Because wrist rotation dynamics are dominated by stiffness (Charles SK, Hogan N. J Biomech 44: 614-621, 2011), understanding how humans plan and execute coordinated rotations requires knowledge of the characteristics joint. In past, passive joint has been measured in 1 degree freedom (DOF). Although these 1-DOF measurements inform us neuromuscular system must overcome to rotate pure flexion-extension (FE) or radial-ulnar deviation (RUD), rarely rotates FE RUD. Instead, natural combinations...

There is a difference of opinion concerning the advisability surgery for extramacular fraction retinal detachment (EMTRD) in diabetic patients before development macular detachment. Ninety-nine eyes with EMTRD 84 observed without had rate 13.8% one year. This compares favorably reported 30% to 47% failure subjected vitrectomy.

Mounting evidence suggests that human motor control uses dynamic primitives, attractors of neuromechanical systems require minimal central supervision. However, advantages for may be offset by compromised versatility. Extending recent results showing humans could not sustain discrete movements as duration decreased, this study tested whether smoothly rhythmic maintained increased. Participants performed horizontal between two targets, paced sounds with intervals increased from 1 to 6 s 200...

In 1991, a novel robot named MIT-MANUS was introduced as test bed to study the potential of using robots assist in and quantify neuro-rehabilitation motor function. It new brand therapy, offering highly backdrivable mechanism with soft stable feel for user. proved an excellent fit shoulder elbow rehabilitation stroke patients, showing clinical trials reduction impairment these joints. The greater observed group muscles exercised. This suggests need additional rehabilitate other target areas...

In Brief Objective: To evaluate the anatomic and functional success of phacovitrectomy intraocular gas tamponade for macular hole surgery with only first night face down posturing. Methods: This was a nonrandomized observational prospective trial over 9 months, data collection on 28 eyes 26 consecutive patients who underwent phacovitrectomy, internal limiting membrane peel, (C2F6) stage 2, 3, 4 holes. Data included sex, age, latency Gass stage, preoperative postoperative visual acuity ocular...

Because the dynamics of wrist rotations are dominated by stiffness, understanding requires a thorough characterization stiffness in multiple degrees freedom. The only prior measurement multivariable was confined to approximately one-seventh range motion (ROM). Here, we present precise nonlinear passive joint over three times greater, which covers 70% functional ROM wrist. We measured torque-displacement vector field 24 directions and fit data using thin-plate spline smoothing optimized with...

Given the vast complexity of human actions and interactions with objects, we proposed that control sensorimotor behavior may utilize dynamic primitives. However, greater computational simplicity come at cost reduced versatility. Evidence for primitives be garnered by revealing such limitations. This study tested subjects performing a sequence progressively faster discrete movements in order to "stress" system. We hypothesized increasing pace would elicit transition rhythmic movements,...

When humans rotate their wrist in flexion-extension, radial-ulnar deviation, and combinations, the resulting paths (like path of a laser pointer on screen) exhibit distinctive pattern curvature. In this report we show that passive stiffness is sufficient to account for pattern. Simulating dynamics rotations using demonstrably realistic model under variety conditions, can explain all characteristics observed We also provide evidence against other possible causes. further demonstrate...

Background: It is unclear which muscles contribute most to tremor and should therefore be targeted by suppression methods. Previous studies used mathematical models investigate how upper-limb biomechanics affect muscles’ potential generate tremor. These investigations yielded principles, but the included at only 15 muscles. Here we expand previous include 50 muscles, simulate propagation, test validity of previously postulated principles. Methods: Tremor propagation was characterized using...

Smoothness is a hallmark of healthy movement. Past research indicates that smoothness may be side product control strategy minimizes error. However, this not the only reason for smooth movements. Our musculoskeletal system itself contributes to movement smoothness: mechanical impedance (inertia, damping, and stiffness) our limbs joints resists sudden change, resulting in natural smoothing effect. How biomechanics neural interact result an observed level clear. The purpose study 1)...

Pathological tremor is an oscillation of body parts at 3–10 Hz, determined by the output spinal motor neurons (MNs), which receive synaptic inputs from supraspinal centers and muscle afferents. The behavior MNs during not well understood, especially in relation to activation multiple muscles involved. Recent studies on patients with essential have shown that antagonist MN pools shared input frequency. In this study, we investigated related voluntary movement, their coordination across...

Although tremor is the most common movement disorder, there are few noninvasive treatment options. Creating effective suppression devices requires a knowledge of where originates mechanically (which muscles) and how it propagates through limb (to which degrees-of-freedom (DOF)). To simulate propagation, we created simple model upper limb, with tremorogenic activity in 15 major superficial muscles as inputs tremulous joint displacement seven DOF outputs. The approximated muscle...

Although upper-limb movement impairments are common, the primary tools for assessing and tracking in clinical settings limited. Markerless motion capture (MMC) technology has potential to provide a large amount of quantitative, objective data routine use. Many past studies have focused on whether MMC sufficiently accurate. However, another necessary step is create meaningful tests that can be administered via robust manner. Four conventional motor common assessments (visually guided...

Although Essential Tremor is one of the most common movement disorders, current treatment options are relatively limited. Peripheral tremor suppression methods have shown potential, but we do not currently know which muscles responsible for patients' tremor, making it difficult to optimize methods. The purpose this study was quantify relationships between tremorogenic activity in throughout upper limb. Muscle recorded from 15 major superficial upper-limb 24 subjects with while they held...

Transcutaneous electrical stimulation has been applied in tremor suppression applications. Out-of-phase strategies above or below motor threshold result a significant attenuation of pathological tremor. For to be properly timed, the varying phase relationship between agonist-antagonist muscle activity during needs accurately estimated real-time. Here we propose an online and frequency tracking technique for customized control stimulation, based on phase-locked loop (PLL) system neural drive...