Transcutaneous auricular vagus nerve stimulation modifies cortical excitability in middle-aged and older adults.

There is a growing interest in the clinical application of transcutaneous auricular vagus nerve stimulation (taVNS). However, its effect on cortical excitability, and whether this is modulated by stimulation duration, remains unclear. We evaluated whether taVNS can modify excitability in the primary motor cortex (M1) in middle-aged and older adults and whether the stimulation duration moderates this effect. In addition, we evaluated the blinding efficacy of a commonly reported sham method. In a double-blinded randomized cross-over sham-controlled study, 23 healthy adults (mean age 59.91 ± 6.87 years) received three conditions: active taVNS for 30 and 60 min and sham for 30 min. Single and paired-pulse transcranial magnetic stimulation was delivered over the right M1 to evaluate motor-evoked potentials. Adverse events, heart rate and blood pressure measures were evaluated. Participant blinding effectiveness was assessed via guesses about group allocation. There was an increase in short-interval intracortical inhibition (F = 7.006, p = .002) and a decrease in short-interval intracortical facilitation (F = 4.602, p = .014) after 60 min of taVNS, but not 30 min, compared to sham. taVNS was tolerable and safe. Heart rate and blood pressure were not modified by taVNS (p > .05). Overall, 96% of participants detected active stimulation and 22% detected sham stimulation. taVNS modifies cortical excitability in M1 and its effect depends on stimulation duration in middle-aged and older adults. taVNS increased GABAAergic inhibition and decreased glutamatergic activity. Sham taVNS protocol is credible but there is an imbalance in beliefs about group allocation.

Clinical application of transcutaneous auricular vagus nerve stimulation: a scoping review.

PURPOSE: Transcutaneous auricular vagus nerve stimulation (taVNS) is an emerging non-invasive neuromodulation therapy. This study aimed to explore the therapeutic use of taVNS, optimal stimulation parameters, effective sham protocols, and safety. METHODS: A scoping review was conducted. Five databases and grey literature were searched. The data extracted included stimulation parameters, adverse events (AEs), and therapeutic effects on clinical outcomes. RESULTS: 109 studies were included. taVNS was used across 21 different clinical populations, most commonly in psychiatric, cardiac, and neurological disorders. Overall, 2,214 adults received active taVNS and 1,017 received sham taVNS. Reporting of stimulation parameters was limited and inconsistent. taVNS appeared to have a favourable therapeutic effect across a wide range of clinical populations with varied parameters. Three sham protocols were reported but their effectiveness was documented in only two of the 54 sham-controlled studies. Most reported adverse events were localised to stimulation site. CONCLUSION: There is growing evidence for taVNS therapeutic effect. taVNS appears safe and tolerable. Sham protocols need evaluation. Standardised and comprehensive reporting of both stimulation parameters and adverse events is required. Two different questionnaires have been proposed to evaluate adverse events and the effectiveness of sham methods in blinding participants.

Transcutaneous auricular vagus nerve stimulation (taVNS) showed therapeutic effect across a wide range of clinical populations including depression, epilepsy, and strokeThere is a preliminary indication that daily/weekly dose and overall duration of treatment are important to show therapeutic effectivenessWhen using taVNS as an intervention, the questionnaires proposed in this review should be used to evaluate blinding effectiveness and adverse events.

Robotic Kinematic measures of the arm in chronic Stroke: part 1 - Motor Recovery patterns from tDCS preceding intensive training.

BACKGROUND: Effectiveness of robotic therapy and transcranial direct current stimulation is conventionally assessed with clinical measures. Robotic metrics may be more objective and sensitive for measuring the efficacy of interventions on stroke survivor's motor recovery. This study investigated if robotic metrics detect a difference in outcomes, not seen in clinical measures, in a study of transcranial direct current stimulation (tDCS) preceding robotic therapy. Impact of impairment severity on intervention response was also analyzed to explore optimization of outcomes by targeting patient sub-groups. METHODS: This 2020 study analyzed data from a double-blind, sham-controlled, randomized multi-center trial conducted from 2012 to 2016, including a six-month follow-up. 82 volunteers with single chronic ischemic stroke and right hemiparesis received anodal tDCS or sham stimulation, prior to robotic therapy. Robotic therapy involved 1024 repetitions, alternating shoulder-elbow and wrist robots, for a total of 36 sessions. Shoulder-elbow and wrist kinematic and kinetic metrics were collected at admission, discharge, and follow-up. RESULTS: No difference was detected between the tDCS or sham stimulation groups in the analysis of robotic shoulder-elbow or wrist metrics. Significant improvements in all metrics were found for the combined group analysis. Novel wrist data showed smoothness significantly improved (P < ·001) while submovement number trended down, overlap increased, and interpeak interval decreased. Post-hoc analysis showed only patients with severe impairment demonstrated a significant difference in kinematics, greater for patients receiving sham stimulation. CONCLUSIONS: Robotic data confirmed results of clinical measures, showing intensive robotic therapy is beneficial, but no additional gain from tDCS. Patients with severe impairment did not benefit from the combined intervention. Wrist submovement characteristics showed a delayed pattern of motor recovery compared to the shoulder-elbow, relevant to intensive intervention-related recovery of upper extremity function in chronic stroke. TRIAL REGISTRATION: http://www.clinicaltrials.gov . Actual study start date September 2012. First registered on 15 November 2012. Retrospectively registered. Unique identifiers: NCT01726673 and NCT03562663 .

Robotic Kinematic measures of the arm in chronic Stroke: part 2 - strong correlation with clinical outcome measures.

BACKGROUND: A detailed sensorimotor evaluation is essential in planning effective, individualized therapy post-stroke. Robotic kinematic assay may offer better accuracy and resolution to understand stroke recovery. Here we investigate the added value of distal wrist measurement to a proximal robotic kinematic assay to improve its correlation with clinical upper extremity measures in chronic stroke. Secondly, we compare linear and nonlinear regression models. METHODS: Data was sourced from a multicenter randomized controlled trial conducted from 2012 to 2016, investigating the combined effect of robotic therapy and transcranial direct current stimulation (tDCS). 24 kinematic metrics were derived from 4 shoulder-elbow tasks and 35 metrics from 3 wrist and forearm evaluation tasks. A correlation-based feature selection was performed, keeping only features substantially correlated with the target attribute (R > 0.5.) Nonlinear models took the form of a multilayer perceptron neural network: one hidden layer and one linear output. RESULTS: Shoulder-elbow metrics showed a significant correlation with the Fugl Meyer Assessment (upper extremity, FMA-UE), with a R = 0.82 (P < 0.001) for the linear model and R = 0.88 (P < 0.001) for the nonlinear model. Similarly, a high correlation was found for wrist kinematics and the FMA-UE (R = 0.91 (P < 0.001) and R = 0.92 (P < 0.001) for the linear and nonlinear model respectively). The combined analysis produced a correlation of R = 0.91 (P < 0.001) for the linear model and R = 0.91 (P < 0.001) for the nonlinear model. CONCLUSIONS: Distal wrist kinematics were highly correlated to clinical outcomes, warranting future investigation to explore our nonlinear wrist model with acute or subacute stroke populations. TRIAL REGISTRATION: http://www.clinicaltrials.gov . Actual study start date September 2012. First registered on 15 November 2012. Retrospectively registered. Unique identifiers: NCT01726673 and NCT03562663 .

Telehealth Intervention Programs for Seniors: An Observational Study of a Community-Embedded Health Monitoring Initiative.

Background:Chronic disease in older adults is estimated to account for 84% of annual health care spending in the United States, with many preventable costs expected to rise as the population continues to age.Introduction:Telehealth Intervention Programs for Seniors (TIPS) is a community-embedded program targeting low-income older adults, providing weekly assessment of vital signs and subjective wellness, and wrap-around aging services.Materials and Methods:TIPS recruited 765 volunteers over 55 years, who were Medicaid and/or Medicare eligible. Data were collected from 2014 to 2016 [median enrollment 343 days (105-435)] using 12 TIPS sites. This observational study evaluated the efficacy of TIPS by measuring within-subject changes in self-reported hospital visits and <30-day readmissions, before and during TIPS participation. Data of 617 participants (median age 74.3; interquartile range 16) were analyzed.Results:Self-reported hospital visits were reduced by 28.9% (p = 0.0013). Medicare participants benefited the most, with a 50% (p < 0.0001) reduction in hospital visits, and a 75.5% (p = 0.017) reduction in <30-day readmissions. Multivariate analysis revealed that participants (1) Medicaid-registered (odds ratio [OR] = 2.72, 95% confidence interval [CI] 0.392-1.611), (2) reporting feeling unwell (OR = 1.33, 95% CI 0.118-0.459), and (3) living alone (OR = 2.34, 95% CI 0.115-1.592) were significantly more likely than other participants to experience a hospital visit.Discussion:TIPS demonstrates that community-embedded health services can reduce rates of hospital visits in older adults.Conclusion:The success of TIPS highlights the potential of successfully deployed remote patient-monitoring initiatives in reducing the utilization of costly health services.

Passive Wrist Stiffness: The Influence of Handedness.

OBJECTIVE: This paper reports on the quantification of passive wrist joint stiffness and investigates the potential influence of handedness and gender on stiffness estimates. METHODS: We evaluated the torque-angle relationship during passive wrist movements in 2 degrees of freedom (into flexion-extension and radial-ulnar deviation) in 13 healthy subjects using a wrist robot. Experimental results determined intrasubject differences between dominant and nondominant wrist and intersubject differences between male and female participants. RESULTS: We found differences in the magnitude of passive stiffness of left- and right-hand dominant males and right-hand dominant females suggesting that the dominant hand tends to be stiffer than the nondominant hand. Left-hand stiffness magnitude was found to be 37% higher than the right-hand stiffness magnitude in the left-handed male group and the right-hand stiffness magnitude was 11% and 40% higher in the right-handed male and female groups, respectively. Other joint stiffness features such as the orientation and the anisotropy of wrist stiffness followed the expected pattern from previous studies. CONCLUSION: The observed difference in wrist stiffness between the dominant and nondominant limb is likely due to biomechanical adaptations to repetitive asymmetric activities (such as squash, tennis, basketball, or activities of daily living such as writing, teeth brushing, etc.). SIGNIFICANCE: Understanding and quantifying handedness influence on stiffness may have critical implication for the optimization of surgical and rehabilitative interventions.

Patient Engagement Is Related to Impairment Reduction During Digital Game-Based Therapy in Stroke.

OBJECTIVE: Upper limb impairment in the chronic phase of stroke recovery is persistent, disabling, and difficult to treat. The objectives of this study were to determine whether therapeutic enjoyment is related to clinical improvement after upper limb rehabilitation and to assess the feasibility of a therapy gaming system. MATERIALS AND METHODS: Ten chronic stroke survivors with persistent upper limb impairment were enrolled in the study. Upper limb impairment was evaluated by using the Fugl-Meyer Assessment of Upper Extremity Function (FMA-UE). The Physical Activity Enjoyment Scale (PACES) assessed the level of therapy enjoyment, and the System Usability Scale (SUS) measured the ease of operation of the game. Upper limb therapy involved 30 minutes of novel digital gaming therapy, three times per week, for 6 weeks. RESULTS: The average improvement in the FMA-UE after the digital gaming therapy was 2.8 (±2.1) points. Participants scored the digital gaming system as having good usability (SUS: 72 ± 7.9), and the physical activity as enjoyable (PACES: 65.8 ± 10.6). There was a strong positive correlation between improvement in the FMA-UE score and the PACES (Spearman's Rho = 0.84; P < 0.002). CONCLUSION: This pilot study demonstrates the feasibility and potential for improvements in upper limb motor function by using digital gaming in the chronic stroke patient population. The positive correlation found between therapy enjoyment and clinical gains highlights the importance of engagement in therapy to optimize outcomes in chronic stroke survivors.

MIT-Skywalker: On the use of a markerless system.

This paper describes our efforts to employ the Microsoft Kinect as a low cost vision control system for the MIT-Skywalker, a robotic gait rehabilitation device. The Kinect enables an alternative markerless solution to control the MIT-Skywalker and allows a more user-friendly set-up. A study involving eight healthy subjects and two stroke survivors using the MIT-Skywalker device demonstrates the advantages and challenges of this new proposed approach.

Effects of partial body-weight support and functional electrical stimulation on gait characteristics during treadmill locomotion: Pros and cons of saddle-seat-type body-weight support.

Robotic therapy for rehabilitation of the lower extremity is currently in its early stage of development. Aiming at exploring an efficacious intervention for gait rehabilitation, we investigate the characteristics of an end-effector gait-training device that combines saddle-seat-type body-weight-supported treadmill training with functional electrical stimulation (FES). This is a task-oriented approach to restoring voluntary control of locomotion in patients with neuromuscular diseases. We evaluate the differences between walking with saddle-seat-type support and with harness-type support, in terms of personal preference, the preferred walking speed, profiles of kinematics and ground reaction force, and the effectiveness of FES. The results indicate that the proposed gait-training device maintains subjects in a natural posture and supports important gait functions such as hip extension and ankle push-off effectively, in particular, at slow walking speed.

MIT-Skywalker: Evaluating comfort of bicycle/saddle seat.

The MIT-Skywalker is a robotic device developed for the rehabilitation of gait and balance after a neurological injury. This device has been designed based on the concept of a passive walker and provides three distinct training modes: discrete movement, rhythmic movement, and balance training. In this paper, we present our efforts to evaluate the comfort of a bicycle/saddle seat design for the system's novel actuated body weight support device. We employed different bicycle and saddle seats and evaluated comfort using objective and subjective measures. Here we will summarize the results obtained from a study of fifteen healthy subjects and one stroke patient that led to the selection of a saddle seat design for the MIT-Skywalker.