Publicação
Combining neuromuscular and biomechanical features to assess sensorimotor impairments after spinal cord injury or stroke
| Resumo: | Stroke and spinal cord injury (SCI) are the most common causes of paresis and paralysis. Disabilities that follow stroke (hemiparesis, hemiplegia) or SCI (paraplegia, tetraplegia) are the result of an inappropriate muscle coordination and activation, leading to impaired motor functions (e.g., walking, cycling) and, thereby, preventing affected people from healthy-like participation in daily activities. The assessment of sensorimotor impairments has been mainly performed with qualitative methods (classical clinical scales) or subjective assessment from clinical personnel (based on visual observation). These techniques may lead to low inter-rater reliability and, as a consequence, to inadequate interventions. Gait training must have the ability to adapt to individual progression of each patient. Therefore, it is necessary to quantitatively assess locomotor responses after neurological diseases. The main goal of this Ph.D. Thesis is to generate meaningful quantitative metrics to assess sensorimotor impairments of patients that suffered a stroke or an incomplete spinal cord injury (iSCI). To achieve this main goal, it is necessary to advance neurophysiological and biomechanical conceptual foundations underlying gait function. Further design of appropriate protocols and the generation of these metrics may improve future rehabilitation treatments tailored to each of the aforementioned patients. Recent researches on pathological conditions strongly recommend gait analysis to adequately assess and follow-up patients and to support clinical decision on the best treatment. Measures derived from gait analysis provide detailed and quantitative description of motor impairments. On the other hand, a technique called analysis of muscle synergies (groups of co-activated muscles responsible for the control of motor tasks), which is based on statistical analysis of electromyographic (EMG) features, has emerged as a promising tool that can a better the clinician a better view of the neural structure underlying motor behaviors and how they change during the rehabilitation process. Thus, a combination of metrics informing about biomechanical and neuromuscular performance in realistic conditions should lead to a better assessment of motor impairments. To achieve the main goal of this Ph.D. Thesis, four distinct and complementary studies were performed. The first study investigated similar features of walking and cycling under the muscle synergies hypothesis. This study was motivated by the need for novel tools to measure and predict motor performance of neural injured patients. This need has emerged because some patients who suffered neural injuries do not have sufficient muscle force to walk during the early stage of rehabilitation and, as a consequence, cannot be assessed properly during walking tasks. Due to similarities in kinematics and muscle control, cycling might be explored as a possible framework. Results of this study provided evidences for common neuromuscular mechanisms of the two motor tasks. The results of study 1 supported the hypothesis of using cycling to assess gait-related motor performance. Thus, the second study of this research aimed to test this hypothesis on subjects affected by iSCI. First of all, results showed that iSCI patients preserved a synergistic control of muscles during cycling and the similarity of synergies with respect to healthy controls correlated with the degree of impairment. Second, muscle synergies outcomes extracted during cycling correlated with clinical measurements of gait performance and/or spasticity caused by abnormal spatiotemporal muscle co-activation. After iSCI, both body sides may be affected differently, resulting in asymmetric motor control and functional behavior. The third study of this Thesis used some biomechanical features, as well as the analysis of muscle synergies to differentiate most and less affected sides. Results showed that biomechanical analysis was more effective than the analysis of muscle synergies to detect differences between the most and the less affected sides of iSCI patients. Based on the findings of studies 2 and 3, which showed the usefulness of muscle synergies and biomechanical features to assess iSCI patients, the fourth and last study of this Thesis tested whether the combination of a small set of gait features and the analysis of muscle synergies could better predict walking function poststroke than the gold-standard scale (Fugl-Meyer Assessment, FMA). It was possible to find some variables (from both the most and the less affected side) that correlated better with walking function than FMA. In conclusion, this Thesis presented novel methodologies and metrics that allow for a quantitative assessment of sensorimotor impairments in patients that suffered an iSCI or a stroke. In particular, the use of metrics based on EMG and biomechanical features gave a new insight into the motor recovery mechanisms as well as the performance after neural damage. These metrics may be explored in the future as a complement to the current clinical assessment procedures. |
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| Autores principais: | Barroso, Filipe André Oliveira |
| Assunto: | Engenharia e Tecnologia::Outras Engenharias e Tecnologias |
| Ano: | 2016 |
| País: | Portugal |
| Tipo de documento: | tese de doutoramento |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | Stroke and spinal cord injury (SCI) are the most common causes of paresis and paralysis. Disabilities that follow stroke (hemiparesis, hemiplegia) or SCI (paraplegia, tetraplegia) are the result of an inappropriate muscle coordination and activation, leading to impaired motor functions (e.g., walking, cycling) and, thereby, preventing affected people from healthy-like participation in daily activities. The assessment of sensorimotor impairments has been mainly performed with qualitative methods (classical clinical scales) or subjective assessment from clinical personnel (based on visual observation). These techniques may lead to low inter-rater reliability and, as a consequence, to inadequate interventions. Gait training must have the ability to adapt to individual progression of each patient. Therefore, it is necessary to quantitatively assess locomotor responses after neurological diseases. The main goal of this Ph.D. Thesis is to generate meaningful quantitative metrics to assess sensorimotor impairments of patients that suffered a stroke or an incomplete spinal cord injury (iSCI). To achieve this main goal, it is necessary to advance neurophysiological and biomechanical conceptual foundations underlying gait function. Further design of appropriate protocols and the generation of these metrics may improve future rehabilitation treatments tailored to each of the aforementioned patients. Recent researches on pathological conditions strongly recommend gait analysis to adequately assess and follow-up patients and to support clinical decision on the best treatment. Measures derived from gait analysis provide detailed and quantitative description of motor impairments. On the other hand, a technique called analysis of muscle synergies (groups of co-activated muscles responsible for the control of motor tasks), which is based on statistical analysis of electromyographic (EMG) features, has emerged as a promising tool that can a better the clinician a better view of the neural structure underlying motor behaviors and how they change during the rehabilitation process. Thus, a combination of metrics informing about biomechanical and neuromuscular performance in realistic conditions should lead to a better assessment of motor impairments. To achieve the main goal of this Ph.D. Thesis, four distinct and complementary studies were performed. The first study investigated similar features of walking and cycling under the muscle synergies hypothesis. This study was motivated by the need for novel tools to measure and predict motor performance of neural injured patients. This need has emerged because some patients who suffered neural injuries do not have sufficient muscle force to walk during the early stage of rehabilitation and, as a consequence, cannot be assessed properly during walking tasks. Due to similarities in kinematics and muscle control, cycling might be explored as a possible framework. Results of this study provided evidences for common neuromuscular mechanisms of the two motor tasks. The results of study 1 supported the hypothesis of using cycling to assess gait-related motor performance. Thus, the second study of this research aimed to test this hypothesis on subjects affected by iSCI. First of all, results showed that iSCI patients preserved a synergistic control of muscles during cycling and the similarity of synergies with respect to healthy controls correlated with the degree of impairment. Second, muscle synergies outcomes extracted during cycling correlated with clinical measurements of gait performance and/or spasticity caused by abnormal spatiotemporal muscle co-activation. After iSCI, both body sides may be affected differently, resulting in asymmetric motor control and functional behavior. The third study of this Thesis used some biomechanical features, as well as the analysis of muscle synergies to differentiate most and less affected sides. Results showed that biomechanical analysis was more effective than the analysis of muscle synergies to detect differences between the most and the less affected sides of iSCI patients. Based on the findings of studies 2 and 3, which showed the usefulness of muscle synergies and biomechanical features to assess iSCI patients, the fourth and last study of this Thesis tested whether the combination of a small set of gait features and the analysis of muscle synergies could better predict walking function poststroke than the gold-standard scale (Fugl-Meyer Assessment, FMA). It was possible to find some variables (from both the most and the less affected side) that correlated better with walking function than FMA. In conclusion, this Thesis presented novel methodologies and metrics that allow for a quantitative assessment of sensorimotor impairments in patients that suffered an iSCI or a stroke. In particular, the use of metrics based on EMG and biomechanical features gave a new insight into the motor recovery mechanisms as well as the performance after neural damage. These metrics may be explored in the future as a complement to the current clinical assessment procedures. |
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