Sensory and motor correlates of frailty: dissociation between frailty phenotype and frailty index.

BACKGROUND: Frailty has been associated with a decline in sensory and motor function. However, given that different frailty measures were shown to overlap but also differ in their diagnostic properties, sensory and motor correlates of frailty might be different depending on the operationalization of frailty. Our objective was to identify sensory and motor determinants of frailty and compare the results between frailty phenotype (FP) and frailty index (FI). METHODS: Data from 44 pre-frail and frail subjects aged 65 and above were used. Frailty was measured using the FP and the FI. Sensory function in the visual, auditory, and tactile domain was assessed using visual acuity, absolute hearing threshold and mechanical detection threshold. Upper extremity motor performance was evaluated by the Purdue Pegboard Test and the Short Physical Performance Battery was used to assess lower extremity motor function. Multiple logistic regression models were employed to determine associations of sensory and motor function with frailty vs. pre-frailty for both frailty measures. RESULTS: The frailty measures were moderately correlated (0.497, p ≤ 0.01) and had a Kappa agreement of 0.467 (p = 0.002). Using the FP, frailty was significantly associated with reduced upper extremity motor function only (OR = 0.50, 95% CI 0.29-0.87, p = 0.014). Frailty as assessed by the FI was significantly related to higher hearing thresholds (OR = 1.21, 95% CI 1.02-1.43, p = 0.027) and reduced lower extremity performance (OR = 0.32, 95% CI 0.13-0.77, p = 0.012). CONCLUSION: Frailty is related to reduced performance in measures of sensory and motor function. However, traditional measures of frailty might be differentially sensitive to capture sensory and motor decline, possibly contributing to the much-observed discordance between the diagnostic instruments. This should be taken into account by researchers and clinicians when planning and evaluating therapeutic interventions for frailty. TRIAL REGISTRATION: ClinicalTrials.gov NCT03666039 . Registered 11 September 2018 - Retrospectively registered.

Promoting neuroplasticity and neuropsychological functioning in frailty through an app-based sensorimotor training: study protocol for a randomized trial.

BACKGROUND: Frailty is characterized by an age-related decline in multiple physiological systems, leading to a high vulnerability to stressors, adverse health outcomes, and low quality of life. Neuroscientific models of pathological aging emphasize the loss of sensorimotor stimulation and reduced neuromodulatory capacities as core processes in age-related cognitive and bodily decline, which may be associated with maladaptive plastic changes in the brain. We plan to increase sensorimotor stimulation in frail persons through a newly developed app-based training program and link the training trials to biological and psychological correlates of age-associated vulnerability and health indices. METHODS: We will conduct a randomized trial, applying an app-based sensorimotor home training (N = 30) in people suffering from frailty. An app-based relaxation training will serve as an active control condition (N = 30). Both interventions will last for 90 days each. The sensorimotor training includes unimodal and multimodal sensory discrimination tasks in the visual, auditory, and tactile domain, as well as sensorimotor precision tasks. The tasks will be implemented using an adaptive training algorithm and enriched with motivational components embedded in a virtual training environment. We expect a pre-post reduction of frailty status and associated functional decline related to refinement of representational maps within the sensorimotor system and improved sensorimotor function such as extremity function. Secondary analyses will study the influence of BDNF genotype as moderating variable. Additional outcomes will include measures of perceptual and cognitive functioning, quality of life as well as BDNF serum levels. Measurements will take place before training (baseline), after 60 days (assessment 1), and at the end of the training after 90 days (assessment 2). DISCUSSION: In our randomized trial, we aim to characterize a multidimensional concept of frailty and to target maladaptive behaviors and neuroplasticity using an app-based sensorimotor training. This type of intervention might provide further knowledge and new possibilities for preventing decline and preserving function in older adults. TRIAL REGISTRATION: ClinicalTrials.gov NCT03666039 . Registered 11 September 2018 - Retrospectively registered. Protocol version: Version 4 revised (issue date: 19 May 2021).

Reduced tactile sensitivity is associated with mild cognitive impairment.

BACKGROUND: Sensory impairment has been related to age-associated cognitive decline. While these associations were investigated primarily in the auditory and visual domain, other senses such as touch have rarely been studied. Thus, it remains open whether these results are specific for particular sensory domains, or rather point to a fundamental role of sensory deficits in cognitive decline. METHODS: Data from 31 participants with mild cognitive impairment (MCI), 46 participants with frailty, and 23 non-clinical control participants (NCCs) were included. We assessed sensory function using visual acuity and contrast sensitivity, hearing threshold, and mechanical detection threshold. Cognitive function in participants with MCI was assessed using associative memory performance. Group differences on sensory thresholds were tested using analyses of covariance with age, sex, and years of education as covariates. Associations between measures within participants with MCI were evaluated using Spearman correlations. FINDINGS: We found a significant difference in mechanical detection threshold between the groups (p < 0.001, η2 = 0.18). Participants with MCI showed significantly reduced tactile sensitivity compared to participants with frailty and NCCs. In participants with MCI, lower associative memory performance was significantly related to reduced tactile sensitivity (rs = 0.39, p = 0.031) and auditory acuity (rs = 0.41, p = 0.022). INTERPRETATION: Our results indicate that reduced tactile sensitivity is related to cognitive decline. Prospective studies should investigate the age-related alterations of multimodal sensory processes and their contribution to dementia-related processes. FUNDING: Deutsche Forschungsgemeinschaft (FL 156/41-1) and a grant of the Hector-Stiftung II, Weinheim, Germany.

MicroSim - a microsurgical training simulator.

MicroSim is a training simulator for microsurgical tasks. It is based on a virtual reality environment including a realistic interface and a real-time simulation model. The interface consists of real instruments which are tracked by an optical tracking system. The surgical scene is presented to the user through a stereo display which is similar to the view a surgeon has through a microscope. Abstract training modules, which are used to train basic fine motor skills and the prototype of a microvascular anastomosis have been implemented in cooperation with VRmagic GmbH.

Effects of an app-based sensorimotor training in promoting neuroplasticity and neuropsychological functioning in frailty: A randomized controlled trial.

BACKGROUND: Loss of sensorimotor stimulation and maladaptive plastic changes of the brain may play a major role in problematic aging phenomena such as frailty. However, it is not clear if interventions specifically targeting neuroplasticity can reverse or slow the development of frailty. OBJECTIVES: We compared the effect of a tablet-based neuroplasticity-oriented sensorimotor training (experimental group, EG) and a tablet-based relaxation training (control group, CG) on frailty and sensorimotor brain function. METHODS: Interventions consisted of daily 30 min sessions distributed over 90 days. Assessments took place at baseline, after 60 days, and after 90 days. A total of N = 48 frail older adults (EG: n = 24; CG: n = 24) were assigned to the two groups and reassessed after 60 days. Primary outcomes included frailty phenotype (FP) and frailty index (FI). Sensorimotor brain activity was evaluated using functional magnetic resonance imaging and single-pulse transcranial magnetic stimulation. RESULTS: After 60 days of training, both groups showed a reduction in the number of FP criteria (p < 0.001) with a trend towards a significant time-by-group interaction (p = 0.058) indicating a stronger reduction of frailty in the EG (p < 0.001) compared to the CG (p = 0.039). In addition, pain was significantly reduced in the EG but not the CG. No significant effects were found for measures of brain function. DISCUSSION: We provided initial evidence that a neuroplasticity-oriented sensorimotor training could be beneficial in counteracting frailty as well as chronic pain. Further studies are needed to determine the potentially underlying neuroplastic mechanisms and the influence of plasticity-related biomarkers as well as their clinical significance. TRIAL REGISTRATION: ClinicalTrials.gov NCT03666039 (registered 11 September 2018).

An aneurysm clipping training module for the neurosurgical training simulator NeuroSim.

Having introduced NeuroSim, the prototype of a neurosurgical training simulator at MMVR18, we present our first medical training module. NeuroSim is based on virtual reality and uses real-time algorithms for simulating tissue. It provides a native interface by using a real surgical microscope and original instruments. Having implemented some abstract tasks to train basic skills like hand-eye coordination or the handling of the microscope last year, we now present a medical module where an aneurysm has to be clipped. NeuroSim has been developed in cooperation with the neurosurgical clinic of the University of Heidelberg and VRmagic GmbH in Mannheim.

On a Linear Gromov-Wasserstein Distance.

Gromov-Wasserstein distances are generalization of Wasserstein distances, which are invariant under distance preserving transformations. Although a simplified version of optimal transport in Wasserstein spaces, called linear optimal transport (LOT), was successfully used in practice, there does not exist a notion of linear Gromov-Wasserstein distances so far. In this paper, we propose a definition of linear Gromov-Wasserstein distances. We motivate our approach by a generalized LOT model, which is based on barycentric projection maps of transport plans. Numerical examples illustrate that the linear Gromov-Wasserstein distances, similarly as LOT, can replace the expensive computation of pairwise Gromov-Wasserstein distances in applications like shape classification.

NeuroSim--the prototype of a neurosurgical training simulator.

We present NeuroSim, the prototype of a training simulator for open surgical interventions on the human brain. The simulator is based on virtual reality and uses real-time simulation algorithms to interact with models generated from MRT- or CT-datasets. NeuroSim provides a native interface by using a real surgical microscope and original instruments tracked by a combination of inertial measurement units and optical tracking. Conclusively an immersive environment is generated. In a first step the navigation in an open surgery setup as well as the hand-eye coordination through a microscope can be trained. Due to its modular design further training modules and extensions can be integrated. NeuroSim has been developed in cooperation with the neurosurgical clinic of the University of Heidelberg and the VRmagic GmbH in Mannheim.

Real-time Marker-based Tracking of a Non-rigid Object.

Real-time tracking of non-rigid objects for use in interfaces of VR-simulators is presented. Markers are attached to the objects and observed by several cameras with integrated image-processing hardware which extracts relevant marker data (centroid, area & color) in real-time. Data from the different cameras is then matched in the host PC to reconstruct the 3D positions. We present two approaches to this special matching problem because standard image feature based algorithms are not feasible for marker-based tracking. A model of the deformation is extracted from the reconstructed 3D point cloud and the simulation model is updated accordingly. Experiments with a prototype of a deformable eye interface for the ophthalmosurgical simulator EYESI show that latency, robustness and accuracy of the deformation tracking are adequate for application in VR simulators. The approach is extensible to other types of simulators where deformable tissue has to be tracked.

Randomized comparison of percutaneous coronary intervention with sirolimus-eluting stents versus coronary artery bypass grafting in unprotected left main stem stenosis.

OBJECTIVES: The purpose of this randomized study was to compare sirolimus-eluting stenting with coronary artery bypass grafting (CABG) for patients with unprotected left main (ULM) coronary artery disease. BACKGROUND: CABG is considered the standard of care for treatment of ULM. Improvements in percutaneous coronary intervention (PCI) with use of drug-eluting stents might lead to similar results. The effectiveness of drug-eluting stenting versus surgery has not been established in a randomized trial. METHODS: In this prospective, multicenter, randomized trial, 201 patients with ULM disease were randomly assigned to undergo sirolimus-eluting stenting (n = 100) or CABG using predominantly arterial grafts (n = 101). The primary clinical end point was noninferiority in freedom from major adverse cardiac events, such as cardiac death, myocardial infarction, and the need for target vessel revascularization within 12 months. RESULTS: The combined primary end point was reached in 13.9% of patients after surgery, as opposed to 19.0% after PCI (p = 0.19 for noninferiority). The combined rates for death and myocardial infarction were comparable (surgery, 7.9% vs. stenting, 5.0%; noninferiority p < 0.001), but stenting was inferior to surgery for repeat revascularization (5.9% vs. 14.0%; noninferiority p = 0.35). Perioperative complications including 2 strokes were higher after surgery (4% vs. 30%; p < 0.001). Freedom from angina was similar between groups (p = 0.33). CONCLUSIONS: In patients with ULM stenosis, PCI with sirolimus-eluting stents did not show noninferiority [corrected] to CABG at 12-month follow-up with respect to freedom from major adverse cardiac events, which is mainly influenced by repeated revascularization, whereas for hard endpoints, [corrected] PCI results are favorable. A longer follow-up is warranted. [corrected]

Short- and long-term outcome after carotid artery stenting with neuroprotection: single-center experience within a prospective registry.

BACKGROUND: Carotid artery stenting is an alternative method to surgical endarterectomy for treatment of carotid artery stenosis. METHODS AND RESULTS: Three hundred and seventy-one consecutive patients (71+/-9 years) undergoing 405 carotid artery interventions at a single cardiologic center were studied prospectively within a therapy registry. In general, the interventional procedure was performed using neuroprotective devices to prevent distal embolization. Stents were used routinely whenever possible. Independent neurological assessment took place prior to and after carotid stenting. The neurological event rate was assessed in the early (<30 days) and late post interventional period. In asymptomatic patients, 286 interventions were done with a 30-day stroke rate of 1.3% (ipsilateral 1.0%). In symptomatic patients, strokes occurred in a significantly (p<0.005) higher rate of 5.0% after 119 interventions (all ipsilateral). At long-term follow-up (mean 728+/-548 days) additional strokes occurred ipsilateral to the side of carotid intervention in 0.4% of asymptomatic patients (1.7% of symptomatic patients); contralateral strokes were seen at long-term follow-up in 1.1% of asymptomatic (1.7% of symptomatic) patients. Due to their comorbidities, 1.6% of patients died early, and an additional 11.1% late after carotid stenting. CONCLUSION: Carotid artery stenting with the general use of neuroprotective devices yields acceptable shortterm results with respect to neurological events. Asymptomatic patients have significantly less periprocedural strokes than symptomatic patients. Neurological events during long-term follow-up are rare, in particular ipsilateral to the side of carotid stenting. Thus, carotid artery stenting with neuroprotection is a safe method for carotid revascularization, with acceptable periprocedural events, particularly in asymptomatic patients, and a good long-term neurologic outcome.