A novel attention-based gated recurrent unit and its efficacy in speech emotion recognition

Abstract Notwithstanding the significant advancements in the field of deep learning, the basic long short-term memory (LSTM) or Gated Recurrent Unit (GRU) units have largely remained unchanged and unexplored. There are several possibilities in advancing the state-of-art by rightly adapting and enhancing the various elements of these units. Activation functions are one such key element. In this work, we explore using diverse activation functions within GRU and bi-directional GRU (BiGRU) cells in the context of speech emotion recognition (SER). We also propose a novel Attention ReLU GRU (AR-GRU) that employs attention-based Rectified Linear Unit (AReLU) activation within GRU and BiGRU cells. We demonstrate the effectiveness of AR-GRU on one exemplary application using the recently proposed network for SER namely Interaction-Aware Attention Network (IAAN). Our proposed method utilising AR-GRU within this network yields significant performance gain and achieves an unweighted accuracy of 68.3% (2% over the baseline) and weighted accuracy of 66.9 % (2.2 % absolute over the baseline) in four class emotion recognition on the IEMOCAP database

Personalised depression forecasting using mobile sensor data and ecological momentary assessment

Introduction Digital health interventions are an effective way to treat depression, but it is still largely unclear how patients’ individual symptoms evolve dynamically during such treatments. Data-driven forecasts of depressive symptoms would allow to greatly improve the personalisation of treatments. In current forecasting approaches, models are often trained on an entire population, resulting in a general model that works overall, but does not translate well to each individual in clinically heterogeneous, real-world populations. Model fairness across patient subgroups is also frequently overlooked. Personalised models tailored to the individual patient may therefore be promising. Methods We investigate different personalisation strategies using transfer learning, subgroup models, as well as subject-dependent standardisation on a newly-collected, longitudinal dataset of depression patients undergoing treatment with a digital intervention (N=65 patients recruited). Both passive mobile sensor data as well as ecological momentary assessments were available for modelling. We evaluated the models’ ability to predict symptoms of depression (Patient Health Questionnaire-2; PHQ-2) at the end of each day, and to forecast symptoms of the next day. Results In our experiments, we achieve a best mean-absolute-error (MAE) of 0.801 (25% improvement) for predicting PHQ-2 values at the end of the day with subject-dependent standardisation compared to a non-personalised baseline (MAE=1.062). For one day ahead-forecasting, we can improve the baseline of 1.539 by 12% to a MAE of 1.349 using a transfer learning approach with shared common layers. In addition, personalisation leads to fairer models at group-level. Discussion Our results suggest that personalisation using subject-dependent standardisation and transfer learning can improve predictions and forecasts, respectively, of depressive symptoms in participants of a digital depression intervention. We discuss technical and clinical limitations of this approach, avenues for future investigations, and how personalised machine learning architectures may be implemented to improve existing digital interventions for depression

Toward Detecting and Addressing Corner Cases in Deep Learning Based Medical Image Segmentation

Translating machine learning research into clinical practice has several challenges. In this paper, we identify some critical issues in translating research to clinical practice in the context of medical image segmentation and propose strategies to systematically address these challenges. Specifically, we focus on cases where the model yields erroneous segmentation, which we define as corner cases. One of the standard metrics used for reporting the performance of medical image segmentation algorithms is the average Dice score across all patients. We have discovered that this aggregate reporting has the inherent drawback that the corner cases where the algorithm or model has erroneous performance or very low metrics go unnoticed. Due to this reporting, models that report superior performance could end up producing completely erroneous results, or even anatomically impossible results in a few challenging cases, albeit without being noticed.We have demonstrated how corner cases go unnoticed using the Magnetic Resonance (MR) cardiac image segmentation task of the Automated Cardiac Diagnosis Challenge (ACDC) challenge. To counter this drawback, we propose a framework that helps to identify and report corner cases. Further, we propose a novel balanced checkpointing scheme capable of finding a solution that has superior performance even on these corner cases. Our proposed scheme leads to an improvement of 44.6% for LV, 46.1% for RV and 38.1% for the Myocardium on our identified corner case in the ACDC segmentation challenge. Further, we establish the generalisability of our proposed framework by also demonstrating its applicability in the context of chest X-ray lung segmentation. This framework has broader applications across multiple deep learning tasks even beyond medical image segmentation

HEAR4Health: a blueprint for making computer audition a staple of modern healthcare

Recent years have seen a rapid increase in digital medicine research in an attempt to transform traditional healthcare systems to their modern, intelligent, and versatile equivalents that are adequately equipped to tackle contemporary challenges. This has led to a wave of applications that utilise AI technologies; first and foremost in the fields of medical imaging, but also in the use of wearables and other intelligent sensors. In comparison, computer audition can be seen to be lagging behind, at least in terms of commercial interest. Yet, audition has long been a staple assistant for medical practitioners, with the stethoscope being the quintessential sign of doctors around the world. Transforming this traditional technology with the use of AI entails a set of unique challenges. We categorise the advances needed in four key pillars: Hear, corresponding to the cornerstone technologies needed to analyse auditory signals in real-life conditions; Earlier, for the advances needed in computational and data efficiency; Attentively, for accounting to individual differences and handling the longitudinal nature of medical data; and, finally, Responsibly, for ensuring compliance to the ethical standards accorded to the field of medicine