Arnau Dillen

Mr. Arnau Dillen

Human Physiology and Sports Physiotherapy, Vrije Universiteit Brussel, Brussels, Brussels-Capital Region, Belgium
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Research Focus & Metrics

Academic Career Length

5Years (2022-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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20 December 2022 in IEEE Transactions on Cybernetics
Verified
Journal Article
Closed access
MDMaría Alejandra Díaz
María Alejandra Díaz
MVMatthias Voß
Matthias Voß
ADArnau Dillen
Arnau Dillen
BTBruno Tassignon
Bruno Tassignon
LFLouis Flynn
Louis Flynn
KPKevin De Pauw
Kevin De Pauw
This article presents a systematic review on wearable robotic devices that use human-in-the-loop optimization (HILO) strategies to improve human–robot interaction. A total of 46 HILO studies were identified and divided into upper and lower limb robotic devices. The main aspects from HILO were identified, reviewed, and classified in four areas: 1) human–machine systems; 2) optimization methods; 3) control strategies; and 4) experimental protocols. A variety of objective functions (physiological, biomechanical, and subjective), optimization strategies, and optimized control parameters configurations used in different control strategies are presented and analyzed. An overview of experimental protocols is provided, including metrics, tasks, and conditions tested. Moreover, the relevance given to training or adaptation periods was explored. We outline an HILO framework that includes current wearable robots, optimization strategies, objective functions, control strategies, and experimental protocols. We conclude by highlighting current research gaps and defining future directions to improve the development of advanced HILO strategies in upper and lower limb wearable robots.

12 April 2022 in Database: The Journal of Biological Databases and Curation
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Journal Article
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CNCharlotte Nachtegael
Charlotte Nachtegael
BGBarbara Gravel
Barbara Gravel
ADArnau Dillen
Arnau Dillen
GSGuillaume Smits
Guillaume Smits
ANAnn Nowe
Ann Nowe
TLTom Lenaerts
Tom Lenaerts
Improving the understanding of the oligogenic nature of diseases requires access to high-quality, well-curated Findable, Accessible, Interoperable, Reusable (FAIR) data. Although first steps were taken with the development of the Digenic Diseases Database, leading to novel computational advancements to assist the field, these were also linked with a number of limitations, for instance, the ad hoc curation protocol and the inclusion of only digenic cases. The OLIgogenic diseases DAtabase (OLIDA) presents a novel, transparent and rigorous curation protocol, introducing a confidence scoring mechanism for the published oligogenic literature. The application of this protocol on the oligogenic literature generated a new repository containing 916 oligogenic variant combinations linked to 159 distinct diseases. Information extracted from the scientific literature is supplemented with current knowledge support obtained from public databases. Each entry is an oligogenic combination linked to a disease, labelled with a confidence score based on the level of genetic and functional evidence that supports its involvement in this disease. These scores allow users to assess the relevance and proof of pathogenicity of each oligogenic combination in the database, constituting markers for reporting improvements on disease-causing oligogenic variant combinations. OLIDA follows the FAIR principles, providing detailed documentation, easy data access through its application programming interface and website, use of unique identifiers and links to existing ontologies. https://olida.ibsquare.be

1 February 2022 in Journal of Neural Engineering
Verified
Journal Article
Open access
ADArnau Dillen
Arnau Dillen
DSDenis Steckelmacher
Denis Steckelmacher
KEKyriakos Efthymiadis
Kyriakos Efthymiadis
Kevin LangloisKevin Langlois
Kevin Langlois
ABAlbert De Beir
Albert De Beir
KPKevin De Pauw
Kevin De Pauw
Objective. Biosignal control is an interaction modality that allows users to interact with electronic devices by decoding the biological signals emanating from the movements or thoughts of the user. This manner of interaction with devices can enhance the sense of agency for users and enable persons suffering from a paralyzing condition to interact with everyday devices that would otherwise be challenging for them to use. It can also improve control of prosthetic devices and exoskeletons by making the interaction feel more natural and intuitive. However, with the current state of the art, several issues still need to be addressed to reliably decode user intent from biosignals and provide an improved user experience over other interaction modalities. One solution is to leverage advances in deep learning (DL) methods to provide more reliable decoding at the expense of added computational complexity. This scoping review introduces the basic concepts of DL and assists readers in deploying DL methods to a real-time control system that should operate under real-world conditions. Approach. The scope of this review covers any electronic device, but with an emphasis on robotic devices, as this is the most active area of research in biosignal control. We review the literature pertaining to the implementation and evaluation of control systems that incorporate DL to identify the main gaps and issues in the field, and formulate suggestions on how to mitigate them. Main results. The results highlight the main challenges in biosignal control with DL methods. Additionally, we were able to formulate guidelines on the best approach to designing, implementing and evaluating research prototypes that use DL in their biosignal control systems. Significance. This review should assist researchers that are new to the fields of biosignal control and DL in successfully deploying a full biosignal control system. Experts in their respective fields can use this article to identify possible avenues of research that would further advance the development of biosignal control with DL methods.

1 October 2024 in Journal of Neural Engineering
Verified
Journal Article
Open access
ADArnau Dillen
Arnau Dillen
Mohsen OmidiMohsen Omidi
Mohsen Omidi
FGFakhreddine Ghaffari
Fakhreddine Ghaffari
Bram VanderborghtBram Vanderborght
Bram Vanderborght
Bart RoelandsBart Roelands
Bart Roelands
KPKevin De Pauw
Kevin De Pauw
Objective. Brain–computer interface (BCI) control systems monitor neural activity to detect the user’s intentions, enabling device control through mental imagery. Despite their potential, decoding neural activity in real-world conditions poses significant challenges, making BCIs currently impractical compared to traditional interaction methods. This study introduces a novel motor imagery (MI) BCI control strategy for operating a physically assistive robotic arm, addressing the difficulties of MI decoding from electroencephalogram (EEG) signals, which are inherently non-stationary and vary across individuals. Approach. A proof-of-concept BCI control system was developed using commercially available hardware, integrating MI with eye tracking in an augmented reality (AR) user interface to facilitate a shared control approach. This system proposes actions based on the user’s gaze, enabling selection through imagined movements. A user study was conducted to evaluate the system’s usability, focusing on its effectiveness and efficiency. Main results. Participants performed tasks that simulated everyday activities with the robotic arm, demonstrating the shared control system’s feasibility and practicality in real-world scenarios. Despite low online decoding performance (mean accuracy: 0.52 9, F1: 0.29, Cohen’s Kappa: 0.12), participants achieved a mean success rate of 0.83 in the final phase of the user study when given 15 min to complete the evaluation tasks. The success rate dropped below 0.5 when a 5 min cutoff time was selected. Significance. These results indicate that integrating AR and eye tracking can significantly enhance the usability of BCI systems, despite the complexities of MI-EEG decoding. While efficiency is still low, the effectiveness of our approach was verified. This suggests that BCI systems have the potential to become a viable interaction modality for everyday applications in the future.

29 November 2022 in BMC Public Health
Verified
Journal Article
Open access
PDF file
ELElke Lathouwers
Elke Lathouwers
ADArnau Dillen
Arnau Dillen
MDMaría Alejandra Díaz
María Alejandra Díaz
BTBruno Tassignon
Bruno Tassignon
JVJo Verschueren
Jo Verschueren
KPKevin De Pauw
Kevin De Pauw
Background: Falls are a major problem associated with ageing. Yet, fall-risk classification models identifying older adults at risk are lacking. Current screening tools show limited predictive validity to differentiate between a low- and high-risk of falling. Objective: This study aims at identifying risk factors associated with higher risk of falling by means of a quality-of-life questionnaire incorporating biological, behavioural, environmental and socio-economic factors. These insights can aid the development of a fall-risk classification algorithm identifying community-dwelling older adults at risk of falling. Methods: The questionnaire was developed by the Belgian Ageing Studies research group of the Vrije Universiteit Brussel and administered to 82,580 older adults for a detailed analysis of risk factors linked to the fall incidence data. Based on previously known risk factors, 139 questions were selected from the questionnaire to include in this study. Included questions were encoded, missing values were dropped, and multicollinearity was assessed. A random forest classifier that learns to predict falls was trained to investigate the importance of each individual feature. Results: Twenty-four questions were included in the classification-model. Based on the output of the model all factors were associated with the risk of falling of which two were biological risk factors, eight behavioural, 11 socioeconomic and three environmental risk factors. Each of these variables contributed between 4.5 and 6.5% to explaining the risk of falling. Conclusion: The present study identified 24 fall risk factors using machine learning techniques to identify older adults at high risk of falling. Maintaining a mental, physical and socially active lifestyle, reducing vulnerability and feeling satisfied with the living situation contributes to reducing the risk of falling. Further research is warranted to establish an easy-to-use screening tool to be applied in daily practice.

14 August 2024 in Sensors
Verified
Journal Article
Open access
PDF file
ADArnau Dillen
Arnau Dillen
Mohsen OmidiMohsen Omidi
Mohsen Omidi
FGFakhreddine Ghaffari
Fakhreddine Ghaffari
OROlivier Romain
Olivier Romain
Bram VanderborghtBram Vanderborght
Bram Vanderborght
KPKevin De Pauw
Kevin De Pauw
This study evaluates an innovative control approach to assistive robotics by integrating brain–computer interface (BCI) technology and eye tracking into a shared control system for a mobile augmented reality user interface. Aimed at enhancing the autonomy of individuals with physical disabilities, particularly those with impaired motor function due to conditions such as stroke, the system utilizes BCI to interpret user intentions from electroencephalography signals and eye tracking to identify the object of focus, thus refining control commands. This integration seeks to create a more intuitive and responsive assistive robot control strategy. The real-world usability was evaluated, demonstrating significant potential to improve autonomy for individuals with severe motor impairments. The control system was compared with an eye-tracking-based alternative to identify areas needing improvement. Although BCI achieved an acceptable success rate of 0.83 in the final phase, eye tracking was more effective with a perfect success rate and consistently lower completion times (p<0.001). The user experience responses favored eye tracking in 11 out of 26 questions, with no significant differences in the remaining questions, and subjective fatigue was higher with BCI use (p=0.04). While BCI performance lagged behind eye tracking, the user evaluation supports the validity of our control strategy, showing that it could be deployed in real-world conditions and suggesting a pathway for further advancements.