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dc.contributor.advisorBoyd, Laraen_US
dc.contributor.authorSiengsukon, Catherine
dc.date.accessioned2008-08-05T12:48:09Z
dc.date.available2008-08-05T12:48:09Z
dc.date.issued2008-05-01en_US
dc.date.submitted2008en_US
dc.identifier.otherhttp://dissertations.umi.com/ku:2496en_US
dc.identifier.urihttp://hdl.handle.net/1808/4066en_US
dc.description.abstractStroke affects nearly 780,000 individuals each year in the United States and is a leading cause of adult disability. More than half of individuals following stroke experience persistent loss of function. Learning new motor skills and re-learning old motor skills is an important component of rehabilitation following stroke. Examining methods that hasten or increase the efficiency of motor skill learning following stroke is an important clinical endeavor. Sleep has been demonstrated to produce off-line improvements in motor learning in young, neurologically intact individuals. However, the role of sleep in motor learning following stroke is unclear. Addressing this question was the purpose of this body of work. Chapter 2 utilized the discrete serial reaction time (SRT) task to examine the difference in both motor performance and learning for forty-two participants who either remained unaware of the presence of the sequence (implicit condition), were given no instruction of the sequence prior to the start of practice but gained explicit awareness during practice (acquired explicit condition), or were provided explicit instruction prior to practice (explicit condition). Results demonstrate a benefit of explicit knowledge to improve response time both during task practice and at retention regardless of whether it was acquired during or provided in advance of practice. This study highlights the frequent ability of people to acquire awareness of the regularities of the task being practice, creating a continuum of implicit motor learning from "pure" implicit learning where the participants have no awareness of the regularities being practiced to full explicit motor learning with the participants having complete awareness of the task regularities. This study led us to utilize a continuous tracking task to examine the role of sleep and type of instruction in off-line motor learning following stroke and in healthy, older control participants in order to differentiate between off-line implicit and explicit motor learning. While mounting evidence demonstrates sleep is critical for motor skill learning in healthy, younger individuals, the importance of sleep for off-line motor learning after stroke is unknown. Therefore, Chapter 3 examined sleep-dependent off-line motor learning of an implicit continuous tracking task. Eighteen individuals following stroke in the MCA distribution practiced the tracking task and then either slept (sleep condition) or stayed awake (no-sleep condition) for a similar period of time before retention testing to assess off-line motor learning. Eighteen sex- and age-matched participants served as controls. Only the stroke participants who slept between practice and retention testing demonstrated off-line implicit motor learning at retention. The stroke participants who stayed awake between practice and retention did not demonstrate off-line motor learning nor did either of the control groups. This study provides the first evidence that individuals following stroke benefit from sleep to enhance implicit motor learning off-line. Other learning variables, such as type of instruction, have been shown to influence the beneficial role of sleep in off-line motor skill learning in young, neurologically intact individuals. Therefore, Chapter 4 extended the findings of Chapter 3 and examined sleep-dependent off-line motor learning of both an implicit and explicit version of the continuous tracking task. Forty individuals post-stroke and 40 control participants were assigned to either the sleep group or the no-sleep group, as in Chapter 3. To examine the influence of type of instruction on off-line learning, half of the individuals in both the sleep and no-sleep condition were provided explicit instruction regarding the presence of a repeating sequence (explicit condition) while the other half were not (implicit condition). The individuals post-stroke who slept between practice and retention testing demonstrated sleep-dependent off-line motor learning of both the implicit and explicit version of the continuous tracking task. Individuals with stroke who stayed awake between practice and retention testing did not demonstrate an off-line improvement in motor performance at retention. The healthy control participants did not demonstrate off-line improvements in performance regardless of sleep of type of instruction. These results demonstrate that after stroke, individuals benefit from sleep to improve performance of a tracking task off-line regardless of type of memory system involved. Learning a motor skill requires the integration of the spatial and temporal movement components of the task. Little is known if particular components of a motor skill task (spatial and/or temporal components) are preferentially enhanced following sleep in individuals following stroke. Chapter 5 sought to address this question by deconstructing the overall change in tracking accuracy displayed by the participants in Chapter 4 into spatial and temporal movement components. The results reveal that the individuals with stroke who demonstrated overall off-line improvements in motor learning attributable to sleep improved spatial accuracy as well as reduced the time lag of tracking off-line. Participants following stroke who stayed awake between practice and retention testing did not demonstrate an improvement in either spatial accuracy or a reduction in time lag of tracking at retention. Likewise, the control participants did not demonstrate sleep- or time-dependent enhancement of either movement component. This study provides the first evidence that sleep enhances both spatial and temporal movement components of a motor learning task in individuals following stroke. In summary, this body of work demonstrates that individuals following stroke benefit from sleep to enhance both implicit and explicit off-line motor learning. In addition, this sleep-dependent off-line motor learning extends to both the spatial and temporal movement components of the tracking task. This work also provides concurrent evidence that healthy, older adults fail to benefit from sleep to enhance off-line motor learning. While it remains unclear why individuals following stroke are able to benefit from sleep to promote off-line motor learning and healthy, older adults are not, we propose that alterations in sleep architecture and changes in cortical excitability following stroke likely contribute to sleep-dependent off-line motor learning. The findings of this body of work are important because evidence that sleep enhances off-line motor learning following stroke could impact the design of rehabilitation interventions; to maximize motor learning and recovery after stroke it may be critical to ensure that sleep occurs between practice sessions.
dc.format.extent189 pagesen_US
dc.language.isoen_USen_US
dc.publisherUniversity of Kansasen_US
dc.rightsThis item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.en_US
dc.subjectHealth sciences
dc.subjectRehabilitation and therapy
dc.titleSleep to Learn after Stroke: The Role of Sleep and Instruction in Off-line Motor Learning
dc.typeDissertationen_US
dc.thesis.degreeDisciplinePhysical Therapy & Rehabilitation Sciences
dc.thesis.degreeLevelPH.D.
kusw.oastatusna
kusw.oapolicyThis item does not meet KU Open Access policy criteria.
kusw.bibid6599432
dc.rights.accessrightsopenAccessen_US


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