Neural coupling between upper and lower limb muscles in Parkinsonian gait

The Effects of Whole-Body Vibration Therapy in Weight-Bearing and Non-Weight-Bearing Positions for Upper and Lower Extremities on Balance and Function in Cerebral Palsy Children: A Randomized Controlled Trial

Background and objective Cerebral palsy (CP) is one of the most prevalent neurological conditions affecting children; it is characterized by poor motor control, restricted range of motion (ROM), and poor balance. While whole-body vibration therapy (WBVT) has been used to treat these symptoms, its efficacy in different configurations remains unexplored. Hence, this study aimed to determine and compare the effects of WBVT applied to either the upper extremities, lower extremities, or both upper and lower extremities in weight-bearing and non-weight-bearing positions on ROM (shoulders, elbows, wrists, hips, knees, and ankle joints), balance, and function in children with spastic hemiplegic CP. Methods This randomized clinical trial involved 60 hemiplegic spastic CP children aged 5-15 years. After randomization, all the participants were divided into six groups of equal size based on the WBVT application for upper extremities, lower extremities, or both in weight-bearing or non-weight-bearing positions. The therapy was applied three times per week for four consecutive weeks. The outcome measures were ROM, hand grip strength, balance quantification score using My Fitness Trainer (MFT) 2.0, and timed up and go (TUG) scores. Results While all the groups were homogenous before treatment, after treatment, it was observed that all the ranges improved significantly in all groups. The same was observed for hand grip strength, balance score, and TUG test scores (p<0.05). The post-hoc analysis revealed that the weight-bearing position for the upper and lower extremities combined showed the highest level of improvement. Conclusions Based on our findings, WBVT in weight-bearing positions produces more significant results than in non-weight-bearing positions. We also observed that when WBVT is applied to the upper extremities, it can improve the function of the lower extremities and vice versa.

Is there frequency-specificity in the motor control of walking? The putative differential role of alpha and beta oscillations

Alpha and beta oscillations have been assessed thoroughly during walking due to their potential role as proxies of the corticoreticulospinal tract (CReST) and corticospinal tract (CST), respectively. Given that damage to a descending tract after stroke can cause walking deficits, detailed knowledge of how these oscillations mechanistically contribute to walking could be utilized in strategies for post-stroke locomotor recovery. In this review, the goal was to summarize, synthesize, and discuss the existing evidence on the potential differential role of these oscillations on the motor descending drive, the effect of transcranial alternate current stimulation (tACS) on neurotypical and post-stroke walking, and to discuss remaining gaps in knowledge, future directions, and methodological considerations. Electrophysiological studies of corticomuscular, intermuscular, and intramuscular coherence during walking clearly demonstrate that beta oscillations are predominantly present in the dorsiflexors during the swing phase and may be absent post-stroke. The role of alpha oscillations, however, has not been pinpointed as clearly. We concluded that both animal and human studies should focus on the electrophysiological characterization of alpha oscillations and their potential role to the CReST. Another approach in elucidating the role of these oscillations is to modulate them and then quantify the impact on walking behavior. This is possible through tACS, whose beneficial effect on walking behavior (including boosting of beta oscillations in intramuscular coherence) has been recently demonstrated in both neurotypical adults and stroke patients. However, these studies still do not allow for specific roles of alpha and beta oscillations to be delineated because the tACS frequency used was much lower (i.e., individualized calculated gait frequency was used). Thus, we identify a main gap in the literature, which is tACS studies actually stimulating at alpha and beta frequencies during walking. Overall, we conclude that for beta oscillations there is a clear connection to descending drive in the corticospinal tract. The precise relationship between alpha oscillations and CReST remains elusive due to the gaps in the literature identified here. However, better understanding the role of alpha (and beta) oscillations in the motor control of walking can be used to progress and develop rehabilitation strategies for promoting locomotor recovery.