Tele-operated high speed anthropomorphic dextrous hands with object shape and texture identification

This paper reports on the development of two number of robotic hands have been developed which focus on tele-operated high speed anthropomorphic dextrous robotic hands. The aim of developing these hands was to achieve a system that seamlessly interfaced between humans and robots. To provide sensory feedback, to a remote operator tactile sensors were developed to be mounted on the robotic hands. Two systems were developed, the first, being a skin sensor capable of shape reconstruction placed on the palm of the hand to feed back the shape of objects grasped and the second is a highly sensitive tactile array for surface texture identification

Assessment of prospective memory: A validity study of memory for intentions screening test

Aim: The goal of the present study was to validate the Czech version of the Memory for Intentions (Screening) Test (MIST, 2010). We included standardized testing material, translation of administration and scoring, and assessment of normative data for the MIST in the Czech population. Introduction: Prospective memory (PM), i.e., the ability to remember and implement intentions after a delay, is essential as a subsystem of episodic memory for the maintenance of independence and execution of activities of daily living. PM assessment thus plays an important role in the dia gnosis of episodic memory disorders. However, there are currently no standardized and validated PM tools in Czech language. Methods: The Czech version of MIST was administered to 30 healthy persons. Results: The MIST Summary score correlated at a medium level with a range of neuropsychological measures including memory retention, mental flexibility, and resistance to interference (all rho = 0.37– 0.42; all p < 0.05). The reliability of MIST in terms of internal consistency was insufficient when analyzing the eight individual MIST trials (� = 0.50), as was split- half reliability (split- half reliability = 0.56). In contrast, there was a high degree of reliability between six subscales classified by type (delay, cue and mode of response; � = 0.88, split- half = 0.95). Conclusion: The reliability and validity of the Czech version of MIST is comparable to the original English version. The study opens access to standardized PM assessment in clinical populations in the Czech Republic

Mild cognitive impairment disrupts attention network connectivity in Parkinson's disease: A combined multimodal MRI and meta-analytical study

Mild cognitive impairment (MCI) affects approximately one-third of non-demented Parkinson's Disease (PD) patients. We aimed at investigating the neural correlates of MCI in PD combining multimodal magnetic resonance imaging (MRI) with large-scale data from the literature. We analyzed 31 PD patients and 30 matched controls. The standard neuropsychological assessment of PD-MCI covered memory, attention, executive functions, language and visuospatial abilities. Following validated criteria, 16 patients were classified as showing MCI. Whole-brain functional connectivity and structural volume changes were assessed, respectively, by means of eigenvector centrality (EC) and voxel-based morphometry. To address the involvement of specific functional brain networks, we validated our results by building a meta-analytic co-activation map (MACM) based on the previous literature and then testing its overlap with the parcellation of functional networks derived from 1000 healthy controls. The EC comparison between PD with normal cognition and controls showed a selective decline in interconnectedness in the bilateral lentiform nuclei. Differently, comparing PD with MCI and controls revealed additional changes in non-motor areas. Directly comparing PD with and without MCI, we found a reduced interconnectedness in the bilateral superior parietal lobules and precuneus. No differences in brain volume were detected comparing these patient groups. The MACM and overlap analyses showed that the observed connectivity changes were localized in the hubs of the dorsal attention network. Notably, this aligned with the predominant attention deficit observed in our sample. Overall, functional impairment in the dorsal attention network seems to be the hallmark of MCI due to PD, thus extending previous findings of brain connectivity disruption in non-motor networks

Frontal assessment battery in Parkinson’s disease: Validity and morphological correlates

Objectives: Executive dysfunction is a common feature in Parkinson’s disease (PD). However, there is a lack of brief validated instruments for executive dysfunction in PD. Methods: The aim of the present study was to assess the relation of Frontal Assessment Battery (FAB) scores to age and education, to verify the utility of FAB in the evaluation of executive dysfunction in PD and to differentiate between controls (n=41), PD patients with normal cognition (PD-NC; n=41; Hoehn and Yahr stages 2–3) and PD with mild cognitive impairment (PD-MCI; n=32; Hoehn and Yahr stages 2–3). In addition, we studied the relation between voxel-based morphometric (VBM) data and FAB results in PD. Results: We found that FAB scores are significantly related to age and education. The FAB has shown discriminative validity for the differentiation of PD-MCI from PD-NC and controls (area under the curve >.80). Also, the VBM analysis revealed lower FAB scores are specifically related to lower gray matter density in the right ventromedial prefrontal areas and precuneus. Conclusions: The FAB can be recommended as a valid instrument for PD-MCI Level I screening. FAB is sensitive to frontal lobe involvement in PD as reflected by lower gray matter density in prefrontal areas

Unraveling connectivity changes due to dopaminergic therapy in chronically treated Parkinson’s disease patients

The effects of dopaminergic therapy for Parkinson’s disease (PD) on the brain functional architecture are still unclear. We investigated this topic in 31 PD patients (disease duration: 11.2 ± (SD) 3.6 years) who underwent clinical and MRI assessments under chronic dopaminergic treatment (duration: 8.3 ± (SD) 4.4 years) and after its withdrawal. Thirty healthy controls were also included. Functional and morphological changes were studied, respectively, with eigenvector centrality mapping and seed-based connectivity, and voxel-based morphometry. Patients off medication, compared to controls, showed increased connectivity in cortical sensorimotor areas extending to the cerebello-thalamo-cortical pathway and parietal and frontal brain structures. Dopaminergic therapy normalized this increased connectivity. Notably, patients showed decreased interconnectedness in the medicated compared to the unmedicated condition, encompassing putamen, precuneus, supplementary motor and sensorimotor areas bilaterally. Similarly, lower connectivity was found comparing medicated patients to controls, overlapping with the within-group comparison in the putamen. Seed-based analyses revealed that dopaminergic therapy reduced connectivity in motor and default mode networks. Lower connectivity in the putamen correlated with longer disease duration, medication dose, and motor symptom improvement. Notably, atrophy and connectivity changes were topographically dissociated. After chronic treatment, dopaminergic therapy decreases connectivity of key motor and default mode network structures that are abnormally elevated in PD off condition

Regional gray matter changes and age predict individual treatment response in Parkinson's disease

We aimed at testing the potential of biomarkers in predicting individual patient response to dopaminergic therapy for Parkinson's disease. Treatment efficacy was assessed in 30 Parkinson's disease patients as motor symptoms improvement from unmedicated to medicated state as assessed by the Unified Parkinson's Disease Rating Scale score III. Patients were stratified into weak and strong responders according to the individual treatment response. A multiple regression was implemented to test the prediction accuracy of age, disease duration and treatment dose and length. Univariate voxel-based morphometry was applied to investigate differences between the two groups on age-corrected T1-weighted magnetic resonance images. Multivariate support vector machine classification was used to predict individual treatment response based on neuroimaging data. Among clinical data, increasing age predicted a weaker treatment response. Additionally, weak responders presented greater brain atrophy in the left temporoparietal operculum. Support vector machine classification revealed that gray matter density in this brain region, including additionally the supplementary and primary motor areas and the cerebellum, was able to differentiate weak and strong responders with 74% accuracy. Remarkably, age and regional gray matter density of the left temporoparietal operculum predicted both and independently treatment response as shown in a combined regression analysis. In conclusion, both increasing age and reduced gray matter density are valid and independent predictors of dopaminergic therapy response in Parkinson's disease

Memory impairment in Parkinson's disease: The retrieval versus associative deficit hypothesis revisited and reconciled

Objective: Our study explored the retrieval deficit and the associative deficit hypotheses of memory impairments in Parkinson's disease (PD). The former supports a memory deficit mediated by attention/executive dysfunctions, whereas the latter hypothesizes a hippocampal memory impairment in PD. Method: We studied 31 controls and 34 PD patients classified as PD with normal cognition (PD-NC; n = 18) and PD with mild cognitive impairment (PD-MCI; n= 16). To test the retrieval deficit hypothesis, we measured the performance in encoding, retention, and recognition in verbal and visual domains; to test the associative deficit hypothesis, we used a specific associative binding measure. Using resting-state functional-MRI, we compared the functional connectivity of different hippocampal subfields between PD patients and controls, and we related it to memory performance. Results: Consistently with the retrieval deficit hypothesis, PD-MCI, and PD-NC, were impaired in free recall encoding and retention in comparison to controls, especially in the visual domain. However, as predicted by the associative deficit hypothesis, PD-MCI and, to a lesser extent, PD-NC, showed also significant associative and binding deficits in cued recall. Notably, PD patients compared to controls did not show structural differences, although they had lower connectivity between the anterior hippocampi and the precuneus/superior parietal cortex. Worse performance in memory was associated with a more severe disruption of the hippocampal connectivity. Conclusions: The pervasive pattern of memory impairment in PD supports both hypotheses. The interplay between the hippocampus, related to associative memory deficits, and the precuneus, related to attentional control, provides a neural signature that reconciles them

Brain connectivity changes when comparing effects of subthalamic deep brain stimulation with levodopa treatment in Parkinson's disease

Levodopa and, later, deep brain stimulation (DBS) have become the mainstays of therapy for motor symptoms associated with Parkinson's disease (PD). Although these therapeutic options lead to similar clinical outcomes, the neural mechanisms underlying their efficacy are different. Therefore, investigating the differential effects of DBS and levodopa on functional brain architecture and associated motor improvement is of paramount interest. Namely, we expected changes in functional brain connectivity patterns when comparing levodopa treatment with DBS. Clinical assessment and functional magnetic resonance imaging (fMRI) was performed before and after implanting electrodes for DBS in the subthalamic nucleus (STN) in 13 PD patients suffering from severe levodopa-induced motor fluctuations and peak-of-dose dyskinesia. All measurements were acquired in a within subject-design with and without levodopa treatment, and with and without DBS. Brain connectivity changes were computed using eigenvector centrality (EC) that offers a data-driven and parameter-free approach—similarly to Google's PageRank algorithm—revealing brain regions that have an increased connectivity to other regions that are highly connected, too. Both levodopa and DBS led to comparable improvement of motor symptoms as measured with the Unified Parkinson's Disease Rating Scale motor score (UPDRS-III). However, this similar therapeutic effect was underpinned by different connectivity modulations within the motor system. In particular, EC revealed a major increase of interconnectedness in the left and right motor cortex when comparing DBS to levodopa. This was accompanied by an increase of connectivity of these motor hubs with the thalamus and cerebellum. We observed, for the first time, significant functional connectivity changes when comparing the effects of STN DBS and oral levodopa administration, revealing different treatment-specific mechanisms linked to clinical benefit in PD. Specifically, in contrast to levodopa treatment, STN DBS was associated with increased connectivity within the cortico-thalamo-cerebellar network. Moreover, given the favorable effects of STN DBS on motor complications, the changes in the patients' clinical profile might also contribute to connectivity changes associated with STN-DBS. Understanding the observed connectivity changes may be essential for enhancing the effectiveness of DBS treatment, and for better defining the pathophysiology of the disrupted motor network in PD