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.

Coherence and phase locking disruption in electromyograms of patients with amyotrophic lateral sclerosis

Dissertação para obtenção do Grau de Mestre em Engenharia Biomédica

O biofeedback cinemático na realização de exercícios escápulo-torácicos

RESUMO: O Biofeedback cinemático na realização de exercícios escápulo-torácicos Patrícia Ribeiro; Ricardo Matias Desenho do estudo: Estudo quantitativo, experimental, prospetivo de fator único. Objetivos: Determinar a efetividade do biofeedback cinemático tridimensional (3D) em tempo real, como informação de retorno extrínseca, no reconhecimento da zona neutra da omoplata, em indivíduos saudáveis; medir o desempenho temporal, através do tempo que os sujeitos demoram a atingir a posição pretendida, e o desempenho no percurso, através da diferença entre o percurso efetuado e aquele que seria o percurso mais curto, sem Informação de Retorno Extrínseca (IRE), com Informação de Retorno Extrínseca clinica verbal e palpatória (IRE-VP) e com informação de retorno extrínseca visual cinemática (IRE-VC). Enquadramento: Reconhecer aquela que deve ser a posição adequada da omoplata e tomar consciência da importância dessa posição para a estabilidade e correto funcionamento da articulação gleno-umeral é uma tarefa difícil, pois a grande maioria do indivíduos não têm os conhecimentos necessários. É reconhecido o contributo que a IRE tem na reaprendizagem motora, em especial na primeira fase da aprendizagem motora – a consciencialização. Vários estudos se têm debruçado em avaliar a influencia da IRE na reabilitação de indivíduos com disfunção do ombro, tendo-se limitado ao formato electromiográfico. No sentido de encontrar novas estratégias para facilitar o processo de reaprendizagem motora nestes indivíduos, foi escolhido biofeedback cinemático tridimensional. Métodos: Participaram no estudo 60 sujeitos, sem queixas de dor no ombro, com idades compreendidas entre os 18 e os 54 anos, com um valor médio de 21,66 anos (±5.89), divididos aleatoriamente em três grupos com uma tarefa comum: o reconhecimento da zona neutra da omoplata. Um grupo não recebeu qualquer tipo de IRE - Grupo Controlo (GC), outro grupo recebeu IRE-VP e outro recebeu IRE-VC. Para efeitos de análise da performance foram consideradas duas variáveis: tempo e qualidade da execução. A abordagem estatística destas variáveis consistiu numa análise de variância simples e num teste de comparações múltiplas. Resultados: Observámos que o grupo controlo e o grupo IRE-VC efetuaram a tarefa pedida em menos tempo que o grupo IRE-VP (p<0.01) e que o grupo IRE-VC obteve melhores resultados no que respeita à qualidade da execução da tarefa do que o GC e o grupo IRE-VP (p<0.01). Conclusão: Pelos resultados obtidos, na tarefa de reconhecimento da zona neutra da omoplata, podemos concluir que o biofeedback cinemático é mais efetivo na facilitação da obtenção de melhor qualidade de execução da tarefa do que o feedback clinico ou a inexistência de feedback e igualmente efetivo à inexistência de IRE no que respeita ao tempo demorado a reconhecer essa posição. -------------- ABSTRACT:Study Design: Single factor experimental design. Objectives: To determine the effectiveness of real time cinematic biofeedback as extrinsic information in the recognition of the neutral zone of the scapula in healthy subjects; to measure the temporal performance and quality of the execution without extrinsic feedback, with clinical feedback and with cinematic feedback. Background: To recognize the proper scapula position and to be aware of the importance of this position to the stability and correct function of the gleno-umeral joint is a difficult task, because most people don’t have the necessary knowledge. It is known that extrinsic feedback is effective in motor learning, specially in the early stages. There are several studies that evaluated the influence of extrinsic feedback in rehabilitation of shoulder dysfunctions, but only in the electromyography format. Material and Methods: Sixty healthy subjects were randomly divided into 3 groups that received no feedback (group 1 – control group), verbal and palpatory feedback (group 2) and real time cinematic feedback (group 3). The performance variables considered – time and quality of execution - were statistically analyzed with ANOVA one-way and multiple comparisons test. Results: Control group and group 3 executed the task in less time that group 2 (p<0.01) and group 3 executed the task with better quality than control group and group 2 (p<0.01). Conclusions: From the results of this study we conclude that in the studied task, the cinematic feedback is more effective to facilitate a better quality of execution than no feedback or clinical feedback and, regarding to time taken to attain the requested position, equally effective to no feedback.

Evaluation of motor neuron excitability by CMAP scanning with modulated current

It is important to have better evaluation and understanding of the motor neuron physiology, with the goal to early and objectively diagnose and treat patients with neurodegenerative pathologies. The Compound Muscle Action Potential (CMAP) scan is a non-invasive diagnosis technique for neurodegenerative pathologies, such as ALS, and enables a quick analysis of the muscle action potentials in response to motor nerve stimulation. This work aims to study the influence of different pulse modulated waveforms in peripheral nerve excitability by CMAP scan technique on healthy subjects. A total of 13 healthy subjects were submitted to the same test. The stimuli were applied in the medium nerve on the right wrist and electromyography signal collected on the Abductor Pollicis Brevis (APB) muscle surface on the right thumb. Stimulation was performed with an increasing intensities range from 4 to 30 mA, with varying steps, 3 stimuli per step. The procedure was repeated 4 times per subject, each repetition using a different single pulse stimulation waveform: monophasic square, monophasic triangular, monophasic quadratic and biphasic square. Results were retrieved from the averaging of the stimuli on each current intensity step. The square pulse needs less current intensity to generate the same response amplitude regarding the other waves and presents a more steep curve slope and this effect is gradually decreasing for the triangular and quadratic pulse,respectively, being the difference even more evident regarding the biphasic pulse. The control of the waveform stimulation pulse allows varying the stimulusresponse curve slope.

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.

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.

Study of the muscular activation in obese and non-obese subjects during lifting loads

The obesity prevalence is increasing among the workforce of the developed countries. However, obesity seems to negatively affect the individuals’ work performance. In occupational contexts, manual lifting tasks are frequent and can produce significant muscle loading. With the aim of analysing the possible effect of obesity on workers’ muscular activation, surface electromyography data were collected from six muscles recruited during these tasks. In the current study, 6 different tasks of manual lifting (3 loads × 2 lifting styles) were performed by 14 participants with different obesity levels. Electromyography data normalization was based on the percentage of maximum contraction during each task. The muscles’ activation times before each task were also calculated. The current study suggests that obesity can increase the maximum contraction during each task and the delays on muscles’ activation time. This study suggests that obese individuals can present some changes on their muscle activation during lifting, when comparing with non-obese individuals, and reinforces the need to develop further studies focused on obesity as a risk factor for musculoskeletal disorders development.

Vestuário interactivo para desporto e reabilitação

Dissertação de mestrado em Design e Marketing

The influence of nitrogen and oxygen additions on the thermal characteristics of aluminium-based thin films

The ternary aluminium oxynitride (AlNxOy) system offers the possibility to obtain a wide range of properties by tailoring the ratio between pure Al, AlNx and AlOy and therefore opening a significant number of possible applications. In this work the thermal behaviour of AlNxOy thin films was analysed by modulated infrared radiometry (MIRR), taking as reference the binary AlOy and AlNx systems. MIRR is a non-contact and non-destructive thermal wave measurement technique based on the excitation, propagation and detection of temperature oscillations of very small amplitudes. The intended change of the partial pressure of the reactive gas (N2 and/or O2) influenced the target condition and hence the deposition characteristics which, altogether, affected the composition and microstructure of the films. Based on the MIRR measurements and their qualitative and quantitative interpretation, some correlations between the thermal transport properties of the films and their chemical/physical properties have been found. Furthermore, the potential of such technique applied in this oxynitride system, which present a wide range of different physical responses, is also discussed. The experimental results obtained are consistent with those reported in previous works and show a high potential to fulfil the demands needed for the possible applications of the systems studied. They are clearly indicative of an adequate thermal response if this particular thin film system is aimed to be applied in small sensor devices or in electrodes for biosignal acquisition, such as those for electroencephalography or electromyography as it is the case of the main research area that is being developed in the group.

Differences in muscular activity between obese and non-obese workers during manual lifting

The prevalence of obesity is increasing throughout the workforce. Manual lifting tasks are common and can produce significant muscle loading. This study compared muscular activity between obese and non-obese subjects, using surface Electromyography (EMG), during manual lifting. Six different lifting tasks (with 5, 10 and 15 kg loads in free and constrained styles) were performed by 14 participants with different obesity levels. EMG data normalization was based on the percentage of Maximum Contraction during each Task (MCT). Muscle Activation Times (AT) before each task were also evaluated. The study suggests that obesity can increase MCT and delay muscle AT. These findings reinforce the need to develop further studies focused on obesity as a risk factor for the development of musculoskeletal disorders.

Sportliche Leistungsfähigkeit und zeitabhängiges Frequenzverhalten von Oberflächenelektromyogrammen

Electromyography, EMG, spectral analysis, median frequency, non-stationary signals, sports performance, modelling, simulation, intramuscular coordination, motor unit, fuzzy control

Subclinical femoral neuropathy after anterior cruciate ligament reconstruction

Background and aim of the study: Patients with anterior cruciate ligament (ACL) reconstruction and femoral catheter analgesia may develop quadriceps amyotrophy. We aimed to determine whether this amyotrophy might be related to a femoral neuropathy. Material and method: After Ethical Committee approval and patients' written informed consent, 17 patients ASA I and II scheduled to undergo ACL reconstruction were recruited. An electromyography (EMG) was performed before the operation in order to exclude a femoral neuropathy. A femoral nerve catheter was inserted before the surgery with the aid of a nerve stimulator, and 20 ml of 0.5% ropivacaine was injected. The operation was done under spinal or general anaesthesia. Postoperative analgesia was provided with 0.2% ropivacaine for 72 hours, in association with oxycodone, paracetamol and ibuprofen. A second EMG was performed 4 weeks after the ACL repair. A femoral neuropathy was defined as a reduction of the surface of the motor response of more than 20%, compared to the first EMG. A third EMG was performed at 6 months if a neuropathy was present. Results: Mean age of this group of patients was 27 years old (range 18-38 y.). Among the 17 patients, 4 developed a transient femoral neuropathy (incidence of 24%) without clinical complain. Conclusion: In this study, the incidence of subclinical femoral neuropathy after ACL reconstruction is high. This lesion may be caused by the femoral catheter (mechanical damage, toxicity of local anaesthesia) or by the Tourniquet. Further studies are needed to investigate the incidence of subclinical neuropathy, according to the type of analgesia (epidural analgesia, PCA) and surgery.

Controlled study of 50-Hz repetitive transcranial magnetic stimulation for the treatment of Parkinson disease.

OBJECTIVE: To investigate the safety and efficacy of 50-Hz repetitive transcranial magnetic stimulation (rTMS) in the treatment of motor symptoms in Parkinson disease (PD). BACKGROUND: Progression of PD is characterized by the emergence of motor deficits that gradually respond less to dopaminergic therapy. rTMS has shown promising results in improving gait, a major cause of disability, and may provide a therapeutic alternative. Prior controlled studies suggest that an increase in stimulation frequency might enhance therapeutic efficacy. METHODS: In this randomized, double blind, sham-controlled study, the authors investigated the safety and efficacy of 50-Hz rTMS of the motor cortices in 8 sessions over 2 weeks. Assessment of safety and clinical efficacy over a 1-month period included timed tests of gait and bradykinesia, Unified Parkinson's Disease Rating Scale (UPDRS), and additional clinical, neurophysiological, and neuropsychological parameters. In addition, the safety of 50-Hz rTMS was tested with electromyography-electroencephalogram (EMG-EEG) monitoring during and after stimulation. RESULTS: The authors investigated 26 patients with mild to moderate PD: 13 received 50-Hz rTMS and 13 sham stimulation. The 50-Hz rTMS did not improve gait, bradykinesia, and global and motor UPDRS, but there appeared a short-lived "on"-state improvement in activities of daily living (UPDRS II). The 50-Hz rTMS lengthened the cortical silent period, but other neurophysiological and neuropsychological measures remained unchanged. EMG/EEG recorded no pathological increase of cortical excitability or epileptic activity. There were no adverse effects. CONCLUSION: It appears that 50-Hz rTMS of the motor cortices is safe, but it fails to improve motor performance and functional status in PD. Prolonged stimulation or other techniques with rTMS might be more efficacious but need to be established in future research.

Sleep EEG changes after middle cerebral artery infarcts in mice: different effects of striatal and cortical lesions.

STUDY OBJECTIVES: Hemispheric stroke in humans is associated with sleep-wake disturbances and sleep electroencephalogram (EEG) changes. The correlation between these changes and stroke extent remains unclear. In the absence of experimental data, we assessed sleep EEG changes after focal cerebral ischemia of different extensions in mice. DESIGN: Following electrode implantation and baseline sleep-wake EEG recordings, mice were submitted to sham surgery (control group), 30 minutes of intraluminal middle cerebral artery (MCA) occlusion (striatal stroke), or distal MCA electrocoagulation (cortical stroke). One and 12 days after stroke, sleep-wake EEG recordings were repeated. The EEG recorded from the healthy hemisphere was analyzed visually and automatically (fast Fourier analysis) according to established criteria. MEASUREMENTS AND RESULTS: Striatal stroke induced an increase in non-rapid eye movement (NREM) sleep and a reduction of rapid eye movement sleep. These changes were detectable both during the light and the dark phase at day 1 and persisted until day 12 after stroke. Cortical stroke induced a less-marked increase in NREM sleep, which was present only at day 1 and during the dark phase. In cortical stroke, the increase in NREM sleep was associated in the wake EEG power spectra, with an increase in the theta and a reduction in the beta activity. CONCLUSION: Cortical and striatal stroke lead to different sleep-wake EEG changes in mice, which probably reflect variable effects on sleep-promoting and wakefulness-maintaining neuronal networks.

Patient-ventilator asynchrony during non-invasive ventilation for acute respiratory failure: a multicenter study.

OBJECTIVE : To determine the prevalence of patient-ventilator asynchrony in patients receiving non-invasive ventilation (NIV) for acute respiratory failure. DESIGN : Prospective multicenter observation study. SETTING : Intensive care units in three university hospitals. METHODS: Patients consecutively admitted to ICU were included. NIV, performed with an ICU ventilator, was set by the clinician. Airway pressure, flow, and surface diaphragmatic electromyography were recorded continuously for 30 min. Asynchrony events and the asynchrony index (AI) were determined from visual inspection of the recordings and clinical observation. RESULTS: A total of 60 patients were included, 55% of whom were hypercapnic. Auto-triggering was present in 8 (13%) patients, double triggering in 9 (15%), ineffective breaths in 8 (13%), premature cycling 7 (12%) and late cycling in 14 (23%). An AI > 10%, indicating severe asynchrony, was present in 26 patients (43%), whose median (25-75 IQR) AI was 26 (15-54%). A significant correlation was found between the magnitude of leaks and the number of ineffective breaths and severity of delayed cycling. Multivariate analysis indicated that the level of pressure support and the magnitude of leaks were weakly, albeit significantly, associated with an AI > 10%. Patient comfort scale was higher in pts with an AI < 10%. CONCLUSION: Patient-ventilator asynchrony is common in patients receiving NIV for acute respiratory failure. Our results suggest that leaks play a major role in generating patient-ventilator asynchrony and discomfort, and point the way to further research to determine if ventilator functions designed to cope with leaks can reduce asynchrony in the clinical setting.