Ankle anticipatory postural adjustments during gait initiation in healthy and post-stroke subjects

Background: Anticipatory postural adjustments during gait initiation have an important role in postural stability but also in gait performance. However, these first phase mechanisms of gait initiation have received little attention, particularly in subcortical post-stroke subjects, where bilateral postural control pathways can be impaired. This study aims to evaluate ankle anticipatory postural adjustments during gait initiation in chronic post-stroke subjects with lesion in the territory of middle cerebral artery. Methods: Eleven subjects with post-stroke hemiparesis with the ability to walk independently and twelve healthy controls participated in this study. Bilateral electromyographic activity of tibialis anterior, soleus and medial gastrocnemius was collected during gait initiation to assess the muscle onset timing, period of activation/deactivation and magnitude of muscle activity during postural phase of gait initiation. This phase was identified through centre of pressure signal. Findings: Post-stroke group presented only half of the tibialis anterior relative magnitude observed in healthy subjects in contralesional limb (t=2.38, p=0.027) and decreased soleus deactivation period (contralesional limb, t=2.25, p=0.04; ipsilesional limb, t=3.67, p=0.003) as well its onset timing (contralesional limb, t=3.2. p=0.005; ipsilesional limb, t=2.88, p=0.033) in both limbs. A decreased centre of pressure displacement backward (t=3.45, p=0.002) and toward the first swing limb (t=3.29, p=0.004) was observed in post-stroke subjects. Interpretation: These findings indicate that chronic post-stroke subjects with lesion at middle cerebral artery territory present dysfunction in ankle anticipatory postural adjustments in both limbs during gait initiation.

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

Introduction: Lesions at ipsilateral systems related to postural control at ipsilesional side, may justify the lower performance of stroke subjects during walking. Purpose: To analyse bilateral ankle antagonist coactivation during double-support in stroke subjects. Methods: Sixteen (8 females; 8 males) subjects with a first isquemic stroke, and twenty two controls (12 females; 10 males) participated in this study. The double support phase was assessed through ground reaction forces and electromyography of ankle muscles was assessed in both limbs. Results: Ipsilesional limb presented statistical significant differences from control when assuming specific roles during double support, being the tibialis anterior and soleus pair 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.

A Rare Variant of the Ulnar Artery with Important Clinical Implications: a Case Report

BACKGROUND: Variations in the major arteries of the upper limb are estimated to be present in up to one fifth of people, and may have significant clinical implications. CASE PRESENTATION: During routine cadaveric dissection of a 69-year-old fresh female cadaver, a superficial brachioulnar artery with an aberrant path was found bilaterally. The superficial brachioulnar artery originated at midarm level from the brachial artery, pierced the brachial fascia immediately proximal to the elbow, crossed superficial to the muscles that originated from the medial epicondyle, and ran over the pronator teres muscle in a doubling of the antebrachial fascia. It then dipped into the forearm fascia, in the gap between the flexor carpi radialis and the palmaris longus. Subsequently, it ran deep to the palmaris longus muscle belly, and superficially to the flexor digitorum superficialis muscle, reaching the gap between the latter and the flexor carpi ulnaris muscle, where it assumed is usual position lateral to the ulnar nerve. CONCLUSION: As far as the authors could determine, this variant of the superficial brachioulnar artery has only been described twice before in the literature. The existence of such a variant is of particular clinical significance, as these arteries are more susceptible to trauma, and can be easily confused with superficial veins during medical and surgical procedures, potentially leading to iatrogenic distal limb ischemia.

Efeito da compressão isquémica no ponto gatilho latente do trapézio superior, na magnitude de atividade muscular do complexo articular do ombro

Introdução: A síndrome dolorosa miofascial é um dos principais problemas encontrados na prática clínica, tendo como principais características os pontos gatilho (PG), ativos ou latentes. Os PG latentes têm uma elevada prevalência na musculatura da cintura escapular, nomeadamente ao nível do trapézio superior (TS), influenciando o controlo motor do ombro. A compressão isquémica aplicada no PG do TS poderá influenciar o comportamento muscular dos sinergistas durante o movimento de abdução no plano da omoplata. Objetivos: Este estudo visa estudar a influência da compressão isquémica aplicada no PG do TS na magnitude de ativação dos músculos TS, trapézio inferior (TI), grande dentado (GD), infra-espinhoso (IE) e deltóide médio (DM), assim como a relação muscular através da razão entre o TS e os restantes músculos em análise, durante o movimento de abdução no plano da omoplata. Métodos: O presente estudo é experimental, aleatório e controlado. Foram criados dois grupos, grupo controlo (GC) (n=14) e grupo experimental (GE) (n=15), a partir de uma amostra de 67 indivíduos. No GC foi aplicado um procedimento placebo e no GE foi aplicada no PG latente do TS a técnica de compressão isquémica. Antes e após a intervenção foi recolhida a atividade eletromiográfica dos músculos em análise, assim como os dados cinemáticos, durante o movimento de elevação do ombro no plano da omoplata. Para a análise registou-se a amplitude máxima de abdução e foi analisada a atividade muscular individual dos músculos em estudo assim como a razão entre o TS e os restantes músculos. Esta análise foi realizada em intervalos de 30° até ao final do movimento. Resultados: Não se verificaram diferenças na amplitude máxima de abdução, nem entre grupos (1º momento p=0,608, t=0,816; 2º momento p=0,119; t=1,252) nem entre os dois momentos em cada grupo (GC, t=-1,119; p=0,256; GE, t=-1,604, p=0,135). Na magnitude de ativação individual de cada músculo também não se verificaram diferenças significativas com a aplicação da técnica, tendo-se verificado no DM uma tendência para o aumento da ativação aquando da intervenção, ao longo de todo o arco de movimento, em comparação com a pré-intervenção, já no GC de controlo não se verificaram alterações entre momentos. Também na análise da razão entre músculos não se verificaram diferenças entre grupos. Conclusão: A intervenção realizada não influenciou nenhum dos parâmetros em análise do complexo articular do ombro nem a amplitude de movimento de abdução.

Bridging present and future of brain-computer interfaces: an assessment of impacts

Based on the report for the “Project III” unit of the PhD programme on Technology Assessment under the supervision of Prof. António B. Moniz. This report was discussed also at the 2nd Winter School on Technology Assessment held at Universidade Nova de Lisboa, Caparica Campus, Portugal on December 2011.

EFFECTS OF VITAMIN C SUPPLEMENTATION ON THE CHRONIC PHASE OF CHAGAS DISEASE

Introduction:In order to examine the effectiveness of vitamin C (ascorbic acid) in combating the oxidative insult caused by Trypanosoma cruzi during the development of the chronic phase of Chagas disease, Swiss mice were infected intraperitoneally with 5.0 × 104 trypomastigotes of T. cruzi QM1strain.Methods:Mice were given supplements of two different doses of vitamin C for 180 days. Levels of lipid oxidation (as indicated by thiobarbituric acid reactive substances-TBARS), total peroxide, vitamin C, and reduced glutathione were measured in the plasma, TBARS, total peroxide and vitamin C were measured in the myocardium and histopathologic analysis was undertaken in heart, colon and skeletal muscle.Results:Animals that received a dose equivalent to 500 mg of vitamin C daily showed increased production of ROS in plasma and myocardium and a greater degree of inflammation and necrosis in skeletal muscles than those that received a lower dose or no vitamin C whatsoever.Conclusion:Although some research has shown the antioxidant effect of vitamin C, the results showed that animals subject to a 500 mg dose of vitamin C showed greater tissue damage in the chronic phase of Chagas disease, probably due to the paradoxical actions of the substance, which in this pathology, will have acted as a pro-oxidant or pro-inflammatory.

Symmetry-out asymmetry-in: the role of DMRT2

Dissertation presented to obtain the PhD degree in Biology

Spatiotemporal mechanisms for actomyosin ring assembly and contraction in budding yeast cell division

Dissertation presented to obtain the Ph.D degree in Molecular Medicine

Estudo dos rácios trapézio inferior/ trapézio superior e grande dentado/ trapézio superior, em exercícios com envolvimento das articulações escapulo-torácica e gleno-umeral : recurso à electromiografia de superfície

RESUMO: Introdução: A estabilidade dinâmica relativa ao complexo articular do ombro depende de uma interacção perfeita entre músculos da coifa dos rotadores e músculos escapulares, como o binómio rotador da escápula – trapézio superior e trapézio inferior e o grande dentado. A compreensão dessas sinergias musculares em sujeitos assintomáticos permite, em última instância, o desenvolvimento de linhas orientadoras de raciocínio na abordagem clínica. Objectivo: Estudar o rácio de activação entre os músculos trapézio inferior e trapézio superior e entre grande dentado e trapézio superior, através de um conjunto de cinco exercícios aplicados a uma amostra de sujeitos assintomáticos, estabelecendo uma hierarquia entre esses rácios. Metodologia: Trata-se de um estudo descritivo, com uma amostra de 15 sujeitos saudáveis (n=9 homens; n=6 mulheres), com idades compreendidas entre os 19 e 27 anos (média=21 anos, dp=2,24), tendo sido avaliados por um sistema de electromiografia de superfície, em dois momentos de recolha diferentes. Os exercícios foram realizados em cadeia cinética aberta, sem qualquer aplicação de resistências externas. Resultados: De entre os exercícios analisados com envolvimento escapulo-torácico e gleno-umeral simultaneamente, destacaram-se com melhor rácio trapézio inferior/trapézio superior e grande dentado/trapézio superior (activação dos músculos trapézio inferior e grande dentado superior à activação do trapézio superior) os movimentos de flexão do ombro até aos 90º no plano sagital e a abdução do ombro até aos 90º no plano da escápula, considerando ambas as recolhas. Nos exercícios apenas com envolvimento escapulotorácico, destacaram-se com melhor rácio os movimentos de adução e depressão das escápulas bilateralmente com os membros superiores em repouso, seguido da abdução da escápula, com o ombro a 90º de flexão e mantendo a escápula em depressão (“murro à frente”), em ambas as recolhas. O exercício de abdução do ombro até aos 90º no plano frontal obteve sempre o pior rácio muscular, nos dois momentos de recolha. Conclusões: O presente trabalho estudou as interacções dos músculos escapulotorácicos em cinco exercícios realizados até aos 90º de elevação do membro superior,em cadeia cinética aberta e sem recurso a resistências externas. Será, eventualmente possível, enquadrar os exercícios propostos nas fases de consciencialização e associação de reaprendizagem motora. Sugerem-se futuros estudos com uso de análise cinemática. --------------------ABSTRACT: Introduction: Stability of the shoulder and scapula depend upon a perfect interaction between rotator cuff of the shoulder and scapular muscles, such as upper and lower trapezius and serratus anterior. A deeper comprehension of these synergies in healthy subjects allows, ultimately, the development of a better reasoning in the clinical approach. Goal: To study the ratios between lower trapezius/ upper trapezius and between serratus anterior/ upper trapezius in five different exercises, applied to healthy subjects, presenting a hierarchy between ratios. Methods: It’s an observational descriptive study including 15 healthy subjects (n= 9 men; n=6 women) with ages between 19 and 27 years (mean of 21 years, SD of 2,24). Surface electromyography was used in two different recording moments. All the exercises were performed in open kinetic chain, without external resistance. Results: Of the exercises studied that involved the shoulder and scapula together, the best ratios between lower trapezius/upper trapezius and serratus anterior/ upper trapezius (greater activity for lower trapezius and serratus anterior and less for upper trapezius) were found in shoulder flexion to 90º and in shoulder abduction to 90º in the plane of the scapula, in both recording moments. Considering the exercises that included only the scapula, the best ratio were found in bilateral adduction and depression of the scapula with the upper limbs resting and in abduction of the scapula, while being in depression, with the shoulder flexed at 90º, considering both recordings. Shoulder abduction to 90º in the coronal plane presented the worse ratio in both recording moments. Conclusions: This present paper studied the interaction of the scapula upward rotator muscles in five exercises performed below 90º of shoulder flexion or abduction, in open kinetic chain, with no external resistance. It may be possible to associate our exercises with the motor learning phases of association and consciousness. Future studies are suggested with kinematic analysis.

Imaging the Hypoglossal Nerve

The hypoglossal nerve is a pure motor nerve. It provides motor control to the intrinsic and extrinsic tongue muscles thus being essential for normal tongue movement and coordination. In order to design a useful imaging approach and a working differential diagnosis in cases of hypoglossal nerve damage one has to have a good knowledge of the normal anatomy of the nerve trunk and its main branches. A successful imaging evaluation to hypoglossal diseases always requires high resolution studies due to the small size of the structures being studied. MRI is the preferred modality to directly visualize the nerve, while CT is superior in displaying the bony anatomy of the neurovascular foramina of the skull base. Also, while CT is only able to detect nerve pathology by indirect signs, such as bony expansion of the hypoglossal canal, MRI is able to visualize directly the causative pathological process as in the case of small tumors, or infectious/inflammatory processes affecting the nerve. The easiest way to approach the study of the hypoglossal nerve is to divide it in its main segments: intra-axial, cisternal, skull base and extracranial segment, tailoring the imaging technique to each anatomical area while bearing in mind the main disease entities affecting each segment.

Brain-computer interface (BCI): a methodological proposal to assess the impacts of medical applications in 2022

Based on the report for “Project IV” unit of the PhD programme on Technology Assessment (Doctoral Conference) at Universidade Nova de Lisboa (December 2011). This thesis research has the supervision of António Moniz (FCT-UNL and ITAS-KIT) and Armin Grunwald (Karlsruhe Institute of Technology-ITAS, Germany). Other members of the thesis committee are Mário Forjaz Secca (FCT-UNL) and Femke Nijboer (University of Twente, Netherlands).

Molecular tools to dissect the role of Dmrt2a and Dmrt2b in the left-right axis formation in zebrafish

Dissertação para obtenção do Grau de Mestre em Genética Molecular e Biomedicina

Study of the electromyographic signal dynamic behavior in Amyotrophic Lateral Sclerosis (ALS)

Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disease characterized by motor neurons degeneration, which reduces muscular force, being very difficult to diagnose. Mathematical methods are used in order to analyze the surface electromiographic signal’s dynamic behavior (Fractal Dimension (FD) and Multiscale Entropy (MSE)), evaluate different muscle group’s synchronization (Coherence and Phase Locking Factor (PLF)) and to evaluate the signal’s complexity (Lempel-Ziv (LZ) techniques and Detrended Fluctuation Analysis (DFA)). Surface electromiographic signal acquisitions were performed in upper limb muscles, being the analysis executed for instants of contraction for ipsilateral acquisitions for patients and control groups. Results from LZ, DFA and MSE analysis present capability to distinguish between the patient group and the control group, whereas coherence, PLF and FD algorithms present results very similar for both groups. LZ, DFA and MSE algorithms appear then to be a good measure of corticospinal pathways integrity. A classification algorithm was applied to the results in combination with extracted features from the surface electromiographic signal, with an accuracy percentage higher than 70% for 118 combinations for at least one classifier. The classification results demonstrate capability to distinguish members between patients and control groups. These results can demonstrate a major importance in the disease diagnose, once surface electromyography (sEMG) may be used as an auxiliary diagnose method.

Electromyography function, disability degree, and pain in leprosy patients undergoing neural mobilization treatment

INTRODUCTION: This study aimed to evaluate the effect of the neural mobilization technique on electromyography function, disability degree, and pain in patients with leprosy. METHODS: A sample of 56 individuals with leprosy was randomized into an experimental group, composed of 29 individuals undergoing treatment with neural mobilization, and a control group of 27 individuals who underwent conventional treatment. In both groups, the lesions in the lower limbs were treated. In the treatment with neural mobilization, the procedure used was mobilization of the lumbosacral roots and sciatic nerve biased to the peroneal nerve that innervates the anterior tibial muscle, which was evaluated in the electromyography. RESULTS: Analysis of the electromyography function showed a significant increase (p<0.05) in the experimental group in both the right (Δ%=22.1, p=0.013) and the left anterior tibial muscles (Δ%=27.7, p=0.009), compared with the control group pre- and post-test. Analysis of the strength both in the movement of horizontal extension (Δ%right=11.7, p=0.003/Δ%left=27.4, p=0.002) and in the movement of back flexion (Δ%right=31.1; p=0.000/Δ%left=34.7, p=0.000) showed a significant increase (p<0.05) in both the right and the left segments when comparing the experimental group pre- and post-test. The experimental group showed a significant reduction (p=0.000) in pain perception and disability degree when the pre- and post-test were compared and when compared with the control group in the post-test. CONCLUSIONS: Leprosy patients undergoing the technique of neural mobilization had an improvement in electromyography function and muscle strength, reducing disability degree and pain.

Degree of disability, pain levels, muscle strength, and electromyographic function in patients with Hansen's disease with common peroneal nerve damage

INTRODUCTION: This study evaluated the degree of disability, pain levels, muscle strength, and electromyographic function (RMS) in individuals with leprosy. METHODS: We assessed 29 individuals with leprosy showing common peroneal nerve damage and grade 1 or 2 disability who were referred for physiotherapeutic treatment, as well as a control group of 19 healthy participants without leprosy. All subjects underwent analyses of degree of disability, electromyographic tests, voluntary muscle force, and the Visual Analog Pain Scale. RESULTS: McNemar's test found higher levels of grade 2 of disability (Δ = 75.9%; p = 0.0001) among individuals with leprosy. The Mann-Whitney test showed greater pain levels (Δ = 5.0; p = 0.0001) in patients with leprosy who had less extension strength in the right and left extensor hallucis longus muscles (Δ = 1.28, p = 0.0001; Δ = 1.55, p = 0.0001, respectively) and dorsiflexion of the right and left feet (Δ = 1.24, p = 0.0001; Δ = 1.45, p = 0.0001, respectively) than control subjects. The Kruskal-Wallis test showed that the RMS score for dorsiflexion of the right (Δ = 181.66 m·s-2, p = 0.001) and left (Δ = 102.57m·s-2, p = 0.002) feet was lower in patients with leprosy than in control subjects, but intragroup comparisons showed no difference. CONCLUSIONS: Leprosy had a negative influence on all of the study variables, indicating the need for immediate physiotherapeutic intervention in individuals with leprosy. This investigation opens perspectives for future studies that analyze leprosy treatment with physical therapeutic intervention.