Thesis (Ph. D.)--University of Oregon, 2005. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 115-119). Also available for download via the World Wide Web; free to University of Oregon users.

Thesis (Ph. D.)--University of Oregon, 2005. / Includes bibliographical references (leaves 115-119)

Thesis (M. Sc.)--University of Oregon, 2006. / Includes bibliographical references.

Thesis (M.S.)--University of Oregon, 2006. / Includes bibliographical references (leaves 77-81). Also available online (PDF file) by a subscription to the set or by purchasing the individual file.

Thesis (M.A.)--University of North Carolina at Chapel Hill, 2004. / Includes bibliographical references (leaves 132-135). Also available online (PDF file) by a subscription to the set or by purchasing the individual file.

xiii, 103 p. : ill. A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / The purpose of this dissertation was (1) to investigate the effects of dual task conditions on the development of postural control during gait in typically developing children while walking and obstacle crossing, and (2) to investigate the attentional requirements of gait in children with cerebral palsy (CP). Forty younger and older typically developing (YTD and OTD) children and 10 children with CP performed a gait task with and without a concurrently auditory Stroop task. Gait and cognitive performance were measured. In study 1, dual task interference with gait performance was found in YTD and OTD children, but not in healthy young adults (HYA). In general, gait performance decrements under dual task contexts were greater in YTD than OTD children, whereas cognitive performance decrements during dual tasking were not different between the two groups of children. Dual task interference was lowest in HYA and highest in YTD children when compared among groups. As the difficulty of the gait task was increased, dual task affects on cognitive performance were now found in YTD and OTD children, but not HYA. In study 2, there were significant differences in dual task interference affecting gait performance in all groups of children. When performing the gait task with a concurrent auditory Stroop task, OTD children showed greater dual-task costs than children with CP for accuracy, but children with CP demonstrated greater dual-task costs than OTD and YTD children for medial Center of Mass-Ankle-joint-center inclination angle. This increased medio-lateral inclination angle in dual task situations has also been seen in older adults with balance deficits and may be associated with an increased risk for falls. YTD children showed dual-task costs in a slowing of gait velocity and stride time, a safer strategy than that used by children with CP. The lower cognitive performance during dual tasking for OTD children suggests that they allocate greater attention to maintain gait stability, whereas YTD children and children with CP do not. In addition, children with CP use a behavior that may increase their risk of falls in complex environments. This dissertation includes unpublished co-authored material. / Committee in charge: Marjorie Woollacott, Chairperson, Human Physiology; Paul van Donkelaar, Member, Human Physiology; Li-Shan Chou, Member, Human Physiology; Paul Dassonville, Outside Member, Psychology

Made available in DSpace on 2014-11-10T11:09:54Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-06-30Bitstream added on 2014-11-10T11:57:44Z : No. of bitstreams: 1 000789739_20160130.pdf: 333032 bytes, checksum: 5511608aa67ffcb4c325f7f9e62387a5 (MD5) Bitstreams deleted on 2016-02-01T10:15:45Z: 000789739_20160130.pdf,. Added 1 bitstream(s) on 2016-02-01T10:16:40Z : No. of bitstreams: 1 000789739.pdf: 388187 bytes, checksum: 9d9a9e3ad8b38181e60d06031d9774d8 (MD5) / O trabalho teve por objetivos identificar parâmetros cinéticos e têmporo-espaciais de baixa variabilidade em grupos heterogêneos de cães, bem como avaliar a correlação linear entre a frequência de passada e as variáveis analisadas. Foram utilizados 29 cães hígidos, que foram divididos em dois grupos: Grupo 1 composto por 15 animais caminhando, 8 machos e 7 fêmeas, com peso variando de 11,50 até 50 kg (média de 22,31 Kg ± 10,04); Grupo 2 formado por 14 animais trotando, 6 machos e 7 fêmeas, com peso variando de 1,95 até 21,35 kg (média de 6,49 Kg ± 4,74). Os dados cinéticos e têmporo-espacias foram obtidos com o uso da plataforma de pressão. A velocidade foi mantida entre 0,9 e 1,1 m/s. Foram determinados o Pico de Força Vertical, o Impulso Vertical, a duração do ciclo da passada, o tempo de apoio, o tempo de balanço, o comprimento da passada e a distribuição do peso para os quatro membros. Para cada variável foi calculado o índice de assimetria entre os lados direito e esquerdo, para os membros torácicos e pélvicos. Para avaliar a correlação linear entre a frequência de passada e as demais variáveis foi realizado o teste de correlação de Pearson. Com exceção da porcentagem de distribuição de peso, todos os demais parâmetros cinéticos e têmporo-espaciais diferiram entre os grupos. A porcentagem de distribuição de peso foi em média 29,85 para os membros torácicos e 20,15 para os membros pélvicos. Não houve diferença estatística entre os índices de assimetria entre os Grupos 1 e 2. Foram observadas correlação forte negativa para a maioria dos parâmetros têmporo-espaciais e correlação forte positiva para a porcentagem de balanço. Não houve correlação significativa entre a frequência das passadas e a porcentagem de distribuição de peso corpóreo. Pelos resultados obtidos, pode-se afirmar que a frequência de passadas, apresenta correlação linear com os parâmetros temporo-espaciais ... / The aim of this study was to identify kinetic and temporospatial parameters of low variability in a heterogeneous group of dogs, and to evaluate a linear correlation between stride frequency and the variables. Twenty-nine clinically healthy dogs organized into two groups were used. Group 1 had 15 dogs walking, 8 males and 7 females, weighing from 11.50 kg to 50 kg (mean 22.31 kg ± 10.04 SD). Group 2 had 14 dogs trotting, 6 males and 8 females, weighing from 1.95 to 21.35 (mean 6.49 kg ± 4.74 SD). The kinetic data and temporospatial parameters were obtained using a pressure-sensitive walkway. The velocity was maintained between 0.9 and 1.1 m/s. The peak vertical force, vertical impulse, gait cycle time, stance time, swing time, stride length, percentage of body distribution among the four limbs were determined. For each variable the asymmetry indices between right and left sides, for both forelimbs and hind limbs, were calculated. Pearson's correlation coefficient was used to evaluate the linear correlation between stride frequency and other variables. Except for the percentage of body weight distribution, all other kinetic and temporospatial parameters differed between groups. The mean of percentage of body distribution was 29.85 and 20.15 for forelimbs and hind limbs, respectively. There was no statistically significant difference of the asymmetry indices between Groups 1 and 2. Strong negative correlation was observed for most of the temporospatial parameters and strong positive correlation to percentage of swing. There was no significant correlation between stride frequency and percentage of body weight distribution. In conclusion, in a heterogeneous group of dogs in controlled velocity, the percentage of body weight distribution and asymmetry index had low variability. Based on results obtained from correlations, the standardization of stride frequency may be an alternative to minimize the variability of temporospatial parameters

Orientador: Sheila Canevese Rahal / Banca: Nilva Maria Freres Mascarenhas / Banca: Lídia Mitsuko Matsubara / Resumo: O trabalho teve por objetivos identificar parâmetros cinéticos e têmporo-espaciais de baixa variabilidade em grupos heterogêneos de cães, bem como avaliar a correlação linear entre a frequência de passada e as variáveis analisadas. Foram utilizados 29 cães hígidos, que foram divididos em dois grupos: Grupo 1 composto por 15 animais caminhando, 8 machos e 7 fêmeas, com peso variando de 11,50 até 50 kg (média de 22,31 Kg ± 10,04); Grupo 2 formado por 14 animais trotando, 6 machos e 7 fêmeas, com peso variando de 1,95 até 21,35 kg (média de 6,49 Kg ± 4,74). Os dados cinéticos e têmporo-espacias foram obtidos com o uso da plataforma de pressão. A velocidade foi mantida entre 0,9 e 1,1 m/s. Foram determinados o Pico de Força Vertical, o Impulso Vertical, a duração do ciclo da passada, o tempo de apoio, o tempo de balanço, o comprimento da passada e a distribuição do peso para os quatro membros. Para cada variável foi calculado o índice de assimetria entre os lados direito e esquerdo, para os membros torácicos e pélvicos. Para avaliar a correlação linear entre a frequência de passada e as demais variáveis foi realizado o teste de correlação de Pearson. Com exceção da porcentagem de distribuição de peso, todos os demais parâmetros cinéticos e têmporo-espaciais diferiram entre os grupos. A porcentagem de distribuição de peso foi em média 29,85 para os membros torácicos e 20,15 para os membros pélvicos. Não houve diferença estatística entre os índices de assimetria entre os Grupos 1 e 2. Foram observadas correlação forte negativa para a maioria dos parâmetros têmporo-espaciais e correlação forte positiva para a porcentagem de balanço. Não houve correlação significativa entre a frequência das passadas e a porcentagem de distribuição de peso corpóreo. Pelos resultados obtidos, pode-se afirmar que a frequência de passadas, apresenta correlação linear com os parâmetros temporo-espaciais ... / Abstract: The aim of this study was to identify kinetic and temporospatial parameters of low variability in a heterogeneous group of dogs, and to evaluate a linear correlation between stride frequency and the variables. Twenty-nine clinically healthy dogs organized into two groups were used. Group 1 had 15 dogs walking, 8 males and 7 females, weighing from 11.50 kg to 50 kg (mean 22.31 kg ± 10.04 SD). Group 2 had 14 dogs trotting, 6 males and 8 females, weighing from 1.95 to 21.35 (mean 6.49 kg ± 4.74 SD). The kinetic data and temporospatial parameters were obtained using a pressure-sensitive walkway. The velocity was maintained between 0.9 and 1.1 m/s. The peak vertical force, vertical impulse, gait cycle time, stance time, swing time, stride length, percentage of body distribution among the four limbs were determined. For each variable the asymmetry indices between right and left sides, for both forelimbs and hind limbs, were calculated. Pearson's correlation coefficient was used to evaluate the linear correlation between stride frequency and other variables. Except for the percentage of body weight distribution, all other kinetic and temporospatial parameters differed between groups. The mean of percentage of body distribution was 29.85 and 20.15 for forelimbs and hind limbs, respectively. There was no statistically significant difference of the asymmetry indices between Groups 1 and 2. Strong negative correlation was observed for most of the temporospatial parameters and strong positive correlation to percentage of swing. There was no significant correlation between stride frequency and percentage of body weight distribution. In conclusion, in a heterogeneous group of dogs in controlled velocity, the percentage of body weight distribution and asymmetry index had low variability. Based on results obtained from correlations, the standardization of stride frequency may be an alternative to minimize the variability of temporospatial parameters / Mestre

This study examined: the features and extent of the gait velocity decrement following stroke; the nature of the balance disorder and; investigated relationships between gait and balance. Twenty, fully-ambulant, hemiplegic subjects (12 men and 8 women), with a mean age of 57.2 years (± 10.7), were compared with 20 age- and sex-matched controls. Spatiotemporal gait kinematics were measured at five walking speeds ranging from "very slow" to "very fast". Balance was then measured while subjects maintained a variety of weight shift postures both with feet parallel and then in diagonal positions similar to those assumed during the double support phases of gait. Location and variability of centre of pressure (CP) were measured and the ranges over which CP could be shifted were calculated. Stroke subjects walked very slowly with their "fastest" walking speed (0.5 stat/s ± 0.23) no different from the "slowest" speed (0.38 stat/s ± 0.11) of the controls (p > 0.05). Differences between the other parameters were also found, many of which could be attributed to the differences in walking speeds. However, where the subjects walked at similar velocities, the hemiplegic sample walked with quicker and shoner strides suggesting a "cautious" gait pattern. The single support asymmetry of the strokes decreased with increasing walking speed. The positions of CP in the hemiplegic sample were found to be significantly displaced towards the unaffected leg and deficiencies were found in posterior shifts (p < 0.05). Postural sway was significantly greater in the hemiplegic sample implying less stable balance and the ranges over which the hemiplegic sample shifted weight were significantly less than the controls. The diagonal weight shift tests revealed the difficulty the stroke subjects experienced in shifting CP posterolaterally over the affected leg. Significant correlations were detected confmning the presence of relationships between static balance performance and gait. However, these correlation findings left considerable percentages of variance unexplained. These findings suggest that future rehabilitation should address the poverty of range of walking speed possessed by hemiplegic subjects as well as the reduced ability to weight shift over the hemiplegic limb, particularly posterolaterally. Further study to test these proposals is indicated.

Background: Huntington’s disease (HD) and Parkinson’s disease (PD) are neurodegenerative diseases causing dysfunction and death of cells within the basal ganglia, and thus disruption of pathways with resultant impairment of cognition, motor function, and behavior. These impairments result in decreasing independence in activities of daily living and quality of life even from relatively early in the disease. Among the many motor deficits in HD and PD, impaired gait initiation is a cardinal motor characteristic in both diseases. However, the neurophysiological deficits that underlie gait impairments in people with HD and PD are not well understood. Movement related potentials derived from EEG may insight into the dynamics of areas of the brain involved in motor planning in people with HD and PD. Findings from this study provide a bridge between functional deficits and neuropathology in the progression of HD and has the potential to impact mechanistic understanding of gait initiation in basal ganglia disorders, and inform the development of clinical outcome measures and potential non-invasive biomarkers. The aims of this study were to: 1) identify the differences in movement-related potentials in individuals with manifest HD and mid-stage PD, and non-neurological peers, 2) verify kinetic differences in gait initiation reflective of postural stability in HD and PD, 3) determine force modulation impairments during gait initiation in the mediolateral (ML) and anteroposterior (AP) direction in HD and PD, and 4) determine the tolerance of a high repetition gait initiation protocol. Methods: EEG data were collected for participants for 5 blocks of 15 trials of gait initiation. Kinetic data was collected using an embedded force plate. EEG was time-locked with kinetic data in real-time. RPs amplitudes and latencies, and CNV amplitudes and latencies were determined prior to the onset of the first APA and heel-off. Center of pressure (COP) displacement averages and excursions were determined in the mediolateral (ML) and anteroposterior (AP) direction as measures of postural stability. COP accelerations and coefficient of variance (COV) of force were derived from gait initiation windows in the ML and AP direction as measures of force modulation. Tolerability of the protocol was determined by assessing fatigue from changes in COP averages and excursions from the first block of gait as compared to the last block of gait. Mean values, standard deviations, and mean differences between HD and PD were determined for individual and group data. Results: Three individuals with HD and three with PD were recruited with mean ages of 52.67 and 74.3 respectively. Mean differences and effect sizes indicated that HD participants had a greater average COP in the x direction and greater COP max excursions in the y direction relative to PD participants. PD displayed greater COP max excursions in the y direction relative to HD. There were no differences among COP max measures in the x direction. Similarly, there were no differences between HD and PD participants for CNV amplitudes and latencies, and RP amplitudes and latencies prior to APA onset and heel-off. Among impulse values, there were no differences in ML APA impulse between HD and PD participants, however PD participants exhibited a larger impulse in the AP APA. Lastly, participants were able to tolerate the high repetition protocol as indicated by COP values over three blocks of trials. Discussion: Results confirmed previous findings for kinetic parameters and validated the methodology in its ability to measure movement-related potentials prior to gait initiation in people with HD and PD. No study to date has used wireless EEG technology to measure neural signal in real-time during gait initiation in PD and HD. The values obtained from this system and methods were similar to the results determined in wired and tethered systems. The MRP amplitudes present in the PD participants, along with latencies of MRPs between HD and PD, may indicate potential specificity of MRP responses according to disease-stage and medication-state. Future work will explore the use of MRPs in larger cross-sectional studies and for the development of a meaningful clinical outcome measure.