopenia is diagnosed when respiratory muscle weakness and decreased respiratory muscle mass are observed. If respiratory muscle mass is difficult to measure, we can use appendicular skeletal muscle mass as a surrogate. Probable respiratory sarcopenia is defined when respiratory muscle weakness and decreased appendicular skeletal muscle mass are observed. If only respiratory muscle strength is decreased without a decrease in respiratory function, the patient is diagnosed with possible respiratory sarcopenia. Respiratory muscle strength is assessed using maximum inspiratory pressure and maximum expiratory pressure. Ultrasonography and computed tomography are commonly used to assess respiratory muscle mass; however, there are insufficient data to propose the cutoff values for defining decreased respiratory muscle mass. It was jointly prepared by the representative authors and authorized by the Japanese Society for Respiratory Care and Rehabilitation, Japanese Association on Sarcopenia and Frailty, Japanese Society of Respiratory Physical Therapy and Japanese Association of Rehabilitation Nutrition. Geriatr Gerontol Int 2023; 23: 5-15.

The relationship of respiratory functions and respiratory muscle strength with trunk control, functional capacity, and functional independence in post‐stroke hemiplegic patients

BACKGROUND

Cardiorespiratory system involvement and early fatigue observed in stroke patients complicate the rehabilitation process and affect their ability to perform daily activities and functional independence.

AIM

It was aimed to determine the relationship between respiratory functions and respiratory muscle strength with trunk control, functional capacity, and functional independence in hemiplegic patients after stroke.

MATERIALS AND METHODS

Twenty-five volunteers who were diagnosed with post-stroke hemiplegia were included in the study. Sociodemographic and physical characteristics were recorded. Pulmonary function test (PFT), respiratory muscle strength, Trunk Impairment Scale (TIS), Timed-Up and Go Test (TUG), and Barthel Index (BI) were applied.

RESULTS

There was a moderate negative correlation between TUG scores and PFT results (r = 0.413-0.502; p = 0.011-0.04), except for PEF (%) and FEV1/FVC. Also, there were statistically significant correlation between TIS scores and FEV1(%) (r = 0.505; p = 0.012), FVC(%) (r = 0.449; p = 0.024). On the other hand, there was no statistically significant relationship between BI results and any parameter of the PFT (p > 0.05). There was no statistically significant correlation between respiratory muscle strength and TUG, TIS, BI (p > 0.05).

CONCLUSION

It has been shown that respiratory functions are associated with functional capacity and trunk control. However, it was found that there was no relationship between respiratory muscle strength and functional capacity, trunk control, and functional independence. It is thought that considering these parameters in the assessment of patients will contribute to the creation of individual and effective rehabilitation programs. The respiratory system should be systematically assessed in stroke rehabilitation and considered as part of a holistic approach.

CLINICAL TRIAL REGISTRATION

NCT05290649 (retrospectively registered) (clinicaltrials.gov).

Breathing Exercises for Improving Cognitive Function in Patients with Stroke

Patients with stroke may experience a certain degree of cognitive decline during the period of recovery, and a considerable number of such patients have been reported to show permanent cognitive damage. Therefore, the period of recovery and rehabilitation following stroke is critical for rapid cognitive functional improvements. As dysfunctional breathing has been reported as one of the factors affecting the quality of life post stroke, a number of studies have focused on the need for improving the breathing function in these patients. Numerous breathing exercises have been reported to enhance the respiratory, pulmonary, cognitive, and psychological functions. However, scientific evidence on the underlying mechanisms by which these exercises improve cognitive function is scattered at best. Therefore, it has been difficult to establish a protocol of breathing exercises for patients with stroke. In this review, we summarize the psychological, vascular, sleep-related, and biochemical factors influencing cognition in patients and highlight the need for breathing exercises based on existing studies. Breathing exercises are expected to contribute to improvements in cognitive function in stroke based on a diverse array of supporting evidence. With relevant follow-up studies, a protocol of breathing exercises can be developed for improving the cognitive function in patients with stroke.

Optimizing acute stroke outcome prediction models: Comparison of generalized regression neural networks and logistic regressions

Background

Generalized regression neural network (GRNN) and logistic regression (LR) are extensively used in the medical field; however, the better model for predicting stroke outcome has not been established. The primary goal of this study was to compare the accuracies of GRNN and LR models to identify the most optimal model for the prediction of acute stroke outcome, as well as explore useful biomarkers for predicting the prognosis of acute stroke patients.

Method

In a single-center study, 216 (80% for the training set and 20% for the test set) acute stroke patients admitted to the Shenzhen Second People’s Hospital between December 2019 to June 2021 were retrospectively recruited. The functional outcomes of the patients were measured using Barthel Index (BI) on discharge. A training set was used to optimize the GRNN and LR models. The test set was utilized to validate and compare the performances of GRNN and LR in predicting acute stroke outcome based on the area under the receiver operating characteristic curve (AUROC), accuracy, sensitivity, and the Kappa value.

Result

The LR analysis showed that age, the National Institute Health Stroke Scale score, BI index, hemoglobin, and albumin were independently associated with stroke outcome. After validating in test set using these variables, we found that the GRNN model showed a better performance based on AUROC (0.931 vs 0.702), sensitivity (0.933 vs 0.700), specificity (0.889 vs 0.722), accuracy (0.896 vs 0.729), and the Kappa value (0.775 vs 0.416) than the LR model.

Conclusion

Overall, the GRNN model demonstrated superior performance to the LR model in predicting the prognosis of acute stroke patients. In addition to its advantage in not affected by implicit interactions and complex relationship in the data. Thus, we suggested that GRNN could be served as the optimal statistical model for acute stroke outcome prediction. Simultaneously, prospective validation based on more variables of the GRNN model for the prediction is required in future studies.

Stroke and breathing

Stroke remains a leading cause of neurologic disability with wide ranging effects, including a variety of respiratory abnormalities. Stroke may influence the central control of the respiratory drive and breathing pattern, airway protection and maintenance, and the respiratory mechanics of inspiration and expiration. In the acute phase of stroke, the central control of breathing is affected by changes in consciousness, cerebral edema, and direct damage to brainstem respiratory centers, resulting in abnormalities in respiratory pattern and loss of airway protection. Common acute complications related to respiratory dysfunction include dysphagia, aspiration, and pneumonia. Respiratory control centers are located in the brainstem, and brainstem stroke causes specific patterns of respiratory dysfunction. Depending on the exact location and extent of stroke, respiratory failure may occur. While major respiratory abnormalities often improve over time, sleep-disordered breathing remains common in the subacute and chronic phases and worsens outcomes. Respiratory mechanics are impaired in hemiplegic or hemiparetic stroke, contributing to worse cardiopulmonary health in stroke survivors. Interventions to address the respiratory complications are under researched, and further investigation in this area is critical to improving outcomes among stroke survivors.

Respiratory muscle training improves exercise tolerance and respiratory muscle function/structure post-stroke at short term: A systematic review and meta-analysis

BACKGROUND

Previous reviews relating to the effects of respiratory muscle training (RMT) after stroke tend to focus on only one type of training (inspiratory or expiratory muscles) and most based the results on poor-quality studies (PEDro score ≤4).

OBJECTIVES

With this systematic review and meta-analysis, we aimed to determine the effects of RMT (inspiratory or expiratory muscle training, or mixed) on exercise tolerance, respiratory muscle function and pulmonary function and also the effects depending on the type of training performed at short- and medium-term in post-stroke.

METHODS

Databases searched were MEDLINE, PEDro, CINAHL, EMBASE and Web of Science up to the end of April 2020. The quality and risk of bias for each included study was examined by the PEDro scale (including only high-quality studies) and Cochrane Risk of Bias tool.

RESULTS

Nine studies (463 patients) were included. The meta-analysis showed a significant increase in exercise tolerance [4 studies; n = 111; standardized mean difference [SMD] = 0.65 (95% confidence interval 0.27-1.04)]; inspiratory muscle strength [9 studies; n = 344; SMD = 0.65 (0.17-1.13)]; inspiratory muscle endurance [3 studies; n = 81; SMD = 1.19 (0.71-1.66)]; diaphragm thickness [3 studies; n = 79; SMD = 0.9 (0.43-1.37)]; and peak expiratory flow [3 studies; n = 84; SMD = 0.55 (0.03-1.08)] in the short-term. There were no benefits on expiratory muscle strength and pulmonary function variables (forced expiratory volume in 1 s) in the short-term.

CONCLUSIONS

The meta-analysis provided moderate-quality evidence that RMT improves exercise tolerance, diaphragm thickness and pulmonary function (i.e., peak expiratory flow) and low-quality evidence for the effects on inspiratory muscle strength and endurance in stroke survivors in the short-term. None of these effects are retained in the medium-term. Combined inspiratory and expiratory muscle training seems to promote greater respiratory changes than inspiratory muscle training alone.

Comparison of Two Protocols for the Assessment of Maximal Respiratory Pressures: Spanish Society of Pulmonology and Thoracic Surgery Versus American Thoracic Society/European Respiratory Society

Background The measurement of maximal respiratory pressures (MRPs) is commonly used to assess respiratory muscle strength. However, in Spain, there is no consensus on which is the most adequate measurement protocol, as theSpanish Society of Pneumology and Thoracic Surgery (SEPAR) protocol differs from the one endorsed by the American Thoracic Society/European Respiratory Society(ATS/ERS). This study compared the absolute and predictive values of maximal expiratory and inspiratory pressures (MEP and MIP) in healthy adults obtained with the two protocols. Methods A cross-sectional study with a sample of healthy adults was conducted. Lung function and MRPs were assessed. MEP and MIP were measured using a digital manometer according to the SEPAR and ATS/ERS. Protocols were applied in random order by the same trained physiotherapist. The comfort experienced with each protocol was assessed through a short questionnaire. Paired t-tests were used to compare the results from both protocols. Results A total of 31 subjects (mean age 35.7±12.4 years; 14 females; FEV1=108.3±10.5%; FVC=103.7±10%) were included. There was a significant difference between MRPs favouring the SEPAR protocol, with the mean difference being 34.9±28.1 cmH2O (p˂0.001) for MEP and 8±11.6 cmH2O (p=0.001) for MIP. ATS/ERS protocol was, however, considered more comfortable than SEPAR (p<0.005). Conclusions This study shows that, in healthy adults, higher MRPs are obtained using the SEPAR protocol. Yet, the ATS/ERS protocol is experienced as more comfortable. Future studies are needed to analyse the application of both protocols in other populations and their associated comfort.

Effects of respiratory muscle training on cough function in neurological disorders: A systematic review with meta-analysis

BACKGROUND

Patients with neurological disorders can present the weakness of respiratory muscle and impaired cough function. Previous studies have shown that respiratory muscle strength training (RMT) is an effective method of improving the strength of respiratory muscle. The effects of RMT on cough function remain controversial.

OBJECTIVE

We aimed to analyze randomized controlled trials (RCTs) that investigated the effects of RMT on cough function of patients with neurological disorders.

METHODS

Pubmed, Medline, Embase, and the Cochrane Library were searched electronically for RCTs. Two reviewers independently performed data extraction and quality assessment. Data were analyzed by using RevMan 5.3 software of The Cochrane Collaboration.

RESULTS

Five studies with 185 participants were included. The mean PEDro score was 6.2 (range 5 to 7), showing moderate methodological quality. Random-effects meta-analyses showed that respiratory muscle training improved peak expiratory cough flow of voluntary cough by 2.16 (95% CI 1.16 to 3.17) and involuntary cough by 2.84 (95% CI 1.29 to 4.39), with statistical significance (P < 0.0001, P = 0.0003). The experimental group had an improvement of 0.19 cmH2O (95% CI -0.12 to 0.5) on the maximal inspiratory pressure, 0.09 cmH2O (95% CI -0.23 to 0.42) on the maximal expiratory pressure, but with no statistical significance (P = 0.23, P = 0.58) between groups.

CONCLUSION

Respiratory muscle training was considered as an effective method for improving cough function. However, this review was insufficient to conclude whether respiratory muscle training was effective in improving inspiratory and expiratory muscle strength, this was opposite with previous meta-analysis. These effects might due to the small samples and different diseases.

Asthma and stroke: a narrative review

Asthma is a heterogeneous disease, usually characterized by chronic airway inflammation, bronchial reversible obstruction and hyperresponsiveness to direct or indirect stimuli. It is a severe disease causing approximately half a million deaths every year and thus possessing a significant public health burden. Stroke is the second leading cause of death and a major cause of disability worldwide. Asthma and asthma medications may be a risk factors for developing stroke. Nevertheless, since asthma is associated with a variety of comorbidities, such as cardiovascular, metabolic and respiratory, the increased incidence of stroke in asthma patients may be due to a confounding effect. The purpose of this review is to analyze the complex relationship between asthma and stroke.