This dissertation presents work towards the development of a multiple finger, worn, dynamic display device, which utilizes a method of texture encoded information to haptically render graphical images for individuals who are blind or visually impaired. The device interacts directly with the computer screen, using the colors and patterns displayed by the image as a means to encode complex patterns of vibrotactile output, generating the texture feedback to render the image. In turn, the texture feedback was methodically designed to enable parallel processing of certain coarse information, speeding up the exploration of the diagram and improving user performance. The design choices were validated when individuals who are blind or visually impaired, using the multi-fingered display system, performed three-times better using textured image representations versus outline representations. Furthermore, in an open-ended object identification task, the display device saw on average two-times better performance accuracy than that previously observed for raised-line diagrams, the current standard for tactile diagrams.

Individuals with limited motor control are often unable to interact with their environment. Recently, near-infrared spectroscopy (NIRS) systems have been investigated as potential brain-computer interfaces (BCI). Previous studies examined data offline, preventing users from understanding how their thoughts triggered the NIRS system. This thesis focused on understanding the short-term effects of feedback on user’s ability to learn how to control BCIs. Data were collected from control and experimental groups over seven sessions, as they performed fast singing imagery or mental arithmetic. Significant differences were observed between the control group’s results in non-feedback sessions and the experimental group’s results in feedback sessions. Qualitative results from 3 of the 10 participants suggested they had control of the feedback system. They performed the task with online accuracies of 61% - 88% in the final 2 sessions with feedback. These results suggest that continued investigation of NIRS feedback systems is warranted.

Individuals with limited motor control are often unable to interact with their environment. Recently, near-infrared spectroscopy (NIRS) systems have been investigated as potential brain-computer interfaces (BCI). Previous studies examined data offline, preventing users from understanding how their thoughts triggered the NIRS system. This thesis focused on understanding the short-term effects of feedback on user’s ability to learn how to control BCIs. Data were collected from control and experimental groups over seven sessions, as they performed fast singing imagery or mental arithmetic. Significant differences were observed between the control group’s results in non-feedback sessions and the experimental group’s results in feedback sessions. Qualitative results from 3 of the 10 participants suggested they had control of the feedback system. They performed the task with online accuracies of 61% - 88% in the final 2 sessions with feedback. These results suggest that continued investigation of NIRS feedback systems is warranted.

A partir da necessidade de medir a força aplicada em uma muleta ou bengala quando o paciente está caminhando, o que seria extremamente complexo com uma balança comum, desenvolveu-se meios utilizando sensores e circuitos eletrônicos que possibilitem tal aquisição do valor da força aplicada. O sensor utilizado foi acoplado na própria haste da muleta. O circuito eletrônico constituiu-se das seguintes etapas: a de amplificação, a de conversão analógica-digital e a de um microcontrolador para gerenciar todo o processo. Para que os dados referentes à carga descarregada na muleta fossem tratados de uma maneira que o pesquisador ou o clínico tivessem facilidade de compreensão e análise, um software foi desenvolvido. Este permite a construção de gráficos e análises estatísticas. Foram desenvolvidos ainda, configurações que permitissem sincronismo com outros equipamentos de análise de forças de marcha. O trabalho conta também com exemplos práticos de aquisições com pacientes que possuem alguma debilidade motora, demonstrando a utilidade da muleta instrumentalizada no apoio ao clínico ou em pesquisas na área de engenharia de reabilitação. / Because of the necessity of measuring the forces in a cane or crutch while the patient walking, an extremely complex task, a system has been developed to measure these forces, using sensors and electronic circuits. The sensors have been applied directly to the shaft of the metal crutch. The electronic circuit has the following stages: amplification, analog to digital conversion and the microcontroler to manage the whole process. A software has been developed to analyze the data and to be user friendly. The software allows the construction of graphics and the statistical analysis. This project has also shown practical examples with patients that have some gait pathologies, showing the usefulness of the instrumented crutch in supporting the physician, or in the rehabilitation engineering research.

Powered wheelchairs offer a means of independent mobility for older adults who are unable to walk and cannot propel a manual wheelchair. Unfortunately, cognitively impaired older adults may be denied this means of independent mobility. There is concern that these adults are unable to drive a powered wheelchair safely or properly. Intelligent wheelchairs offer an approach to address this problem. This research outlines the development and evaluation of an Intelligent Wheelchair System (IWS) that is proposed to make powered wheelchairs safer and easier to use for cognitively impaired older adults. The IWS has anti-collision and navigation functions. Hardware results show a 1000% increase in computational speed compared to the previous IWS. Clinical results with dementia patients show that the IWS has the potential to increase safety by reducing frontal collisions, and by promoting safe completion of movement tasks. Usability of the system may be an issue.

Orthostatic hypotension (OH) is a prevalent condition among individuals with spinal cord injury (SCI). After an injury, OH often reduces the benefit of neurorehabilitation and also prolongs periods of inactivity that lead to secondary complications. This study investigated whether the cardiovascular response to head-up tilting can be improved using functional electrical stimulation (FES) and rhythmic passive movements of the lower extremities. Participants with high thoracic and cervical SCI were recruited. While the participants were tilted head-up to 70 degrees, four conditions were applied in a random sequence: 1) no intervention, 2) rhythmic passive leg movements, 3) isometric FES, and 4) a combination of FES and passive leg movements. The measured cardiovascular parameters indicated that a combination of FES and passive leg movements induced the most desirable response to head-up tilting. The proposed intervention will enable more individuals with SCI to participate in beneficial neurorehabilitation that uses a novel tilt table.

Orthostatic hypotension (OH) is a prevalent condition among individuals with spinal cord injury (SCI). After an injury, OH often reduces the benefit of neurorehabilitation and also prolongs periods of inactivity that lead to secondary complications. This study investigated whether the cardiovascular response to head-up tilting can be improved using functional electrical stimulation (FES) and rhythmic passive movements of the lower extremities. Participants with high thoracic and cervical SCI were recruited. While the participants were tilted head-up to 70 degrees, four conditions were applied in a random sequence: 1) no intervention, 2) rhythmic passive leg movements, 3) isometric FES, and 4) a combination of FES and passive leg movements. The measured cardiovascular parameters indicated that a combination of FES and passive leg movements induced the most desirable response to head-up tilting. The proposed intervention will enable more individuals with SCI to participate in beneficial neurorehabilitation that uses a novel tilt table.

Powered wheelchairs offer a means of independent mobility for older adults who are unable to walk and cannot propel a manual wheelchair. Unfortunately, cognitively impaired older adults may be denied this means of independent mobility. There is concern that these adults are unable to drive a powered wheelchair safely or properly. Intelligent wheelchairs offer an approach to address this problem. This research outlines the development and evaluation of an Intelligent Wheelchair System (IWS) that is proposed to make powered wheelchairs safer and easier to use for cognitively impaired older adults. The IWS has anti-collision and navigation functions. Hardware results show a 1000% increase in computational speed compared to the previous IWS. Clinical results with dementia patients show that the IWS has the potential to increase safety by reducing frontal collisions, and by promoting safe completion of movement tasks. Usability of the system may be an issue.

The goal of the study was to use electrical signals from primary motor cortex to generate accurate predictions of the movement onset time of performed movements, for potential use in asynchronous brain-machine interface (BMI) systems. Four subjects, two with electroencephalogram and two with electrocorticogram electrodes, performed various movements while activity from their primary motor cortices was recorded. An analysis program used several criteria (change point, fractal dimension, spectral entropy, sum of differences, bandpower, bandpower integral, phase, and variance), derived from the neural recordings, to generate predictions of movement onset time, which it compared to electromyogram activity onset time, determining prediction accuracy by receiver operating characteristic curve areas. All criteria, excepting phase and change-point analysis, generated accurate predictions in some cases.

The goal of the study was to use electrical signals from primary motor cortex to generate accurate predictions of the movement onset time of performed movements, for potential use in asynchronous brain-machine interface (BMI) systems. Four subjects, two with electroencephalogram and two with electrocorticogram electrodes, performed various movements while activity from their primary motor cortices was recorded. An analysis program used several criteria (change point, fractal dimension, spectral entropy, sum of differences, bandpower, bandpower integral, phase, and variance), derived from the neural recordings, to generate predictions of movement onset time, which it compared to electromyogram activity onset time, determining prediction accuracy by receiver operating characteristic curve areas. All criteria, excepting phase and change-point analysis, generated accurate predictions in some cases.