Orientador: Maria Aparecida Neves Jardini / Resumo: A estimulação elétrica (EE) tem sido usada no tratamento de lesões crônicas apresentando resultados favoráveis no fechamento da lesão cutânea entre outras aplicações clínicas. No entanto, a literatura carece de estudos avaliando se os efeitos da EE no fechamento da lesão oral. Diante disso, torna-se relevante investigar os efeitos da EE durante o processo de reparo da lesão oral em camundongos (Swiss). Métodos: Noventa animais foram divididos em grupos: Controle (C; n=45) que receberam a aplicação da EE com o aparelho desligado e Teste (EE; n=45) que receberam a EE (100 µA; 9 kHz; 660 mVpp; 1x/dia por 3 dias). Uma lesão de espessura total foi realizada com punch de biópsia de 1,5 mm de diâmetro. Os animais foram eutanasiados no 1o, 3o e 5o dia após a confecção da lesão. As amostras foram fixadas em paraformaldeído 4%, descalcificadas em ácido fórmico 20% e emblocadas em parafina. Os parâmetros avaliados foram: fechamento clínico da lesão; distância de reparação epitelial (DRE) e conjuntiva (DRC), concentração de citocinas IL-1β, IL-6, IL-8, IL-10, TNF-α e VEGF; porcentagem de fibras colágenas e quantificação das proteínas de sinalização Smad2. Resultados: A área de fechamento clínico foi reduzida no grupo EE no 5º dia de avaliação (p=0,01). As DRE e DRC do grupo EE apresentaram menor distância em todos os tempos avaliados (p<0,05) com reduzida concentração de IL-6, TNF-α, IL-10 e VEGF (p<0,05). Não houve diferença na porcentagem de fibras colágenas e na phospho-Smad2. Conclus... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Background: Since Electrical Stimulation (ES) has used for chronic wounds treatment and other clinical applications showing favorable results in wound closure, it was hypothesized whether it could bring good results in oral wound closure. The aim was to investigate the ES effects during the oral wound healing process in mice (Swiss). Methods: Ninety animals were divided in groups: Control (C; n=45) which received a fictitious ES application, i.e. the ES applicance was shutted off and ES (ES; n=45) which received ES (100 µA; 9 kHz; 660 mVpp) once time a day for 3 days consecutively. A full thickness wound was done using a 1.5 mm diameter biopsy punch in the hard palate. The animals were euthanized on 1st, 3rd and 5th day post-wounding. The samples were fixed, decalcified and embedded in paraffin. The parameters evaluated were: clinical wound closure; distance of epithelial and connective wound edges (EWD and CWD); cytokines (IL-1β, IL-6, IL-8, IL-10), TNF-α and VEGF by multiplex, percentage of collagen fibers and Smad proteins. Results: Clinical wound closure area was reduced on day 5 in ES group (p = 0.01). Both EWD and CWD distance were shorter in all times (p < 0.05) with a reduction of inflammatory cytokines production (p < 0.05). There were no difference in collagen percentage and phospho-Smad2. Conclusion: ES had a positive effect on clinical and histomorphometric wound closure outcomes showing a modulation of inflammatory response in the beginning of wound healing. / Doutor

We can hold conversations with people in environments where typically there are additional simultaneous talkers in background acoustic space or noise like vehicles on the street or music playing at a café on the sidewalk. This seemingly trivial everyday task is difficult for people with hearing deficits and is extremely hard to model in machines. This dissertation focuses on exploring the neural mechanisms of how the human brain encodes such complex acoustic environments and how cognitive processes like attention shapes processing of the attended speech. My initial experiments explore the representation of acoustic features that help us localize single sound sources in the environment- features like direction and spectrotemporal content of the sounds, and the interaction of these representations with each other. I play natural American English sentences coming from five azimuthal directions in space. Using intracranial electrocorticography (ECoG) recordings from the human auditory cortex of the listener, I show that the direction of sound and the spectrotemporal content are encoded in two distinct aspects of neural response, the direction modulates the mean of the response and the spectrotemporal features contributes to the modulation of neural response around its mean. Furthermore, I show that these features are orthogonal to each other and do not interact. This representation enables successful decoding of both spatial and phonetic information. These findings contribute to defining the functional organization of responses in the human auditory cortex, with implications for more accurate neurophysiological models of spatial speech processing. I take a step further to investigate the role of attention in encoding the direction and phonetic features of speech. I play a mixture of male and female spatialized talkers eg. male at left side to the listener and female at right side (talker’s locations switch randomly after each sentence). I ask the listener to follow a given talker e.g. follow male talker as they switch their location after each uttered sentence. While the listener performs this experiment, I collect intracranial EEG data from their auditory cortex. I investigate the bottom-up stimulus dependent and attention independent encoding of such a cocktail party speech and the top-down attention driven role in the encoding of location and speech features. I find a bottom-up stimulus driven contralateral preference in encoding of the mixed speech i.e. Left brain hemisphere automatically and predominantly encodes speech coming from right direction and vice-versa. On top of this bottom-up representation, I find that attended talker’s direction modulates the baseline of the neural response and attended talker’s voice modulates the spectrotemporal tuning of the neural response. Moreover, the modulation to attended talker’s location is present throughout the auditory cortex but the modulation to attended talker’s voice is present only at higher order auditory cortex areas. My findings provide crucially needed evidence to determine how bottom-up and top-down signals interact in the auditory cortex in crowded and complex acoustic scenes to enable robust speech perception. Furthermore, they shed light on the hierarchical encoding of attended speech that have implications on bettering the auditory attention decoding models. Finally, I talk about a clinical case study where we show that electrical stimulation to specific sites in planum temporale (PT) of an epilepsy patient implanted with intracranial electrode leads to enhancement in speech in noise perception. When noisy speech is played with such an electrical stimulation, the patient perceives that the noise disappears, and that the speech is similar to clean speech that they hear without any noise. We performed series of analysis to determine functional organization of the three main sub regions of the human auditory cortex- planum temporale (PT), Heschl’s gyrus (HG) and superior temporal gyrus (STG). Using Cortico-Cortical Evoked Potentials (CCEPs), we modeled the PT sites to be located between the sites in HG and STG. Furthermore, we find that the discriminability of speech from nonspeech sounds increased in population neural responses from HG to the PT to the STG sites. These findings causally implicate the PT in background noise suppression and may point to a novel potential neuroprosthetic solution to assist in the challenging task of speech perception in noise. Together, this dissertation shows new evidence for the neural encoding of spatial speech; interaction of stimulus driven, and attention driven neural processes in spatial multi-talker speech perception and enhancement of speech in noise perception by electrical brain stimulation.

<p>Predmet istraživanja ove doktorske disertacije je pronalaženje re&scaron;enja<br />problema automatske funkcionalne provere uređaja potro&scaron;ačke elektronike<br />koji su zasnovani na ekranu osetljivom na dodir. Osnovni izazov je pronaći<br />efikasan i pouzdan način električne stimulacije ekrana, bez mehaničke<br />pobude. Drugi izazov je definisati algoritam za proveru sadržaja na ekranu<br />posmatrajući ga sa stanovi&scaron;ta percepcije korisnika, pomoću kamere. Rezultat<br />istraživanja je integrisani sistem sa stimulacionom pločom koja kontrolisano<br />pobuđuje ekran električnim stimulusom, bez mehaničkih pokreta. Provera<br />uređaja se vr&scaron;i po principu crne kutije. Cilj sistema je proveriti da li se uređaj i<br />njegova programska podr&scaron;ka pona&scaron;aju očekivano.</p> / <p>Topic of research of this PhD thesis is finding the solution for the mentioned<br />problem of automated functional verification of consumer electronics devices<br />with touchscreens. The main challenge is to find a reliable and efficient way<br />of electric stimulation of touchscreens, without mechanical movements. The<br />second challenge is to design an algorithm for analysis of content on the<br />touchscreen, observing it from the user&rsquo;s perception, with the help of a<br />camera. Result of the research is the integrated system with the stimulation<br />board for controllable electrical stimulation of touchscreens, without<br />mechanical movements. The integrated system verifies whether the device<br />and its software behave as expected.</p>

<p>Ciljevi: U kliničkoj praksi se rutinski upotrebljava vizuelna metoda evaluacije TOF testa, koja ne pruža u potpunosti precizne podatke u periodu oporavka neuromi&scaron;ićne blockade. Neophodno je ispitati mogućnost upotrebe specifičnije i preciznije metode u TOF monitoring, kao &scaron;to je kvantitativna TOF metoda. Određivanje razlike između vrednosti T1 i T4 mi&scaron;ićnih kontrakcija, dobijenih kvantitativnom TOF metodom, može biti precizan pokazatelj prisustva neuromi&scaron;ićne blokade na testiranom mi&scaron;iću. Takođe, aplikacijom kvantitativne TOF metode, neophodno je utvrditi da li kod različitih mi&scaron;ića postoji različit period oporavka od prisustva neuromi&scaron;ićne blokade. Upotreba kvantitativne TOF metode, i poređenje T4 / T1 odnosa između različitih mi&scaron;ića, može biti pokazatelj postojanja razlika u oporavku od prisustva neuromi&scaron;ićne blokade. Materijal i metode: U istraživanju je analiziran oporavak od prisustva neromi&scaron;ićne blokade na m.abductor hallucis i m. interosseus dorsalis primus aplikacijom kvantitativnog TOF testa u toku ortopedskih hirur&scaron;kih procedura na kičmenom stubu uz upotrebu intraoperativnog neurofiziolo&scaron;kog monitoring kod 147 bolesnika. T4/T1 odnos je određen na testiranom mi&scaron;iću stopala i &scaron;ake, obavljena je klasifikacija ispitanika u odnosu na dozu neuromi&scaron;ićnog blokatora i proteklo vreme od apilikacije. Poređenjem T4/T1 odnosa između testiranih mi&scaron;ića utvrđene su razlike u oporavku od prisustva neuromi&scaron;ićne blokade. Vizuelnom TOF metodom je vr&scaron;ena procena neuromi&scaron;ićne blokade od strane anesteziologa, stimulacijom n.ulnaris i praćenjem kontrakcije m.adductor pollicis. Rezultati dobijeni vizuelnom TOF metodom su upoređeni sa rezultatima dobijenim kvantitativnom TOF metodom na m. interosseus dorsalis primus. Rezultati: Postoje značajne razlike u T4/T1 odnosu između testiranih mi&scaron;ića na stopalu i &scaron;aci (p&lt;0.05). T4/T1 odnos određen na m.abductor hallucis ima niže vrednosti, odnosno brži oporavak, u odnosu na m. interosseus dorsalis primus (p&lt;0.05). Kvantitativnom TOF metodom dobijeni su pouzdani rezultati o proceni neuromi&scaron;ićne blokade kod svih testiranih bolesnika, dok su vizuelnom TOF metodom dobijeni kod 40 % testiranih bolesnika. Rezultati pokazuju da postoje značajne razlike u pouzdanosti i preciznosti između kvantitativne i vizuelne TOF metode. Zaključak: Kvantitativna TOF metoda je klinički prihvatljiva i pouzdana metoda u proceni prisustva neuromi&scaron;ićne blokade. Razlike u oporavku od neuromi&scaron;ićne blokade uočene kod različitih mi&scaron;ića, ukazuju da je TOF monitoring neophodan na određenoj mi&scaron;ićnoj regiji koja pruža pouzdane i precizne podatke o neuromi&scaron;ićnoj blokadi regije na kojoj se hirur&scaron;ka procedura obavlja. Kvantitativna TOF metoda pruža preciznije podatke o stepenu prisustva neuromi&scaron;ićne blokade u odnosu na vizuelnu subjektivnu TOF metodu.</p> / <p>Purpose: In clinical practice routinely used method of TOF test is visual method of interpretation. This method does not provide completely reliable data in period of spontaneous recovery from neuromuscular blockade. It is necessary to investigate possibility of application of more specific and more accurate method in TOF monitoring, such as quantitative TOF method. Determination of difference between the values of T1 and T4 muscle contraction, obtained by quantitative TOF method, may indicate the presence of neuromuscular blockade on tested muscle. In addition to this, by application of quantitative TOF method, it is necessary to determine is there a difference in period of recovery from neuromuscular blockade between defferent muscles. Comparison of T4/T1 ratios between different muscles may indicate presence of different period of recovery from neuromuscular blockade. Methods: Study analyzed differences between recovery of foot - abductor hallucis muscle and hand - first dorsal interosseous muscle by application of quantitative TOF test on 147 patients undergoing lumbar spine surgery. T1 to T4 decrements on hand and foot TOF were determined and classified into different groups, depending of neuromuscular blocking agents (NMBA) dose and elapsed time after administration. T1 - T4 decrements were compared between hand and foot TOF and differences between muscle recovery were determined. Visual method of TOF test was performed by anesthesiologists, by using peripheral nerve stimulator and stimulating ulnar nerve. Quantitative TOF test was measured on first dorsal interosseous muscle, and compared with visual TOF results obtained on adductor pollicis muscle. Results: There are significant differences between T1 - T4 decrements obtained on tested muscles of hand and foot (p&lt;0.05). T1-T4 decrement determined on abductor hallucis muscle had lower values, respectively more rapid recovery, than first dorsal interosseous muscle (p&lt;0.05). Quantitative method of TOF test had reliable and correct results in all tested subjects, while visual interpretation of TOF method showed accurate results in 40 % of all cases. Results indicated that significant difference was present between quantitative and visual method of TOF interpretation. Conclusions: Difference between observed recovery of hand and foot muscles is indicating that quantitative TOF test should be performed on specific site for which accurate data about the level of neuromuscular blockade is needed. During lumbar spine surgery, in addition to hand TOF, foot TOF should be included as it provides more accurate data needed for neurophysiological intraoperative monitoring. Quantitative TOF method provides more accurate data about level of neuromuscular blockade if compared with subjective visual TOF method.</p>

L’objectif de ce travail de thèse a été d’analyser les stratégies de réduction de la fatigue musculaire en course de trail et potentiellement d’identifier certains paramètres d’influence de cette fatigue. La course de trail est un nouveau sport en essor qui induit une combinaison spécifique de fatigue et dommages musculaires des principaux muscles locomoteurs. Afin de pouvoir conduire des études interventionnelles, une étude descriptive préliminaire a été conduite pour caractériser la fatigue spécifique et les dommages musculaires induits par ce type d’épreuve de trail. Ensuite, la reproductibilité du trail comme modèle de fatigue a été vérifiée afin de pouvoir l’utiliser dans un contexte d’intervention. Enfin, deux études visant à réduire la fatigue induite par le trail ont été conduites. D’une part l’utilisation des vêtements de compression - très à la mode en trail a été analysée comme stratégie d’optimisation de la performance. D’autre part, a aussi été étudié l’effet d’un réchauffement préalable du muscle sur les dommages musculaires : Dans cette optique, une étude contrôlée en laboratoire a été menée, examinant les effets d’un réchauffement passif sur les conséquences fonctionnelles de course en descente chez une population non-entraînée. En résumé, les travaux conduits au sein de cette thèse fournissent une description de la fatigue en trail, et valident l’utilisation du trail comme modèle reproductible de terrain pour investiguer les stratégies de réduction de la fatigue. De plus, ils relativisent l’effet positif des vêtements de compression sur la performance et montrent le lien fonctionnel entre le réchauffement musculaire et la réduction des dommages musculaires induits par un travail excentrique. / The aim of this thesis was to analyse strategies to reduce muscular fatigue in trail running and potentially draw conclusions on the underlying mechanisms. Trail running is a new and upcoming sport that induces a combination of fatigue and muscle damage in the main locomotor muscles. To obtain conclusive evidence on the effect of intervention studies a preliminary descriptive study was undertaken to characterise typical fatigue and damage. Subsequently a model was developed and validated that would allow the investigation of interventions in an applied field setting. A popular current strategy in trail running is the use of compression garments; therefore the effect of these on performance was studied as an intervention. Furthermore, prior heating is anecdotally considered beneficial and recent research has suggested a potential mechanism to link this with reduced muscle damage. Therefore a controlled laboratory study was conducted, examining the effects of passive heating on functional consequences of downhill running in an untrained population. In synopsis, the research conducted for this thesis provides descriptive evidence and a validated terrain model to further investigate fatigue reduction strategies in trail running. Additionally it adds to the current literature in disproving a positive effect of compression garments on performance and demonstrating the functional link between heating and eccentric-induced muscle damage reduction.

A eletroestimulação nervosa transcutânea (ENT) é um recurso que consiste em administrar impulsos ou estímulos elétricos de frequência variável, assimétricos ou simétricos de correntes bifásicas através de eletrodos superficiais aplicados sobre a região dolorosa. O objetivo deste estudo foi avaliar o efeito da ENT no alívio da dor na fase ativa da dilatação, no trabalho de parto, e constatar o grau de satisfação das parturientes em relação à experiência vivida durante o estudo. Trata-se de um ensaio clínico randomizado e controlado com 46 parturientes, divididas em grupo controle (GC) e grupo de intervenção (GI). Todas as pacientes eram primigestas, com dilatação cervical de 4 cm, em trabalho de parto espontâneo, com contrações regulares para essa fase, sem uso de drogas ocitócicas ao longo do trabalho de parto, de baixo risco gestacional, com membranas ovulares íntegras e feto único. A aplicação da ENT foi feita pela pesquisadora responsável, fixando dois pares de eletrodos nas regiões paravertebrais, um nas raízes nervosas de T10 a L1 e outro par entre S2 e S4. Os parâmetros utilizados na ENT foram: frequência de 100 Hz, largura de pulso de 100 us, intensidade de acordo com a sensibilidade da paciente e duração da aplicação de 30 minutos contínuos. A avaliação da dor foi realizada imediatamente, antes e após a terapêutica, com a escala categórica numérica (ECN), a escala visual analógica (EVA), o diagrama corporal da localização e Questionário McGill na forma reduzida. No puerpério, além dessas avaliações, o grau de satisfação da paciente com relação à intervenção e a presença de um profissional de saúde durante a fase ativa do trabalho de parto foram pesquisados. Os resultados mostraram que houve diferenças estatísticas significantes entre os dois grupos estudados, com relação à intensidade da dor, após a aplicação da ENT, com apenas 34% das pacientes do GI mantendo a classificação da dor como 7 ou mais, em contraste com 83% das pacientes do GC. Por outro lado, não houve diferenças estatísticas em relação à localização da dor, após a aplicação da ENT. As parturientes do GI ficaram mais satisfeitas com a experiência vivida e com o suporte contínuo recebido, durante o período estudado. Os resultados maternos e perinatais foram semelhantes nos dois grupos estudados. Os resultados encontrados demonstram que a aplicação da ENT, no início da fase ativa do trabalho de parto, alivia a dor das parturientes. Além disso, a presença de suporte contínuo exerce efeito positivo sobre as pacientes submetidas a essa intervenção / The transcutaneous electrical nervous stimulation (TENS) is a resource that consists of administering electrical impulses or stimuli of variable frequency, asymmetric or symmetric of two-phase chains to superficial electrodes applied on the painful region. The objective of this study was to evaluate the effect of TENS for pain relief during the active phase of cervix dilation in labor and to assess the degree of maternal satisfaction related to the experience during the study. This is a randomized controlled trial with 46 pregnant women, divided into control group (CG) and intervention group (IG). All patients were primiparous with cervical dilation of 4 cm in spontaneous labor with regular contractions for this phase without the use of oxytocic drugs during labor, lowrisk pregnant women with intact membranes and a single fetus. The application of the TENS was made by the researcher in charge, setting two pairs of electrodes in the paravertebral regions, at the level of the nerve roots from T10 to L1 and another pair between S2 to S4. The parameters used in TENS were: frequency 100 Hz, pulse width 100 us, intensity according to the sensitivity of the patient and duration of application of 30 continuous minutes. Pain assessment was performed immediately before and after therapy with the numerical categorical scale (ECN), the visual analogue scale (VAS), the body chart for pain location and the reduced form of McGill Questionnaire. In the puerperium, in addition to these assessments, the level of patient satisfaction related to the intervention and the presence of a health professional during the active phase of labor has been searched. The results showed statistically significant differences between the two groups regarding the intensity of pain following the implementation of the TENS, with only 34% of IG patients maintaining the score of pain as 7 or more, in contrast to 83% of CG patients. On the other hand, no statistical differences related to the location of the pain after the application of TENS. The mothers of the IG were more satisfied with the experience and the ongoing support received during the study period. The maternal and perinatal outcomes were similar in both groups. The results show that the application of TENS in the early active phase of labor relieves maternal pain. Moreover, the presence of ongoing support has a positive effect on patients undergoing this intervention

Onze pacientes com diagnóstico de esquizofrenia pelo DSM-IV-TR e alucinações auditivas mesmo em uso de clozapina foram distribuídos aleatoriamente para receber estimulação magnética transcraniana de repetição (EMTr) ativa (n=6) ou inativa (n=5) no córtex têmporo-parietal esquerdo. Um total de 160 minutos de EMTr a 1 Hz foi administrada ao longo de 10 dias, 90% do limiar motor, com desenho paralelo, com pacientes e avaliadores cegos, em desenho controlado com grupo inativo. Houve um efeito de grupo significativo nos escores da escala de alucinações (realidade e influência: p=0,0360 e p=0,0493 respectivamente) e no subitem sintomas positivos da PANSS. A EMTr ativa em associação com clozapina pode ser administrada com segurança para tratar as alucinações auditivas. Embora a amostra consistia de pacientes extremamente refratários, estes resultados sugerem haver alguns efeitos da EMTr a 1 Hz no córtex têmporo-parietal esquerdo. / Eleven schizophrenics patients according to DSM-IV-TR criteria and experiencing auditory hallucinations in spite of treatment with clozapine were randomly allocated to receive repetitive transcranial magnetic stimulation (rTMS) (n=6) or sham stimulation (n=5) over left temporo-parietal cortex. A total of 160 minutes of 1 Hz rTMS was administered over 10 days at 90% motor threshold, with patients and raters blind to treatment modality, using a sham-controlled, parallel design. There was a significant group effect for the Auditory Hallucinations Rating Scale scores (reality and attencional salience: p=0.0360 and p=0.0493 respectively) and the sub item positive symptoms of PANSS. Active rTMS in association with clozapine can be administered safely to treat auditory hallucinations. Although the sample consisted of extremely refractory patients, the results suggest some effects of 1 Hz rTMS over Left temporoparietal.

A estimulação elétrica neuromuscular (EENM) é um importante recurso utilizado na medicina esportiva para acelerar processos de recuperação. O objetivo deste estudo foi analisar os efeitos da EENM durante a imobilização do músculo gastrocnêmio, em posições de alongamento (LP) e encurtamento (SP). Para tanto, 60 ratas fêmeas jovens WISTAR foram distribuídas em seis grupos e acompanhadas durante 7 dias: controle (C), eletroestimuladas (EE), imobilizadas em encurtamento (ISP), imobilizadas em alongamento (ILP), imobilizadas em encurtamento e eletroestimuladas (ISP+EE) e imobilizadas em alongamento e eletroestimuladas (ILP+EE). Para a imobilização, o membro posterior direito foi envolvido por uma malha tubular e ataduras de algodão juntamente à atadura gessada. A EENM foi utilizada com uma freqüência de 50 Hz, 10 minutos por dia, totalizando 20 contrações em cada sessão. Após 7 dias os animais foram submetidos à eutanásia e os músculos gastrocnêmios foram retirados para a realização do ensaio mecânico de tração em uma máquina universal de ensaios (EMIC®). A partir dos gráficos carga versus alongamento foram calculadas as seguintes propriedades mecânicas: alongamento no limite de proporcionalidade (ALP), carga no limite de proporcionalidade (CLP), alongamento no limite máximo (ALM), carga no limite máximo (CLM) e rigidez. As imobilizações SP e LP promoveram reduções significativas (p<0,05) nas propriedades de ALP, CLP, ALM e CLM sendo mais acentuada, principalmente, no grupo ISP. Quando utilizada a EENM, houve acréscimo significativo (p<0,05) destas propriedades somente no grupo ISP. Já, em relação à rigidez, foi observada redução significativa (p<0,05) somente do grupo C para o grupo ISP. Quando utilizada a EENM, a rigidez do grupo ILP+EE foi significativamente (p<0,05) maior e mais próxima do grupo C que a do grupo ISP+EE. Neste modelo experimental, a imobilização dos músculos em alongamento atrasou a queda das propriedades e a estimulação elétrica, contribuiu para a manutenção das propriedades mecânicas durante o período de imobilização, principalmente no grupo ILP+EE. / The neuromuscular electric stimulation (NMES) is an important tool used in sport medicine to accelerate the recovery process. The objective of this study was to analyze the effects of NMES during the immobilization of the gastrocnemius muscle, in lengthened (LP) and shortened positions (SP). Sixty young female rats WISTAR were distributed into six groups and followed for 7 days: control (C), electric stimulation (ES), immobilized in shortened (ISP), immobilized in lengthened (ILP), immobilized in shortened and electric stimulation (ISP+ES) and immobilized in lengthened and electric stimulation (ILP+ES). For the immobilization, the right hind limb was involved by a tubular mesh and cotton rolls and plaster. NMES was used in a frequency of 50 Hz, 10 minutes a day, totaling 20 contractions in each session. After 7 days the animals were killed and their gastrocnemius muscles of the right side were submitted to a mechanical test in traction in an universal test machine (EMIC®). From the curves load versus elongation the following mechanical properties were obtained: elongation in the yield limit (EPL), load in the yield limit (LPL), elongation in the ultimate load (EUL), ultimate load (UL) and stiffness. The immobilizations SP and LP promoted significant reductions (p<0,05) in the properties of EPL, LPL, EUL and UL being more accentuated mainly in group ISP. When used NMES, there was significant increment (p<0,05) of such properties only in group ISP. As for stiffness, significant reduction was observed (p<0,05) only of the group C for group ISP. When the NMES was used, the stiffness of group ILP+EE was significantly (p<0,05) higher and closer to group C than for group ISP+EE. We conclude that in this experimental model the immobilization of the muscles in the lengthened position delayed the reduction of the properties and the electric stimulation contributed to the maintenance of the mechanical properties during the immobilization period, mainly for group ILP+ES.

Cardiac Resynchronization Therapy (CRT) is a treatment option for heart failure patients with ventricular dyssynchrony. CRT corrects for dyssynchrony by electrically stimulating the septal and lateral walls of the left ventricle (LV), forcing synchronous con- traction and improving cardiac output. Current selection criteria for CRT rely upon the QRS duration, measured from a surface electrocardiogram, as a marker of electrical dyssynchrony. Unfortunately, 30-40% of patients undergoing CRT fail to benefit from the treatment. A multitude of studies have shown that presence of mechanical dyssynchrony in the LV is an important factor in determining if a patient will benefit from CRT. Furthermore, recent evidence suggests that patient response can be improved by placing the LV pacing lead in the most dyssynchronous or latest contracting segment. The overall goal of this project was to develop methods that allow for accurate assessment and display of regional mechanical dyssynchrony throughout the LV and at the site of the LV pacing lead. To accomplish this goal, we developed a method for quantifying regional dyssynchrony from standard short-axis cine magnetic resonance (MR) images. To assess the effects of LV lead placement, we developed a registration method that allows us to project the LV lead location from dual-plane fluoroscopy onto MR measurements of cardiac function. By applying these techniques in patients undergoing CRT, we were able to investigate the relationship between regional dyssynchrony, LV pacing lead location, and CRT response.

Diss. Linköping : Univ., 2002.