The Effect of Split-Belt Treadmill Interventions on Step Length Asymmetry in Individuals Poststroke: A Systematic Review With Meta-Analysis

Background Individuals poststroke experience gait asymmetries that result in decreased community ambulation and a lower quality of life. A variety of studies have utilized split-belt treadmill training to investigate its effect on gait asymmetry, but many employ various methodologies that report differing results. Objective The purpose of this meta-analysis was to determine the effects of split-belt treadmill walking on step length symmetry in individuals poststroke both during and following training. Methods A comprehensive search of PubMed/MEDLINE, CINAHL, Web of Science, and Scopus was conducted to find peer-reviewed journal articles that included individuals poststroke that participated in a split-belt treadmill walking intervention. Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) was used to assess risk of bias. Pooled Hedge’s g with random effects models were used to estimate the effect of split-belt training on step length symmetry. Results Twenty-one studies were assessed and included in the systematic review with 11 of them included in the meta-analysis. Included studies had an average STROBE score of 16.2 ± 2.5. The pooled effects for step length asymmetry from baseline to late adaptation were not significant ( g = 0.060, P = .701). Large, significant effects were found at posttraining after a single session ( g = 1.04, P < .01), posttraining after multiple sessions ( g = −0.70, P = .01), and follow-up ( g = −0.718, P = .023). Conclusion Results indicate split-belt treadmill training with the shorter step length on the fast belt has the potential to improve step length symmetry in individuals poststroke when long-term training is implemented, but randomized controlled trials are needed to confirm the efficacy of split-belt treadmill training.

Direct and indirect effects of cathodal cerebellar TDCS on visuomotor adaptation of hand and arm movements

Adaptation of movements involving the proximal and distal upper-limb can be differentially facilitated by anodal transcranial direct current stimulation (TDCS) over the cerebellum and primary motor cortex (M1). Here, we build on this evidence by demonstrating that cathodal TDCS impairs motor adaptation with a differentiation of the proximal and distal upper-limbs, relative to the site of stimulation. Healthy young adults received M1 or cerebellar cathodal TDCS while making fast ‘shooting’ movements towards targets under 60° rotated visual feedback conditions, using either whole-arm reaching or fine hand and finger movements. As predicted, we found that cathodal cerebellar TDCS resulted in impairment of adaptation of movements with the whole arm compared to M1 and sham groups, which proved significantly different during late adaptation. However, cathodal cerebellar TDCS also significantly enhanced adaptation of hand movements, which may reflect changes in the excitability of the pathway between the cerebellum and M1. We found no evidence for change of adaptation rates using arm or finger movements following cathodal TDCS directly over M1. These results are further evidence to support movement specific effects of TDCS, and highlight how the connectivity and functional organisation of the cerebellum and M1 must be considered when designing TDCS-based therapies.

On the Buryat-Yakut Ethnic Connections: *J̌imken || *Yemkon, *Žemkon

The article is devoted to the analysis of the Yakut ethnonym *J̌emkon and *Yemkon, which can be identified in the personal onomastics (the name Zhemkon and surname Yemkonov) and derived names of various administrativeterritorial units (Yemkonskaya or Yamkonskaya volost’, Zhemkonskiy nasleg) recorded in the Russian documents. For the first time, the ethnonym becomes known in the documents of 17th century related to the population of the Lena River valley, which later became part of the Kangalasskiy ulus. Later the name was recorded in Vilyuy region. The modern Yakut spelling cöppön, cökpön, cökkön, cömkön reflects a late adaptation in the Yakut environment. In this connection the authors of the article draw their attention to the ethnonym known among the Buryats. It is widespread in different versions over vast territories among several ethnic-territorial groups of the Buryats. It is form Zemχed (letter ǰimked) of the Khori (Qori) tribe Khudai (Qudai). The various forms of the ethnonym and the corresponding eponyms as Yenχen, Zenχen, Ženχen, Žinχen are widely represented both among the Khori (Qori) tribe Galzut (Γalzuud) settled not only among the Khori (Qori) and Aga Buryats, and among the Verkholensk, Ol’khon, and Barguzin ethno-territorial groups of Western Buryats. The analysis shows that the Russian spelling of the Yakut ethnonym could reflect an adaptation of the original variant to be close to the pronunciation of *ǰimken (~ *dʹimken?), which in turn makes it possible to characterize its phonetic appearance as tending to Western Buryat dialects. Therefore, there are reasons to associate the penetration of this ethnonym into the Yakut environment with native speakers of a Western Buryat type language. The etymology of the analyzed name is difficult. Formal analysis of morphology leads to the opinion that the possible reconstructed semantics would be more likely to a personal name or toponym. It is also noted that it is possible to consider the spelling *J̌imken ~ *Yimken as correspond in its Mongolic form to the name known from the sources of the 11th–14th centuries and related to the Turkic tribe Yemäk ~ Yimäk. However, the authors leave this remark only as a hypothesis to be possible for further discussions.

Pre-movement changes in sensorimotor beta oscillations predict motor adaptation drive

Beta frequency oscillations in scalp electroencephalography (EEG) recordings over the primary motor cortex have been associated with the preparation and execution of voluntary movements. Here, we test whether changes in beta frequency are related to the preparation of adapted movements in human, and whether such effects generalise to other species (cat). Eleven healthy adult humans performed a joystick visuomotor adaptation task. Beta (15-25Hz) scalp EEG signals recorded over the motor cortex during a pre-movement preparatory phase were, on average, significantly reduced in amplitude during early adaptation trials compared to baseline or late adaptation trials (p=0.01). The changes in beta were not related to measurements of reaction time or duration of the reach. We also recorded LFP activity within the primary motor cortex of three cats during a prism visuomotor adaptation task. Analysis of these signals revealed similar reductions in motor cortical LFP beta frequencies during early adaptation. This effect was also present when controlling for any influence of the reaction time and reaching duration. Overall, the results are consistent with a reduction in pre-movement beta oscillations predicting an increase in adaptive drive in upcoming task performance when motor errors are largest in magnitude and the rate of adaptation is greatest.

A nyelés képességének helyreállítása lúgivás utáni nyelőcsőszűkületben

The authors discuss their experience in the surgical treatment of caustic stenosis in the upper gastrointestinal tract. They present operative solutions using isoperistaltic transverse colonic segment in oesophageal stenosis caused by gastric outlet obstruction, or when these two presented together. Further indications for the above were bronchial or tracheo-oesophageal fistulas and oesophageal perforation. Late adaptation of the colonic grafts were measured by radiokinematography and histochemistry. The overall morbidity was 4.9%. Postoperative salivary fistulas closed spontaneously. Late postoperative complications (13.5%) were treated successfully. The multihaustral motility of the graft prevented the reflux, while the altered mucopolysaccharides of the colonic mucosa prevented the ulcer formation. Orv Hetil. 2019; 160(16): 613–618.

Split-Belt Treadmill Walking Alters Lower Extremity Frontal Plane Mechanics

Interventions that manipulate gait speed may also affect the control of frontal plane mechanics. Expanding the current knowledge of frontal plane adaptations during split-belt treadmill walking could advance our understanding of the influence of asymmetries in gait speed on frontal plane mechanics and provide insight into the breadth of adaptations required by split-belt walking (SBW). Thirteen young, healthy participants, free from lower extremity injury walked on a split-belt treadmill with belts moving simultaneously at different speeds. We examined frontal plane mechanics of the ankle, knee, and hip joints during SBW, as well as medio-lateral ground reaction forces (ML-GRF). We did not observe alterations in the frontal mechanics produced during early or late adaptation of SBW when compared to conditions where the belts moved together. We did observe that ML-GRF and hip moment impulse of the fast limb increased over time with adaptation to SBW. These results suggest this modality may provide a unique therapy for individuals with gait pathologies, impairments, or compensation(s).

Locomotor control of limb force switches from minimal intervention principle in early adaptation to noise reduction in late adaptation

During movement, errors are typically corrected only if they hinder performance. Preferential correction of task-relevant deviations is described by the minimal intervention principle but has not been demonstrated in the joints during locomotor adaptation. We studied hopping as a tractable model of locomotor adaptation of the joints within the context of a limb-force-specific task space. Subjects hopped while adapting to shifted visual feedback that induced them to increase peak ground reaction force (GRF). We hypothesized subjects would preferentially reduce task-relevant joint torque deviations over task-irrelevant deviations to increase peak GRF. We employed a modified uncontrolled manifold analysis to quantify task-relevant and task-irrelevant joint torque deviations for each individual hop cycle. As would be expected by the explicit goal of the task, peak GRF errors decreased in early adaptation before reaching steady state during late adaptation. Interestingly, during the early adaptation performance improvement phase, subjects reduced GRF errors by decreasing only the task-relevant joint torque deviations. In contrast, during the late adaption performance maintenance phase, all torque deviations decreased in unison regardless of task relevance. In deadaptation, when the shift in visual feedback was removed, all torque deviations decreased in unison, possibly because performance improvement was too rapid to detect changes in only the task-relevant dimension. We conclude that limb force adaptation in hopping switches from a minimal intervention strategy during performance improvement to a noise reduction strategy during performance maintenance, which may represent a general control strategy for locomotor adaptation of limb force in other bouncing gaits, such as running.

Reversal of the late phase of spike frequency adaptation in cat spinal motoneurons during fictive locomotion

In spinal motoneurons, late spike frequency adaptation (SFA) is defined as the slowing of the firing rate over tens of seconds and can be seen during sustained or intermittent current injection. Although the function of late SFA is not known, it may result in a decrease in force production over time, or muscle fatigue. Because locomotion can persist for long periods of time without fatigue, late SFA was studied using intracellular recordings from adult cat motoneurons during fictive locomotion. Of eight lumbar motoneurons studied, all showed late adaptation during control conditions, but none demonstrated late adaptation during locomotor activity. The most consistent properties that correlated with the presence or absence of late SFA were those related to availability of fast, inactivating sodium channels, particularly action potential rate of rise. Evidence of the reversal of late SFA during locomotion was present for several minutes following locomotor trials, consistent with the suggestion that SFA is modulated through slow metabotropic pathways. The abolition of late adaptation in spinal motoneurons during fictive locomotion is an example of a state-dependent change in the “intrinsic” properties of mammalian motoneurons. This change contributes to increased excitability of motoneurons during locomotion and results in robust firing during sustained locomotion.