89 research outputs found
Premutation expansion of CGG triplet repeats affects brain: a study of male carriers of Fragile X Syndrome
No full textA virtual coach for low-literates to practice societal participation
No full textThis thesis presents the research, design, and evaluation of the learning support system VESSEL: Virtual Environment to Support the Societal participation Education of Low-literates. The project was started from the premise that people of low literacy in the Netherlands participate in society less often and less effectively than literate people do: Their lower ability to read, write, speak, and understand the Dutch language hampers their ability to independently be part of society. Our goal was to create learning support prototypes with a re-usable design rationale, aimed at helping these people of low literacy learn to improve their societal participation. To achieve this, low-literate learners participated throughout the entire design process, ensuring that we addressed their wants and needs with regard to learning and the perceived shortcomings of existing learning materials and kept in mind their skills and capabilities in order to ensure effective learning. Particularly, we investigated the possible ways that digital learning, Virtual Learning Environments (VLE), and Embodied Conversational Agents (ECA) could help fulfill the societal participation needs of this target group. We used the Socio-Cognitive Engineering (SCE) methodology to organize and structure this research, distinguishing the foundation, specification and evaluation of the VESSEL design. Two studies provided a grounded foundation for VESSEL, which was refined and worked out into three subsequent studies that provided the consequential design specifications and prototype evaluations (all prototypes have been tested with a human ’Wizard of Oz’ simulating VESSEL functionality).Interactive Intelligenc
Using scaffolding to formalize digital coach support for low-literate learners
No full textIn this study, we attempt to specify the cognitive support behavior of a previously designed embodied conversational agent coach that provides learning support to low-literates. Three knowledge gaps are identified in the existing work: an incomplete specification of the behaviors that make up ‘support,’ an incomplete specification of how this support can be personalized, and unclear speech recognition rules. We use the socio-cognitive engineering method to update our foundation of knowledge with new online banking exercises, low-level scaffolding and user modeling theory, and speech recognition. We then refine the design of our coach agent by creating comprehensive cognitive support rules that adapt support based on learner needs (the ‘Generalized’ approach) and attune the coach’s support delay to user performance in previous exercises (the ‘Individualized’ approach). A prototype is evaluated in a 3-week within- and between-subjects experiment. Results show that the specified cognitive support is effective: Learners complete all exercises, interact meaningfully with the coach, and improve their online banking self-efficacy. Counter to hypotheses, the Individualized approach does not improve on the Generalized approach. Whether this indicates suboptimal operationalization or a deeper problem with the Individualized approach remains as future work.Interactive Intelligenc
Relations between depressed mood and vocal parameters before, during and after sleep deprivation: a circadian rhythm study
No full textThe mechanism underlying improvement after total sleep deprivation (TSD) was studied in 14 major depressed patients. The suggestions that (1) circadian processes and/or (2) dimensions of arousal may play a role in the response to TSD were investigated. Diurnal variation of depressed mood and of mood- and arousal-related vocal parameters was studied in relation to the effect of TSD on depressed mood and vocal parameters. During 3 baseline days, during TSD and 2 days after TSD vocal parameters and depressed mood were assessed 6 and 3 times daily respectively.
The mean fundamental frequency (frequency of vocal fold vibration, F0) (presumably reflecting aspects of arousal) as well as the range of the F0 (proposed to reflect sadness) showed a clear circadian pattern with a peak at about 4.00 p.m. TSD affected the circadian organization of the mean F0 and advanced the peak of the curve. After one night of subsequent sleep this effect disappeared. In addition, improvement after TSD coincided with an increase of the mean F0. The diurnal variation of mood before TSD predicted the mood response to TSD, whereas diurnal variation of vocal parameters did not. Moreover, circadian changes in vocal parameters were not related to changes in depressed mood. These findings suggest that the diurnal variations in mood and vocal parameters are regulated by different mechanisms. Data support the presumption that circadian as well as arousal processes are involved in the mood response to TSD. Circadian changes in vocal parameters due to TSD are not likely to reflect changes in the biological clock.
Estrogen therapy and Alzheimer's dementia
No full textPrevious studies in postmenopausal women have reported that estrogen treatment (ET) modulates the risk for developing Alzheimer's disease (AD). It has recently been hypothesized that there may be a "critical period" around the time of menopause during which the prescription of ET may reduce the risk of developing AD in later life. This effect may be most significant in women under 49 years old. Furthermore, prescription of ET after this point may have a neutral or negative effect, particularly when initiated in women over 60-65 years old. In this paper, we review recent studies that use in vivo techniques to analyze the neurobiological mechanisms that might underpin estrogen's effects on the brain postmenopause. Consistent with the "critical period" hypothesis, these studies suggest that the positive effects of estrogen are most robust in young women and in older women who had initiated ET around the time of menopause
Design of an Affordable, Modular Implant Device for Soft Tissue Tension Assessment and Range of Motion Tracking During Total Hip Arthroplasty
No full textBackground: In hip arthroplasties, surgeons rely on their experience to assess the stability and balance of hip tissues when fitting the implant to their patients. During the operation, surgeons use a modular, temporary set of implants to feel the tension in the surrounding soft tissues and adjust the implant configuration. This process is naturally subjective and therefore depends on the operator. Inexperienced surgeons undertaking hip arthroplasties are twice as likely to experience errors than their experienced colleagues, leading to dislocations, pain and discomfort for the patients. Methods: To address this issue, a new, 3DOF force measurement system was developed and integrated into the modular, trial implants that can quantify forces and movements intraoperatively in 3D. The prototypes were evaluated in three post-mortem human specimens (PMHSs), to provide surgeons with objective data to help determine the optimal implant fit and configuration. The devices comprise a deformable polymer material providing strain-based displacements measured with electromagnetic-based sensors and an inertial measurement unit (IMU) for motion data. Results: Device results show a relative accuracy of approx. 2% and a sensitivity of approx. 1%. PMHS results indicated that soft tissue forces on the hip joint peak in the order of ~100 N and trend with positions of the leg during range of motion (ROM) tests, although force patterns differ between each PMHS. Conclusion: By monitoring forces and force patterns of hip soft tissues, in combination with standardised ROM tests, the force patterns could shed a light on potential anomalies that can be addressed during surgery. Clinical and Translational Impact Statement: The development of an instrumented hip implant device for use during surgery knowledge will eventually allow us to develop a predictive model for soft tissue balancing, that can be used for pre- and intra-operative planning for each patient on a tailored and personalised basis. Ultimately, we hope that with this device, patients will benefit from a faster recovery, from a more-precisely fitted hip, and an improved quality of life.Medical Instruments & Bio-Inspired TechnologyBiomaterials & Tissue Biomechanic
Modelling Human Word Learning and Recognition Using Visually Grounded Speech
No full textMany computational models of speech recognition assume that the set of target words is already given. This implies that these models learn to recognise speech in a biologically unrealistic manner, i.e. with prior lexical knowledge and explicit supervision. In contrast, visually grounded speech models learn to recognise speech without prior lexical knowledge by exploiting statistical dependencies between spoken and visual input. While it has previously been shown that visually grounded speech models learn to recognise the presence of words in the input, we explicitly investigate such a model as a model of human speech recognition. We investigate the time course of noun and verb recognition as simulated by the model using a gating paradigm to test whether its recognition is affected by well-known word competition effects in human speech processing. We furthermore investigate whether vector quantisation, a technique for discrete representation learning, aids the model in the discovery and recognition of words. Our experiments show that the model is able to recognise nouns in isolation and even learns to properly differentiate between plural and singular nouns. We also find that recognition is influenced by word competition from the word-initial cohort and neighbourhood density, mirroring word competition effects in human speech comprehension. Lastly, we find no evidence that vector quantisation is helpful in discovering and recognising words, though our gating experiment does show that the LSTM-VQ model is able to recognise the target words earlier.Multimedia Computin
Subtypes in 22q11.2 deletion syndrome associated with behaviour and neurofacial morphology
No full text22q11.2 deletion syndrome (22q11DS) has a complex phenotype with more than 180 characteristics, including cardiac anomalies, cleft palate, intellectual disabilities, a typical facial morphology, and mental health problems. However, the variable phenotype makes it difficult to predict clinical outcome, such as the high prevalence of psychosis among adults with 22q11DS (∼25-30% vs. ∼1% in the general population). The purpose of this study was to investigate whether subtypes exist among people with 22q11DS, with a similar phenotype and an increased risk of developing mental health problems. Physical, cognitive and behavioural data from 50 children and adolescents with 22q11DS were included in a k-means cluster analysis. Two distinct phenotypes were identified: Type-1 presented with a more severe phenotype including significantly impaired verbal memory, lower intellectual and academic ability, as well as statistically significant reduced total brain volume. In addition, we identified a trend effect for reduced temporal grey matter. Type-1 also presented with autism-spectrum traits, whereas Type-2 could be described as having more 22q11DS-typical face morphology, being predominately affected by executive function deficits, but otherwise being relatively high functioning with regard to cognition and behaviour. The confirmation of well-defined subtypes in 22q11DS can lead to better prognostic information enabling early identification of people with 22q11DS at high risk of psychiatric disorders. The identification of subtypes in a group of people with a relatively homogenous genetic deletion such as 22q11DS is also valuable to understand clinical outcomes
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