Letter from the editorial board

Letter from the editorial board of MSJP

On the perception of facial expressions in affective disorders and potential technological uses

Facial expressions are inherently linked to emotions and are a visual tool to communicate emotions to the surrounding world. A number of studies have evaluated the aptitude of different portions of the population in recognizing specific facial expressions. It is known that certain differences in the ability to correctly identify or assess the intensity of a facial expression can be attributed to psychological disorders. In particular, specific disorders seem to affect the processing of a particular emotion and the perception and interpretation of its associated facial expression. This work aims to summarize existing findings in literature on the topic and provide an outlook for potential technological use-cases, which can be applicable in the field of psychotherapy

Letter from the Editorial Board

Letter from the Editorial Board of the MSJP

Protocol of the SOMNIA project : an observational study to create a neurophysiological database for advanced clinical sleep monitoring

Introduction Polysomnography (PSG) is the primary tool for sleep monitoring and the diagnosis of sleep disorders. Recent advances in signal analysis make it possible to reveal more information from this rich data source. Furthermore, many innovative sleep monitoring techniques are being developed that are less obtrusive, easier to use over long time periods and in the home situation. Here, we describe the methods of the Sleep and Obstructive Sleep Apnoea Monitoring with Non-Invasive Applications (SOMNIA) project, yielding a database combining clinical PSG with advanced unobtrusive sleep monitoring modalities in a large cohort of patients with various sleep disorders. The SOMNIA database will facilitate the validation and assessment of the diagnostic value of the new techniques, as well as the development of additional indices and biomarkers derived from new and/or traditional sleep monitoring methods. Methods and analysis We aim to include at least 2100 subjects (both adults and children) with a variety of sleep disorders who undergo a PSG as part of standard clinical care in a dedicated sleep centre. Full-video PSG will be performed according to the standards of the American Academy of Sleep Medicine. Each recording will be supplemented with one or more new monitoring systems, including wrist-worn photoplethysmography and actigraphy, pressure sensing mattresses, multimicrophone recording of respiratory sounds including snoring, suprasternal pressure monitoring and multielectrode electromyography of the diaphragm

Determinants of self-reported sleep quality in healthy sleepers and patients

A clear clarification of which objective variables are predictive of the subjective sleep experience, and furthermore, which variables of the subjective sleep variables are an adequate representation of the sleep quality score are missing. This may lead to people not identifying possible sleep problems or to people who feel misunderstood when the problem is not objectively observed. Data from the SIESTA database were used, which consists of two consecutive nights of polysomnography and includes subjective data of 156 healthy persons and 95 patients (age range 20–95). Among other things, the strongest significant correlations were found when the difference between nights was taken, for instance, between the subscore “Sleep Quality” of the Subjective sleep and awakening questionnaire (SSA-1) and total sleep time (r = .423, p < .001). For the mental disorder group, stronger correlations were observed between the absolute sleep measurements of night 1 and SSA-1 (wake time after sleep onset: r = .732, p < .001). The subscore “Sleep Quality” was sufficient as a representative for the subjective sleep quality score. Our findings indicate that intra-individual variability plays a role and to enhance the insight more nights are needed when investigating the association between subjective sleep quality and objective sleep measurements

Applying Delaunay triangulation augmentation for deep learning facial expression generation and recognition

Generating and recognizing facial expressions has numerous applications, however, those are limited by the scarcity of datasets containing labeled nuanced expressions. In this paper, we describe the use of Delaunay triangulation combined with simple morphing techniques to blend images of faces, which allows us to create and automatically label facial expressions portraying controllable intensities of emotion. We have applied this approach on the RafD dataset consisting of 67 participants and 8 categorical emotions and evaluated the augmentation in a facial expression generation and recognition tasks using deep learning models. For the generation task, we used a deconvolution neural network which learns to encode the input images in a high-dimensional feature space and generate realistic expressions at varying intensities. The augmentation significantly improves the quality of images compared to previous comparable experiments and it allows to create images with a higher resolution. For the recognition task, we evaluated pre-trained Densenet121 and Resnet50 networks with either the original or augmented dataset. Our results indicate that the augmentation alone has a similar or better performance compared to the original. Implications of this method and its role in improving existing facial expression generation and recognition approaches are discussed

Letter from the editors

Letter from the editors for Vol. 3 of the Maastricht Student Journal of Psychology and Neuroscienc

The Impact of the Choice of Data Source in Record Linkage Studies Estimating Mortality in Venous Thromboembolism

Linked electronic healthcare databases are increasingly being used in observational research. The objective of this study was to investigate the impact of the choice of data source in estimating mortality following VTE, with a secondary aim to investigate the influence of the denominator definition. We used the UK Clinical Practice Research Datalink (CPRD) to identify patients aged 18+ with venous thromboembolism (VTE). Multiple cohorts were identified in order to assess how mortality rates differed with a range of data sources. For each of the cohorts, incidence rates per 1,000 person years (/1000py) and relative rates (RRs) of all-cause mortality were calculated. The lowest mortality rate was found when only primary care data were used for both the exposure (VTE) and the outcome (death) (108.4/1000py). The highest mortality rate was found for patients diagnosed in secondary care (237.2/1000py). When linked primary and secondary care data were included for eligible patients and for the overlapping period of data collection, a mortality rate of 173.2/1000py was found. Sensitivity analyses varying the denominator definition provided a range of results (140.6-164.3/1000py). The relative rates of mortality by gender and age were comparable across all cohorts. Depending on the choice of data source, the population studied may be different. This may have substantial impact on the main findings, in particular on incidence rates of mortality following VTE

Sleep EEG characteristics associated with sleep onset misperception

Study objective To study sleep EEG characteristics associated with misperception of Sleep Onset Latency (SOL). Methods Data analysis was based on secondary analysis of standard in-lab polysomnographic recordings in 20 elderly people with insomnia and 21 elderly good sleepers. Parameters indicating sleep fragmentation, such as number of awakenings, wake after sleep onset (WASO) and percentage of NREM1 were extracted from the polsysomnogram, as well as spectral power, microarousals and sleep spindle index. The correlation between these parameters during the first sleep cycle and the amount of misperceived sleep was assessed in the insomnia group. Additionally, we made a model of the minimum duration that a sleep fragment at sleep onset should have in order to be perceived as sleep, and we fitted this model to subjective SOLs of both subject groups. Results Misperception of SOL was associated with increased percentage of NREM1 and more WASO during sleep cycle 1. For insomnia subjects, the best fit of modelled SOL with subjective SOL was found when assuming that sleep fragments shorter than 30 min at sleep onset were perceived as wake. The model indicated that healthy subjects are less sensitive to sleep interruptions and perceive fragments of 10 min or longer as sleep. Conclusions Our findings suggest that sleep onset misperception is related to sleep fragmentation at the beginning of the night. Moreover, we show that people with insomnia needed a longer duration of continuous sleep for the perception as such compared to controls. Further expanding the model could provide more detailed information about the underlying mechanisms of sleep misperception