Mediolateral damping of an overhead body weight support system assists stability during treadmill walking.

BACKGROUND: Body weight support systems with three or more degrees of freedom (3-DoF) are permissive and safe environments that provide unloading and allow unrestricted movement in any direction. This enables training of walking and balance control at an early stage in rehabilitation. Transparent systems generate a support force vector that is near vertical at all positions in the workspace to only minimally interfere with natural movement patterns. Patients with impaired balance, however, may benefit from additional mediolateral support that can be adjusted according to their capacity. An elegant solution for providing balance support might be by rendering viscous damping along the mediolateral axis via the software controller. Before use with patients, we evaluated if control-rendered mediolateral damping evokes the desired stability enhancement in able-bodied individuals. METHODS: A transparent, cable-driven robotic body weight support system (FLOAT) was used to provide transparent body weight support with and without mediolateral damping to 21 able-bodied volunteers while walking at preferred gait velocity on a treadmill. Stability metrics reflecting resistance to small and large perturbations were derived from walking kinematics and compared between conditions and to free walking. RESULTS: Compared to free walking, the application of body weight support per-se resulted in gait alterations typically associated with body weight support, namely increased step length and swing phase. Frontal plane dynamic stability, measured by kinematic variability and nonlinear dynamics of the center of mass, was increased under body weight support, indicating reduced balance requirements in both damped and undamped support conditions. Adding damping to the body weight support resulted in a greater increase of frontal plane stability. CONCLUSION: Adding mediolateral damping to 3-DoF body weight support systems is an effective method of increasing frontal plane stability during walking in able-bodied participants. Building on these results, adjustable mediolateral damping could enable therapists to select combinations of unloading and stability specifically for each patient and to adapt this in a task specific manner. This could extend the impact of transparent 3-DoF body weight support systems, enabling training of gait and active balance from an early time point onwards in the rehabilitation process for a wide range of mobility activities of daily life.

Robotic body weight support enables safe stair negotiation in compliance with basic locomotor principles.

BACKGROUND: After a neurological injury, mobility focused rehabilitation programs intensively train walking on treadmills or overground. However, after discharge, quite a few patients are not able to independently negotiate stairs, a real-world task with high physical and psychological demands and a high injury risk. To decrease fall risk and improve patients' capacity to navigate typical environments, early stair negotiation training can help restore competence and confidence in safe stair negotiation. One way to enable early training in a safe and permissive environment is to unload the patient with a body weight support system. We here investigated if unloaded stair negotiation complies with basic locomotor principles, in terms of enabling performance of a physiological movement pattern with minimal compensation. METHODS: Seventeen able-bodied participants were unloaded with 0-50% bodyweight during self-paced ascent and descent of a 4-tread staircase. Spatio-temporal parameters, joint ranges of motion, ground reaction forces and myoelectric activity in the main lower limb muscles of participants were compared between unloading levels. Likelihood ratio tests of separated linear mixed models of the investigated outcomes assessed if unloading affects the parameters in general. Subsequent post-hoc testing revealed which levels of unloading differed from unsupported stair negotiation. RESULTS: Unloading affected walking velocity, joint ranges of motion, vertical ground reaction force parameters and myoelectric activity in all investigated muscles for stair ascent and descent while step width and single support duration were only affected during ascent. A reduction with increasing levels of body weight support was seen in walking velocity (0.07-0.12 m/s), ranges of motion of the knee and hip (2-10°), vertical ground reaction force peaks (10-70%) and myoelectric activity (17-70%). An increase with unloading was only seen during ascent for ankle range of motion and tibialis anterior activity at substantial unloading. CONCLUSIONS: Body weight support facilitates stair negotiation by providing safety and support against gravity. Although unloading effects are present in most parameters, up to 30% body weight support these changes are small, and no dysfunctional patterns are introduced. Body weight support therefore fulfills all the necessary requirements for early stair negotiation training.

Chronic intrahypothalamic rather than subcutaneous liraglutide treatment reduces body weight gain and stimulates the melanocortin receptor system.

BACKGROUND: The GLP-1 receptor agonist liraglutide is marketed for obesity treatment where it induces body weight reduction possibly via the hypothalamus, which regulates energy homeostasis. In animal studies, acute liraglutide treatment triggers satiety, weight loss and activates thermogenesis in adipose tissue. However, the precise mechanisms how liraglutide affects in particular chronic weight loss are still under investigation. OBJECTIVES: We aimed to evaluate whether chronic hypothalamic or chronic subcutaneous administration of liraglutide induces sustained weight loss through altered adipose tissue function and to what extent hypothalamic neuronal appetite regulators are involved in the liraglutide-induced weight loss in healthy lean rats on a normal diet. MATERIALS/METHODS: We continuously administered liraglutide either intrahypothalamically (10 µg per day) or subcutaneously (200 µg kg-1 per day) for 28 days to lean Sprague Dawley rats (n=8 each). We assessed changes in body weight, adipose tissue mass, adipocyte size and adipose tissue volume in the abdominal region by using micro-CT. We analyzed genetic expression patterns of browning, thermogenic and adipocyte differentiation regulators in adipose tissues as well as particular neuronal appetite regulators in the hypothalamus. RESULTS: Intrahypothalamic liraglutide administration induced an 8% body weight reduction at day 9 compared with the control group (P<0.01) and a 7% body weight loss at day 9 compared with subcutaneous liraglutide treatment (P<0.01), supported by a significant reduction in adipose tissue mass and volume with intrahypothalamic liraglutide administration (P<0.05). Our data show that chronic intrahypothalamic liraglutide treatment triggered an 18-fold induction of the hypothalamic mc4r gene (P<0.01) accompanied by a significant increase in circulating thyroxine (T4) levels (P<0.05). CONCLUSIONS: Chronic intrahypothalamic liraglutide administration resulted in a profound reduction in body weight and fat mass loss most likely mediated by the hypothalamic melanocortin system rather than by adipose tissue browning or improved thermogenesis.

Combination of transvaginal sonography and clinical examination for preoperative diagnosis of pelvic endometriosis.

BACKGROUND: The aim of the present study was to evaluate the accuracy of routine clinical examination (per vaginam, PV) combined with transvaginal sonography (TVS) for presurgical, non-invasive diagnosis of endometriosis. METHODS: Two-hundred women with symptoms suggestive of endometriosis were prospectively assessed by PV and TVS prior to laparoscopy and radical resection of disease and histological confirmation. RESULTS: Prevalence of endometriosis on the right/left (r/l) ovary, r/l uterosacral ligament (USL), pouch of Douglas (POD), vagina, bladder, rectovaginal space (RVS) and rectum was 12%, 13%, 12%, 22%, 15%, 11%, 2%, 4% and 24%. Sensitivities, specificities, positive and negative predictive values and positive and negative likelihood ratios for combined use of TVS and PV resulted in 96/100%, 100/99%, 100/93%, 93/100% and -;0.04/87.0;- for the r/l ovarian endometriosis; 67/84%, 97/86%, 73/62%, 96/95% and 19.56;0.35/5.97;0.19 for the r/l USL disease; 87%, 98%, 90%, 98% and 49.11;0.14 for involvement of the POD; 82%, 99%, 95%, 98% and 145.64;0.18 for vaginal endometriosis; 88%, 99%, 78%, 99% and 84.0;0.13 for endometriosis of the RVS; 75%, 98%, 50%, 99% and 49.0;0.25 for bladder involvement and 96%, 98%, 94%, 99% and 48.56;0.04 for rectal endometriosis. CONCLUSIONS: The combination of PV and TVS accurately predicts the presence of endometriosis affecting the ovaries, vagina, rectum, USL, RVS and POD in patients with suspected endometriosis. We suggest the routine combination of PV and TVS as an essential part of the standard primary assessment of pelvic pain patients with suspected endometriosis.

Multidirectional transparent support for overground gait training.

Gait and balance training is an essential ingredient for locomotor rehabilitation of patients with neurological impairments. Robotic overhead support systems may help these patients train, for example by relieving them of part of their body weight. However, there are only very few systems that provide support during overground gait, and these suffer from limited degrees of freedom and/or undesired interaction forces due to uncompensated robot dynamics, namely inertia. Here, we suggest a novel mechanical concept that is based on cable robot technology and that allows three-dimensional gait training while reducing apparent robot dynamics to a minimum. The solution does not suffer from the conventional drawback of cable robots, which is a limited workspace. Instead, displaceable deflection units follow the human subject above a large walking area. These deflection units are not actuated, instead they are implicitly displaced by means of the forces in the cables they deflect. This leads to an underactuated design, because the deflection units cannot be moved arbitrarily. However, the design still allows accurate control of a three-dimensional force vector acting on a human subject during gait. We describe the mechanical concept, the control concept, and we show first experimental results obtained with the device, including the force control performance during robot-supported overground gait of five human subjects without motor impairments.

Optimisation of the mean boat velocity in rowing.

In rowing, motor learning may be facilitated by augmented feedback that displays the ratio between actual mean boat velocity and maximal achievable mean boat velocity. To provide this ratio, the aim of this work was to develop and evaluate an algorithm calculating an individual maximal mean boat velocity. The algorithm optimised the horizontal oar movement under constraints such as the individual range of the horizontal oar displacement, individual timing of catch and release and an individual power-angle relation. Immersion and turning of the oar were simplified, and the seat movement of a professional rower was implemented. The feasibility of the algorithm, and of the associated ratio between actual boat velocity and optimised boat velocity, was confirmed by a study on four subjects: as expected, advanced rowing skills resulted in higher ratios, and the maximal mean boat velocity depended on the range of the horizontal oar displacement.

[ENZIAN-score, a classification of deep infiltrating endometriosis]. / ENZIAN-Score, eine Klassifikation der tief infiltrierenden Endometriose.

The ENZIAN-Score is presented as a new instrument to classify the deep infiltrating endometriosis. Especially the retroperitoneal part of the severe endometriosis is focussed on. In analogy to an oncological staging four different stages are pronounced. The localisation and the expansion of the endometriosis nodule was indicated to different subgroups. The still used rAFS-score is of no clinical evidence, as we pointed out in a retrospective study of our patients with severe intestinal endometriosis.