364 research outputs found
Preserved decision making ability in early multiple sclerosis
Background : The purpose of this study was to assess decision making in patients with multiple sclerosis (MS) at the earliest clinically detectable time point of the disease. Methods : Patients with definite MS (n = 109) or with clinically isolated syndrome (CIS, n = 56), a disease duration of 3 months to 5 years, and no or only minor neurological impairment (Expanded Disability Status Scale [EDSS] score 0-2.5) were compared to 50 healthy controls using the Iowa Gambling Task (IGT). Results : The performance of definite MS, CIS patients, and controls was comparable for the two main outcomes of the IGT (learning index: p = 0.7; total score: p = 0.6). The IGT learning index was influenced by the educational level and the co-occurrence of minor depression. CIS and MS patients developing a relapse during an observation period of 15 months dated from IGT testing demonstrated a lower learning index in the IGT than patients who had no exacerbation (p = 0.02). When controlling for age, gender and education, the difference between relapsing and non-relapsing patients was at the limit of significance (p = 0.06). Conclusion : Decision making in a task mimicking real life decisions is generally preserved in early MS patients as compared to controls. A possible consequence of MS relapsing activity in the impairment of decision making ability is also suspected in the early phase of M
Applicability of an orthogonal cutting slip-line field model for the microscale
Mechanical micromachining is a very flexible and widely exploited process, but its knowledge should still be improved
since several incompletely explained phenomena affect the microscale chip removal. Several models have been developed
to describe the machining process, but only some of them consider a rounded edge tool, which is a typical condition in
micromachining. Among these models, the Waldorf’s slip-line field model for the macroscale allows to separately evaluate
shearing and ploughing force components in orthogonal cutting conditions; therefore, it is suitable to predict cutting
forces when a large ploughing action occurs, as in micromachining. This study aims at demonstrating how this model is
suitable also for micromachining conditions. To achieve this goal, a clear and repeatable procedure has been developed
for objectively validating its force prediction performance at low uncut chip thickness (less than 50 mm) and relatively
higher cutting edge radius. The proposed procedure makes the model generally applicable after a suitable and nonextensive
calibration campaign. This article shows how calibration experiments can be selected among the available cutting
trial database based on the model force prediction capability. Final validation experiments have been used to show
how the model is robust to a cutting speed variation even if the cutting speed is not among the model quantities. A suitable
set-up, especially designed for microturning conditions, has been used to measure forces and chip thickness. Tests
have been performed on 6082-T6 Aluminum alloy with different cutting speeds and different ratios between uncut chip
thickness and cutting edge radius
Machine Learning in Clinical Psychology and Psychotherapy Education: A Mixed Methods Pilot Survey of Postgraduate Students at a Swiss University
Background: There is increasing use of psychotherapy apps in mental health care.Objective: This mixed methods pilot study aimed to explore postgraduate clinical psychology students' familiarity and formal exposure to topics related to artificial intelligence and machine learning (AI/ML) during their studies.Methods: In April-June 2020, we conducted a mixed-methods online survey using a convenience sample of 120 clinical psychology students enrolled in a two-year Masters' program at a Swiss University.Results: In total 37 students responded (response rate: 37/120, 31%). Among respondents, 73% (n = 27) intended to enter a mental health profession, and 97% reported that they had heard of the term “machine learning.” Students estimated 0.52% of their program would be spent on AI/ML education. Around half (46%) reported that they intended to learn about AI/ML as it pertained to mental health care. On 5-point Likert scale, students “moderately agreed” (median = 4) that AI/M should be part of clinical psychology/psychotherapy education. Qualitative analysis of students' comments resulted in four major themes on the impact of AI/ML on mental healthcare: (1) Changes in the quality and understanding of psychotherapy care; (2) Impact on patient-therapist interactions; (3) Impact on the psychotherapy profession; (4) Data management and ethical issues.Conclusions: This pilot study found that postgraduate clinical psychology students held a wide range of opinions but had limited formal education on how AI/ML-enabled tools might impact psychotherapy. The survey raises questions about how curricula could be enhanced to educate clinical psychology/psychotherapy trainees about the scope of AI/ML in mental healthcare.</jats:p
The aerodynamics of the curled wake: a simplified model in view of flow control
When a wind turbine is yawed, the shape of the wake changes and a curled wake
profile is generated. The curled wake has drawn a lot of interest because of
its aerodynamic complexity and applicability to wind farm controls. The main
mechanism for the creation of the curled wake has been identified in the
literature as a collection of vortices that are shed from the rotor plane
when the turbine is yawed. This work extends that idea by using aerodynamic
concepts to develop a control-oriented model for the curled wake based on
approximations to the Navier–Stokes equations. The model is tested and
compared to time-averaged results from large-eddy simulations using actuator
disk and line models. The model is able to capture the curling mechanism for
a turbine under uniform inflow and in the case of a neutral atmospheric
boundary layer. The model is then incorporated to the FLOw Redirection and
Induction in Steady State (FLORIS)
framework and provides good agreement with power predictions for cases with
two and three turbines in a row.</p
Characterization of social cognition impairment in multiple sclerosis
Multiple sclerosis (MS) has been associated with deficits in social cognition. However, little is known about which domains of social cognition are predominantly affected and what other factors are associated with it. The aim was (i) to characterize social cognition deficit in a group of MS outpatients and (ii) to relate impairment in social cognition to overall cognitive status, depression and fatigue.Methods: Thirty-five MS patients (mean disease duration 12.9 years, median Expanded Disability Status Scale (EDSS) 3 and 34 healthy controls (HCs) were examined using the German version of the Geneva Social Cognition Scale to measure different domains of social cognition. Standard neuropsychological testing was applied to all patients and to 20 HCs. Patient-reported outcomes included questionnaires for fatigue, depression, anxiety and executive-behavioural disturbances.Results: The mean social cognition raw score was lower in the MS patients compared to the HCs (86.5 ± 8.7 vs. 91.2 ± 5.9, P = 0.005; d = 0.6) and did not correlate with EDSS or disease duration. The difference was driven by facial affect recognition and the understanding of complex social situations (14% and 23% of patients respectively under the cut-off). The impairment in these two tasks did not correlate with general cognitive performance or depression but with fatigue.Conclusions: The impairment in our group was restricted to high order and affective social cognition tasks and independent of general cognitive performance, EDSS, disease duration and depression. Fatigue correlated with social cognition performance, which might be due to common underlying neuronal networks
Multimodal approach to predict neurological outcome after cardiac arrest: A single-center experience
Introduction: The aims of this study were to assess the concordance of different tools and to describe the accuracy of a multimodal approach to predict unfavorable neurological outcome (UO) in cardiac arrest patients. Methods: Retrospective study of adult (>18 years) cardiac arrest patients who underwent multimodal monitoring; UO was defined as cerebral performance category 3-5 at 3 months. Predictors of UO were neurological pupillary index (NPi) 64 2 at 24 h; highly malignant patterns on EEG (HMp) within 48 h; bilateral absence of N20 waves on somato-sensory evoked potentials; and neuron-specific enolase (NSE) > 75 \u3bcg/L. Time-dependent decisional tree (i.e., NPi on day 1; HMp on day 1-2; absent N20 on day 2-3; highest NSE) and classification and regression tree (CART) analysis were used to assess the prediction of UO. Results: Of 137 patients, 104 (73%) had UO. Abnormal NPi, HMp on day 1 or 2, the bilateral absence of N20 or NSE >75 mcg/L had a specificity of 100% to predict UO. The presence of abnormal NPi was highly concordant with HMp and high NSE, and absence of N20 or high NSE with HMp. However, HMp had weak to moderate concordance with other predictors. The time-dependent decisional tree approach identified 73/103 patients (70%) with UO, showing a sensitivity of 71% and a specificity of 100%. Using the CART approach, HMp on EEG was the only variable significantly associated with UO. Conclusions: This study suggests that patients with UO had often at least two predictors of UO, except for HMp. A multimodal time-dependent approach may be helpful in the prediction of UO after CA. EEG should be included in all multimodal prognostic models
Auditory time perception in Huntington’s disease
Huntington's disease (HD) is characterized by early involvement of the striatum. It affects the pace of repetitive motor activity, as motor timing depends on basal ganglia activity. However, data are lacking on the impact of this process on auditory time perception in motor non-affected gene carriers.Objective: This work aims to test the performance in time perception of a group of mutation carriers, either without motor symptoms or at an early stage of motor involvement. This should allow designing therapies targeting compensation strategies and possibly be used as a disease progression marker.Method: Time was assessed using two different tasks. An absolute, duration-based time perception was assessed in a first task and a relative, beat-based time perception was assessed in a second one. HD-mutation carriers with low-to-middle grades of motor involvement (HD-motor, n = 10) or without motor signs (HD-premotor n = 21), were compared with age- and sex-matched healthy controls (control (n = 27)). Thresholds of time difference perception where assessed.Results: For both tasks, poorer performances were found in HD-motor patients as compared with HD-premotor and controls. Thresholds of time difference perception correlated positively with the CAP score for the whole group of HD-gene carriers in both tasks. In a post-hoc exploratory analysis performed by a multiple regression, a negative correlation was found between the thresholds in both tasks and the Stroop interference test. Furthermore, in the first task, a positive correlation was found between thresholds and a trail making B test and a negative one with a total functional score.Conclusion: Our data confirm that the impairment in time perception in persons affected by HD correlates with the advancing disease. They also suggest that time perception depends on similar cognitive mechanisms as the ones sub-serving the Stroop interference test
Orthographic Depth Modulates Reading Route Selection: An Electrical Neuroimaging Study
Introduction
The orthographic Depth Hypothesis (Katz and Feldman, 1983) posits that different reading routes are engaged depending on the expertise of the reader but also on the type of grapheme/phoneme correspondence of the language being read. Shallow orthographies (e.g. German and Italian) with consistent grapheme to phoneme correspondences favor encoding via non-lexical pathways, where each phoneme is sequentially mapped to its corresponding grapheme. In contrast, deep orthographies (e.g. French and English), with inconsistent grapheme to phoneme correspondences favor lexical pathways, where phonemes are retrieved from memory structures. Only few studies investigated the impact of orthographic depth on brain response while reading. Moreover, because they used between subject or cross-language designs, the interpretability of previous studies on the effect of orthographic depth is limited. The aim of the present study was to investigate the impact of orthographic depth on reading route selection using an experimental design enabling isolating the effect of orthographic depth.
Method
We presented the same pseudowords (PWs) to highly proficient bilinguals and manipulated the orthographic depth of PW reading by embedding them among two separated language contexts (German and French), implicating either shallow or deep orthography. High density 128-channel electroencephalography was recorded during the task.
Results
The topographies of the event-related potential were different between PWs read in deep orthographic context and PWs read in shallow orthographic context at 300-360ms after stimulus onset, indicating distinct brain networks engaged in reading during this time window. The brain source underlying these topographic effects were located within left inferior frontal, left parietal and left cingular areas.
Conclusion
We propose that in deep orthographic context, reading PWs cannot rely on the routine lexical pathways and thus switching to the non-lexical route is necessary. In controast, reading in a shallow orthographic context favors non-lexical route processing which fits PW reading. The topographic modulation might thus reflect the recruitment of lexical pathways in the deep but not in the shallow context. Analysis of electrical source estimation over the period of topographic modulation supports this hypothesis by showing that inferior frontal areas, a region shown to subserve phonological processing, is differentially engaged between the deep vs shallow conditions. In addition, a difference in the activity of parietal-cingular areas suggests a modulation of attentional demands related to route selection processes. Non-lexical route may be less automatized than lexical route processing. These collective results support a modulation of reading route selection by orthographic depth
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