published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

The effects of pre-stroke exercise and levesl of brain-derived neurotrophic factor (BDNF) on behavioural and functional recovery were examined following focal cortical ischemic infarct. Intracortical microstimulation (ICMS) was used to derive topographical maps of forelimb representations within the motor cortex and ischemia was induced via bipolar coagulation of surface vasculature. One month of excerise prior to ischemia significantly increased the amount of peri-infarct movement represnetations and initiates vascular changes within motor cortex. Further, this exercise-induced preservation of peri-infarct movement representations is associated with behavioural recovery and is dependent on BDNF levels in the motor cortex. These results provide further support for the idea that endurance exercise prior to stroke may enhance functional and behavioural recovery. / 140 leaves : ill. (some col.) ; 29 cm.

This thesis investigates the reading and writing of two patients with brain injuries due to cerebro-vascular accidents. Background tests show both patients to be moderately anomic and to have severe impairments in reading and writing nonwords. Investigations of the locus of impairment in AN's nonword reading showed her to have normal orthographic analysis capabilities but impairments in converting single and multiple graphemes into phonemes and in phonemic blending. The central issue studied was the role of lexical but non-semantic processes in reading aloud, writing to dictation and copying. For this purpose a "familiar nonword" paradigm was developed in which the patients learned to read or write a small set of nonwords either with or without any associated semantics. Both AN and AM were able to learn to read nonwords to which no meanings were attached but they could still not read novel nonwords. Both patients were unable to report any meanings for the familiar nonwords when they read them and there was no evidence that learning to read them improved their sub-lexical processing abilities. These results are evidence for a direct lexical route from print to sound that is dedicated to processing whole familiar words. It was also shown with AN that if nonwords are given meanings then learning is faster than if they are not given meanings. Experiments designed to test the hypothesis that nonwords are read by analogy to words found no support for it. Both patients have severe impairments in writing novel nonwords to dictation. As they can repeat spoken nonwords after they have failed to write them, this is not due to a short-term memory impairment. Despite their nonword writing impairments, both patients were able to write to dictation the meaningless nonwords that they had previously learned to read at the first attempt, and AN did so one month after learning to read them. Neither patient however, could write novel nonwords made by reordering the letters of the familiar nonwords. Furthermore, the familiar nonwords used spellings that are of a priori low probability. The familiar nonwords must therefore have been written using lexical knowledge. Tests of semantic association showed that the familiar nonwords evoked no semantic information that the patients could report. Function words dictated to AN evoked little semantic information but she wrote them to dictation significantly better than nonwords made by reordering their letters. These results are evidence for a direct lexical route for writing to dictation. Copying was studied both with and without a five second delay between presentation and response. AN was better at delayed copying of meaningless but familiar nonwords than she was at copying novel nonwords. She was also better at delayed copying of six-letter, bi-syllabic nonwords that she had been trained to copy than she was at copying novel nonwords made by recombining the first and second halves of the familiar nonwords such that these halves retained their positions from the parent nonwords. AN was better at copying function words than nonwords made by reordering their letters. She was also better at copying function words than she was at reading or writing them to dictation. These results are evidence for a direct lexical route for copying. AN and AM were both able to write to dictation nonwords that they had never heard or written before but with which they had been made visually familiar during a visual discrimination task. They must have used lexical knowledge to do so because the spellings used were of a priori very low probability. The creation of lexical orthographic information which can be retrieved from novel auditory input raises difficulties for current models and various possible interpretations are discussed. Finally, some of the possible implications of the re-learning abilities shown by these patients, for rehabilitation procedures are discussed briefly.

M.A. / The purpose of this research was to compile a psychological information program on stroke, and to provide this psychological information to the spouse of the stroke patient.The emotional status of the spouse of the stroke patient was evaluated during the intervention.The final goal of this research was to give a phenomenological description of the experiences of the spouse of the stroke patient. The method for collecting data was 1) to evaluate the emotional status of the spouse of the stroke patient with the POMS (Profile Of Mood State) inventory before he was exposed to the content of the psychological information program on stroke.2) The spouse of the stroke patient was then introduced to the psychological information program, and any questions which arose were answered. 3) A follow up appointment was arranged for ten days later. During this appointment the POMS inventory was administered again to assess the spouse's emotional status after exposure to the psychological informationprogram on stroke.Any further questions were answered.Within a framework of identified themes a phenomenological description of the experiences of the spouse of the stroke patient was given.The most important experiences were identified as confusion, anxiety, tension, rage, frustration, tiredness, and feelings of not being motivated and depression.The phenomenological themes were "Om-te-wees (Dasein)", "Die wereld", "In-die-wereld-wees", "Om-ingegooi-tewees- in-die-wereld", "Angs as basiese ingesteldheid tot die wereld" and "Liggaamlikheid". The current research was motivated after a thorough study of the literature on stroke.The literature survey revealed a deficiency in terms of availability of information on stroke to the spouse of the stroke patient after the stroke has occured.The literature survey disclosed that the focus of research has been on the stroke patient.Research identified the spouse of the stroke patient as the primary caretaker.Therefore it is important that the spouse of the stroke patient will have access to psychological information on stroke to assist them during their tasks of caretaking. Certain variables influenced theresults of the present research project.These variables were 1) the time when the psychological information was provided to the subjects, 2) the emotional status after the stroke had occurred, and 3) the extent of information the subjects received from other resources. During the current research project the subjects confirmed the value of the availability of psychological information on stroke.The psychological information on stroke is important in assisting the spouse of the stroke patient during their tasks of caret•king.The psychological information on stroke provides the spouse of the stroke patient with 1) a better understanding of the stroke patient, 2) knowledge of what to expect after a stroke had occured, and 3) realistic goals for the future.

No description available.

This research project focuses on age as a predictor in the emotional adjustment of a spouse following his/her partner's stroke. The medical records of 80 stroke cases were reviewed at Kaiser Permanente Medical Center, Fontana, California. Patients and spouses were examined in two age groupings, age 55 and below, and ages 56 and above. Study of these two age groups afforded the most meaningful division to study spouse adjustment.

Post stroke rehabilitation is effective when a large number of motor repetitions are provided to patients. However, conventional physical therapy or traditional desktop-size robot aided rehabilitation do not provide sufficient number of repetitions due to cost and logistical barriers. Our vision is to realize a wearable and functional hand orthosis that could be used outside of controlled, clinical settings, thus allowing for more training repetitions. Furthermore, if such a device can prove effective for Activities of Daily Living (ADLs) while actively worn, this can incentivize patients to increase its use, further enhancing rehabilitative effects. However, in order to provide such clinical benefits, the device must be completely wearable without obtrusive features, and intuitive to control even for non-experts. In this thesis, we thus focus on wearability, functionality, and intuitive intent detection technology for a novel hand robot, and assess its performance when used both as a rehabilitative device and an assistive tool. A fully wearable device must deliver meaningful manipulation capability in small and lightweight package. In this context, we investigate the capability of single-actuator devices to assist whole hand movement patterns through a network of exotendons. Our prototypes combine a single linear actuator (mounted on a forearm splint) with a network of exotendons (routed on the surface of a soft glove). We investigate two possible tendon network configurations: one that produces full finger extension (overcoming flexor spasticity) and one that combines proximal flexion with distal extension at each finger. In experiments with stroke survivors, we measure the force levels needed to overcome various levels of spasticity and to open the hand for grasping using the first of these configurations, and qualitatively demonstrate the ability to execute fingertip grasps using the second. Our results support the feasibility of developing future wearable devices able to assist a range of manipulation tasks. In order to further improve the wearability of the device, we propose two designs that provide effective force transmission by increasing moment arms around finger joints. We evaluate the designs with geometric models and experiment using a 3D-printed artificial finger to find force and joint angle characteristics of the suggested structures. We also perform clinical tests with stroke patients to demonstrate the feasibility of the designs. The testing supports the hypothesis that the proposed designs efficiently elicit extension of the digits in patients with spasticity as compared to existing baselines. With the suggested transmission designs, the device can deliver sufficient extension force even when the users have increased muscle tone due to fatigue. The vision of an orthotic device used for ADLs can only be realized if the patients are able to operate the device themselves. However, the field is generally lacking effective methods by which the user can operate the device: such controls must be effective, intuitive, and robust to the wide range of possible impairment patterns. The variety of encountered upper limb impairment patterns in stroke patients means that a single sensing modality, such as electromyography, might not be sufficient to enable controls for a broad range of users. To address this significant gap, we introduce a multimodal sensing and interaction paradigm for an active hand orthosis. In our proof-of-concept implementation, EMG is complemented by other sensing modalities, such as finger bend and contact pressure sensors. We propose multimodal interaction methods that utilize this sensory data as input, and show they can enable tasks for stroke survivors who exhibit different impairment patterns. We then assess the performance of the robotic orthosis for two possible roles: as a therapeutic tool that facilitates device mediated hand exercises to recover neuromuscular function, or as an assistive device for use in everyday activities to aid functional use of the hand. 11 chronic stroke (> 2 years) patients with moderate muscle tone (Modified Ashworth Scale ≤ 2 in upper extremity) engage in a month-long training protocol using the orthosis. Individuals are evaluated using standardized outcome measures, both with and without orthosis assistance. The results highlight the potential for wearable and user-driven robotic hand orthoses to extend the use and training of the affected upper limb after stroke. The advances proposed in this thesis have the potential to enable robotic based hand rehabilitation during daily activities (as opposed to isolated hand exercises with limited upper limb engagement) and over extended periods of time, even in a patient’s home environment. Numerous challenges must still be overcome in order to achieve this vision, related to design (compact devices with easier donning/doffing), control (robust yet intuitive intent inferral), and effectiveness (improved functionality in a wider range of metrics). However, if these challenges can be addressed, wearable robotic devices have the potential to greatly extend the use and training of the affected upper limb after stroke, and help improve the quality of life for a large patient population.

Depression is the most common psychological sequela associated with stroke, affecting approximately 33% of stroke survivors (Hackett, Yapa, Parag, & Anderson, 2005) with corresponding impacts on spouses, partners, or other informal caregivers (Han & Haley, 1999; Low, Payne, & Roderick, 1999). Although stroke is more common in older persons, persons of all ages are at risk for stroke and especially post-stroke depression (Centers for Disease Control and Prevention [CDC], 2007; Barker-Collo, 2007; Hughes, Giobbie-Hurder, Weaver, Kubal, & Henderson, 1999). One of the factors which could explain increased risk of depression is "biographical disruption" (Bury, 1982), which happens when couples experience chronic illnesses that are developmentally off schedule or unexpected (Faircloth, Boylstei, Rittman, Young, & Gubrium, 2004; Pound, Gompertz, & Ebrahim, 1998; Roding, Lindstrom, Malms, & Ohman, 2003). The goal of this dissertation study was to examine modifiable factors associated with depression in stroke survivor-spouse dyads, including the potential moderating effects of biographical disruption. This goal was accomplished by pursuing three specific aims: (1) investigating the extent to which dyad-level factors are associated with current depression in stroke survivor-spouse dyads, above and beyond the influence of individual-level factors; (2) investigating the extent to which biographical disruption associated with stroke moderates the strength of association between individual and dyad-level factors and depression; and (3) exploring additional individual- and dyad-level features of disruption from stroke not included in the structured portion of the interview, and to explore how the experience of stroke may be different for couples in different developmental stages of life. Thirty-two recent stroke survivor-spouse dyads were interviewed using a combination of standardized measures and semi-structured interviews. Results showed that several dyad-level factors such as relationship quality, illness appraisal, and coping patterns were significant predictors of depression for survivors and spouses. The presence of biographical disruption did not statistically moderate these relationships, although the qualitative aspect of the study uncovered many aspects of disruption not addressed in the structured interview and the illness experience was clearly unique for couples in different developmental stages. These results have relevance for the development of effective interventions for post-stroke depression in couples, and are encouraging with respect to operationalizing and measuring the notion of biographical disruption from chronic illness across the lifespan.

Indiana University-Purdue University Indianapolis (IUPUI)

Indiana University-Purdue University Indianapolis (IUPUI) / Stroke is the leading cause of adult disability with over 5 million American adults experiencing physical, psychological, and/or social limitations related to stroke. Although depressive symptoms and poor quality of life (QOL) are key outcomes for stroke survivors, little is understood about how these outcomes are affected by stroke survivors’ evaluation of their experience. The concept of cognitive appraisal, an evaluation of the meaning of a situation for one’s well-being, may explain some of the factors associated with post-stroke depressive symptoms and QOL. The purpose of this study was to determine factors associated with post-stroke depressive symptoms and QOL using a conceptual model derived from the transactional theory of stress originally proposed by Lazarus and Folkman. Three aims guided this study: to determine whether (a) depressive symptoms at 4 months after stroke are predictive of stroke-specific QOL at 10 months; (b) perceived social support, self-esteem, and optimism at 1 month after stroke predict depressive symptoms among stroke survivors at 4 months; and (c) threat appraisal at 1 month after stroke is a mediating variable between perceived social support, self-esteem, and optimism at 1 month after stroke and depressive symptoms at 4 months. A secondary analysis of data from 392 stroke survivors in the Randomized Trial of Treatment for Post-stroke Depression (AIM study) was conducted. Using a descriptive correlational design and multiple regression analyses, longitudinal associations among perceived social support, self-esteem, optimism, threat appraisal, depressive symptoms and stroke-specific QOL were examined. Perceived social support, self-esteem, and optimism were significantly associated with threat appraisal. Threat appraisal was significantly associated with post-stroke depressive symptoms. Stroke-specific QOL was found to be stable between 4 and 10 months. Partial mediation of the relationship between the explanatory variables and depressive symptoms by threat appraisal at one month post-stroke was demonstrated. In conclusion, threat appraisal is an important factor to consider in future research and intervention development in relation to post-stroke depressive symptoms.