Background: Muscle synergies analysis can provide a deep understanding of motor impairment after stroke and of changes after rehabilitation. In this study, the neuro-mechanical analysis of leg cycling was used to longitudinally investigate the motor recovery process coupled with cycling training augmented by Functional Electrical Stimulation (FES) in subacute stroke survivors. Methods: Subjects with ischemic subacute stroke participated in a 3-week training of FES-cycling with visual biofeedback plus usual care. Participants were evaluated before and after the intervention through clinical scales, gait spatio-temporal parameters derived from an instrumented mat, and a voluntary pedaling test. Biomechanical metrics (work produced by the two legs, mechanical effectiveness and symmetry indexes) and bilateral electromyography from 9 leg muscles were acquired during the voluntary pedaling test. To extract muscles synergies, the Weighted Nonnegative Matrix Factorization algorithm was applied to the normalized EMG envelopes. Synergy complexity was measured by the number of synergies required to explain more than 90% of the total variance of the normalized EMG envelopes and variance accounted for by one synergy. Regardless the inter-subject differences in the number of extracted synergies, 4 synergies were extracted from each patient and the cosine-similarity between patients and healthy weight vectors was computed. Results: Nine patients (median age of 75 years and median time post-stroke of 2 weeks) were recruited. Significant improvements in terms of clinical scales, gait parameters and work produced by the affected leg were obtained after training. Synergy complexity well correlated to the level of motor impairment at baseline, but it did not change after training. We found a significant improvement in the similarity of the synergy responsible of the knee flexion during the pulling phase of the pedaling cycle, which was the mostly compromised at baseline. This improvement may indicate the re-learning of a more physiological motor strategy. Conclusions: Our findings support the use of the neuro-mechanical analysis of cycling as a method to assess motor recovery after stroke, mainly in an early phase, when gait evaluation is not yet possible. The improvement in the modular coordination of pedaling correlated with the improvement in motor functions and walking ability achieved at the end of the intervention support the role of FES-cycling in enhancing motor re-learning after stroke but need to be confirmed in a controlled study with a larger sample size. Trial registration: ClinicalTrial.gov, NCT02439515. Registered on May 8, 2015, .

There is a need for unobtrusive and valid tools to collect gait parameters in patients with Parkinson’s disease (PD). The novel promising tools are pressure-sensing insoles connected to a smartphone app; however, few studies investigated their measurement properties during simple or challenging conditions in PD patients. This study aimed to examine the validity and reliability of gait parameters computed by pressure-sensing insoles (FeetMe^® insoles, Paris, France). Twenty-five PD patients (21 males, mean age: 69 (7) years) completed two walking assessment sessions. In each session, participants walked on an electronic pressure-sensitive walkway (GaitRite^®, CIR System Inc., Franklin, NJ, USA) without other additional instructions (i.e., single-task condition) and while performing a concurrent cognitive task (i.e., dual-task condition). Spatiotemporal gait parameters were measured simultaneously using the pressure-sensing insoles and the electronic walkway. Concurrent validity was assessed by correlation coefficients and Bland–Altman methodology. Test–retest reliability was examined by intraclass correlation coefficients (ICC) and minimal detectable changes (MDC). The validity results showed moderate to excellent correlations and good agreement between the two systems. Concerning test–retest reliability, moderate-to-excellent ICC values and acceptable MDC demonstrated the repeatability of the measured gait parameters. Our findings support the use of these insoles as complementary instruments to conventional tools during single and dual-task conditions.

Purpose: Increasing evidence demonstrates that gender-related factors, and not only biological sex, are relevant in the physiological and pathophysiological mechanisms of the cardiovascular system, including the cardiac autonomic regulation. Sex and gender may also affect daytime and night-time cardiac autonomic control. This meta-analysis aimed to provide a comparison between healthy women and men on heart rate variability using 24-h ECG recordings pointing out sex- and gender-related factors. Methods: A systematic search was conducted to include studies focusing on both sex and gender differences related to heart rate variability indices in the time and frequency domains. Descriptive data were extracted by two independent reviewers. For each index, standardized mean differences with 95% confidence intervals were computed and a pooled estimate using a fixed- or random-effects model was applied. Results: Twenty-seven studies were included in the meta-analysis. The results showed that only seven studies reported some information about gender-related factors. Concerning sex-related differences, women had a shorter mean RR interval and lower variability of the time domain indices than men. Sex-related differences concerning frequency domain indices were more evident during night-time compared to daytime. Conclusion: The characterization of gender-related factors in the study of heart rate variability using 24-h ECG recordings is still sporadic and underexplored. The meta-analysis results could not conclusively support a significant increase of high frequency power in women, although women showed a reduced total power and low frequency to high frequency ratio. There is a strong need for considering heart rate variability in relation to gender-related variables.

To investigate the effects of cycling with functional electrical stimulation on walking, muscle power and tone, balance and activities of daily living in subacute stroke survivors. Ten electronic databases were searched from inception to February 2020. Inclusion criteria were: subacute stroke survivors (<6 months since stroke), an experimental group performing any type of cycling training with electrical stimulation, alone or in addition to usual care, and a control group performing usual care alone. Two reviewers assessed eligibility, extracted data and analyzed the risks of bias. Standardized Mean Difference (SMD) or Mean Difference (MD) with 95% Confidence Intervals (CI) were estimated using fixed- or random-effects models to evaluate the training effect. Seven randomized controlled trials recruiting a total of 273 stroke survivors were included in the meta-analyses. There was a statistically significant, but not clinically relevant, effect of cycling with electrical stimulation compared to usual care on walking (six studies, SMD [95% CI] = 0.40 [0.13, 0.67]; P = 0.004), capability to maintain a sitting position (three studies, MD [95% CI] = 7.92 [1.01, 14.82]; P = 0.02) and work produced by the paretic leg during pedaling (2 studies, MD [95% CI] = 8.13 [1.03, 15.25]; P = 0.02). No significant between-group differences were found for muscular power, tone, standing balance, and activities of daily living. Cycling training with functional electrical stimulation cannot be recommended in terms of being better than usual care in subacute stroke survivors. Further investigations are required to confirm these results, to determine the optimal training parameters and to evaluate long-term effects.

Temporal asymmetry is a peculiar aspect of heart period (HP) variability (HPV). HPV asymmetry (HPVA) is reduced with aging and pathology, but its origin is not fully elucidated. Given the impact of respiration on HPV resulting in the respiratory sinus arrhythmia (RSA) and the asymmetric shape of the respiratory pattern, a possible link between HPVA and RSA might be expected. In this study we tested the hypothesis that HPVA is significantly associated with RSA and asymmetry of the respiratory rhythm. We studied 42 middle-aged healthy (H) subjects, and 56 chronic heart failure (CHF) patients of whom 26 assigned to the New York Heart Association (NYHA) class II (CHF-II) and 30 to NYHA class III (CHF-III). Electrocardiogram and lung volume were monitored for 8 minutes during spontaneous breathing (SB) and controlled breathing (CB) at 15 breaths/minute. The ratio of inspiratory (INSP) to expiratory (EXP) phases, namely the I/E ratio, and RSA were calculated. HPVA was estimated as the percentage of negative HP variations, traditionally measured via the Porta’s index (PI). Departures of PI from 50% indicated HPVA and its significance was tested via surrogate data. We found that RSA increased during CB and I/E ratio was smaller than 1 in all groups and experimental conditions. In H subjects the PI was about 50% during SB and it increased significantly during CB. In both CHF-II and CHF-III groups the PI was about 50% during SB and remained unmodified during CB. The PI was uncorrelated with RSA and I/E ratio regardless of the experimental condition and group. Pooling together data of different experimental conditions did not affect conclusions. Therefore, we conclude that the HPVA cannot be explained by RSA and/or I/E ratio, thus representing a peculiar feature of the cardiac control that can be aroused in middle-aged H individuals via CB.

Background: Movement sonification has been recently introduced into the field of neuromotor rehabilitation alongside Neurologic Music Therapy and music-based interventions. This study introduces the use of musical auditory cues encompassing the melodic-harmonic aspect of music. Methods: Nineteen patients with Parkinson’s disease were randomly assigned to the experimental (n = 10) and control (n = 9) groups and underwent thrice-weekly sessions of the same gait training program, with or without sonification. Functional and motor parameters, as well as fatigue, quality of life, and the impact of intervention on patients’ well-being, were assessed at baseline (PRE), the end of treatment (POST), and at follow-up (FU). Between-group differences were assessed for each outcome measure using linear mixed-effects models. The outcome measure was entered as the dependent variable, group and time as fixed effects, and time by group as the interaction effect. Results: Mini BESTest and Dynamic Gait Index scores significantly improved in the experimental group (p = 0.01 and p = 0.03, respectively) from PRE to FU, demonstrating a significant impact of the sonification treatment on balance. No other significant differences were observed in the outcome measures. Conclusions: Larger sample sizes are needed to confirm the effectiveness of sonification approaches in Parkinson’s disease, as well as in other neurological disorders.