Dominic E. Nathan

Development of ADLER: The Activities of Daily Living Exercise Robot

Robot-assisted therapy devices are being used in the physical and neurological rehabilitation of persons after stroke, which is the leading cause of disability among adults in the United States. Motor gains after robot-assisted therapy may not transfer to functioning on activities of daily living. It is conceivable that carryover after training may be improved through the use of training activities that are patient-centered, engaging and focused on daily living activities. We have developed the activities of daily living exercise robot (ADLER) stroke training environment to test this idea. This environment permits the consistent and repeated practice of daily living tasks such as drinking. This paper describes the ADLER training system

Design and validation of low-cost assistive glove for hand assessment and therapy during activity of daily living-focused robotic stroke therapy

Hand and arm impairment is common after stroke. Robotic stroke therapy will be more effective if hand and upper-arm training is integrated to help users practice reaching and grasping tasks. This article presents the design, development, and validation of a low-cost, functional electrical stimulation grasp-assistive glove for use with task-oriented robotic stroke therapy. Our glove measures grasp aperture while a user completes simple-to-complex real-life activities, and when combined with an integrated functional electrical stimulator, it assists in hand opening and closing. A key function is a new grasp-aperture prediction model, which uses the position of the end-effectors of two planar robots to define the distance between the thumb and index finger. We validated the accuracy and repeatability of the glove and its capability to assist in grasping. Results from five nondisabled subjects indicated that the glove is accurate and repeatable for both static hand-open and -closed tasks when compared with goniometric measures and for dynamic reach-to-grasp tasks when compared with motion analysis measures. Results from five subjects with stroke showed that with the glove, they could open their hands but without it could not. We present a glove that is a low-cost solution for in vivo grasp measurement and assistance.

Findings from Structural MR Imaging in Military Traumatic Brain Injury

PURPOSE To describe the initial neuroradiology findings in a cohort of military service members with primarily chronic mild traumatic brain injury (TBI) from blast by using an integrated magnetic resonance (MR) imaging protocol. MATERIALS AND METHODS This study was approved by the Walter Reed National Military Medical Center institutional review board and is compliant with HIPAA guidelines. All participants were military service members or dependents recruited between August 2009 and August 2014. There were 834 participants with a history of TBI and 42 participants in a control group without TBI (not explicitly age- and sex-matched). MR examinations were performed at 3 T primarily with three-dimensional volume imaging at smaller than 1 mm(3) voxels for the structural portion of the examination. The structural portion of this examination, including T1-weighted, T2-weighted, before and after contrast agent administrtion T2 fluid attenuation inversion recovery, and susceptibility-weighted images, was evaluated by neuroradiologists by using a modified version of the neuroradiology TBI common data elements (CDEs). Incident odds ratios (ORs) between the TBI participants and a comparison group without TBI were calculated. RESULTS The 834 participants were diagnosed with predominantly chronic (mean, 1381 days; median, 888 days after injury) and mild (92% [768 of 834]) TBI. Of these participants, 84.2% (688 of 817) reported one or more blast-related incident and 63.0% (515 of 817) reported loss of consciousness at the time of injury. The presence of white matter T2-weighted hyperintense areas was the most common pathologic finding, observed in 51.8% (432 of 834; OR, 1.75) of TBI participants. Cerebral microhemorrhages were observed in a small percentage of participants (7.2% [60 of 834]; OR, 6.64) and showed increased incidence with TBI severity (P < .001, moderate and severe vs mild). T2-weighted hyperintense areas and microhemorrhages did not collocate by visual inspection. Pituitary abnormalities were identified in a large proportion (29.0% [242 of 834]; OR, 16.8) of TBI participants. CONCLUSION Blast-related injury and loss of consciousness is common in military TBI. Structural MR imaging demonstrates a high incidence of white matter T2-weighted hyperintense areas and pituitary abnormalities, with a low incidence of microhemorrhage in the chronic phase.

Task-oriented and Purposeful Robot-Assisted Therapy

Robot-assisted therapy devices are available for rehabilitation of persons after stroke, which is the leading cause of disability among adults in the United States (AHA 2006, Volpe et al. 2002). Improving upper extremity function after stroke is critical for performance of one’s life-role and the completion of unilateral and bilateral activities of daily living (ADLs). Carryover to real-life activities after rehabilitation training cannot be assumed (Sterr et al. 2000; Maclean et al. 2000; Ma and Trombly 2002; Trombly and Ma 2002; Prange et al. 2006). For example, the existence of learned non-use behavior indicates that motor gains after rehabilitation therapies may not transfer to long-term functioning on ADLs (Taub et al. 1994; Taub et al. 1999; Sterr et al. 2000). This behavior is present when persons with hemiparesis due to strokes demonstrate significant differences between residual movement capabilities and spontaneous use of the impaired arm in real world. There is a need to address barriers to the carryover of motor gains during training to stroke function in real life. This chapter reviews examples of current upper arm robot-assisted therapy environments and present findings from case study experiments with a new task-oriented, robot therapy system focused on improving carryover of motor improvements to functional activities of daily living. We draw attention to influence of function on arm movements during robot training and explore how future environments can be more functional and engaging. Robot-assisted therapy devices are now being used more frequently in the rehabilitation of persons with physical disabilities due to neurological trauma caused by stroke and spinal cord injury. These therapy robots provide semi- or fully-autonomous training and permit patients using them to engage in repeated and intense practice of goal-directed tasks (Volpe et al 2002; Prange et al 2006; Burgar et al. 2000; Loureiro et al. 2003; Patton et al. 2006; Krebs et al. 2003; MacClellan et al. 2005, Kahn et al. 2006). Typically, the automation of therapeutic exercises involves generating trajectories that guide reaching movements and the application of forces directly or indirectly to the impaired arm to assist, resist, and/or passively support it during the reaching exercise. For example, the MIT-MANUS (Krebs et

Design of a Grasp Assistive Glove for ADL-focused, Robotic Assisted Therapy after Stroke

Reaching to grasp is an essential process in our everyday lives. Individual who suffer a stroke experience major deficits in this ability leading to compromised activities of daily living (ADL), employment, and social interaction. Robotic aided therapy is at the forefront of stroke rehabilitation, however not many systems support functional goal oriented therapy using real world objects. We are interested in designing a grasp assistive component for our ADL-focused robotic therapy environment. This paper reports on the glove development and a static validation study to determine the accuracy and repeatability of the glove in the measurement of joint angles of the thumb and index fingers and grasp aperture, which is the distance between the fingers. Our results showed no significant differences between the glove and a hand-held goniometer for the measured joint angles and the derived grasp aperture. The results suggest that the glove is repeatable and has the potential to measure in vivo grasp aperture during a functional tasks. Our next steps are to complete a dynamic validation study and integrate the glove with our robotic environment.

Feasibility of integrating FES grasp assistance with a task-oriented robot-assisted therapy environment: A case study

Reaching-to-grasp is a vital skill to be relearned following stroke. Robotic aided stroke rehabilitation reduces motor impairment but has is limited in improving ADL function. We present a case study examining the feasibility of a custom developed glove to provide grasp assistance in a robotic therapy environment dedicated to the practice of real activities, ADLER. The case study consists of three subjects, a high functioning, and a low functioning stroke subject and a healthy subject. Results suggest that the glove system was able to providing grasp-assistance and that it was capable of collecting grasp aperture information during reach to grasp activities.

Examining intrinsic thalamic resting state networks using graph theory analysis: Implications for mTBI detection

A major challenge associated with understanding mild traumatic brain injury (mTBI) is the absence of biomarkers in standard clinical imaging modalities. Furthermore, the inhomogeneity of mTBI location and intensity, combined with latent symptoms further complicates identification and treatment. A growing body of evidence suggests that the thalamus may be injured or susceptible to change as the result of mTBI. A significant number of connections to and from cortical, subcortical, cerebellar and brain stem regions converge at the thalamus. Furthermore, the thalamus is also involved with information processing, integration and the regulation of specific behaviors. We use graph theory analysis to evaluate intrinsic functional networks of the left and right thalamus in mTBI subjects (N=15) and neurologically intact healthy controls (N=12). We also explore neural correlates of the thalamic network architecture with clinical assessments. Our results suggest the presence of distinct unilateral thalamic differences in mTBI subjects. We also observe correlations of the thalamic changes with clinical assessments. The findings from this study have implications for functional networks in the thalamus and its projections for application as a potential biomarker for mTBI detection.

Should Object Function Matter during Modeling of Functional Reach-to-Grasp Tasks in Robot-Assisted Therapy?

Recent literature support the idea of using an intense, task-oriented, stroke rehabilitation to promote motor learning and cerebral reorganization. Supporting a task-oriented, robot-assisted therapy approach requires better understanding of the components of real tasks and the limitations and benefits of current trajectory models. We set out to understand natural reach-to-grasp kinematics as it relates to various functional bilateral and unilateral tasks so as to better map this information to a robotic reach-to-grasp therapy systems. To do so, we investigated the influence of arm use and object functionality on four reaching kinematics in reach-to-grasp daily living tasks. We compared our results with the minimum jerk trajectory model used in robot-assisted therapy with the goal of understanding how best to support these real movements in a robotic environment. Eight neurologically intact, right handed subjects participated in the motion analysis study. They completed unilateral and bilateral reaching to objects in the same location with the same orientation, and with handles of the same size and shape. We discuss our results in terms of the minimum jerk model, which is typically used in robot-assisted trajectory planning. Our results showed significant differences in peak velocities, movement time and total displacement across tasks and across arm use conditions

Art therapy and underlying fMRI brain patterns in military TBI: A case series

ABSTRACT TBI and PTSD are global issues and are often referred to as signature wounds of the Iraq and Afghanistan wars. Art therapy can provide unique insights into military service members’ injuries and states of mind via externalisation within an art product; however, interpretation of results is complex and subjective. Advance neuroimaging tools such as resting state fMRI can be employed to demonstrate objective measures of brain structure and activity. This case series highlights two distinct patient profiles, suggesting a relationship between resting state connectivity maps and dynamic thalamic connectivity (as well as PCL-C and NSI scores and brain scars) and the corresponding visual elements of masks made during art therapy treatment. Ultimately, this study indicates a need for future research examining potential neurological changes pre- and post-art therapy treatment.

Assessing Quantitative Changes in Intrinsic Thalamic Networks in Blast and Nonblast Mild Traumatic Brain Injury: Implications for Mechanisms of Injury.

In the global war on terror, the increased use of improvised explosive devices has resulted in increased incidence of blast-related mild traumatic brain injury (mTBI). Diagnosing mTBI is both challenging and controversial due to heterogeneity of injury location, trauma intensity, transient symptoms, and absence of focal biomarkers on standard clinical imaging modalities. The goal of this study is to identify a brain biomarker that is sensitive to mTBI injury. Research suggests the thalamus may be sensitive to changes induced by mTBI. A significant number of connections to and from various brain regions converge at the thalamus. In addition, the thalamus is involved in information processing, integration, and regulation of specific behaviors and mood. In this study, changes in task-free thalamic networks as quantified by graph theory measures in mTBI blast (N = 186), mTBI nonblast (N = 80), and controls (N = 21) were compared. Results show that the blast mTBI group had significant hyper-connectivity compared with the controls and nonblast mTBI group. However, after controlling for post-traumatic stress symptoms (PTSS), the blast mTBI group was not different from the controls, but the nonblast mTBI group showed significant hypo-connectivity. The results suggest that there are differences in the mechanisms of injury related to mTBI as reflected in the architecture of the thalamic networks. However, the effect of PTSS and its relationship to mTBI is difficult to distinguish and warrants more research.