Biomechanical Assessment Methods Used in Chronic Stroke: A Scoping Review of Non-Linear Approaches.

Non-linear and dynamic systems analysis of human movement has recently become increasingly widespread with the intention of better reflecting how complexity affects the adaptability of motor systems, especially after a stroke. The main objective of this scoping review was to summarize the non-linear measures used in the analysis of kinetic, kinematic, and EMG data of human movement after stroke. PRISMA-ScR guidelines were followed, establishing the eligibility criteria, the population, the concept, and the contextual framework. The examined studies were published between 1 January 2013 and 12 April 2023, in English or Portuguese, and were indexed in the databases selected for this research: PubMed®, Web of Science®, Institute of Electrical and Electronics Engineers®, Science Direct® and Google Scholar®. In total, 14 of the 763 articles met the inclusion criteria. The non-linear measures identified included entropy (n = 11), fractal analysis (n = 1), the short-term local divergence exponent (n = 1), the maximum Floquet multiplier (n = 1), and the Lyapunov exponent (n = 1). These studies focused on different motor tasks: reaching to grasp (n = 2), reaching to point (n = 1), arm tracking (n = 2), elbow flexion (n = 5), elbow extension (n = 1), wrist and finger extension upward (lifting) (n = 1), knee extension (n = 1), and walking (n = 4). When studying the complexity of human movement in chronic post-stroke adults, entropy measures, particularly sample entropy, were preferred. Kinematic assessment was mainly performed using motion capture systems, with a focus on joint angles of the upper limbs.

Assessing Postural Control From Birth to Adulthood Among Individuals Born Preterm: A Systematic Review.

Premature life exposure, meaning an immature central nervous system, presents a significant challenge for the development of postural control and, in turn, overall motor development. Preventing motor delay thus requires identifying, characterizing, and quantifying deficit in postural control as early as possible. In our study, we reviewed the procedures used in past studies to assess postural control among individuals born preterm, specifically the characterization of participants, the instruments and motor tasks involved, the types of data collected and analyzed, and the outcomes. To that end, we performed a literature search on PubMed, Wiley Online Library, Web of Science, and Scopus using Boolean logic and assessed the quality of the studies with a standardized assessment based on the Strengthening the Reporting of Observational Studies in Epidemiology guidelines and the Cochrane Handbook for Systematic Reviews of Interventions. Of 35 potential studies, 24 were included; all evaluated infants born preterm, but six did not include a control group of full-term infants. Although the heterogeneity of measurements, variability of instruments, and divergence in motor tasks examined limit definitive conclusions based on quantitative synthesis and the generalization of the results, most studies revealed dysfunctional postural control among individuals born preterm.

Postural control during turn on the light task assisted by functional electrical stimulation in post stroke subjects.

Postural control mechanisms have a determinant role in reaching tasks and are typically impaired in post-stroke patients. Functional electrical stimulation (FES) has been demonstrated to be a promising therapy for improving upper limb (UL) function. However, according to our knowledge, no study has evaluated FES influence on postural control. This study aims to evaluate the influence of FES UL assistance, during turning on the light task, in the related postural control mechanisms. An observational study involving ten post-stroke subjects with UL dysfunction was performed. Early and anticipatory postural adjustments (EPAs and APAs, respectively), the weight shift, the center of pressure and the center of mass (CoM) displacement were analyzed during the turning on the light task with and without the FES assistance. FES parameters were adjusted to improve UL function according to a consensus between physiotherapists' and patients' perspectives. The ANOVA repeated measures, Paired sample t and McNemar tests were used to compare postural control between the assisted and non-assisted conditions. When the task was assisted by FES, the number of participants that presented APAs increased (p = 0.031). UL FES assistance during turning on the light task can improve postural control in neurological patients with UL impairments.

Methodological Considerations in Assessing Interlimb Coordination on Poststroke Gait: A Scoping Review of Biomechanical Approaches and Outcomes.

Objective: To identify and summarize biomechanical assessment approaches in interlimb coordination on poststroke gait. Introduction: Interlimb coordination involves complex neurophysiological mechanisms that can be expressed through the biomechanical output. The deepening of this concept would have a significant contribution in gait rehabilitation in patients with an asymmetric neurological impairment as poststroke adults. Inclusion criteria: Poststroke adults (>19 years old), with assessment of interlimb coordination during gait, in an open context, according to the Population, Concept, Context framework. Methods: A literature search was performed in PubMed, Web of Science™, Scopus, and gray literature in Google Scholar™, according to the PRISMA-ScR recommendations. Studies written in Portuguese or English language and published between database inception and 14 November 2021 were included. Qualitative studies, conference proceedings, letters, and editorials were excluded. The main conceptual categories were "author/year", "study design", "participant's characteristics", "walking conditions", "instruments" and "outcomes". Results: The search identified 827 potentially relevant studies, with a remaining seven fulfilling the established criteria. Interlimb coordination was assessed during walking in treadmill (n = 3), overground (n = 3) and both (n = 1). The instruments used monitored electromyography (n = 2), kinetics (n = 2), and kinematics (n = 4) to assess spatiotemporal parameters (n = 4), joint kinematics (n = 2), anteroposterior ground reaction forces (n = 2), and electromyography root mean square (n = 2) outcomes. These outcomes were mostly used to analyze symmetry indices or ratios, to calculate propulsive impulse and external mechanical power produced on the CoM, as well as antagonist coactivation. Conclusions: Assessment of interlimb coordination during gait is important for consideration of natural auto-selected overground walking, using kinematic, kinetic, and EMG instruments. These allow for the collection of the main biomechanical outcomes that could contribute to improve better knowledge of interlimb coordination assessment in poststroke patients.

Ocorrência de perigos físicos em alimentos / Occurrence of physical hazards in food

A ocorrência de matérias estranhas com potencial perigo físico em alimentos é um grande desafio para a indústria alimentícia, e a análise microscópica é provavelmente o instrumento mais útil para detectá-las e identificá-las. Considerando a escassez de dados sobre os perigos físicos em produtos alimentícios no Brasil, o objetivo deste estudo foi descrever essa ocorrência nos produtos analisados no Núcleo de Morfologia e Microscopia do Centro de Alimentos do Laboratório Central do Instituto Adolfo Lutz (IAL), em São Paulo, no período de 2008 a 2020. Os resultados revelaram que, das 7.221 amostras de alimentos analisadas, 89 (1,2%) estavam em desacordo com a legislação em vigor, por conterem perigos físicos. De acordo com a categoria de alimentos, a ocorrência foi maior para bebidas (43%), seguida de cereais, farinha e farelo (22%). Quanto ao tipo de matéria estranha, os plásticos (duros e flexíveis) foram os mais frequentes (48%), seguidos dos metais (15%) entre as partículas perigosas detectadas nas amostras. A detecção e identificação de perigos físicos, por meio de análises microscópicas, contribuem para a segurança e qualidade dos produtos alimentícios oferecidos à população (AU).

The occurrence of physical hazards in food is a great challenge for the food industry, and microscopic analysis is probably the most useful instrument to detect and identify them. Considering the scarcity of data on physical hazards in food products in Brazil, the aim of this study was to describe this occurrence in the products analyzed at the Nucleus of Morphology and Microscopy of the Food Center of the Adolf Lutz Institute's Central Laboratory (IAL) in São Paulo, from 2008 to 2020. Results revealed that of the 7,221 analyzed food samples, 89 (1.2%) did not comply with the legislation due to the presence of physical hazards. According to the food category, the occurrence was higher in beverages (43%), followed by cereals, yeasts, flour and bran (22%). Regarding the type of foreign matter, among the dangerous particles detected, the most frequently found were plastics (48%) (hard and flexible), followed by metals (15%). The detection and identification of physical hazards by microscopic analysis contributes to the safety and quality of food products offered to the public. (AU)

Usability of Functional Electrical Stimulation in Upper Limb Rehabilitation in Post-Stroke Patients: A Narrative Review.

Stroke leads to significant impairment in upper limb (UL) function. The goal of rehabilitation is the reestablishment of pre-stroke motor stroke skills by stimulating neuroplasticity. Among several rehabilitation approaches, functional electrical stimulation (FES) is highlighted in stroke rehabilitation guidelines as a supplementary therapy alongside the standard care modalities. The aim of this study is to present a comprehensive review regarding the usability of FES in post-stroke UL rehabilitation. Specifically, the factors related to UL rehabilitation that should be considered in FES usability, as well a critical review of the outcomes used to assess FES usability, are presented. This review reinforces the FES as a promising tool to induce neuroplastic modifications in post-stroke rehabilitation by enabling the possibility of delivering intensive periods of treatment with comparatively less demand on human resources. However, the lack of studies evaluating FES usability through motor control outcomes, specifically movement quality indicators, combined with user satisfaction limits the definition of FES optimal therapeutical window for different UL functional tasks. FES systems capable of integrating postural control muscles involving other anatomic regions, such as the trunk, during reaching tasks are required to improve UL function in post-stroke patients.

Healthcare, Clinical Factors and Rehabilitation Predicting Quality of Life in First-time Stroke Patients: A 12-month Longitudinal Study.

OBJECTIVES: One of the long-term rehabilitation goals in stroke survivors is to achieve the best health-related quality of life (HRQoL). This study analyzes the evolution of HRQoL one-year post-stroke to establish the main pre-stroke, clinical, health care and rehabilitation predictors. MATERIALS AND METHODS: This study uses patient-level data from a one-year single-center prospective cohort study of first stroke patients, assessed at baseline, 3, 6 and 12 months. A generalized linear model with a linear response determined independent predictors of HRQol with EQ-5D-3L and SF-6D. The model included age, gender, scholarity, monthly income, residence, occupation, National Institute of Health Stroke Scale (NIHSS), Modified Rankin Scale (mRS), Barthel Index (BI), Mini-Mental State Examination (MMSE), length of stay, door-to-neurological examination time, access, frequency, and satisfaction with rehabilitation care. RESULTS: A total of 391 acute stroke patients, with a mean disability of 3.7 and severity of 11.7 participated. A decline of HRQoL was observed from baseline to the first three months in both indexes, with an increase in HRQoL at 3 months until 12 months. Scores were significantly lower compared to corresponding population norms throughout follow-up, mostly affected by stroke severity, disability, rehabilitation access and frequency. Higher HRQoL was associated with lower mRS, NIHSS, age, length of stay, and with higher BI, MMSE, scholarity, occupation, and rehabilitation care. CONCLUSION: Clinical measures and rehabilitation care were the strongest HRQoL predictors of stroke survivors regardless of severity levels. These findings may contribute to the development of future health policies that focus on post-stroke recovery.

Optimal multi-field functional electrical stimulation parameters for the "drinking task - reaching phase" and related upper limb kinematics repeatability in post stroke subjects.

BACKGROUND: No specific guidelines for the management of functional electrical stimulation (FES) parameters in post stroke patients have been defined yet, despite its frequent use. The purpose of this study is to characterize the optimal FES parameters that assist the reaching phase of drinking task ("drinking task - reaching phase") on post stroke subjects and to analyze the related upper limb (UL) movement quality indicators repeatability. METHODS: An observational study with a test and re-test design involving ten post stroke subjects with UL dysfunction was performed. End-point and joint kinematics of contralesional UL were assessed during the "drinking task - reaching phase" with FES through a test and retest design. FES parameters were adjusted to improve UL function according to a consensus between physiotherapists and patients' perspective. FINDINGS: It was possible to establish reliable FES parameters that assisted the "drinking task - reaching phase". All FES parameters presented high to very high repeatability and led to moderate to very high repeatability in almost UL movement quality indicators during the "drinking task - reaching phase". INTERPRETATION: These findings show that the main characteristics of FES parameters that improves patient perception of change are quite stable, which facilitate its implementation in clinical practice by allowing consistence between intervention sessions.

Optimal Multifield Functional Electrical Stimulation Parameters for the "Turn on the Light" Task and Related Upper Limb Kinematics Repeatability in Poststroke Subjects.

OBJECTIVE: To characterize the optimal functional electrical stimulation (FES) parameters that assist the turn on the light task (TOTL) on poststroke participants and to analyze the related upper limb (UL) kinematics repeatability. DESIGN: Cross-sectional study. SETTING: Human movement research center. PARTICIPANTS: Poststroke individuals (N=11) with history of a single unilateral stroke that resulted in a motor control dysfunction of the contralesional UL. INTERVENTIONS: FES based on surface multifield technology applied to the contralesional wrist and finger extensors during the TOTL. MAIN OUTCOME MEASURES: FES outcome metrics (virtual electrodes, stimulation duration, intensity) and kinematic metrics (end-point kinematics [absolute and relative duration, mean and peak velocities, relative instant of peak velocity, index of curvature, number of movement units] and joint kinematics [shoulder, elbow, wrist end position and range of movement]). Outcome measures were assessed 2 times with a 72-hour maximum time interval. CONCLUSION: It was possible to establish reliable FES parameters that assisted the TOTL on poststroke participants. These stimulation parameters led to high to very high repeatability in terms of UL kinematics for most of the cases.

Isolamento e identificação microscópica de elementos histológicos vegetais: contribuições para o controle de qualidade e segurança dos alimentos / Isolation and microscopic identification of vegetable histological elements: contributions to quality control and food safety

A microscopia alimentar atua no controle da qualidade e identidade dos alimentos utilizando recursos microscópicos para a identificação de elementos histológicos vegetais e de matérias estranhas. O objetivo do estudo foi apresentar as principais contribuições da análise microscópica de isolamento e identificação de elementos histológicos vegetais na vigilância dos alimentos analisados no Instituto Adolfo Lutz Central (IAL), de 2016 a 2020. Os dados das análises realizadas no período do estudo foram tabulados para categorização e avaliação dos resultados. Foram analisadas 4.189 amostras de alimentos e água, sendo 1.096 para pesquisa e identificação de elementos histológicos vegetais, com maior demanda para as análises de controle. As categorias de alimentos mais analisadas foram as misturas para o preparo de alimentos e alimentos prontos para consumo; café, cevada, chá, erva-mate e produtos solúveis; e os suplementos alimentares. Dentre as amostras analisadas, 5% não estavam de acordo com a rotulagem, principalmente devido à adição de ingrediente, com destaque para os açúcares e produtos para adoçar; as especiarias, temperos, molhos; e os suplementos alimentares. Por meio da análise microscópica foram verificadas adulterações em diversas categorias de produtos, demonstrando a sua contribuição às ações de vigilância na prevenção de fraudes e na segurança dos alimentos. (AU)

Food microscopy acts to control the quality and identity of foods using microscopic resources to identify vegetable histological elements and foreign matter.The aim of the study was to present the main contributions from microscopic analysis on isolation and identification of vegetable histological elements in the surveillance of foods analyzed at the Instituto Adolfo Lutz Central (IAL) from 2016 to 2020. Data from the analysis performed during the studied period were tabulated for categorization and further evaluation. Altogether, 4.189 food and water samples were analyzed and 1.096 samples underwent research and identification of vegetable histological elements, with greater demand for the control analysis.The most analyzed food categories were mixtures for food preparation and ready-to-eat foods; coffee, barley, tea, yerba mate and soluble products; and food supplements. Among the analyzed samples, 5% were not in accordance with the labeling, mainly due to the addition of an ingredient, especially sugars and sweetening products; spices, seasonings, sauces; and food supplements. Through microscopic analysis, adulterations were found in several categories of products, demonstrating its relevance to surveillance actions in fraud prevention and food safety. (AU)

Parâmetros microscópicos de açúcar de coco comercializados na cidade de São Paulo, Brasil: identidade e qualidade / Microscopic parameters of coconut sugar marketed in the city of São Paulo, Brazil: identity and quality

O açúcar de coco vem se tornando popular no Brasil e no mundo devido às alegações nutricionais de ser um adoçante natural e mais saudável em relação a outros açúcares. Sua produção ocorre de forma artesanal a partir da extração da seiva do floema da inflorescência da palmeira. Este trabalho teve por objetivo analisar microscopicamente a identidade e a presença de matérias estranhas em amostras de açúcar de coco, bem como verificar sua conformidade em relação às legislações sanitárias brasileiras. Foram analisadas 13 amostras comerciais de açúcar de coco da cidade de São Paulo quanto aos ensaios de pesquisa e identificação de elementos histológicos e pesquisa de matérias estranhas. A identificação de elementos histológicos vegetais revelou a presença de amidos morfologicamente semelhantes ao padrão de Tr iti c um sp. (trigo), Manihot sp. (mandioca) e Oryza sativa (arroz), além de amidos alterados. Também foram encontrados elementos histológicos vegetais compatíveis com padrão de Saccharum officinarum (cana-de-açúcar) e de Cocos nucifera (coco). Todas as amostras analisadas continham matérias estranhas com predomínio de fragmentos de insetos em 100% delas. Os resultados do estudo indicam falhas nas Boas Práticas de produção do açúcar de coco e a necessidade da adequação deste produto em relação às normas vigentes. (AU)

Coconut sugar has become popular in Brazil and worldwide due to the nutritional claims of being a natural and healthier sweetener compared to other sugars. Its production takes places in an artisanal way from the extraction of phloem sap from the inflorescence of the palm. The aim of this work was to microscopically analyze the identity and the presence of foreign matter in samples of coconut sugar, as well as to verify its compliance with Brazilian health legislation. Thirteen commercial samples of coconut sugar from the city of São Paulo were analyzed for the research and identification of histological elements and foreign matter. The identification of vegetable histological elements revealed the presence of starches morphologically similar to the Tr iti c um sp. (wheat), Manihot sp. (cassava) and Oryza sativa (rice) pattern, besides altered starches. Vegetable histological elements compatible with the Saccharum officinarum (sugar cane) and Cocos nucifera (coconut) pattern were also found. All samples analyzed contained foreign matter with predominance of insect fragments in 100% of the samples. The results of the study indicate flaws in the Good Practices for the production of coconut sugar and the need to adapt this product to current standards. (AU)

Parâmetros microscópicos de açúcar de coco comercializados na cidade de São Paulo, Brasil: identidade e qualidade / Microscopic parameters of coconut sugar marketed in the city of São Paulo, Brazil: identity and quality

O açúcar de coco vem se tornando popular no Brasil e no mundo devido às alegações nutricionais de ser um adoçante natural e mais saudável em relação a outros açúcares. Sua produção ocorre de forma artesanal a partir da extração da seiva do floema da inflorescência da palmeira. Este trabalho teve por objetivo analisar microscopicamente a identidade e a presença de matérias estranhas em amostras de açúcar de coco, bem como verificar sua conformidade em relação às legislações sanitárias brasileiras. Foram analisadas 13 amostras comerciais de açúcar de coco da cidade de São Paulo quanto aos ensaios de pesquisa e identificação de elementos histológicos e pesquisa de matérias estranhas. A identificação de elementos histológicos vegetais revelou a presença de amidos morfologicamente semelhantes ao padrão de Triticum sp. (trigo), Manihot sp. (mandioca) e Oryza sativa (arroz), além de amidos alterados. Também foram encontrados elementos histológicos vegetais compatíveis com padrão de Saccharum officinarum (cana-de-açúcar) e de Cocos nucifera (coco). Todas as amostras analisadas continham matérias estranhas com predomínio de fragmentos de insetos em 100% delas. Os resultados do estudo indicam falhas nas Boas Práticas de produção do açúcar de coco e a necessidade da adequação deste produto em relação às normas vigentes.

Coconut sugar has become popular in Brazil and worldwide due to the nutritional claims of being a natural and healthier sweetener compared to other sugars. Its production takes places in an artisanal way from the extraction of phloem sap from the inflorescence of the palm. The aim of this work was to microscopically analyze the identity and the presence of foreign matter in samples of coconut sugar, as well as to verify its compliance with Brazilian health legislation. Thirteen commercial samples of coconut sugar from the city of São Paulo were analyzed for the research and identification of histological elements and foreign matter. The identification of vegetable histological elements revealed the presence of starches morphologically similar to the Triticum sp. (wheat), Manihot sp. (cassava) and Oryza sativa (rice) pattern, besides altered starches. Vegetable histological elements compatible with the Saccharum officinarum (sugar cane) and Cocos nucifera (coconut) pattern were also found. All samples analyzed contained foreign matter with predominance of insect fragments in 100% of the samples. The results of the study indicate flaws in the Good Practices for the production of coconut sugar and the need to adapt this product to current standards.

Stroke rehabilitation and research: consideration of the role of the cortico-reticulospinal system.

A cerebrovascular accident, otherwise known as stroke, has the potential to damage multiple areas within the brain affecting descending motor control via a multitude of pathways resulting in a wide variety of movement problems. The cortico-reticulospinal system, one of the largest motor systems, is frequently affected, compromising its output, resulting in postural control deficits. The identification of clinically relevant instruments and scales to document and evaluate recovery in post-stroke patients is vital. However, the availability of such measures and scales which take into consideration the role of postural control as an integral component of functional movement performance are scarce. This paper will critically discuss the importance of integrating current neuroscience and motor control knowledge in order to better understand and describe the clinical presentation of persons post-stroke such that the effectiveness of stroke rehabilitation can be appropriately measured.

The role of the ipsilesional side in the rehabilitation of post-stroke subjects.

Most stroke lesions occur in the middle cerebral artery territory, presenting a high probability of damage of pathways with predominant ipsilesional disposition, mainly related to postural control. Despite the high probability of bilateral postural control dysfunction based on neuroanatomical fundaments, both research and clinical rehabilitation involving stroke subjects have been focused on contralesional side (also named affected side) impairments, while ipsilesional side (also named non-affected side) impairments have been attributed to an adaptive strategy. This paper aims to present a critical understanding about the state-of-the-art that sustains the hypothesis that stroke subjects with middle cerebral artery territory lesion at the subcortical level show an atypical behaviour in the ipsilateral side associated with the lesion itself and the possible implications.

Primary intimal sarcoma of the left atrium presenting with constitutional symptoms.

Intimal (spindle-cell) sarcomas are exceptionally rare and are highly aggressive cardiac tumors. The authors describe a case of a 43-year-old female, presenting with a 3-month history of constitutional symptoms with fever, night sweats, anorexia and weight loss, associated with productive cough and pleural effusion that was admitted with clinical suspicion of pulmonary tuberculosis. The patient developed sudden acute heart failure symptoms during hospitalization, leading to mechanical ventilation. Computed tomography scan with contrast showed a cardiac tumor filling the left atrium causing compression of pulmonary veins. Surgical resection was performed and histologic examination revealed an intimal sarcoma. Although commenced on adjuvant chemotherapy, local tumor recurrence occurred with pericardium invasion. The patient died within 4 months of initial diagnosis. This report aims to describe an unusual presentation of this rare disease entity, and to discuss its highly aggressive clinical course.

Subserous Eosinophilic Gastroenteritis: A Rare Cause of Ascites.

Eosinophilic gastroenteritis is an inflammatory gastrointestinal disease characterized by eosinophilic infiltration of the digestive tract. The subserous type is the rarest form and diagnosis is challenging because the symptoms are heterogeneous and endoscopy may be non-diagnostic. The authors describe the clinical case of a 41-year-old female patient who was diagnosed with subserous eosinophilic gastroenteritis. This case highlights the importance of clinical suspicion of eosinophilic gastroenteritis in patients in the third to fifth decades of life with gastrointestinal symptoms, ascites and eosinophilia. LEARNING POINTS: Subserous eosinophilic gastroenteritis is an uncommon inflammatory gastrointestinal disease with a challenging diagnosis because the symptoms are heterogeneous and endoscopy may be non-diagnostic.The diagnosis should be suspected in the presence of gastrointestinal symptoms, and peripheral eosinophilia is confirmed by the presence of eosinophilic infiltration of the gastrointestinal tract or ascites with a predominance of eosinophils, after the exclusion of other causes of eosinophilia.Automated cell counting analysis of the ascitic fluid can wrongly identify eosinophils as neutrophils, which can delay the diagnosis.

An Itchy Problem: A Clinical Case of Crusted Scabies.

Scabies is an infestation of the skin by the mite Sarcoptes scabiei. A more severe form called crusted or Norwegian scabies may occur in immunosuppressed patients and the elderly. Crusted scabies mostly differs from normal scabies by the exuberance of its lesions, body distribution and high contagiousness, and requires different and more prolonged treatment. Early recognition of the lesions and isolation precautions are crucial for disease control and prevention of transmission. The authors describe a clinical case of crusted scabies with pruritus and exuberant cutaneous lesions. LEARNING POINTS: Crusted scabies is an infestation of the skin by the mite Sarcoptes scabiei that is highly contagious and results in an intensely pruritic eruption with exuberant cutaneous lesions.Crusted scabies occurs in patients with AIDS, lymphoma or compromised cellular immunity, and sometimes in older patients. It is characterized by an elevated burden of mites and does not have a characteristic distribution pattern.This disease requires strict isolation measures and treatment which differs from and is more prolonged than for scabies.

Ankle Intrinsic Stiffness in Subcortical Poststroke Subjects.

The authors' purpose was to evaluate bilateral ankle intrinsic stiffness in subcortical poststroke subjects. Ten subcortical poststroke subjects and 10 healthy controls participated in this study. The ankle passive stiffness at 3 different speeds and the electromyographic activity of the soleus, the gastrocnemius, and the tibialis anterior muscles of poststroke contralesional (CONTRA) and ipsilesional (IPSI) limbs and of one limb of healthy subjects were assessed. Ankle electromyographic activity was collected to ensure that reflexive or voluntary muscle activity was not being elicited during the passive movements. A significant interaction was observed between the effects of the limb (IPSI vs. CONTRA vs. control) and ankle position, F(4, 28) = 3.285, p = .025, and between the effects of the limb and the velocity of stretch, F(2, 14) = 4.209, p = .037. While increased intrinsic stiffness was observed in the CONTRA limb of poststroke subjects at ankle neutral position when the passive stretch was applied with a velocity of 1°/s (p = .021), the IPSI limb of poststroke subjects presented increased stiffness at 20º of plantar flexion when the stretch was applied with a velocity of 5°/s (p = .009) when compared to healthy group. Subcortical poststroke subjects present increased intrinsic stiffness in both the CONTRA and IPSI limbs in specific ankle amplitudes.

Ankle antagonist coactivation in the double-support phase of walking: Stroke vs. healthy subjects.

INTRODUCTION: Lesions in ipsilateral systems related to postural control in the ipsilesional side may justify the lower performance of stroke subjects during walking. PURPOSE: To analyze bilateral ankle antagonist coactivation during double support in stroke subjects. METHODS: Sixteen (8 females; 8 males) subjects with a first isquemic stroke and 22 controls (12 females; 10 males) participated in this study. The double-support phase was assessed through ground reaction forces and the electromyography of ankle muscles was assessed in both limbs. RESULTS: The ipsilesional limb presented statistically significant differences from the control when assuming specific roles during double support. The tibialis anterior and soleus pair was the one in which this atypical behavior was more pronounced. CONCLUSION: The ipsilesional limb presents a dysfunctional behavior when a higher postural control activity was demanded.