Shashank Ghai

Effect of rhythmic auditory cueing on parkinsonian gait: A systematic review and meta-analysis

The use of rhythmic auditory cueing to enhance gait performance in parkinsonian patients’ is an emerging area of interest. Different theories and underlying neurophysiological mechanisms have been suggested for ascertaining the enhancement in motor performance. However, a consensus as to its effects based on characteristics of effective stimuli, and training dosage is still not reached. A systematic review and meta-analysis was carried out to analyze the effects of different auditory feedbacks on gait and postural performance in patients affected by Parkinson’s disease. Systematic identification of published literature was performed adhering to PRISMA guidelines, from inception until May 2017, on online databases; Web of science, PEDro, EBSCO, MEDLINE, Cochrane, EMBASE and PROQUEST. Of 4204 records, 50 studies, involving 1892 participants met our inclusion criteria. The analysis revealed an overall positive effect on gait velocity, stride length, and a negative effect on cadence with application of auditory cueing. Neurophysiological mechanisms, training dosage, effects of higher information processing constraints, and use of cueing as an adjunct with medications are thoroughly discussed. This present review bridges the gaps in literature by suggesting application of rhythmic auditory cueing in conventional rehabilitation approaches to enhance motor performance and quality of life in the parkinsonian community.

Effects of dual tasks and dual-task training on postural stability: a systematic review and meta-analysis

The use of dual-task training paradigm to enhance postural stability in patients with balance impairments is an emerging area of interest. The differential effects of dual tasks and dual-task training on postural stability still remain unclear. A systematic review and meta-analysis were conducted to analyze the effects of dual task and training application on static and dynamic postural stability among various population groups. Systematic identification of published literature was performed adhering to Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines, from inception until June 2016, on the online databases Scopus, PEDro, MEDLINE, EMBASE, and SportDiscus. Experimental studies analyzing the effects of dual task and dual-task training on postural stability were extracted, critically appraised using PEDro scale, and then summarized according to modified PEDro level of evidence. Of 1,284 records, 42 studies involving 1,480 participants met the review’s inclusion criteria. Of the studies evaluating the effects of dual-task training on postural stability, 87.5% of the studies reported significant enhancements, whereas 30% of the studies evaluating acute effects of dual tasks on posture reported significant enhancements, 50% reported significant decrements, and 20% reported no effects. Meta-analysis of the pooled studies revealed moderate but significant enhancements of dual-task training in elderly participants (95% CI: 1.16–2.10) and in patients suffering from chronic stroke (−0.22 to 0.86). The adverse effects of complexity of dual tasks on postural stability were also revealed among patients with multiple sclerosis (−0.74 to 0.05). The review also discusses the significance of verbalization in a dual-task setting for increasing cognitive–motor interference. Clinical implications are discussed with respect to practical applications in rehabilitation settings.

The influence of below-knee compression garments on knee-joint proprioception

OBJECTIVE The purpose of the study was to assess the influence of below-knee compression garments on proprioception accuracy under, information processing constraints designed to cause high or low conscious attention to the task. METHODS In a counterbalanced, single-blinded, crossover trial, 44 healthy participants (26 male/18 female) with a mean age of 22.7±6.9 years performed an active joint repositioning task using their nondominant and their dominant leg, with and without below-knee compression and with and without conducting a secondary task. RESULTS Analysis of variance revealed no main effect of leg dominance and no interactions (ps>0.05). However, a main effect was evident for both compression (F1, 43=84.23, p<0.001, ηp2=0.665) and secondary task (F1, 43=4.391, p=0.04, ηp2=0.093). CONCLUSIONS The study is the first to evaluate the effects of a belowknee compression garment on knee proprioception under differential information processing constraints. We conclude that proprioception accuracy of the knee joint is significantly enhanced post application of below-knee compression garments and when a secondary task is conducted concurrently with active joint repositioning. The findings suggest that below-knee compression garments may improve proprioception of the knee, regardless of leg dominance, and that secondary tasks that direct attention away from proprioceptive judgments may also improve proprioception, regardless of the presence of compression. Clinical implications are discussed with respect to proprioception in modern.sports and rehabilitation settings.

Effect of rhythmic auditory cueing on gait in cerebral palsy: a systematic review and meta-analysis

Auditory entrainment can influence gait performance in movement disorders. The entrainment can incite neurophysiological and musculoskeletal changes to enhance motor execution. However, a consensus as to its effects based on gait in people with cerebral palsy is still warranted. A systematic review and meta-analysis were carried out to analyze the effects of rhythmic auditory cueing on spatiotemporal and kinematic parameters of gait in people with cerebral palsy. Systematic identification of published literature was performed adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analyses and American Academy for Cerebral Palsy and Developmental Medicine guidelines, from inception until July 2017, on online databases: Web of Science, PEDro, EBSCO, Medline, Cochrane, Embase and ProQuest. Kinematic and spatiotemporal gait parameters were evaluated in a meta-analysis across studies. Of 547 records, nine studies involving 227 participants (108 children/119 adults) met our inclusion criteria. The qualitative review suggested beneficial effects of rhythmic auditory cueing on gait performance among all included studies. The meta-analysis revealed beneficial effects of rhythmic auditory cueing on gait dynamic index (Hedge’s g=0.9), gait velocity (1.1), cadence (0.3), and stride length (0.5). This review for the first time suggests a converging evidence toward application of rhythmic auditory cueing to enhance gait performance and stability in people with cerebral palsy. This article details underlying neurophysiological mechanisms and use of cueing as an efficient home-based intervention. It bridges gaps in the literature, and suggests translational approaches on how rhythmic auditory cueing can be incorporated in rehabilitation approaches to enhance gait performance in people with cerebral palsy.

“Low road” to rehabilitation: a perspective on subliminal sensory neuroprosthetics

Fear can propagate parallelly through both cortical and subcortical pathways. It can instigate memory consolidation habitually and might allow internal simulation of movements independent of the cortical structures. This perspective suggests delivery of subliminal, aversive and kinematic audiovisual stimuli via neuroprosthetics in patients with neocortical dysfunctions. We suggest possible scenarios by which these stimuli might bypass damaged neocortical structures and possibly assisting in motor relearning. Anticipated neurophysiological mechanisms and methodological scenarios have been discussed in this perspective. This approach introduces novel perspectives into neuropsychology as to how subcortical pathways might be used to induce motor relearning.

Auditory Proprioceptive Integration: Effects of Real-Time Kinematic Auditory Feedback on Knee Proprioception

The purpose of the study was to assess the influence of real-time auditory feedback on knee proprioception. Thirty healthy participants were randomly allocated to control (n = 15), and experimental group I (15). The participants performed an active knee-repositioning task using their dominant leg, with/without additional real-time auditory feedback where the frequency was mapped in a convergent manner to two different target angles (40 and 75°). Statistical analysis revealed significant enhancement in knee re-positioning accuracy for the constant and absolute error with real-time auditory feedback, within and across the groups. Besides this convergent condition, we established a second divergent condition. Here, a step-wise transposition of frequency was performed to explore whether a systematic tuning between auditory-proprioceptive repositioning exists. No significant effects were identified in this divergent auditory feedback condition. An additional experimental group II (n = 20) was further included. Here, we investigated the influence of a larger magnitude and directional change of step-wise transposition of the frequency. In a first step, results confirm the findings of experiment I. Moreover, significant effects on knee auditory-proprioception repositioning were evident when divergent auditory feedback was applied. During the step-wise transposition participants showed systematic modulation of knee movements in the opposite direction of transposition. We confirm that knee re-positioning accuracy can be enhanced with concurrent application of real-time auditory feedback and that knee re-positioning can modulated in a goal-directed manner with step-wise transposition of frequency. Clinical implications are discussed with respect to joint position sense in rehabilitation settings.

Understanding antibiotic resistance via outer membrane permeability

Collective antibiotic drug resistance is a global threat, especially with respect to Gram-negative bacteria. The low permeability of the bacterial outer cell wall has been identified as a challenging barrier that prevents a sufficient antibiotic effect to be attained at low doses of the antibiotic. The Gram-negative bacterial cell envelope comprises an outer membrane that delimits the periplasm from the exterior milieu. The crucial mechanisms of antibiotic entry via outer membrane includes general diffusion porins (Omps) responsible for hydrophilic antibiotics and lipid-mediated pathway for hydrophobic antibiotics. The protein and lipid arrangements of the outer membrane have had a strong impact on the understanding of bacteria and their resistance to many types of antibiotics. Thus, one of the current challenges is effective interpretation at the molecular basis of the outer membrane permeability. This review attempts to develop a state of knowledge pertinent to Omps and their effective role in solute influx. Moreover, it aims toward further understanding and exploration of prospects to improve our knowledge of physicochemical limitations that direct the translocation of antibiotics via bacterial outer membrane.

Training proprioception with sound: effects of real-time auditory feedback on intermodal learning: Effects of sonification on intermodal learning

Our study analyzed the effects of real‐time auditory feedback on intermodal learning during a bilateral knee repositioning task. Thirty healthy participants were randomly allocated to control and experimental groups. Participants performed an active knee joint repositioning task for the four target angles (20°, 40°, 60°, and 80°) bilaterally, with or without additional real‐time auditory feedback. Here, the frequency of auditory feedback was mapped to the knees angle range (0–90°). Retention measurements were performed on the same four angles, without auditory feedback, after 15 min and 24 hours. A generalized knee proprioception test was performed after the 24‐h retention measurement on three untrained knee angles (15°, 35°, and 55°). Statistical analysis revealed a significant enhancement of knee proprioception, shown as a lower knee repositioning error with auditory feedback. This enhancement of proprioception also persisted in tests performed between the 5th and 6th auditory–motor training blocks (without auditory feedback). Enhancement in proprioception also remained stable during retention measurements (after 15 min and 24 h). Similarly, enhancement in the generalized proprioception on untrained knee angles was evident in the experimental group. This study extends our previous findings and demonstrates the beneficial effects of real‐time auditory feedback to facilitate intermodal learning by enhancing knee proprioception in a persisting and generalized manner.

Exploring bacterial outer membrane barrier to combat bad bugs

One of the main fundamental mechanisms of antibiotic resistance in Gram-negative bacteria comprises an effective change in the membrane permeability to antibiotics. The Gram-negative bacterial complex cell envelope comprises an outer membrane that delimits the periplasm from the exterior environment. The outer membrane contains numerous protein channels, termed as porins or nanopores, which are mainly involved in the influx of hydrophilic compounds, including antibiotics. Bacterial adaptation to reduce influx through these outer membrane proteins (Omps) is one of the crucial mechanisms behind antibiotic resistance. Thus to interpret the molecular basis of the outer membrane permeability is the current challenge. This review attempts to develop a state of knowledge pertinent to Omps and their effective role in antibiotic influx. Further, it aims to study the bacterial response to antibiotic membrane permeability and hopefully provoke a discussion toward understanding and further exploration of prospects to improve our knowledge on physicochemical parameters that direct the translocation of antibiotics through the bacterial membrane protein channels.