Active inference, evidence accumulation, and the urn task

Deciding how much evidence to accumulate before making a decision is a problem we and other animals often face, but one that is not completely understood. This issue is particularly important because a tendency to sample less information (often known as reflection impulsivity) is a feature in several psychopathologies, such as psychosis. A formal understanding of information sampling may therefore clarify the computational anatomy of psychopathology. In this theoretical letter, we consider evidence accumulation in terms of active (Bayesian) inference using a generic model of Markov decision processes. Here, agents are equipped with beliefs about their own behavior--in this case, that they will make informed decisions. Normative decision making is then modeled using variational Bayes to minimize surprise about choice outcomes. Under this scheme, different facets of belief updating map naturally onto the functional anatomy of the brain (at least at a heuristic level). Of particular interest is the key role played by the expected precision of beliefs about control, which we have previously suggested may be encoded by dopaminergic neurons in the midbrain. We show that manipulating expected precision strongly affects how much information an agent characteristically samples, and thus provides a possible link between impulsivity and dopaminergic dysfunction. Our study therefore represents a step toward understanding evidence accumulation in terms of neurobiologically plausible Bayesian inference and may cast light on why this process is disordered in psychopathology

Clinical Decision Support Systems with Game-based Environments, Monitoring Symptoms of Parkinson’s Disease with Exergames

Parkinson’s Disease (PD) is a malady caused by progressive neuronal degeneration, deriving in several physical and cognitive symptoms that worsen with time. Like many other chronic diseases, it requires constant monitoring to perform medication and therapeutic adjustments. This is due to the significant variability in PD symptomatology and progress between patients. At the moment, this monitoring requires substantial participation from caregivers and numerous clinic visits. Personal diaries and questionnaires are used as data sources for medication and therapeutic adjustments. The subjectivity in these data sources leads to suboptimal clinical decisions. Therefore, more objective data sources are required to better monitor the progress of individual PD patients. A potential contribution towards more objective monitoring of PD is clinical decision support systems. These systems employ sensors and classification techniques to provide caregivers with objective information for their decision-making. This leads to more objective assessments of patient improvement or deterioration, resulting in better adjusted medication and therapeutic plans. Hereby, the need to encourage patients to actively and regularly provide data for remote monitoring remains a significant challenge. To address this challenge, the goal of this thesis is to combine clinical decision support systems with game-based environments. More specifically, serious games in the form of exergames, active video games that involve physical exercise, shall be used to deliver objective data for PD monitoring and therapy. Exergames increase engagement while combining physical and cognitive tasks. This combination, known as dual-tasking, has been proven to improve rehabilitation outcomes in PD: recent randomized clinical trials on exergame-based rehabilitation in PD show improvements in clinical outcomes that are equal or superior to those of traditional rehabilitation. In this thesis, we present an exergame-based clinical decision support system model to monitor symptoms of PD. This model provides both objective information on PD symptoms and an engaging environment for the patients. The model is elaborated, prototypically implemented and validated in the context of two of the most prominent symptoms of PD: (1) balance and gait, as well as (2) hand tremor and slowness of movement (bradykinesia). While balance and gait affections increase the risk of falling, hand tremors and bradykinesia affect hand dexterity. We employ Wii Balance Boards and Leap Motion sensors, and digitalize aspects of current clinical standards used to assess PD symptoms. In addition, we present two dual-tasking exergames: PDDanceCity for balance and gait, and PDPuzzleTable for tremor and bradykinesia. We evaluate the capability of our system for assessing the risk of falling and the severity of tremor in comparison with clinical standards. We also explore the statistical significance and effect size of the data we collect from PD patients and healthy controls. We demonstrate that the presented approach can predict an increased risk of falling and estimate tremor severity. Also, the target population shows a good acceptance of PDDanceCity and PDPuzzleTable. In summary, our results indicate a clear feasibility to implement this system for PD. Nevertheless, long-term randomized clinical trials are required to evaluate the potential of PDDanceCity and PDPuzzleTable for physical and cognitive rehabilitation effects

Effects of augmented visual feedback during balance training in Parkinson's disease: A pilot randomized clinical trial

AbstractBackgroundBalance training has been demonstrated to improve postural control in patients with Parkinson's disease (PD). The objective of this pilot randomized clinical trial was to investigate whether a balance training program using augmented visual feedback is feasible, safe, and more effective than conventional balance training in improving postural control in patients with PD.MethodsThirty-three patients with idiopathic PD participated in a five-week training program consisting of ten group treatment sessions of 60 min. Participants were randomly allocated to (1) an experimental group who trained on workstations consisting of interactive balance games with explicit augmented visual feedback (VFT), or (2) a control group receiving conventional training. Standing balance, gait, and health status were assessed at entry, at six weeks, and at twelve weeks follow-up.ResultsSixteen patients were allocated to the control group and seventeen to the experimental group. The program was feasible to apply and took place without adverse events. Change scores for all balance measures favored VFT, but the change in the primary outcome measure, i.e. the Functional Reach test, did not differ between groups (t(28) = -0.116, p = .908). No other differences between groups were statistically significant.ConclusionsVFT proved to be a feasible and safe approach to balance therapy for patients with PD. In this proof-of-concept study VFT was not superior over conventional balance training although observed trends mostly favored VFT. These trends approached clinical relevance only in few cases: increasing the training load and further optimization of VFT may strengthen this effect.Trial registrationControlled Trials, ISRCTN47046299

Does exergaming promote neurofunctional changes in Parkinson ́s disease? A pilot clinical study

ntrodução: Estudos anteriores demonstraram efeitos bené- ficos em pessoas com doença de Parkinson treinadas com exergames. No entanto, até onde sabe-se, nenhum deles avaliou se esses efeitos são sustentados por alterações neurofuncionais. Objetivo: Avaliar os efeitos neurofuncionais de um treinamento, por meio da ressonância magnética funcional, em pessoas com doença de Parkinson. Métodos: Trata-se de um ensaio clínico piloto cego, randomizado e controlado com delineamento crossover. Os participantes foram submetidos a uma avaliação incluindo desempenho cognitivo e ressonância magnética funcional antes e após treinamentos com Wii® ou controle. Os treinamentos foram aplicados durante 10 dias, em duas semanas consecutivas. Os participantes que começaram o treinamento com Wii® foram depois movidos para o treinamento de controle e vice-versa. Respeitou-se um período de wash-out de 45 dias entre os treinamentos. Resultados: Memória, funções execu- tivas e visuoespaciais e atenção melhoraram significativamente em comparação com a linha de base (p < 0,05). Não foram observadas diferenças na cognição em comparação com o treinamento de controle. Embora não significativos, os resultados das análises de ressonância magnética funcional sugeriram que o treinamento com Wii® poderia promover melhorias na conectividade funcional do cérebro, especialmente em áreas envolvidas na execução motora, planejamento, funções visuais, de memória e somatossensoriais. Conclusão: Em pessoas com doença de Parkinson, um treinamento intensivo com Wii® melhorou o desempenho cognitivo, que destacou mudanças neurofuncionais em áreas envolvidas no processamento cognitivo.Introduction: Previous studies have demonstrated beneficial effects in people with Parkinson ́s disease trained with exergames. However, to the best of our knowledge, none of them evaluated whether these effects are sustained by neurofunctional changes. Objective: To evaluate neurofunctional effects of a training, by means of functional magnetic resonance imaging, in people with Parkinson ́s disease. Methods: This study was a blind, randomized, and controlled pilot clinical trial with crossover design. The participants were submitted to an evaluation including cognitive performance and functional magnetic resonance imaging before and after the WiiTM or control trainings. Trainings were applied for 10 days, in two consecutive weeks. Participants starting with WiiTM training were then moved to the control training and vice versa. A wash-out period of 45 days between the trainings was respected. Results: Memory, executive and visuo-spatial functions, and attention were significantly improved compared to baseline (p < 0.05). No differences were observed in cognition compared to the control training. Though not significant, results of functional magnetic resonance imaging analyses suggested that WiiTM training could promote improvements on the brain functional connectivity especially in areas involved in motor execution, planning, visual, memory and somatosensory functions. Conclusion: In people with Parkinson ́s disease, an intensive WiiTM training improved cognitive performance that underlined neurofunctional changes in areas involved in cognitive processing

Visual correlates of functional difficulties in Parkinson's disease and Alzheimer's disease

Thesis (Ph.D.)--Boston UniversityAlthough motor dysfunction in Parkinson's disease (PD) and memory deficits in Alzheimer's disease (AD) are the respective hallmark symptoms, both neurodegenerative disorders are also associated with significant disruptions in visual functioning. In PD, visuospatial function is impaired, particularly in patients with left-side onset of motor symptoms (LPD), reflecting pathology in right hemisphere brain regions, including the parietal lobe. LPD visuospatial performance is characterized by perceptual distortions, suggesting that lower-level visual processing may contribute to abnormal performance. In AD and PD, reduced contrast sensitivity and other visual difficulties have the potential to impact everyday functioning. The relation of PD visuospatial problems, and AD and PD contrast sensitivity deficits to higher-order impairments is understudied. The present experiments examined visual and visuospatial difficulties in these groups and evaluated an intervention to improve everyday visual function. Experiment I assessed performance on a line bisection task in PD. Participants included non-demented patients (10 LPD, 10 with right-side motor onset [RPD]) and 11 normal control adults (NC). Performance was related to data from measures of retinal structure (Optical Coherence Tomography) and function (Frequency Doubling Technology; FDT) across the eye. Correlations of structure and function were found for all groups. LPD showed predicted downward bisection bias in some sections of the left visual field. Expected rightward bisection bias in LPD was not consistently seen using this presentation method. For RPD, in some sectors, worse FDT sensitivity correlated with upward line bisection bias, as predicted. Experiment II investigated if performance of a complex, familiar visual search task (bingo) could be enhanced in AD and PD by manipulating the visual components of contrast, size, and visual complexity of task stimuli. Participants were 19 younger adults, 14 AD, 17 PD, and 33 NC. Increased stimulus size and decreased complexity improved performance for all groups. Increasing contrast also benefited the AD patients, presumably by compensating for their contrast sensitivity deficit, which was more severe than in the PD and NC groups. The general finding of improved performance across healthy and afflicted groups suggests the value of visual support as an easy-to-apply intervention to enhance cognitive performance

Cognitive Behavioral Therapy Plus a Serious Game as a Complementary Tool for a Patient With Parkinson Disease and Impulse Control Disorder: Case Report

Background: Impulse control disorders (ICDs) are commonly developed among patients who take dopamine agonist drugs as a treatment for Parkinson disease (PD). Gambling disorder and hypersexuality are more frequent in male patients with PD, with a prevalence over 4% in dopamine agonists users. Although impulsive-compulsive behaviors are related to antiparkinsonian medication, and even though ICD symptomatology, such as hypersexuality, often subsides when the dopaminergic dose is reduced, sometimes ICD persists in spite of drug adjustment. Consequently, a multidisciplinary approach should be considered to address these comorbidities and to explore new forms of complementary interventions, such as serious games or therapies adapted to PD. Objective: The aim of this study is to present the case of a patient with ICD (ie, hypersexuality) triggered by dopaminergic medication for PD. A combined intervention was carried out using cognitive behavioral therapy (CBT) for ICD adapted to PD, plus an intervention using a serious game-e-Estesia-whose objective is to improve emotion regulation and impulsivity. The aim of the combination of these interventions was to reduce the harm of the disease. Methods: After 20 CBT sessions, the patient received the e-Estesia intervention over 15 sessions. Repeated measures, before and after the combined intervention, were administered to assess emotion regulation, general psychopathology, and emotional distress and impulsivity. Results: After the intervention with CBT techniques and e-Estesia, the patient presented fewer difficulties to regulate emotion, less emotional distress, and lower levels of impulsivity in comparison to before the treatment. Moreover, the frequency and severity of the relapses also decreased. Conclusions: The combined intervention-CBT and a serious game-showed positive results in terms of treatment outcomes

Virtual Reality: An Evidence-Based Guide for Occupational Therapy

Problem: Virtual reality (VR) is an emerging technology that serves to position the user in control of a virtual environment to maximize interest and function. VR is a context for intervention included in the Occupational Therapy Practice Framework: Domain and Process 3rd edition (OTPF-3; AOTA, 2014). It is crucial that occupational therapy (OT) practitioners enhance their knowledge about VR technology used by their clients to provide effective client-centered practice (AOTA, 2010). There is a lack of organization of the literature and research evidence regarding the use of VR as an intervention modality. While there has been a significant increase in recent literature supporting the use of VR in OT, there is a need for manuals and resources to guide clinicians in using VR as a therapeutic modality (Levac & Miller, 2013; Proffitt & Lange, 2015). Methods: An extensive literature review for articles regarding the use of the Xbox Kinect and Nintendo Wii within OT was conducted using five databases. Relevant data was extracted from each article related to the use of the Xbox Kinect or Nintendo Wii in intervention to synthesize the findings into charts. The construction of the charts followed the organization of the OTPF-3 (AOTA, 2014). Product: The authors of this product created an evidence-based resource to guide OT practitioners\u27 use of VR. The intended purpose of this product, Virtual Reality: An Evidence-Based Guide, is to assist OT practitioners\u27 adaptation and/or modification of VR activities to address individual client needs. Using this product as a guide to current knowledge and evidence regarding intervention in the context of VR, OT practitioners will be better equipped to make safe and effective choices. To further support development of literature regarding VR, the authors of this product recommended areas for future research