Brain activity and event-related potential analysis in healthy and spinal cord injured individuals

Abstract

In recent years, research has shown that transcutaneous spinal cord stimulation (tSCS) can be used to treat spasticity and facilitate walking in spinal cord injury (SCI) in a similar way as epidural spinal cord stimulation (eSCS). Same results have not been achieved for brain-damaged individuals. It is believed that the tSCS affects the spinal cord neural network with inhibiting signals partly replacing the brain’s function. This process is poorly understood. Also, the interaction of the spinal cord with the brain or the effect of tSCS on the spine andbrain has not been the focus of research. Plastic processes in the spinal cord and the brain as a result of SCI are known to some extent but not the effect of tSCS on the same organs. The neural structures influencing the activity of the lower motor neuron are the target forthe treatment of spasticity in the lower extremities. These effects and the structures are to be studied in this work through the connections to the brain or the absence of them. This M.Sc. project aims to develop a processing pipeline and measurement protocol, and set up and evaluate synchronous measurements of the brain and muscle to analyze and evaluate the potentials of the brain that muscles and movements evoke. Event-related potential (ERP) analysis and time-frequency analysis (TFA) of the brain are used to estimate information in time and frequency domains, between the cortex and muscles. Results of the work show that by combining electroencephalogram (EEG) and electromyography (EMG) signals, the interaction between the cerebral motor cortex, sensory cortex, and muscles are investigated. The findings reveal that the influence of the tSCS and patellar tendon reflex is detected in the EEG with the use of the signal processing pipeline. Furthermore, the latency of potentials is detected, and analyses between healthy and spinal cord injured are interpreted. As a result, determining neuromuscular connections can provide information about the theoretical basis for rehabilitation.