Objective: To examine whether alternating training with both the non-paretic and paretic sides (alternating bilateral training), expecting trial-to-trial inter-limb transfer of training effects from ...the nonparetic to the paretic side, improves upper-limb motor performance in post-stroke patients, compared with unilateral training involving only the paretic side.Design: An assessor-blinded pilot randomized controlled trial.Subjects: Twenty-four right-handed post-stroke patients with hemiparesis.Methods: Participants were randomly allocated to either an alternating bilateral training group or a unilateral training group (n = 12/group). Participants underwent dexterity training of the paretic arm using the Nine-Hole Peg Test, completing 10 trials/day for 7 consecutive days. The alternating bilateral training group additionally performed alternating trials with the non-paretic limb. Performance change, assessed 1 day and 1 week after the 7-day training period, was compared between groups.Results: Although the improvement was comparable in both groups at both post-training time-points, a sub-analysis in which those with left hemiparesis and those with right hemiparesis were analyzed separately revealed potential benefits of the alternating bilateral training, specifically for those with left hemiparesis.Conclusion: Alternating bilateral training may augment training effects and improve upper-limb motor function in patients with left hemiparesis.
LAY ABSTRACTPost-stroke patients often experience long-term impairments affecting dexterity and motor control of the paretic upper limb. Recent studies have suggested that a unique training method, based on the inter-limb transfer phenomenon, expecting transfer of the training effect of the trained to the contralateral limb, has the potential to improve the performance of the paretic side. However, this traditional model focuses on training only with the non-paretic side, and thus cannot be directly applied to clinical settings. This study developed and evaluated the effect of a new clinically relevant strategy in which post-stroke patients underwent alternating training of the upper limbs of the non-paretic and paretic sides. Although the training effect was comparable with that of the unilateral training involving only the paretic side, a sub-analysis revealed a potential benefit of the alternating training specifically for left hemiparetic patients. The proposed training strategy could help post-stroke patients improve upper-limb motor function.
As humans, we constantly change our movement strategies to adapt to changes in physical functions and the external environment. We have to walk very slowly in situations with a high risk of falling, ...such as walking on slippery ice, carrying an overflowing cup of water, or muscle weakness owing to aging or motor deficit. However, previous studies have shown that a normal gait pattern at low speeds results in reduced efficiency and stability in comparison with those at a normal speed. Another possible strategy is to change the gait pattern from normal to step-to gait, in which the other foot is aligned with the first swing foot. However, the efficiency and stability of the step-to gait pattern at low speeds have not been investigated yet. Therefore, in this study, we compared the efficiency and stability of the normal and step-to gait patterns at intermediate, low, and very low speeds. Eleven healthy participants were asked to walk with a normal gait and step-to gait on a treadmill at five different speeds (i.e., 10, 20, 30, 40, and 60 m/min), ranging from very low to normal walking speed. The efficiency parameters (percent recovery and walk ratio) and stability parameters (center of mass lateral displacement) were analyzed from the motion capture data and then compared for the two gait patterns. The results suggested that step-to gait had a more efficient gait pattern at very low speeds of 10-30 m/min, with a larger percent recovery, and was more stable at 10-60 m/min in comparison with a normal gait. However, the efficiency of the normal gait was better than that of the step-to gait pattern at 60 m/min. Therefore, step-to gait is effective in improving gait efficiency and stability when faced with situations that force us to walk slowly or hinder quick walking because of muscle weakness owing to aging or motor deficit along with a high risk of falling.
Purpose This study evaluated the effects of repetitive peripheral magnetic stimulation of the soleus muscle on spinal cord and peripheral motor nerve excitability. Subjects and Methods Twelve healthy ...adults (mean age 22 years) who provided written informed consent were administered repetitive peripheral magnetic stimulation for 10 min. Pre-and post-stimulation latencies and amplitudes of H- and M-waves of the soleus muscle were measured using electromyography and compared using paired t-tests. Results Pre- and post-stimulation latencies (28.3 ± 3.3 vs. 29.1 ± 1.3 ms, respectively) and amplitudes (35.8 ± 1.3 vs. 35.8 ± 1.1 mV, respectively) of H-waves were similar. Pre-stimulation latencies of M-waves were significantly higher than post-stimulation latencies (6.1 ± 2.2 vs. 5.0 ± 0.9 ms, respectively), although pre- and post-stimulation amplitudes were similar (12.2 ± 1.4 vs. 12.2 ± 1.3 mV, respectively). Motor neuron excitability, based on the excitability of motor nerves and peripheral nerve action, was increased by M-waves following magnetic stimulation. Conclusion The lack of effect of magnetic stimulation on the amplitude and latency of the H-reflex suggests that magnetic stimulation did not activate sensory nerve synapses of α motor neurons in the spinal cord. However, because motor nerves were stimulated together with sensory nerves, the increased H-wave amplitude may have reflected changes in peripheral rather than in α motor nerves.
Background Although genu recurvatum during walking is a well-known issue in stroke rehabilitation, there are no reliable epidemiological data on its prevalence. The aim of the study was to ...investigate the prevalence of genu recurvatum during walking and associated knee pain among ambulatory community-dwelling patients with chronic hemiplegic stroke. Methods Questionnaires were sent to physical therapists working at 223 adult day care facilities in Chiba Prefecture, Japan. The number of all chronic stroke patients attending the day care who could walk without human assistance, including those who used a walking aid and/or an orthosis; the number of patients with genu recurvatum in the paretic limb during walking; and the number of patients with genu recurvatum who had experienced any knee pain in the last month were investigated. Physical therapists were also asked whether they considered genu recurvatum in stroke patients to be problematic. Results Sixty-four facilities (28.7%) responded, providing data on 1110 ambulatory stroke patients, of whom 217 (19.5%) showed genu recurvatum. Of the patients with genu recurvatum, 25 (11.5%) experienced knee pain in the paretic limb. Of 45 physical therapists who gave an opinion on whether genu recurvatum was problematic, 26 (57.8%) thought it was problematic whereas 19 thought it was not problematic. Conclusion Rates of genu recurvatum and associated knee pain were relatively low among ambulatory community-dwelling stroke survivors attending adult day care.
Highlights ► Compared movement characteristics of the kneeling gait and the normal gait. ► Increased muscle activity was observed in the kneeling gait. ► The kneeling gait might be an effective ...exercise to strengthen the gait-related proximal muscles.
Background Auditory P50 suppression, assessed by using a paired auditory stimulus (S1 and S2) paradigm to record P50 mid-latency evoked potential, is assumed to reflect sensory gating. Recently, P50 ...suppression deficits were found in patients with anxiety disorders, including panic disorder, obsessive compulsive disorder, and posttraumatic stress disorder. The processes of fear conditioning are thought to play roles in pathophysiology of anxiety disorders. Our aim was to investigate whether sensory gating would be physiologically altered by fear conditioning. Methods To clarify the relationship between classical fear conditioning and the sensory gating mechanism, we measured changes of P50 and N100 suppression of 21 healthy volunteers in control (baseline) phase, in fear acquisition phase, and in fear extinction phase. Results The mean P50 S2/S1 ratio in fear acquisition phase was significantly elevated in comparison with that in control phase, and it recovered into basal level in extinction phase. In contrast, the mean N100 S2/S1 ratio showed no changes through all phases from fear acquisition to extinction. Conclusions These results suggest that the P50 but not N100 sensory gating mechanism might be physiologically associated with fear acquisition and extinction.
Transcranial direct current stimulation (tDCS) has been reported to modify cortical function by inducing alterations in the underlying brain function. P50auditory evoked potentials, as assessed using ...a paired auditory stimulus (S1 and S2) paradigm, are thought to reflect a sensory gating process in which the functional involvement of the dorsolateral prefrontal cortex (DLPFC) is suggested. P50 sensory gating has also been reported to be associated with the pathogenesis of psychiatric diseases such as schizophrenia and anxiety-related disorders. Here we investigated whether the tDCS over the DLPFC could modulate the cortical function leading to alteration of the P50 sensory gating. P50 gating indices (the S2/S1 ratio and S1-S2 difference) were measured during the tDCS (current 1.0mA, duration 15min) over the DLPFC with different conditions (anodal, cathodal and sham). Ten male healthy volunteers were studied on separate days in a single blinded paradigm. We observed that the cathodaltDCS significantly altered the mean P50 gating indices compared to the other two conditions. Our results suggest that sensory gating could be modulated by cathodaltDCS on the left DLPFC but not by anodal/sham tDCS.
Auditory P50 suppression, which is assessed using a paired auditory stimuli (S1 and S2) paradigm to record the P50 mid-latency evoked potential, is assumed to reflect sensory gating. Recently, P50 ...suppression deficits were observed in patients with anxiety disorders, including panic disorder, post-traumatic stress disorder and obsessive–compulsive disorder, as we previously reported. The processes of fear conditioning are thought to play a role in the pathophysiology of anxiety disorders. In addition, we found that the P50 sensory gating mechanism might be physiologically associated with fear conditioning and extinction in a simple human fear-conditioning paradigm that involved a light signal as a conditioned stimulus (CS+). Our objective was to investigate the different patterns of P50 suppression in a discrimination fear-conditioning paradigm with both a CS+ (danger signal) and a CS− (safety signal). Twenty healthy volunteers were recruited. We measured the auditory P50 suppression in the control (baseline) phase, in the fear-acquisition phase, and in the fear-extinction phase using a discrimination fear-conditioning paradigm. Two-way (CSs vs. phase) Analysis of variance with repeated measures demonstrated a significant interaction between the two factors. Post-hoc LSD analysis indicated that the P50 S2/S1 ratio in the CS+ acquisition phase was significantly higher than that in the CS− acquisition phase. These results suggest that the auditory P50 sensory gating might differ according to the cognition of the properties (potentially dangerous or safe) of the perceived signal.
► Suppression ratio of auditory evoked potential, P50 is assessed with paired- click. ► We measured P50 suppression ratio in a discrimination fear conditioning paradigm. ► Increased ratio was observed during the presentation of a danger signal. ► However, P50 suppression ratio was unchanged in the presentation of a safety signal. ► Results suggest P50 sensory gating may differ with the perceived signal properties.
Abstract. Purpose This study evaluated the effects of repetitive peripheral magnetic stimulation of the soleus muscle on spinal cord and peripheral motor nerve excitability. Subjects and Methods ...Twelve healthy adults (mean age 22 years) who provided written informed consent were administered repetitive peripheral magnetic stimulation for 10 min. Pre-and post-stimulation latencies and amplitudes of H- and M-waves of the soleus muscle were measured using electromyography and compared using paired t-tests. Results Pre- and post-stimulation latencies (28.3 +- 3.3 vs. 29.1 +- 1.3 ms, respectively) and amplitudes (35.8 +- 1.3 vs. 35.8 +- 1.1 mV, respectively) of H-waves were similar. Pre-stimulation latencies of M-waves were significantly higher than post-stimulation latencies (6.1 +- 2.2 vs. 5.0 +- 0.9 ms, respectively), although pre- and post-stimulation amplitudes were similar (12.2 +- 1.4 vs. 12.2 +- 1.3 mV, respectively). Motor neuron excitability, based on the excitability of motor nerves and peripheral nerve action, was increased by M-waves following magnetic stimulation. Conclusion The lack of effect of magnetic stimulation on the amplitude and latency of the H-reflex suggests that magnetic stimulation did not activate sensory nerve synapses of α motor neurons in the spinal cord. However, because motor nerves were stimulated together with sensory nerves, the increased H-wave amplitude may have reflected changes in peripheral rather than in α motor nerves.
Purpose To examine the effect of slopes on standing balance control. Subjects and Methods Fifteen healthy adults (mean age: 21.0 years) maintained an eyes-open standing position for 30 sec with their ...feet 10 cm apart on level ground, and inclining and declining slopes of 8 degrees while their center of gravity sway was measured using a gravicorder. The Index of Postural Stability (IPS) was also calculated in the anteroposterior and mediolateral directions over a 10-second interval. Results Postural sway on the incline was significantly larger than that on the level ground, but IPS did not differ significantly among the conditions. Conclusion The results suggest that the standing postural control of healthy adults does not differ between sloping and a horizontal surfaces because, while there was a significant difference in sway, IPS did not significantly differ.
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