Changes In Coherence Research Articles

Combining Transcranial Direct Current Stimulation with Exercise to Improve Mobility, Stability, and Tremor Management in 25 Individuals with Parkinson’s Disease

Background/Objectives: Parkinson’s disease (PD) is a neurodegenerative disorder characterized by tremors, balance impairments, and mobility limitations. Innovative approaches like combining transcranial direct current stimulation (tDCS) with exercise show promise in addressing these symptoms. This study investigates the effects of exercise combined with tDCS on mobility and tremor management in PD patients. Methods: Twenty-five individuals aged 60−75 (66.6 ± 7.33), diagnosed with PD (Hoehn and Yahr stage 2−3), were assigned to three groups in a randomized controlled design: exercise with active tDCS (n = 8), exercise with sham tDCS (n = 8), and a control group (n = 9). Dual-task training sessions focusing on walking speed, balance, and force control were conducted over ten sessions. Results: No significant differences were detected across the groups for grip strength or force control measures (p > 0.05). Significant improvements were observed in the intervention group: the Timed Up and Go (TUG) test showed a significant reduction in time (mean difference = 2.498 s, p < 0.001, ηp2 = 0.331); anterior–posterior displacement significantly increased (mean difference = 21.375 mm, p = 0.0269, ηp2 = 0.303); and force-tremor decoupling improved, with coherence in the 1−4 Hz band significantly decreasing (p = 0.0067). Finally, changes in TUG from post- to pre-treatment values were significantly positively correlated with the changes in coherence (R = 0.468, p = 0.018). Conclusions: Combining tDCS with exercise enhances mobility and tremor management in PD patients. These findings support the potential for such interventions to improve functional outcomes and quality of life for individuals with PD.

Bistatic multi‐polarimetric synthetic aperture radar coherence investigation using spatially variant incoherence trimming

AbstractSynthetic Aperture Radar (SAR) Coherent Change Detection allows for the detection of very small scene changes. This is particularly useful for Intelligence, Surveillance and Reconnaissance as small changes such as vehicle tracks can be identified. Rapidly collecting repeat pass SAR imagery is important in these applications. For space‐borne platforms, such repeat passes may however have significant differences, or baselines. Coherent Change Detection products are reliant on high coherence for good interpretability. This work investigates the sources and levels of incoherence associated with bistatic SAR imagery for a variety of baselines using simulations and measured laboratory data for two ground types. Additionally, spatially variant incoherence trimming is implemented. The paper shows the importance of angle‐dependant backscatter on the coherence of sub‐resolution cell scatterers.

Perspective-assisted prototype-based learning for semi-supervised crowd counting

To alleviate the burden of labeling data to train crowd counting models, we propose a prototype-based learning approach for semi-supervised crowd counting with an embeded understanding of perspective. Our key idea is that image patches with the same density of people are likely to exhibit coherent appearance changes under similar perspective distortion, but differ significantly under varying distortions. Motivated by this observation, we construct multiple prototypes for each density level to capture variations in perspective. For labeled data, the prototype-based learning assists the regression task by regularizing the feature space and modeling the relationships within and across different density levels. For unlabeled data, the learnt perspective-embedded prototypes enhance differentiation between samples of the same density levels, allowing for a more nuanced assessment of the predictions. By incorporating regression results, we categorize unlabeled samples as reliable or unreliable, applying tailored consistency learning strategies to enhance model accuracy and generalization. Since the perspective information is often unavailable, we propose a novel pseudo-label assigner based on perspective self-organization which requires no additional annotations and assigns image regions to distinct spatial density groups, which mainly reflect the differences in average density among regions. Extensive experiments on four crowd counting benchmarks demonstrate the effectiveness of our approach.

Effect of lighting conditions on implantable collamer lens vault: Influence of anterior chamber and lens parameters

PurposeTo investigate the change in the vault of the implantable collamer lens (ICL) under dark-to-light conditions and its association with anterior chamber and lens parameters in patients undergoing ICL surgery. MethodsIn 76 eyes from 40 patients, preoperative anterior chamber volume (ACV), pupil diameter (PD), anterior chamber angle, central corneal thickness (CCT), white-to-white (WTW), lens thickness (LT), axial length (AL), spherical equivalent (SE) and patient's age were collected. Postoperative vault, PD and LT were measured under dark and light conditions using anterior segment optical coherence tomography (CASIA2; TOMEY, Japan), and changes and lens displacement under dark-to-light conditions were calculated. Mixed-effects models were used to analyze the correlation between the vault change and the anterior chamber and lens parameters of all subjects and the high-vault subgroup. ResultsThe vault under light condition (648.36 ± 304.47 μm) was significantly smaller compared to the vault under dark condition (708.89 ± 316.15 μm). In all patients, vault change increased with the increase of age, lens displacement and PD change; and increased with the decrease of ACV, LT change and baseline vault (under dark condition). In the high-vault subgroup, vault change increased with the increase of CCT, lens displacement and PD change; and increased with the decrease of ACV. ConclusionsICL vault changes significantly from dark to light, influenced by age, ACV, PD change, LT change, lens displacement, and baseline vault. A higher baseline vault is correlated with a larger LT change, affecting the levels of accommodation under dark-to-light transition.

Wilberforce-like Larmor Magnetic Moment and Spin Precession.

In a Wilberforce pendulum, two mechanical oscillators are coupled: one pertains to the longitudinal (tension) motion and the other to the rotational (twisting) motion. It is shown that the longitudinal magnetic moment of circular currents, and similarly the magnetic moment of a spin-chain, can exhibit a Wilberforce-like vibration. The longitudinal oscillation is related to the Langevin diamagnetism, while the twisting motion is superimposed on the magnetic moment and spin precession. The calculations show that the coupling term is nonlinear in this (longitudinal) vibrating and (magnetic moment) precession system. By increasing the strength of the coupling we arrive at a spectrum, where further vibrational modes can be associated with the rotation of the precession. This means that the extent of the change in coherence can be demonstrated. Since the coupling strength can be different due to local effects, this can be an important factor from the point of view of signal propagation and in preserving signal shapes. The amount specifying the dissipation is introduced to express the degree of deviation. A relationship exists between the parameter characteristic of the coupling strength and how its quantity influences decoherence and dissipation.

Electrical brain networks before and after transcranial pulsed shockwave stimulation in Alzheimer's patients.

Alzheimer's disease (AD) is a neurodegenerative disorder that dramatically affects cognitive abilities and represents the most common cause of dementia. Currently, pharmacological interventions represent the main treatment to deal with the symptoms of AD; however, alternative approaches are readily sought. Transcranial pulse stimulation (TPS) is an emerging non-invasive neuromodulation technique that uses short, repetitive shockwaves with the potential to provide a wide range of vascular, metabolic, and neurotrophic changes and that has recently been shown to improve cognitive abilities in AD. This exploratory study aims to gain insight into the neurophysiological effect of one session of TPS in AD as reflected in electroencephalographic measures, e.g., spectral power, coherence, Tsallis entropy (TE), and cross-frequency coupling (cfc). We document changes in power (frontal and occipital), coherence (frontal, occipital and temporal), and TE (temporal and frontal) as well as changes in cfc (parietal-frontal, parietal-temporal, frontal-temporal). Our results emphasize the role of electroencephalographic measures as prospective markers for the neurophysiological effect of TPS.

Alpha band oscillations in common synaptic input are explanatory of the complexity of isometric knee extensor muscle torque signals.

We investigated whether the strength of oscillations in common synaptic input was explanatory of knee extensor (KE) torque signal complexity during fresh and fatigued submaximal isometric contractions, in adults aged from 18 to 90years. The discharge times of motor units were derived from the vastus lateralis muscle of 60 participants using high-density surface EMG, during 20s isometric KE contractions at 20% of maximal voluntary contraction, performed before and after a fatiguing repeated isometric KE contraction protocol at 60% of maximal voluntary contraction. Within-muscle coherence Z-scores were estimated using frequency-domain coherence analysis, and muscle torque complexity was assessed using multiscale entropy analysis and detrended fluctuation analysis. Alpha band (5-15Hz) coherence was found to predict 23.1% and 31.4% of the variance in the complexity index under 28-scales (CI-28) and detrended fluctuation analysis α complexity metrics, respectively, during the fresh contractions. Delta, alpha and low beta band coherence were significantly increased due to fatigue. Fatigue-related changes in alpha coherence were significantly predictive of the fatigue-related changes in CI-28 and detrended fluctuation analysis α. The fatigue-related increase in sample entropy from scales 11 to 28 of the multiscale entropy analysis curves was significantly predicted by the increase in the alpha band coherence. Age was not a contributory factor to the fatigue-related changes in within-muscle coherence and torque signal complexity. These findings indicate that the strength of alpha band oscillations in common synaptic input can explain, in part, isometric KE torque signal complexity and the fatigue-related changes in torque signal complexity.

Biomarker reconstructions of temperature and hydroclimate variability in Vietnam during Marine Isotope Stage 3

Limited hydrological data coupled with a reliance on the monsoon rains for agriculture make Southeast (SE) Asia vulnerable to climate change. To develop a better understanding of how SE Asia responds to climatic forcings, we provide a paleoclimate perspective by reconstructing temperature and hydroclimate from a wetland outcrop in the Central Highlands of Vietnam (CHV) during Marine Isotope Stage 3 (MIS 3). Mean annual atmospheric temperatures inferred from brGDGTs (branched glycerol dialkyl glycerol tetraethers) indicate an increase from 23 to 26 °C between ∼54 and 37 cal ka BP, which follows an increase in mean annual insolation at the latitude of the site. δDwax data show a shift from a greater proportion of summer monsoon rain derived from the Bay of Bengal between 54 and 49 cal ka BP toward more autumn rain from the South China Sea (also known as the Vietnam East Sea) for most of the rest of the record. brGDGT-inferred soil pH suggests that the climate was wetter at 54 to 49 cal ka BP, then became drier, then returned to wet conditions approaching 37 cal ka BP. Both orbital forcing and changes in the exposure of the Sunda Shelf likely influenced hydroclimate in the CHV. δ13Cwax indicates that C4 plants dominate the vegetation cover during MIS 3. Comparison between our new record from the CHV with existing water isotope proxy records reveals coherent changes with nearby speleothem data, but regional differences between the history of hydroclimate in SE Asia and in the central Indian Monsoon domain. As a snapshot of glacial climate conditions, our data provide new information on the past drivers of climate in an understudied region.

Disrupted coherence between autonomic activation and emotional expression in individuals at clinical high risk for psychosis.

Landmark studies have shown decreased coherence between different emotion response systems (e.g., physiology and facial expressions) in people with psychosis. However, while there is good evidence to suggest broad signs of affective dysfunction (e.g., blunting of facial expression) in the critical clinical high-risk (CHR) state, it is not clear whether these signs fit into a broader pattern of decoupling. This is in part due to there being no studies to date with this population that include a dyadic interaction. The current laboratory-based dyadic interaction study examined whether there is decreased coherence in CHR between autonomic physiology, as indexed by heart rate, and facial expressions of emotion, assessed by automated facial expressions analysis. The study included 145 individuals consisting of 34 CHR-partner and 41 control-partner pairs who completed clinical interviews and engaged in three naturalistic 10-min conversations while their physiology and expressions were continuously monitored. Compared to controls, CHR youth showed decreased coherence between heart rate and positive (t = 4.09) and negative (t = -7.90) facial expressions. Across CHR and control youth, greater severity of psychosis risk symptoms was related to lower coherence between heart rate and positive (t = 3.97-11.69) and neutral expressions (t = 0.06-4.98), and a change in the direction of the relationship between heart rate and negative expression intensity (t = 7.88-10.60). These findings provide the first evidence for changes in coherence between physiology and facial expressions of emotion in CHR individuals, with larger changes in coherence relating to greater general psychotic-like symptom severity. This evidence may be leveraged to identify targets for early diagnosis and intervention. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Sudden change of the geometric quantum discord and quantum coherence in dissipative superconducting circuit systems with the time-dependent electromagnetic field

We investigate the influence of a time-dependent electromagnetic field (TDEF) on the double sudden change of the 1-norm geometric quantum discord (GQD) and sudden change of quantum coherence for superconducting circuit systems under spontaneous emission, where two superconducting qubits are each coupled to their own LC circuit or uniformly coupled to a common LC circuit, respectively. It is shown that the double sudden change of the GQD can be controlled, and the frozen time during which the GQD keeps nearly constant can be lengthened by applying the TDEF. Furthermore, we also find that the TDEF can delay the ‘critical point’ of sudden change for quantum coherence and slow down the decay of quantum coherence. Finally, we explore how the TDEF affects the superconducting circuits system’s information flow by using trace distance and the optimal control scheme is sought by comparing the two coupled modes.

Designed 2D protein crystals as dynamic molecular gatekeepers for a solid-state device

The sensitivity and responsiveness of living cells to environmental changes are enabled by dynamic protein structures, inspiring efforts to construct artificial supramolecular protein assemblies. However, despite their sophisticated structures, designed protein assemblies have yet to be incorporated into macroscale devices for real-life applications. We report a 2D crystalline protein assembly of C98/E57/E66L-rhamnulose-1-phosphate aldolase (CEERhuA) that selectively blocks or passes molecular species when exposed to a chemical trigger. CEERhuA crystals are engineered via cobalt(II) coordination bonds to undergo a coherent conformational change from a closed state (pore dimensions <1 nm) to an ajar state (pore dimensions ~4 nm) when exposed to an HCN(g) trigger. When layered onto a mesoporous silicon (pSi) photonic crystal optical sensor configured to detect HCN(g), the 2D CEERhuA crystal layer effectively blocks interferents that would otherwise result in a false positive signal. The 2D CEERhuA crystal layer opens in selective response to low-ppm levels of HCN(g), allowing analyte penetration into the pSi sensor layer for detection. These findings illustrate that designed protein assemblies can function as dynamic components of solid-state devices in non-aqueous environments.

Fatigue-related changes in intermuscular electromyographic coherence across rotator cuff and deltoid muscles in individuals with and without subacromial pain.

Neuromuscular fatigue induces superior migration of the humeral head in individuals with subacromial pain. This has been attributed to weakness of rotator cuff muscles and overactive deltoid muscles. Investigation of common inputs to motoneuron pools of the rotator cuff and deltoid muscles offers valuable insight into the underlying mechanisms of neuromuscular control deficits associated with subacromial pain. This study aims to investigate intermuscular coherence across the rotator cuff and deltoid muscles during a sustained submaximal isometric fatiguing contraction in individuals with and without subacromial pain. Twenty symptomatic and 18 asymptomatic young adults participated in this study. Surface electromyogram (EMG) was recorded from the middle deltoid (MD) and infraspinatus (IS). Intramuscular EMG was recorded with fine-wire electrodes in the supraspinatus (SS). Participants performed an isometric fatiguing contraction of 30° scaption at 25% maximum voluntary contraction (MVC) until endurance limit. Pooled coherence of muscle pairs (SS-IS, SS-MD, IS-MD) in the 2-5 Hz (delta), 5-15 Hz (alpha), and 15-35 Hz (beta) frequency bands during the initial and final 30 s of the fatigue task were compared. SS-IS and SS-MD delta-band coherence increased with fatigue in the asymptomatic group but not the symptomatic group. In the alpha and beta bands, SS-IS and SS-MD coherence increased with fatigue in both groups. IS-MD beta-band coherence was greater in the symptomatic than the asymptomatic group. Individuals with subacromial pain failed to increase common drive across rotator cuff and deltoid muscles and have altered control strategies during neuromuscular fatigue. This may contribute to glenohumeral joint instability and subacromial pain experienced by these individuals.NEW & NOTEWORTHY Through the computation of shared neural drive across glenohumeral muscles, this study reveals that individuals with subacromial pain were unable to increase shared neural drive within the rotator cuff and across the supraspinatus and deltoid muscles during neuromuscular fatigue induced by sustained isometric contraction. These deficits in common drive across the shoulder muscles likely contribute to the joint instability and pain experienced by these individuals.

Exploring neurocognitive features in adolescents and young adults with anorexia nervosa: Evidence from a longitudinal study.

We aimed to evaluate longitudinal changes in set-shifting and central coherence in a predominantly adolescent cohort with anorexia nervosa (AN) and to explore whether these factors predict long-term eating disorder outcomes. Ninety-two female patients with AN (mean age: 16.2, range: 13-21years) completed neurocognitive tests (Rey Complex Figure Test, Adapted Version of the Wisconsin Card Sorting Test) before and after 12months of psychotherapeutic treatment (n=45 Maudsley AN Treatment, MANTRa; n=47 standard psychotherapy; groups not randomised). Eating disorder severity was assessed at baseline, after 6, 12 and 18months. Central coherence (indicated by an increase in the Rey Figure Style Index) and set-shifting (indicated by a reduction in the percentage of perseverative errors) significantly improved over the course of treatment, with similar outcomes across groups. Lower central coherence was associated with higher eating disorder severity. Individuals with lower baseline set-shifting ability tended to have worse eating disorder outcomes in the long-term. However, this trend did not reach statistical significance in a multilevel linear mixed model. Neurocognitive difficulties in adolescents and young adults with AN can improve after treatment. Interventions specifically addressing flexibility in thinking and behaviour may contribute to treatment success.

Exploring the local field potential signal from the subthalamic nucleus for phase-targeted auditory stimulation in Parkinson's disease

BackgroundEnhancing slow waves, the electrophysiological (EEG) manifestation of non-rapid eye movement (NREM) sleep, could potentially benefit patients with Parkinson's disease (PD) by improving sleep quality and slowing disease progression. Phase-targeted auditory stimulation (PTAS) is an approach to enhance slow waves, which are detected in real-time in the surface EEG signal. ObjectiveWe aimed to test whether the local-field potential of the subthalamic nucleus (STN-LFP) can be used to detect frontal slow waves and assess the electrophysiological changes related to PTAS. MethodsWe recruited patients diagnosed with PD and undergoing Percept™ PC neurostimulator (Medtronic) implantation for deep brain stimulation of STN (STN-DBS) in a two-step surgery. Patients underwent three full-night recordings, including one between-surgeries recording and two during rehabilitation, one with DBS+ (on) and one with DBS- (off). Surface EEG and STN-LFP signals from Percept PC were recorded simultaneously, and PTAS was applied during sleep in all three recording sessions. ResultsOur results show that during NREM sleep, slow waves of the cortex and STN are time-locked. PTAS application resulted in power and coherence changes, which can be detected in STN-LFP. ConclusionOur findings suggest the feasibility of implementing PTAS using solely STN-LFP signal for slow wave detection, thus without a need for an external EEG device alongside the implanted neurostimulator. Moreover, we propose options for more efficient STN-LFP signal preprocessing, including different referencing and filtering to enhance the reliability of cortical slow wave detection in STN-LFP recordings.

Investigating the effects of chiropractic care on resting-state EEG of MCI patients.

Mild cognitive impairment (MCI) is a stage between health and dementia, with various symptoms including memory, language, and visuospatial impairment. Chiropractic, a manual therapy that seeks to improve the function of the body and spine, has been shown to affect sensorimotor processing, multimodal sensory processing, and mental processing tasks. In this paper, the effect of chiropractic intervention on Electroencephalogram (EEG) signals in patients with mild cognitive impairment was investigated. EEG signals from two groups of patients with mild cognitive impairment (n = 13 people in each group) were recorded pre- and post-control and chiropractic intervention. A comparison of relative power was done with the support vector machine (SVM) method and non-parametric cluster-based permutation test showing the two groups could be separately identified with high accuracy. The highest accuracy was obtained in beta2 (25-35 Hz) and theta (4-8 Hz) bands. A comparison of different brain areas with the SVM method showed that the intervention had a greater effect on frontal areas. Also, interhemispheric coherence in all regions increased significantly after the intervention. The results of the Wilcoxon test showed that intrahemispheric coherence changes in frontal-occipital, frontal-temporal and right temporal-occipital regions were significantly different in two groups. Comparison of the results obtained from chiropractic intervention and previous studies shows that chiropractic intervention can have a positive effect on MCI disease and using this method may slow down the progression of mild cognitive impairment to Alzheimer's disease.

Google Earth Engine and Machine Learning for Flash Flood Exposure Mapping—Case Study: Tetouan, Morocco

Recently, the earth’s climate has changed considerably, leading to several hazards, including flash floods (FFs). This study aims to introduce an innovative approach to mapping and identifying FF exposure in the city of Tetouan, Morocco. To address this problem, the study uses different machine learning methods applied to remote sensing imagery within the Google Earth Engine (GEE) platform. To achieve this, the first phase of this study was to map land use and land cover (LULC) using Random Forest (RF), a Support Vector Machine (SVM), and Classification and Regression Trees (CART). By comparing the results of five composite methods (mode, maximum, minimum, mean, and median) based on Sentinel images, LULC was generated for each method. In the second phase, the precise LULC was used as a related factor to others (Stream Power Index (SPI), Topographic Position Index (TPI), Slope, Profile Curvature, Plan Curvature, Aspect, Elevation, and Topographic Wetness Index (TWI)). In addition to 2024 non-flood and flood points to predict and detect FF susceptibility, 70% of the dataset was used to train the model by comparing different algorithms (RF, SVM, Logistic Regression (LR), Multilayer Perceptron (MLP), and Naive Bayes (NB)); the rest of the dataset (30%) was used for evaluation. Model performance was evaluated by five-fold cross-validation to assess the model’s ability on new data using metrics such as precision, score, kappa index, recall, and the receiver operating characteristic (ROC) curve. In the third phase, the high FF susceptibility areas were analyzed for two-way validation with inundated areas generated from Sentinel-1 SAR imagery with coherent change detection (CDD). Finally, the validated inundation map was intersected with the LULC areas and population density for FF exposure and assessment. The initial results of this study in terms of LULC mapping showed that the most appropriate method in this research region is the use of an SVM trained on a mean composite. Similarly, the results of the FF susceptibility assessment showed that the RF algorithm performed best with an accuracy of 96%. In the final analysis, the FF exposure map showed that 2465 hectares were affected and 198,913 inhabitants were at risk. In conclusion, the proposed approach not only allows us to assess the impact of FF in this study area but also provides a versatile approach that can be applied in different regions around the world and can help decision-makers plan FF mitigation strategies.

Когерентность ЭЭГ у детей с ДЦП на фоне реабилитации с применением нейроинтерфейса «мозг – компьютер – экзоскелет кисти»

Neurorehabilitation courses employing a non-invasive brain-computer-hand exoskeleton interface in combination with traditional balneotherapy have been shown to reduce spasticity of hand muscles and improve motor skills in children with cerebral palsy. However, the coherence of the electroencephalogram (EEG) parameters have never been analyzed during such sessions. This study aimed to analyze the coherence changes in the bands of θ, α and β rhythms recorded in the EEG as part of balneotherapy combined with a course of neurorehabilitation prescribed to children with cerebral palsy, and to investigate the relationship of these changes with the indicators of motor activity. The study involved 23 children aged 7 through 15 years, both genders, diagnosed with spastic diplegia; we established coherence coefficients for the intra- and interhemispheric connections of the frontal, central, and parietal regions of the large hemispheres in the context of actions provoking kinesthetic imagery. A significant (p &lt; 0.05) growth of the intrahemispheric connections coherence was registered for α rhythms, decline thereof — for θ, β1 rhythms, the fluctuations accompanied by a significant (p &lt; 0.001) improvement of the motor functions on the Barthel scale. We identified a relationship between — rhythm coherence in the pair of C4–CP4 leads and the value of the Barthel index (r = 0.52; p = 0.04). The specifics of changes in the coherence of intrahemispheric connections within the studied rhythms can be used as indicators of neuroplasticity in children with cerebral palsy during rehabilitation, and support development of the new versions of the neurointerfaces classifier programs.

Interannual changes in atmospheric oxidation over forests determined from space.

The hydroxyl radical (OH) is the central oxidant in Earth's troposphere, but its temporal variability is poorly understood. We combine 2012-2020 satellite-based isoprene and formaldehyde measurements to identify coherent OH changes over temperate and tropical forests with attribution to emission trends, biotic stressors, and climate. We identify a multiyear OH decrease over the Southeast United States and show that with increasingly hot/dry summers the regional chemistry could become even less oxidizing depending on competing temperature/drought impacts on isoprene. Furthermore, while global mean OH decreases during El Niño, we show that near-field effects over tropical rainforests can alternate between high/low OH anomalies due to opposing fire and biogenic emission impacts. Results provide insights into how atmospheric oxidation will evolve with changing emissions and climate.

Improvements in motor control are associated with improved quality of life following an at-home muscle biofeedback program for chronic stroke.

Chronic stroke survivors with severe arm impairment have limited options for effective rehabilitation. High intensity, repetitive task practice (RTP) is known to improve upper limb function among stroke survivors who have some volitional muscle activation. However, clients without volitional movement of their arm are ineligible for RTP-based interventions and require hands-on facilitation from a clinician or robotic therapy to simulate task practice. Such approaches can be expensive, burdensome, and have marginal effects. Alternatively, supervised at-home telerehabilitation using muscle biofeedback may provide a more accessible, affordable, and effective rehabilitation option for stroke survivors with severe arm impairment, and could potentially help people with severe stroke regain enough volitional activation to be eligible for RTP-types of therapies. Feedback of muscle activity via electromyography (EMG) has been previously used with clients who have minimal or no movement to improve functional performance. Specifically, training to reduce unintended co-contractions of the impaired hand using EMG biofeedback may modestly improve motor control in people with limited movement. Importantly, these modest and covert functional changes may influence the perceived impact of stroke-related disability in daily life. In this manuscript, we examine whether physical changes following use of a portable EMG biofeedback system (Tele-REINVENT) for severe upper limb hemiparesis also relate to perceived quality of life improvements. Secondarily, we examined the effects of Tele-REINVENT, which uses EMG to quantify antagonistic muscle activity during movement attempt trials and transform individuated action into computer game control, on several different domains of stroke recovery. For this pilot study, nine stroke survivors (age = 37-73 years) with chronic impairment (Fugl-Meyer = 14-40/66) completed 30 1-hour sessions of home-based training, consisting of six weeks of gaming that reinforced wrist extensor muscle activity while attenuating coactivation of flexor muscles. To assess motor control and performance, we measured changes in active wrist ranges of motion, the Fugl-Meyer Assessment, and Action Research Arm Test. We also collected an EMG-based test of muscle control to examine more subtle changes. To examine changes in perceived quality of life, we utilized the Stroke Impact Scale along with participant feedback. Results from our pilot data suggest that 30 sessions of remote training can induce modest changes on clinical and functional assessments, showing a statistically significant improvement of active wrist ranges of motion at the group level, changes that could allow some people with severe stroke to be eligible for other therapeutic approaches, such as RTP. Additionally, changes in motor control were correlated with the perceived impact of stroke on participation and impairment after training. We also report changes in corticomuscular coherence, which showed a laterality change from the ipsilesional motor cortex towards the contralesional hemisphere during wrist extension attempts. Finally, all participants showed high adherence to the protocol and reported enjoying using the system. Overall, Tele-REINVENT represents a promising telerehabilitation intervention that might improve sensorimotor outcomes in severe chronic stroke, and that improving sensorimotor abilities even modestly may improve quality of life. We propose that Tele-REINVENT may be used as a precursor to help participants gain enough active movement to participate other occupational therapy interventions, such as RTP. Future work is needed to examine if home-based telerehabilitation to provide feedback of individuated muscle activity could increase meaningful rehabilitation accessibility and outcomes for underserved populations.

Altered Cortical Activity during a Finger Tap in People with Stroke.

This study describes electroencephalography (EEG) measurements during a simple finger movement in people with stroke to understand how temporal patterns of cortical activation and network connectivity align with prolonged muscle contraction at the end of a task. We investigated changes in the EEG temporal patterns in the beta band (13-26Hz) of people with chronic stroke (N = 10, 7F/3M) and controls (N = 10, 7F/3M), during and after a cued movement of the index finger. We quantified the change in beta band EEG power relative to baseline as activation at each electrode and the change in task-based phase-locking value (tbPLV) and beta band task-based coherence (tbCoh) relative to baseline coherence as connectivity between EEG electrodes. Finger movements were associated with a decrease in beta power (event related desynchronization (ERD)) followed by an increase in beta power (event related resynchronization (ERS)). The ERS in the post task period was lower in the stroke group (7%), compared to controls (44%) (p < 0.001) and the transition from ERD to ERS was delayed in the stroke group (1.43s) compared to controls (0.90s) in the C3 electrode (p = 0.007). In the same post movement period, the stroke group maintained a heightened tbPLV (p = 0.030 for time to baseline of the C3:Fz electrode pair) and did not show the decrease in connectivity in electrode pair C3:Fz that was observed in controls (tbPLV: p = 0.006; tbCoh: p = 0.023). Our results suggest that delays in cortical deactivation patterns following movement coupled with changes in the time course of connectivity between the sensorimotor and frontal cortices in the stroke group might explain clinical observations of prolonged muscle activation in people with stroke. This prolonged activation might be attributed to the combination of cortical reorganization and changes to sensory feedback post-stroke.