Marcadores Neurales como Indicadores de Funciones Predictivas en Pacientes con Traumatismo Cerebral Moderado a Severo / Neural Markers as Indicators of Predictive Functions in Patients with Moderate to Severe Brain Trauma

Introducción. El traumatismo encéfalo craneano moderado a severo (TEC-MS) es una condición compleja que cambia la estructura y función del cerebro, afectando a personas de distintas edades. Los problemas cognitivos y motores son la mayor causa de discapacidad en individuos con TEC-MS crónico. Sin embargo, muchas de estas dificultades no son visibles de inmediato clasificándose como una "Epidemia silenciosa". Las principales alteraciones reportadas por los pacientes tienen relación con problemas de la memoria, atención y lentitud psicomotora, los cuales tienen un impacto en su independencia y funcionalidad. Objetivo. Este estudio tiene por objetivo discutir y revisar la evidencia disponible acerca de la capacidad de los pacientes crónicos con TEC-MS para generar predicciones en diferentes niveles de procesamiento cerebral. Métodos. Para esto, utilizamos desde las neurociencias el modelo teórico del código predictivo para explicar las respuestas neurofisiológicas adquiridas bajo un paradigma de predicción auditiva. Esta información es complementada con el reporte de datos preliminares de sujetos con TEC-MS y sujetos control, con el fin de ilustrar los aspectos teóricos discutidos. Conclusiones. Esto podría contribuir a una mejor comprensión de los mecanismos neurales detrás de los déficits cognitivos en esta población, aportando una perspectiva que nos oriente al desarrollo de nuestras estrategias terapéuticas.

Background. Moderate to severe traumatic brain injury (TBI-MS) is a complex condition that changes the structure and function of the brain, affecting people of different ages. Cognitive and motor problems are the major cause of disability in individuals with chronic ECT-MS. However, many of these difficulties are not immediately visible, classifying them as a "Silent Epidemic." The main alterations reported by patients are related to problems with memory, attention and psychomotor slowness, which have an impact on their independence and functionality. Objetive. This study aims to discuss and review the available evidence about the ability of chronic ECT-MS patients to generate predictions at different levels of brain processing. Methods. For this, we use the theoretical model of the predictive code from neuroscience to explain the neurophysiological responses acquired under an auditory prediction paradigm. This information is complemented with the report of preliminary data from subjects with ECT-MS and control subjects, in order to illustrate the theoretical aspects discussed. Conclusions. This could contribute to a better understanding of the neural mechanisms behind cognitive deficits in this population, providing a perspective that guides us in the development of our therapeutic strategies.

Uso de Electromiografía de Alta Densidad en las Distrofias Musculares: una Mirada Actual / Use of high-density electromyography in muscular dystrophies: a current look

Introducción. Las distrofias musculares son trastornos genéticamente heredados que causan la degeneración progresiva de las fibras musculares. La electromiografía, especialmente la de alta densidad, se ha convertido en una herramienta valiosa para el diagnóstico y el estudio de la función muscular de trastornos neuromusculares. Objetivo. Describir y discutir el uso actual de esta técnica en las distrofias musculares. Métodos. Se realizó un Scoping Review sobre el uso de electromiografía de alta densidad en personas con distrofia muscular. Se buscó en PubMed, ScienceDirect, Scopus, Web of Science y Biblioteca Cochrane Plus, usando palabras clave en inglés y español. Se consideraron estudios desde 2015 a la fecha. Se identificaron tres artículos que cumplían con los criterios establecidos. Resultados. Los estudios se centraron en aplicaciones clínicas y de bioingeniería para personas con distrofia muscular de Duchenne y distrofia facioescapulohumeral. Los resultados sugieren que variables como la fatiga, la activación temporo-espacial y la dimensionalidad en gestos motores están determinados por la degeneración de las fibras musculares, el reemplazo por tejido fibrótico, los cambios adaptativos y la debilidad muscular progresiva característica de este grupo de condiciones. Se resalta la utilidad de la electromiografía de alta densidad en la evaluación y el manejo de la distrofia muscular. Conclusiones. El uso de esta técnica en estos trastornos neuromusculares sigue en aumento, pero se hace necesario explorar más aristas para ampliar su uso como herramienta en el estudio y en el desarrollo de intervenciones terapéuticas en esta condición por parte de profesionales de la salud.

Background. Muscular dystrophies are genetically inherited disorders that cause progressive degeneration of muscle fibers. Electromyography, especially high-density electromyography, has become a valuable tool for the diagnosis and study of muscle function in neuromuscular disorders, so the objective of this study is to describe and discuss the current use of this technique in muscular dystrophies. Methods. A Scoping Review was carried out on the use of high density electromyography in people with muscular dystrophy. PubMed, ScienceDirect, Scopus, Web of Science, and Cochrane Plus Library were searched using keywords in English and Spanish. Studies from 2015 to date were considered. Three articles were identified that met the established criteria. Results. The studies focused on clinical and bioengineering applications for people with Duchenne muscular dystrophy and facioscapulohumeral dystrophy. The results suggest that variables such as fatigue, temporal-spatial activation and dimensionality in motor gestures are determined by the degeneration of muscle fibers, replacement by fibrotic tissue, adaptive changes and progressive muscle weakness characteristic of this group of conditions. The usefulness of high-density electromyography in the evaluation and management of muscular dystrophy is highlighted. Conclusions. The use of this technique in these neuromuscular disorders continues to increase, but it is necessary to explore more aspects to expand its use as a tool in the management of this condition.

Role of kinesiophobia in the selective motor control during gait in patients with low back-related leg pain.

Fear of movement has been related to changes in motor function in patients with low back pain, but little is known about how kinesiophobia affects selective motor control during gait (ability of muscles performing distinct mechanical functions) in patients with low back-related leg pain (LBLP). The aim of the study was to determine the association between kinesiophobia and selective motor control in patients with LBLP. An observational cross-sectional study was performed on 18 patients. Outcome included: kinesiophobia using the Tampa Scale of Kinesiophobia; pain mechanism using Leeds Assessment of Neuropathic Signs and Symptoms; disability using Roland-Morris Disability Questionnaire; mechanosensitivity using Straight Leg Raise. Surface electromyography was used to assess selective motor control during gait by examining the correlation and coactivation in muscle pairs involved in the stance phase. Pairs included vastus medialis (VM) and medial gastrocnemius (MG), causing opposite moments around the knee joint, and gluteus medius (GM) and MG, as muscles with distinct mechanical functions (weight acceptance vs. propulsion). A strong association was observed between kinesiophobia and correlation (r = 0.63; p = 0.005) and coactivation (r = 0.69; p = 0.001) between VM versus MG. A moderate association was observed between kinesiophobia and correlation (r = 0.58; p = 0.011) and coactivation (r = 0.55; p = 0.019) between GM versus MG. No significant associations were obtained for other outcomes. A high kinesiophobia is associated with low selective motor control of the muscles involved in the weight acceptance and propulsion phases during gait in patients with LBLP. Fear of movement was better associated with decreased neuromuscular control than other clinical variables such as pain mechanism, disability, and mechanosensitivity.

Distrofias Musculares en Adultos y Actividad Física: una Revisión Narrativa / Muscular Dystrophies in Adults and Physical Activity: a Narrative Review

Introducción. Las distrofias musculares son un grupo heterogéneo de trastornos genéticos degenerativos del músculo que comparten características clínicas de debilidad muscular. Recientemente, la actividad física ha vuelto a ser posicionada como una intervención clave en esta población, sin embargo, no existe consenso terapéutico relativo a la prescripción de ejercicio. Junto con describir los principales tipos de distrofias musculares del adulto, el objetivo de esta revisión es describir los efectos clínicos y eventos adversos del ejercicio y la actividad física en las personas adultas con distrofias musculares. Método. Se realizó una revisión narrativa con enfoque cuantitativo en las bases de datos PubMed, Scielo, Scopus y Biblioteca Cochrane Plus utilizando las palabras claves en inglés "muscular dystrophy", "muscular dystrophies", "physical activity", "exercise" y, en español, "distrofia muscular", "distrofias musculares", "actividad física" y "ejercicio" con estudios hasta la fecha. Se seleccionaron siete ensayos controlados aleatorios y un metaanálisis para su revisión. Resultados. En los ocho estudios seleccionados se presentan los outcomes respecto a la fuerza muscular, capacidad aeróbica, capacidades funcionales, dolor, fatiga y efectos adversos. Se presentan resultados que muestran que las intervenciones en modalidad de entrenamiento de fuerza, aeróbica o ambas pueden tener mejoras y/o no tener efecto significativo en sus resultados. Asimismo, ningún estudio mostró efectos negativos y/o deletéreos posteriores a las intervenciones realizadas. Conclusiones. La realización de actividad física en las diversas distrofias musculares prevalentes en el adulto presenta efectos clínicos positivos y/o nulos, sin embargo, se requiere de estudios que aporten una mayor calidad de evidencia.

Introduction. Muscular dystrophies are a heterogeneous group of genetic degenerative muscle disorders that share clinical characteristics of muscle weakness. Recently, physical activity has been positioned as a key intervention in this population. However, there is no therapeutic consensus regarding the exercise prescription. Along with describing the main types of adult muscular dystrophies, this review aims to describe the clinical effects and adverse events of exercise and physical activity in adults with muscular dystrophies. Method. A narrative review with a quantitative approach was carried out in the PubMed, Scielo, Scopus and Cochrane Plus Library databases using the keywords in English "muscular dystrophy", "muscular dystrophies", "physical activity", "exercise" and in Spanish "distrofia muscular", "distrofias musculares", "actividad física" and "ejercicio" with studies to date. Seven randomized controlled trials and one meta-analysis were selected for review. Results. In the eight selected studies, the outcomes regarding muscle strength, aerobic capacity, functional capacities, pain, fatigue, and adverse effects are presented. Results show that interventions in strength training, aerobic training, or both may have improvements and/or not have a significant effect on their results. Likewise, no study showed adverse and/or harmful effects after the interventions were carried out. Conclusions. The performance of physical activity in the various muscular dystrophies prevalent in adults has positive and/or null clinical effects. However, studies that provide a higher quality of evidence are required.

Delta band activity contributes to the identification of command following in disorder of consciousness.

The overt or covert ability to follow commands in patients with disorders of consciousness is considered a sign of awareness and has recently been defined as cortically mediated behaviour. Despite its clinical relevance, the brain signatures of the perceptual processing supporting command following have been elusive. This multimodal study investigates the temporal spectral pattern of electrical brain activity to identify features that differentiated healthy controls from patients both able and unable to follow commands. We combined evidence from behavioural assessment, functional neuroimaging during mental imagery and high-density electroencephalography collected during auditory prediction, from 21 patients and 10 controls. We used a penalised regression model to identify command following using features from electroencephalography. We identified seven well-defined spatiotemporal signatures in the delta, theta and alpha bands that together contribute to identify DoC subjects with and without the ability to follow command, and further distinguished these groups of patients from controls. A fine-grained analysis of these seven signatures enabled us to determine that increased delta modulation at the frontal sensors was the main feature in command following patients. In contrast, higher frequency theta and alpha modulations differentiated controls from both groups of patients. Our findings highlight a key role of spatiotemporally specific delta modulation in supporting cortically mediated behaviour including the ability to follow command. However, patients able to follow commands nevertheless have marked differences in brain activity in comparison with healthy volunteers.

Assessment of activities of daily living in patients post COVID-19: a systematic review.

BACKGROUND: Coronavirus disease has provoked much discussion since its first appearance. Despite it being widely studied all over the world, little is known about the impact of the disease on functional ability related to performing activities of daily living (ADL) in patients post COVID-19 infection. OBJECTIVES: To understand the impact of COVID-19 on ADL performance of adult patients and to describe the common scales used to assess performance of ADL on patients post-COVID-19. METHODS: A systematic review was conducted. We included studies that applied a physical capacity test in COVID-19 patients, post-infection. Two independent reviewers analyzed the studies, extracted the data, and assessed the quality of the evidence. RESULTS: A total of 1,228 studies were included, after removing duplicates, 1,005 abstracts were screened and of those 983 were excluded. A final number of nine studies which met the eligibility criteria were included. The findings revealed worsening of physical function and ADL performance in all patients post COVID-19 infection. CONCLUSION: All included studies found a reduction of ADL beyond the test or scale used, revealing a vital worsening of functional ability in ADL performance and consequently loss of independence in COVID-19 patients after the acute phase of infection. Functional ability status previous to COVID-19 is crucial for predicting the severity of the disease and mortality. Barthel Index and ADL score were the most used assessment tools across subjects with different intrinsic capacity and context levels.

Use of sit-to-stand test to assess the physical capacity and exertional desaturation in patients post COVID-19.

We propose the use of the 1-minute sit-to-stand test (1STST) to evaluate the physical capacity and exertional desaturation one month after discharge in a sample of patients who survived COVID-19 pneumonia. This was a cross-sectional study that collected routine data from consecutive patients admitted to the outpatient program in a public hospital in Chile. Patients were asked to complete a 1STST. Data were analyzed according to those with and without a prolonged hospital stay of >10 days. Eighty-three percent of the patients were able to complete the test (N = 50). The median age was 62.7 ± 12.5 years. The average number of repetitions in the 1STST was 20.9 ± 4.8. Thirty-two percent of patients had a decrease in pulse oxygen saturation (SpO2) ≥ 4 points. The prolonged hospital stay subgroup had a significant increase in exertional desaturation (mean difference = 2.6; 95% CI = 1.2 to 3.9; p = 0.001) and dyspnea (mean difference = 1.1; 95% CI = 0.4 to 2.1; p = 0.042) compared to the group of length of stay ≤10 days. In-hospital survivors of COVID-19, the 1STST showed a decrease in physical capacity at one month in those 90% who were able to complete it. The 1STST was able to discriminate between those with and without a prolonged hospital stay and was able to detect exertional desaturation in some patients.

Capacidad funcional y desempeño de pacientes con neumonía por Covid-19 / Functional capacity and performance of patients with Covid-19 pneumonia

One year after the first case reported by a new coronavirus (COVID-19), the evidence has shown a series of persistent signs and symptoms once the acute process has been overcome.Under the WHO's framework for health and disability, these impairments at cardiorespiratory, cognitive, and musculoskeletal body functions and structures lead, at least in the short and mid-term, to activity limitations and participation restriction. In this review, we discussed the main alterations generating disability and the challenges of implementing effective evaluation strategies in this disease. Along with their role in the health emergency, rehabilitation teams are challenged to design and deliver timely intervention strategies to reduce post-COVID-19 disability. (AU)

Evaluación Funcional y Respiratoria en Pacientes post COVID-19: ¿Cuáles son las mejores pruebas? / Functional and Respiratory Assessment in Post COVID-19 Patients: What are the best tests?

La evaluación de la capacidad respiratoria y funcional en pacientes con COVID-19 después de la fase aguda es esencial para estimar el impacto de los deterioros causados por la enfermedad en el nivel de funcionamiento relacionados con las actividades y tareas y su impacto en la participación. Esta información provee evidencia invaluable del impacto de la enfermedad para implementar las estrategias de rehabilitación más adecuadas. El objetivo de esta revisión es determinar cuáles son las mejores herramientas para evaluar la capacidad respiratoria y funcional en personas post-infección por COVID-19, para ello, se realizó una revisión narrativa de la literatura incluyendo estudios que aplicaron evaluaciones respiratorias y funcionales en pacientes post-infección por COVID-19. Se encontró que las herramientas más utilizadas para evaluar la función respiratoria fueron la capacidad de difusión y la espirometría. Para evaluar la capacidad funcional, las pruebas más utilizadas fueron el test de marcha de 6 minutos, el Sit-to-Stand test, Short Performance Physical Battery y el índice de Barthel. Finalmente, dada la heterogeneidad de la presentación clínica de la COVID-19, es fundamental contar con herramientas sencillas para evaluar y monitorizar las consecuencias de la enfermedad en la función respiratoria y el estado funcional de los pacientes.

The assessment of respiratory and functional capacity in patients with COVID-19 after the acute phase is essential to estimate the impact of the disease's impairments on functioning related to the activities and tasks and their impact on participation. This information provides invaluable evidence of the impact of the disease to implement the most appropriate rehabilitation strategies. This review aims to determine the best tests to assess people's respiratory and functional capacity after COVID-19 infection. A narrative review of the literature was carried out that includes studies that applied respiratory and functional assessment in post-COVID-19 infection patients. It was found that the most used tests to assess respiratory function were diffusion capacity and spirometry. The most widely used tests to assess functional capacity were the 6-minutes walk test, the Sit-to-Stand test, the Short Performance Physical Battery, and the Barthel index. Finally, due to the heterogeneity of the clinical presentation of COVID-19, it is essential to have simple tests to assess and monitor the consequences of the disease on patients' respiratory function and functional status.

Impact of Visual Biofeedback of Trunk Sway Smoothness on Motor Learning during Unipedal Stance.

The assessment of trunk sway smoothness using an accelerometer sensor embedded in a smartphone could be a biomarker for tracking motor learning. This study aimed to determine the reliability of trunk sway smoothness and the effect of visual biofeedback of sway smoothness on motor learning in healthy people during unipedal stance training using an iPhone 5 measurement system. In the first experiment, trunk sway smoothness in the reliability group (n = 11) was assessed on two days, separated by one week. In the second, the biofeedback group (n = 12) and no-biofeedback group (n = 12) were compared during 7 days of unipedal stance test training and one more day of retention (without biofeedback). The intraclass correlation coefficient score 0.98 (0.93-0.99) showed that this method has excellent test-retest reliability. Based on the power law of practice, the biofeedback group showed greater improvement during training days (p = 0.003). Two-way mixed analysis of variance indicates a significant difference between groups (p < 0.001) and between days (p < 0.001), as well as significant interaction (p < 0.001). Post hoc analysis shows better performance in the biofeedback group from training days 2 and 7, as well as on the retention day (p < 0.001). Motor learning objectification through visual biofeedback of trunk sway smoothness enhances postural control learning and is useful and reliable for assessing motor learning.

Effects of body weight-support treadmill training on postural sway and gait independence in patients with chronic spinal cord injury.

OBJECTIVE: To examine the effects of a six-week body weight-support treadmill training (BWSTT) program on center-of-mass control and gait independence in chronic, incomplete spinal cord injury (iSCI) patients. DESIGN: Descriptive. SETTING: Clinica Los Coihues. Neurorehabilitation center in Santiago, Chile. PARTICIPANTS: 17 chronic iSCI patients and 17 healthy subjects. OUTCOME MEASURES: An instrumented sway (ISway) test was performed before and after the implementation of a six-week BWSTT program. The standing balance of participants was measured by Normalized jerk (NJ) and root mean square (RMS). These values were used to assess the standing balance of participants, and were correlated with the scores obtained on the Walking Index Spinal Cord Injury (WISCI) II test. RESULTS: Significant differences were found in standing balance (i.e., through NJ) after the BWSTT program (P = 0.016), but no significant differences were found in RMS values for postural sway (P = 0.693). None of the patients obtained improved WISCI II scores pre- vs. post-intervention. CONCLUSION: While a BWSTT program can improve center-of-mass control in iSCI patients, no effects were recorded for gait independence. TRIAL REGISTRATION: National Clinical Trials, registry number NCT02703883.

Reduced delta-band modulation underlies the loss of P300 responses in disorders of consciousness.

OBJECTIVE: The P300 component of a sensory event-related potential is one of the major electrophysiological markers used to explore remnants of cognitive function in patients with disorders of consciousness (DoC). However, measuring the P300 in patients is complicated by significant inter-trial variability commonly observed in levels of arousal and awareness. To overcome this limitation, we analyzed single-trial modulation of power in the delta and theta frequency bands, which underlie the P300. METHODS: In a preliminary cross-sectional study using a 24-channel EEG and a passive own-name oddball paradigm, we analyzed event-related synchronization (ERS) across trials in the delta and theta bands in a sample of 10 control and 12 DoC subjects. RESULTS: In comparison to controls, DoC subjects presented a low percentage of trials where delta ERS was observed. In particular, coordinated modulation between delta and theta in response to the stimulus was absent, with a high percentage of trials where only theta ERS was observed. Further, we found a positive correlation between the percentage of epochs with delta ERS and the strength of the P300. CONCLUSIONS: Reduced modulation of spectral activity in the delta band in response to stimuli indicates a dissociation in the activity of the neural networks that oscillate in delta and theta ranges and contribute to the generation of the P300. SIGNIFICANCE: The reduction in spectral modulation observed in DoC provides a deeper understanding of neurophysiological dysfunction and the means to develop a more fine-grained marker of residual cognitive function in individual patients.

Visuomotor coordination and cortical connectivity of modular motor learning.

The ability to transfer sensorimotor skill components to new actions and the capacity to use skill components from whole actions are characteristic of the adaptability of the human sensorimotor system. However, behavioral evidence suggests complex limitations for transfer after combined or modular learning of motor adaptations. Also, to date, only behavioral analysis of the consequences of the modular learning has been reported, with little understanding of the sensorimotor mechanisms of control and the interaction between cortical areas. We programmed a video game with distorted kinematic and dynamic features to test the ability to combine sensorimotor skill components learned modularly (composition) and the capacity to use separate sensorimotor skill components learned in combination (decomposition). We examined motor performance, eye-hand coordination, and EEG connectivity. When tested for integrated learning, we found that combined practice initially performed better than separated practice, but differences disappeared after integrated practice. Separate learning promotes fewer anticipatory control mechanisms (depending more on feedback control), evidenced in a lower gaze leading behavior and in higher connectivity between visual and premotor domains, in comparison with the combined practice. The sensorimotor system can acquire motor modules in a separated or integrated manner. However, the system appears to require integrated practice to coordinate the adaptations with the skill learning and the networks involved in the integrated behavior. This integration seems to be related to the acquisition of anticipatory mechanism of control and with the decrement of feedback control.

Patients with Chronic Spinal Cord Injury Exhibit Reduced Autonomic Modulation during an Emotion Recognition Task.

Spinal cord injury (SCI) is a devastating event for individuals, who frequently develop motor and sensory impairment as well as autonomic dysfunction. Previous studies reported that autonomic activity plays a major role in social cognition and that difficulties in the ability to interpret social information are commonly observed in a variety of mental disorders, which in turn correlate with a poor autonomic nervous system (ANS) regulation. It is well established that subjects with SCI have an alteration in ANS regulation mechanisms. We hypothesized that subjects diagnosed with SCI, who are experiencing a period of adaptation and socio-labor insertion suffer alterations in an emotion recognition task, a component of social cognition, which correlate with poor ANS regulation. We evaluated ANS function by measuring the heart rate variability (HRV) in 18 healthy subjects and 10 subjects with SCI. A 5-min baseline HRV was compared to a task period while performing The reading the mind in the eyes test (RMET). We found that while both groups have similar general performance in the test, healthy subjects responded with greater certainty during the RMET. This level of certainty during the RMET was positively correlated with baseline HRV measures in this group. Also, the group of healthy subjects exhibited higher HRV at baseline than participants with SCI. Finally, the changes in HRV between baseline and task condition were significantly higher in healthy individuals than in SCI participants. Our results show that patients with SCI have low levels of autonomic regulation mechanisms which may promote social cognition problems during their reinsertion to daily life.