Graphoepitaxy for translational and orientational ordering of monolayers of rectangular nanoparticles.

The combinations of particle aspect ratio and enthalpic-barrier templates that lead to translational and orientational ordering of monolayers of rectangular particles are determined using Monte Carlo simulations and density functional theory. For sufficiently high enthalpic barriers, we find that only specific combinations of particle sizes and template spacings lead to ordered arrays. The pattern multiplication factor provided by the template extends to approximately ten times the smallest dimension of the particle.

Graphoepitaxy for pattern multiplication of nanoparticle monolayers.

We compute the free energy minimizing structures of particle monolayers in the presence of enthalpic barriers of a finite height ßV(ext) using classical density functional theory and Monte Carlo simulations. We show that a periodic square template with dimensions up to at least 10 times the particle diameter disrupts the formation of the entropically favored hexagonally close-packed 2D lattice in favor of a square lattice. The results illustrate how graphoepitaxy can successfully order nanoparticulate films into desired patterns many times smaller than those of the prepatterned template.

Intensive sensorimotor arm training mediated by therapist or robot improves hemiparesis in patients with chronic stroke.

Investigators have demonstrated that a variety of intensive movement training protocols for persistent upper limb paralysis in patients with chronic stroke (6 months or more after stroke) improve motor outcome. This randomized controlled study determined in patients with upper limb motor impairment after chronic stroke whether movement therapy delivered by a robot or by a therapist using an intensive training protocol was superior. Robotic training (n = 11) and an intensive movement protocol (n = 10) improved the impairment measures of motor outcome significantly and comparably; there were no significant changes in disability measures. Motor gains were maintained at the 3-month evaluation after training. These data contribute to the growing awareness that persistent impairments in those with chronic stroke may not reflect exhausted capacity for improvement. These new protocols, rendered by either therapist or robot, can be standardized, tested, and replicated, and potentially will contribute to rational activity-based programs.

Stochastic estimation of arm mechanical impedance during robotic stroke rehabilitation.

This paper presents a stochastic method to estimate the multijoint mechanical impedance of the human arm suitable for use in a clinical setting, e.g., with persons with stroke undergoing robotic rehabilitation for a paralyzed arm. In this context, special circumstances such as hypertonicity and tissue atrophy due to disuse of the hemiplegic limb must be considered. A low-impedance robot was used to bring the upper limb of a stroke patient to a test location, generate force perturbations, and measure the resulting motion. Methods were developed to compensate for input signal coupling at low frequencies apparently due to human-machine interaction dynamics. Data was analyzed by spectral procedures that make no assumption about model structure. The method was validated by measuring simple mechanical hardware and results from a patient's hemiplegic arm are presented.

Robotics and other devices in the treatment of patients recovering from stroke.

Stroke is the leading cause of permanent disability in the United States despite advances in prevention and novel interventional treatments. Randomized controlled studies have demonstrated the effectiveness of specialized post-stroke rehabilitation units, but administrative orders have severely limited the length of stay, so novel approaches to the treatment of recovery need to be tested in outpatients. Although the mechanisms of stroke recovery depend on multiple factors, a number of techniques that concentrate on enhanced exercise of the paralyzed limb have demonstrated effectiveness in reducing the motor impairment. For example, interactive robotic devices are new tools for therapists to deliver enhanced sensorimotor training for the paralyzed upper limb, which can potentially improve patient outcome and increase patient productivity. New data support the idea that for some post-stroke patients and for some aspects of training-induced recovery, timing of the training may be less important than the quality and intensity of the training. The positive outcome that resulted in the interactive robotic trials contrasts with the failure to find a beneficial result in trials that used a noninteractive device that delivered continuous passive motion only. New pilot data from novel devices to move the wrist demonstrate benefit and suggest that successive improvement of the function of the arm progressing to the distal muscles may eventually lead to significant disability reduction. These data from robotic trials continue to contribute to the emerging scientific basis of neuro-rehabilitation.

Customized interactive robotic treatment for stroke: EMG-triggered therapy.

A system for electromyographic (EMG) triggering of robot-assisted therapy (dubbed the EMG game) for stroke patients is presented. The onset of a patient's attempt to move is detected by monitoring EMG in selected muscles, whereupon the robot assists her or him to perform point-to-point movements in a horizontal plane. Besides delivering customized robot-assisted therapy, the system can record signals that may be useful to better understand the process of recovery from stroke. Preliminary experiments aimed at testing the proposed system and gaining insight into the potential of EMG-triggered, robot-assisted therapy are reported.

Continuous passive motion improves shoulder joint integrity following stroke.

OBJECTIVE: In a pilot study of patients with a first stroke and hemiparesis, we sought to determine whether treatment of the upper limb with continuous passive motion (CPM) that was device delivered would alter impairment, disability or the associated adverse symptoms of shoulder joint instability, pain and tone. DESIGN: Patients were randomly assigned to receive daily CPM treatments or participate in self-range of motion groups under the supervision of an occupational therapist. All patients received standard daily poststroke therapy for 3.5 h per day. A blinded evaluator at admission and discharge assessed patients using standardized scales of impairment, disability and adverse symptoms. SETTING: Specialized stroke unit of an acute rehabilitation hospital. SUBJECTS: Two hundred and eighty consecutive patients were screened and 35 of these with a first unilateral stroke, 13 +/- 6 days following the acute event, provided informed consent and were randomly assigned to CPM treatment or supervised group self-range exercise. MAIN MEASURES: Thirty-two completed the study and were evaluated using standardized measures for motor impairment (Fugl-Meyer, Motor Status Scale and Medical Research Council Motor Power), adverse symptoms (gleno-humeral stability, pain and tone), and disability (Functional Independence Measure). RESULTS: CPM-treated patients demonstrated positive trends towards improved shoulder joint stability (p = 0.06, confidence interval -0.03, 2.3) when compared with patients performing therapist-supervised self-range of motion. There were no significant differences in motor impairment, disability, pain or tone. CONCLUSIONS: Device-delivered continuous passive range of motion may offer an enhanced benefit for some adverse symptom reduction in the hemiplegic arm after stroke over traditional self-range of motion exercise.

Does shorter rehabilitation limit potential recovery poststroke?

OBJECTIVE: To examine retrospectively the recovery of patients engaged in robotic research during a 6 to 7-week course of inpatient rehabilitation. Because timing of the Interim evaluation at 3 1/2 weeks was comparable to the present length of inpatient stroke rehabilitation, the authors assessed whether significant gains in motor abilities occurred after the time when most stroke patients today are discharged home. METHODS: Fifty-six inpatients with a single, unilateral stroke were randomly assigned to a robot therapy or robot exposure group. Therapists blinded to group assignment administered the Fugl-Meyer, Motor Status Score, and MRC motor power test. RESULTS: Significant improvements in upper-limb motor abilities occurred throughout a period approximately twice the present length of stay in inpatient rehabilitation. However, in the latter half of this period, patients who received conventional therapy showed little improvement, whereas patients who received robot training plus conventional therapy continued to improve. CONCLUSION: Further opportunities for recovery after stroke are possible by extending intensive therapy beyond present inpatient rehabilitation stays.

Robotics and other devices in the treatment of patients recovering from stroke.

Stroke is the leading cause of permanent disability in the United States despite advances in prevention and novel interventional treatments. Randomized controlled studies have demonstrated the effectiveness of specialized post-stroke rehabilitation units, but administrative orders have severely limited the length of stay, so novel approaches to the treatment of recovery need to be tested in outpatients. Although the mechanisms of stroke recovery depend on multiple factors, a number of techniques that concentrate on enhanced exercise of the paralyzed limb have demonstrated effectiveness in reducing the motor impairment. For example, interactive robotic devices are new tools for therapists to deliver enhanced sensorimotor training for the paralyzed upper limb, which can potentially improve patient outcome and increase their productivity. New data support the idea that for some post-stroke patients and for some aspects of training-induced recovery, timing of the training may be less important than the quality and intensity of the training. The positive outcome that resulted in the interactive robotic trials contrasts with the failure to find a beneficial result in trials that used a noninteractive device that delivered continuous passive motion only. New pilot data from novel devices to move the wrist demonstrate benefit and suggest that successive improvement of the function of the arm progressing to the distal muscles may eventually lead to significant disability reduction. These data from robotic trials continue to contribute to the emerging scientific basis of neuro-rehabilitation.

Rehabilitation robotics: pilot trial of a spatial extension for MIT-Manus.

BACKGROUND: Previous results with the planar robot MIT-MANUS demonstrated positive benefits in trials with over 250 stroke patients. Consistent with motor learning, the positive effects did not generalize to other muscle groups or limb segments. Therefore we are designing a new class of robots to exercise other muscle groups or limb segments. This paper presents basic engineering aspects of a novel robotic module that extends our approach to anti-gravity movements out of the horizontal plane and a pilot study with 10 outpatients. Patients were trained during the initial six-weeks with the planar module (i.e., performance-based training limited to horizontal movements with gravity compensation). This training was followed by six-weeks of robotic therapy that focused on performing vertical arm movements against gravity. The 12-week protocol includes three one-hour robot therapy sessions per week (total 36 robot treatment sessions). RESULTS: Pilot study demonstrated that the protocol was safe and well tolerated with no patient presenting any adverse effect. Consistent with our past experience with persons with chronic strokes, there was a statistically significant reduction in tone measurement from admission to discharge of performance-based planar robot therapy and we have not observed increases in muscle tone or spasticity during the anti-gravity training protocol. Pilot results showed also a reduction in shoulder-elbow impairment following planar horizontal training. Furthermore, it suggested an additional reduction in shoulder-elbow impairment following the anti-gravity training. CONCLUSION: Our clinical experiments have focused on a fundamental question of whether task specific robotic training influences brain recovery. To date several studies demonstrate that in mature and damaged nervous systems, nurture indeed has an effect on nature. The improved recovery is most pronounced in the trained limb segments. We have now embarked on experiments that test whether we can continue to influence recovery, long after the acute insult, with a novel class of spatial robotic devices. This pilot results support the pursuit of further clinical trials to test efficacy and the pursuit of optimal therapy following brain injury.

Assessing the motor status score: a scale for the evaluation of upper limb motor outcomes in patients after stroke.

The Motor Status Scale (MSS) measures shoulder, elbow (maximum score = 40), wrist, hand, and finger movements (maximum score = 42), and expands the measurement of upper extremity impairment and disability provided by the Fugl-Meyer (FM) score. This work examines the interrater reliability and criterion validity of the MSS performed in patients admitted to a rehabilitation hospital 21 +/- 4 days after stroke. Using the MSS and the FM, 7 occupational therapists masked to each other's judgments, evaluated 12 consecutive patients with stroke. Two therapists evaluated 6 additional patients on consecutive days. Intraclass correlation coefficients were significant for each group of raters for the shoulder/elbow and for the wrist/band (P < 0.0001); test-retest measures were also significant for the shoulder/elbow (Pearson correlation coefficient r = 0.99, P < 0.004) and for the wrist/hand (Pearson correlation coefficient r = 0.99, P < 0.003). The internal item consistency for the overall MSS was significant (Cronbach alpha = 0.98, P < 0.0001). Finally the correlation between the MSS and the FM (R2 = 0.964) was significant (P < 0.0001). The MSS affords a reliable and valid assessment of upper limb impairment and disability following stroke.

Robotics in the rehabilitation treatment of patients with stroke.

Stroke is the leading cause of permanent disability despite continued advances in prevention and novel interventional treatments. Post-stroke neuro-rehabilitation programs teach compensatory strategies that alter the degree of permanent disability. Robotic devices are new tools for therapists to deliver enhanced sensorimotor training and concentrate on impairment reduction. Results from several groups have registered success in reducing impairment and increasing motor power with task-specific exercise delivered by the robotic devices. Enhancing the rehabilitation experience with task-specific repetitive exercise marks a different approach to the patient with stroke. The clinical challenge will be to streamline, adapt, and expand the robot protocols to accommodate healthcare economies, to determine which patients sustain the greatest benefit, and to explore the relationship between impairment reduction and disability level. With these new tools, therapists will measure aspects of outcome objectively and contribute to the emerging scientific basis of neuro-rehabilitation.