But you didn't tell us if any got 100% recovered.
With no measurements of 100% recovery they obviously have no intention of solving stroke at all.
Business 101: If you don't measure it, it is not important, so obviously 100% recovery is not important.
“What's measured, improves.” So said management legend and author Peter F. Drucker
The latest here:
Training muscle activation patterns of the lower paretic extremity using directional exertion improves mobility in persons with hemiparesis: a pilot study
BMC Biomedical Engineering volume 3, Article number: 12 (2021)
Abstract
Background
Controlled static exertion performed in the sagittal plane on a transducer attached to the foot requires coordinated moments of force of the lower extremity. Some exertions and plantarflexion recruit muscular activation patterns similar to synergies previously identified during gait. It is currently unknown if persons with hemiparesis following stroke demonstrate similar muscular patterns, and if force feedback training utilizing static exertion results in improved mobility in this population.
Methods
Electromyographic (EMG) activity of eight muscles of the lower limb were recorded using surface electrodes in healthy participants (n = 10) and in persons with hemiparesis (n = 8) during an exertion exercise (task) performed in eight directions in the sagittal plane of the foot and a plantarflexion exercise performed at 20 and 40% maximum voluntary effort (MVE). Muscle activation patterns identified during these exertion exercises were compared between groups and to synergies reported in the literature during healthy gait using cosine similarities (CS). Functional mobility was assessed in four participants with hemiparesis using GAITRite® and the Timed Up and Go (TUG) test at each session before, during and after static force feedback training. Tau statistics were used to evaluate the effect on mobility before and after training. Measures of MVE and the accuracy of directional exertion were compared before and after training using ANOVAs. Spearman Rho correlations were also calculated between changes in these parameters and changes in mobility before and after the training.
Results
Muscle activation patterns during directional exertion and plantarflexion were similar for both groups of participants (CS varying from 0.845 to 0.977). Muscular patterns for some of the directional and plantarflexion were also similar to synergies recruited during gait (CS varying from 0.847 to 0.951). Directional exertion training in hemiparetic subjects resulted in improvement in MVE (p < 0.040) and task performance accuracy (p < 0.001). Hemiparetic subjects also demonstrated significant improvements in gait velocity (p < 0.032) and in the TUG test (p < 0.022) following training. Improvements in certain directional efforts were correlated with changes in gait velocity (p = 0.001).
Conclusion
Static force feedback training following stroke improves strength and coordination of the lower extremity while recruiting synergies reported during gait and is associated with improved mobility.
Background
Stroke results in major limitations in terms of activities of daily living particularly with regard to mobility [1]. Approximately one-third of individuals who suffer a stroke have not regained independent mobility when discharged from rehabilitation and therefore are unable to walk unsupervised in the community [2]. This reduction in mobility leads to considerable secondary consequences, contributing to diminished social and valued roles [3].
People who experience a stroke demonstrate several sensorimotor impairments, including loss of muscle strength and impaired coordination that negatively impacts gait [4]. A recent meta-analysis found that progressive resistance exercise at higher intensities improves strength in this population [5]. However, systematic reviews and meta-analyses paint an unclear picture of the role that strength training of the lower extremity and associated strength gains play in improving gait in persons who have experienced a stroke [6,7,8]. Possible factors preventing strength gains from translating into functional performance may include suboptimal training intensities and duration and/or a lack of appropriate progression of the intervention [9, 10]. Alternatively, small effect sizes of strength training on gait parameters in this population may be the result of a lack of specificity of muscles selected and a failure to improve multiarticular movements requiring muscle activation of a coordinated group of muscles involved in locomotion. Strengthening exercises involving multiarticular muscles (e.g., leg press) appear to be better at improving strength and function in individuals with hemiparesis than isolated monoarticular exercises such as leg extensions [8].
Coordination of muscle groups involved in gait has been characterized in healthy subjects by EMG analysis of the lower extremity using a non-negative factorization technique [11]. This technique defines spatially grouped muscles (defined as synergies) and their corresponding temporal activation profile during the gait cycle. Four synergies (C1-C4) are usually sufficient to characterize gait in a healthy population [11, 12]. The C1 synergy consists of the activation of the Vastus Medialis (VM), Rectus Femoris (RF) and Gluteus Medius (GM) during the early stance phase; the C2 synergy, with activation of the Soleus (SOL) and Medial Gastrocnemius (MG), is related to forward propulsion during the terminal stance phase of gait; the C3 synergy consists of the activation of the Tibialis Anterior (TA) and RF observed during the initial swing phase while the C4 synergy with activation of the lateral (LH) and medial (MH) hamstring muscles is observed during the terminal swing phase. These four synergies contribute to important biomechanical functions that are required for normal non-impaired gait such as support, forward propulsion, mediolateral control and leg swing [13, 14].
The same or a reduced number of synergies revealed by factorization are observed in the paretic extremity of persons with hemiparesis following stroke [11, 12, 15, 16]. A reduced number of synergies is associated with impaired walking performance [17] and is explained by altered muscle activation or co-contractions of muscles involved in more than one synergy, effectively resulting in the merging of synergies [11, 12, 18]. Merged synergies during gait in people with hemiparesis typically involve synergies C1, C2 and C4, which are associated with different sub-cycles of gait [11,12,13].
People who demonstrate merged synergies following a stroke tend to exhibit a greater number of synergies after a training program for the upper or lower extremity [15, 19]. It has been suggested that a novel rehabilitation approach specifically aimed at retraining synergies may be required to address impairments in muscle activation and to improve function in persons with hemiparesis [13, 20]. During gait, the force that a foot exerted on the floor is opposed by the ground reaction force. The orientation of the ground reaction force (horizontal and vertical components) as well as the position of the joints (hip, knee, ankle) contribute to determine the activities of muscle during gait. Training the direction of force exertion of the extremity on a force plate may be considered an avenue for improving strength and coordination of the lower extremity and for practicing synergies observed during gait. First, directional exertion in healthy participants that requires individuals to control force feedback in two axes of the sagittal plane of the foot was found to recruit similar synergies to those reported in healthy participants during gait [21]. Secondly, persons who have experienced a stroke can coordinate ratios of increasing muscle activation and moments of force acting at different joints and produce a smooth exertion of force on a transducer localized under the foot [22]. Finally, modifying or training the exertion of moments of force and patterns of muscle activation can improve functional task performance [23, 24]. We therefore hypothesized that a progressive force feedback training program based on controlled directional exertions on a static dynamometer, requiring controlled moments of force at various joints of the lower extremity, would recruit synergies identified during gait and that such a program could be used to improve mobility in participants with hemiparesis.
The first objective of this study was to determine if directional exertions and static plantarflexion resulted in similar muscle activation patterns in people with hemiparesis and healthy participants, and if such activation patterns were similar to synergies reported during gait in healthy persons [11]. The second objective was to determine if a training program based on static directional exertions of the lower paretic extremity and static plantarflexion resulted in improved mobility and in people with hemiparesis. We also verified if changes in Maximal Voluntary Effort (MVE), in the accuracy required to perform the exertion exercise, and in muscle activation patterns are observed and associated with improved mobility following training.
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