The ultimate goal of human movement control research is to understand how natural movements performed in daily activities, are controlled. Natural movements require coordination of multiple degrees of freedom (DOF) of the arm. Here, patterns of arm joint control during daily functional tasks were examined, which are performed through rotation of the shoulder, elbow, and wrist with the use of seven DOF: shoulder flexion/extension, abduction/adduction, and internal/external rotation; elbow flexion/extension and pronation/supination; wrist flexion/extension and radial/ulnar deviation. Analyzed movements imitated two activities of daily living: combing the hair and turning the page in a book. Kinematic and kinetic analyses were conducted. The studied kinematic characteristics were displacements of the 7 DOF and contribution of each DOF to hand velocity. The kinetic analysis involved computation of 3-dimensional vectors of muscle torque (MT), interaction torque (IT), gravity torque (GT), and net torque (NT) at the shoulder, elbow, and wrist. Using a relationship NT = MT + GT + IT, the role of active control and the passive factors (gravitation and inter-segmental dynamics) in rotation of each joint was assessed by computing MT contribution (MTC) to NT. MTC was computed using the ratio of the signed MT projection on NT to NT magnitude. Despite the variety of joint movements required across the different tasks, 3 patterns of shoulder and elbow coordination prevailed in each movement: 1) active rotation of the shoulder and predominantly passive rotation of the elbow; 2) active rotation of the elbow and predominantly passive rotation of the shoulder; and 3) passive rotation of both joints. Analysis of wrist control suggested that MT mainly compensates for passive torque and provides adjustment of wrist motion according to requirements of both tasks. The 3 shoulder-elbow coordination patterns during which at least one joint moves largely passively represent joint control primitives underlying performance of well-learned arm movements, although these patterns may be less prevalent during non-habitual movements. The advantage of these control primitives is that they require minimal neural effort for joint coordination, and thus increase neural resources that can be used for cognitive tasks.

The ultimate goal of human movement control research is to understand how natural movements performed in daily reaching activities, are controlled. Natural movements require coordination of multiple degrees of freedom (DOF) of the arm. Patterns of arm joint control were studied during daily functional tasks, which were performed through the rotation of seven DOF in the arm. Analyzed movements which imitated the following 3 activities of daily living: moving an empty soda can from a table and placing it on a further position; placing the empty soda can from initial position at table to a position at shoulder level on a shelf; and placing the empty soda can from initial position at table to a position at eye level on a shelf. Kinematic and kinetic analyses were conducted for these three movements. The studied kinematic characteristics were: hand trajectory in the sagittal plane, displacements of the 7 DOF, and contribution of each DOF to hand velocity. The kinetic analysis involved computation of 3-dimensional vectors of muscle torque (MT), interaction torque (IT), gravity torque (GT), and net torque (NT) at the shoulder, elbow, and wrist. Using the relationship NT = MT + GT + IT, the role of active control and passive factors (gravitation and inter-segmental dynamics) in rotation of each joint by computing MT contribution (MTC) to NT was assessed. MTC was computed using the ratio of the signed MT projection on NT to NT magnitude. Despite a variety of joint movements available across the different tasks, 3 patterns of shoulder and elbow coordination prevailed in each movement: 1) active rotation of the shoulder and predominantly passive rotation of the elbow; 2) active rotation of the elbow and predominantly passive rotation of the shoulder; and 3) passive rotation of both joints. Analysis of wrist control suggested that MT mainly compensates for passive torque and provides adjustment of wrist motion according to requirements of each task. In conclusion, it was observed that the 3 shoulder-elbow coordination patterns (during which at least one joint moved) passively represented joint control primitives, underlying the performance of well-learned arm movements, although these patterns may be less prevalent during non-habitual movements.

Recently, it was demonstrated that startle-evoked-movements (SEMs) are present during individuated finger movements (index finger abduction), but only following intense training. This demonstrates that changes in motor planning, which occur through training (motor learning - a characteristic which can provide researchers and clinicians with information about overall rehabilitative effectiveness), can be analyzed with SEM. The objective here was to determine if SEM is a sensitive enough tool for differentiating expertise (task solidification) in a common everyday task (typing). If proven to be true, SEM may then be useful during rehabilitation for time-stamping when task-specific expertise has occurred, and possibly even when the sufficient dosage of motor training (although not tested here) has been delivered following impairment. It was hypothesized that SEM would be present for all fingers of an expert population, but no fingers of a non-expert population. A total of 9 expert (75.2 ± 9.8 WPM) and 8 non-expert typists, (41.6 ± 8.2 WPM) with right handed dominance and with no previous neurological or current upper extremity impairment were evaluated. SEM was robustly present (all p < 0.05) in all fingers of the experts (except the middle) and absent in all fingers of non-experts except the little (although less robust). Taken together, these results indicate that SEM is a measurable behavioral indicator of motor learning and that it is sensitive to task expertise, opening it for potential clinical utility.

The interaction between visual fixations during planning and performance in a

dexterous task was analyzed. An eye-tracking device was affixed to subjects during

sequences of null (salient center of mass) and weighted (non salient center of mass) trials

with unconstrained precision grasp. Subjects experienced both expected and unexpected

perturbations, with the task of minimizing object roll. Unexpected perturbations were

controlled by switching weights between trials, expected perturbations were controlled by

asking subjects to rotate the object themselves. In all cases subjects were able to

minimize the roll of the object within three trials. Eye fixations were correlated with

object weight for the initial context and for known shifts in center of mass. In subsequent

trials with unexpected weight shifts, subjects appeared to scan areas of interest from both

contexts even after learning present orientation.

Previous work indicates that structural changes in the right hemisphere following left hemisphere stroke may be related to language abilities. However, the mechanisms behind this relationship remain unclear, particularly regarding the relative contributions of gray and white matter. The present study examined how structural and diffusion measures in the right hemisphere differ between chronic left hemisphere stroke survivors and matched control subjects, and the relationships between language and cognition measures and these right hemisphere measures. T1-weighted MRI, diffusion tensor images (DTI), and a battery of cognitive tests were obtained from 27 chronic left hemisphere stroke survivors and 44 neurologically intact matched control participants. Cortical and volumetric measures of gray and white matter in regions of interest were obtained from the T1 images and compared between groups, and correlated with behavioral measures. Tract-Based Spatial Statistics and tractography methods from the DTI were examined in a similar manner. The T1 MRI-based analyses revealed that the stroke survivors did not differ from the control group in any of the gray or white matter volume measurements. The cortical thickness and mean curvature analyses identified right lateral frontal and insular ROIs exhibiting thinner and greater curvature (an indication of atrophy) in the left hemisphere stroke survivors compared to controls. The DTI-based results showed that the stroke survivors had lower fractional anisotropy and fewer reconstructed fibers in the right language ventral-stream tracts. Regarding correlations between the right hemisphere measures and behavioral performance, there were no significant results within the DTI data, and only one significant result in the gray matter analyses: faster processing speed was correlated with greater cortical thickness in the right frontal cortex in chronic left hemisphere stroke survivors. Overall, the present study provides support for the idea that the right hemisphere exhibits post-stroke changes, particularly in right dorsal stream gray matter and the ventral stream’s white matter, and that these differences are not captured by T1-imaging alone; in fact, the DTI tract-specific analyses were perhaps the most revealing. Future studies are needed, perhaps incorporating functional neuroimaging, to elucidate how these right hemisphere differences in left hemisphere stroke survivors is related to language recovery.

My honors thesis focuses on the technological aspects and the legal impacts of prosthetics and advanced prosthetics. There is a lot of case law dealing with early prosthetics when it comes to worker’s compensation, airport security, prisons and sports. However, there has been little case law that has dealt with advanced prosthetics. As prosthetic limbs become more technologically advanced and intertwined with one’s identity, it is crucial that laws are made to draw a new line between person and property. The innovation of prosthetic limbs has just begun and will surely face setbacks along the way, but the benefits will be worth it once the law catches up with the rapidly advancing technology.

Alzheimer’s disease (AD) and Frontotemporal lobe dementia (FTLD) are types of dementia that have distinct differences. To help identify some of the neural differences, researchers use diffusion tensor imaging (DTI) techniques to assist with diagnosing patients and track progression over time. The major objective of this experiment was to use the advanced diffusion tensor imaging techniques of Fractional Anisotropy (FA) and Free water (FW) to help differentiate between AD and FTLD neurodegeneration. The scope of this experiment was to examine literature research on AD and FTLD by gathering the mean values of (FA) and (FW) to identify diffusivity susceptibility in the specific brain regions of the Uncinate Fasciculus (UF) and the Superior Temporal Gyrus (STG). The methods used were the Alzheimer’s Disease Neuroimaging Initiative (ADNI) and the Frontotemporal Lobe Degenerative Neuroimaging Initiative (FTLD): These data repositories provide researchers with study data to define the progression of AD and FTLD. Next, an imaging analysis was used to calculate the average FA and FW through each slice of the brain regions UF and STG in standard space. Then FreeSurfer segmented Superior Temporal Gyrus and the JHU ICBM Atlas of the Uncinate Fasciculus were used as a set of tools for analysis and visualization of structural and functional brain imaging data for processing the cross-sectional and longitudinal data. We calculated 95% Confidence intervals for mean FW and FA at each slice and direction across 21 participants within each dementia group to determine regions of overlap and nonoverlap. Results indicated that for the FA and FW graphs in the x and z directions among UF and STG regions, there were more non-overlap regions between the AD and FTLD in the FW graphs across x and z-directions in particular the UF. Our results indicate that there may be concomitant decline in white and gray matter regions in dementia, and FW may be more sensitive detecting AD related neurodegeneration in the UF and STG regions.

Alzheimer’s disease (AD) and Frontotemporal lobe dementia (FTLD) are types of dementia that have distinct differences. To help identify some of the neural differences, researchers use diffusion tensor imaging (DTI) techniques to assist with diagnosing patients and track progression over time. The major objective of this experiment was to use the advanced diffusion tensor imaging techniques of Fractional Anisotropy (FA) and Free water (FW) to help differentiate between AD and FTLD neurodegeneration. The scope of this experiment was to examine literature research on AD and FTLD by gathering the mean values of (FA) and (FW) to identify diffusivity susceptibility in the specific brain regions of the Uncinate Fasciculus (UF) and the Superior Temporal Gyrus (STG). The methods used were the Alzheimer’s Disease Neuroimaging Initiative (ADNI) and the Frontotemporal Lobe Degenerative Neuroimaging Initiative (FTLD): These data repositories provide researchers with study data to define the progression of AD and FTLD. Next, an imaging analysis was used to calculate the average FA and FW through each slice of the brain regions UF and STG in standard space. Then FreeSurfer segmented Superior Temporal Gyrus and the JHU ICBM Atlas of the Uncinate Fasciculus were used as a set of tools for analysis and visualization of structural and functional brain imaging data for processing the cross-sectional and longitudinal data. We calculated 95% Confidence intervals for mean FW and FA at each slice and direction across 21 participants within each dementia group to determine regions of overlap and nonoverlap. Results indicated that for the FA and FW graphs in the x and z directions among UF and STG regions, there were more non-overlap regions between the AD and FTLD in the FW graphs across x and z-directions in particular the UF. Our results indicate that there may be concomitant decline in white and gray matter regions in dementia, and FW may be more sensitive detecting AD related neurodegeneration in the UF and STG regions.

Alzheimer’s disease (AD) and Frontotemporal lobe dementia (FTLD) are types of dementia that have distinct differences. To help identify some of the neural differences, researchers use diffusion tensor imaging (DTI) techniques to assist with diagnosing patients and track progression over time. The major objective of this experiment was to use the advanced diffusion tensor imaging techniques of Fractional Anisotropy (FA) and Free water (FW) to help differentiate between AD and FTLD neurodegeneration. The scope of this experiment was to examine literature research on AD and FTLD by gathering the mean values of (FA) and (FW) to identify diffusivity susceptibility in the specific brain regions of the Uncinate Fasciculus (UF) and the Superior Temporal Gyrus (STG). The methods used were the Alzheimer’s Disease Neuroimaging Initiative (ADNI) and the Frontotemporal Lobe Degenerative Neuroimaging Initiative (FTLD): These data repositories provide researchers with study data to define the progression of AD and FTLD. Next, an imaging analysis was used to calculate the average FA and FW through each slice of the brain regions UF and STG in standard space. Then FreeSurfer segmented Superior Temporal Gyrus and the JHU ICBM Atlas of the Uncinate Fasciculus were used as a set of tools for analysis and visualization of structural and functional brain imaging data for processing the cross-sectional and longitudinal data. We calculated 95% Confidence intervals for mean FW and FA at each slice and direction across 21 participants within each dementia group to determine regions of overlap and nonoverlap. Results indicated that for the FA and FW graphs in the x and z directions among UF and STG regions, there were more non-overlap regions between the AD and FTLD in the FW graphs across x and z-directions in particular the UF. Our results indicate that there may be concomitant decline in white and gray matter regions in dementia, and FW may be more sensitive detecting AD related neurodegeneration in the UF and STG regions.

SUMMARY: A failed attempt to conduct a systematic review of disparities in racial inclusivity in stroke rehabilitation research: A call to action Group Members: Adeline Beeler & Mikayla McNally Faculty Mentor(s): Dr. Sydney Schaefer & Dr. Keith Lohse Topic Overview: Stroke is responsible for the death of an individual every four minutes in the United States. While all Americans are gravely affected by this statistic, Black Americans are at a significantly increased risk of first stroke incidence when compared to their white counterparts, majorly due to heightened prevalence of stroke risk factors. Not only does race contribute as a factor in stroke incidence, but it also has a considerable impact in the physical impairment of Black Americans following stroke occurrence. While it still remains unclear as to whether or not stroke plays a significant role in stroke rehabilitation efforts, there is a clearly demonstrated need for increased reporting or participation of Black Americans in stroke rehabilitation clinical trials to have the ability to conduct a systematic review of these racial disparities in the near future. In the analysis of 36 stroke rehabilitation-related clinical research studies, 80% of selected trials failed to report any participant racial demographics, with 77.3% of the NIH-funded trials not reporting, as well. Out of the 7 trials that did provide some sort of participant racial information, only 5 successfully provided statistically significant racial data compared to the remainder that simply categorized participants’ race as “white” or “other.” In order to fully investigate the effects of race on stroke rehabilitation, it is imperative that researchers collect and report equally distributed and diverse participant racial data when publishing clinical research. Potential methods of improvement for researchers to include more racially diverse subject populations include more comprehensive and in-depth advertising and recruitment strategies for their studies. Research Methods: In order to produce accurate analyses of the current state of the relationship between race and stroke rehabilitation efforts, 36 stroke rehabilitation clinical research trials from various locations across the United States were identified using the Centralized Open-Access Rehabilitation Database for Stroke (SCOAR). These trials were evaluated in order to extract relevant data, such as number of trial participants, average age of participants, if the research trial was funded by the National Institute of Health (NIH) or not, and any reported participant racial demographic details. Trends across these categories were compared between all trials to determine if any disparities existed in providing data sufficient to support the relationship between varying racial populations and stroke rehabilitation efforts. Future Project Efforts: Future efforts will include the completion of submitting a Point of View/Directions for Research article for publication to offer an opportunity for clinical and basic researchers to examine the discrepancies surrounding racial inclusivity in stroke rehabilitation clinical research. The aim is to improve the ability of clinicians to interpret the literature, translate research studies into practices, and better direct future experiments. Further identification of stroke rehabilitation clinical research trials will be necessary, as well as modifications to current written work content.