Armin Duff

Armin Duff
Pompeu Fabra University | UPF · Department of Information and Communication Technologies (DTIC)

Dr.

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55
Publications
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1,232
Citations

Publications

Publications (55)
Article
Full-text available
Theoretical models of episodic memory have proposed that retrieval depends on interactions between the hippocampus and neocortex, where hippocampal reinstatement of item-context associations drives neocortical reinstatement of item information. Here, we simultaneously recorded intracranial EEG from hippocampus and lateral temporal cortex (LTC) of e...
Article
Full-text available
The impact of rehabilitation on post-stroke motor recovery and its dependency on the patient’s chronicity remain unclear. The field has widely accepted the notion of a proportional recovery rule with a “critical window for recovery” within the first 3–6 mo poststroke. This hypothesis justifies the general cessation of physical therapy at chronic st...
Data
NNR820169_Supplementary_Material – Supplemental material for Effect of Specific Over Nonspecific VR-Based Rehabilitation on Poststroke Motor Recovery: A Systematic Meta-analysis
Article
Full-text available
Full paper: https://journals.sagepub.com/doi/full/10.1177/1545968318820169 Background. Despite the rise of virtual reality (VR)-based interventions in stroke rehabilitation over the past decade, no consensus has been reached on its efficacy. This ostensibly puzzling outcome might not be that surprising given that VR is intrinsically neutral to it...
Preprint
Full-text available
The impact of rehabilitation on post-stroke motor recovery and its dependency on the patient's chronicity remain unclear. The existence and regularity of a, so called, proportional recovery rule across a range of functional deficits and therapies supports the notion that functional interventions have little or no impact beyond spontaneous recovery...
Article
Full-text available
Background: Most stroke survivors continue to experience motor impairments even after hospital discharge. Virtual reality-based techniques have shown potential for rehabilitative training of these motor impairments. Here we assess the impact of at-home VR-based motor training on functional motor recovery, corticospinal excitability and cortical re...
Article
Full-text available
We designed a novel experiment to investigate the modulation of human recognition memory by environmental context. Human participants were asked to navigate through a four-arm Virtual Reality (VR) maze in order to find and memorize discrete items presented at specific locations in the environment. They were later on tested on their ability to recog...
Data
Full-text available
After stroke, patients who suffer from hemiparesis tend to suppress the use of the affected extremity, a condition called learned non-use. Consequently, the lack of training may lead to the progressive deterioration of motor function. Although Constraint-Induced Movement Therapies (CIMT) have shown to be effective in treating this condition, the me...
Article
Full-text available
Background After stroke, patients who suffer from hemiparesis tend to suppress the use of the affected extremity, a condition called learned non-use. Consequently, the lack of training may lead to the progressive deterioration of motor function. Although Constraint-Induced Movement Therapies (CIMT) have shown to be effective in treating this condit...
Article
Background Despite physiotherapy based rehabilitation, approximately 60% of stroke patients experience long-lasting activity limiting arm and hand motor dysfunctions. Here we present a protocol which investigates the question of whether rehabilitation of arm and hand function can be enhanced by interactive computer technologies. Methods We have con...
Article
Full-text available
One third of stroke patients suffer from language disorders. Recently, Intensive Language Action Therapy (ILAT) emerged as a novel paradigm for aphasia rehabilitation. In the present study, we designed and developed a virtual reality (VR) based language rehabilitation tool by integrating ILAT's object request Language Action Game (LAG) in a Rehabil...
Conference Paper
Full-text available
After stroke many patients experience hemiparesis or weakness on one side of the body. In order to compensate for this lack of motor function they tend to overuse their non-affected limb. This so called learned non-use may be one of the most relevant contributors to functional loss after post-stroke hospital discharge. We hypothesize that frequent...
Conference Paper
Full-text available
When exposed to visual perturbations, the motor system rapidly learns to reduce errors through adaptation of future motor commands. However, in cerebellar and stroke patients with proprioceptive impairments, motor adaptation rates are significantly slower. A recent study suggests that adap- tation rates may be modulated by the stability of perturba...
Article
Full-text available
Stroke-induced impairments result from both primary and secondary causes, i.e. damage to the brain and the acquired non-use of the impaired limbs. Indeed, stroke patients often under-utilize their paretic limb despite sufficient residual motor function. We hypothesize that acquired non-use can be overcome by reinforcement-based training strategies....
Conference Paper
Full-text available
After brain lesions some patients show a reduced response to stimuli contra lateral to the lesion due to spatial neglect, in some cases without sensory loss [1]. As the condition is not well understood and some patients are not aware of their impairment, diagnostics is difficult and successful therapies are sparse. Here we investigate the possibili...
Conference Paper
Full-text available
Many fields can profit from the introduction of robots, including that of education. In this paper, our main focus is the advancement of the Synthetic Tutor Assistant (STA), a robot that will act as a peer for knowledge transfer. We propose a theory of a tutoring robotic application that is based on the Distributed Adaptive Control (DAC) theory: a...
Conference Paper
Full-text available
One third of stroke patients suffer from language disorders. These disorders severely impair individuals' communication abilities, which impacts on their quality of life. Recently, the Intensive Language Action Therapy (ILAT) emerged as a novel paradigm for aphasia rehabilitation. ILAT is grounded in three main principles: intense practice, overcom...
Conference Paper
The Expressive Agents for Symbiotic Education and Learning (EASEL) project will explore human-robot symbiotic interaction (HRSI) with the aim of developing an understanding of symbiosis over long term tutoring interactions. The EASEL system will be built upon an established and neurobiologically grounded architecture - Distributed Adaptive Control...
Conference Paper
Full-text available
Stroke is a leading cause of serious long-term disability in adults (Go et al, 2013). The impact of stroke induced impairments goes beyond the mere loss of motor abilities. The psychosocial implications caused by changes in per-formance of the activities of daily living have to be considered in modern reha-bilitation processes since they do influen...
Article
Full-text available
Animals acquire knowledge as they interact with the world. Several authors define this acquisition as a chain of transformations: data is acquired and converted into information that is converted into knowledge. Moreover, theories on cumulative learning suggest that different cognitive layers accumulate this knowledge, building highly complex skill...
Conference Paper
The Expressive Agents for Symbiotic Education and Learning (EASEL) project will explore human-robot symbiotic interaction (HRSI) with the aim of developing an understanding of symbiosis over long term tutoring interactions. The EASEL system will be built upon an established and neurobiologically grounded architecture - Distributed Adaptive Control...
Conference Paper
Full-text available
The fusion of tactile and visual modalities is crucial for understanding objects and learning how to manipulate them. A common modus operandi in robotics is to deal with each of these modalities separately. We propose an integrated approach that associates to local visual features of an object, tactile feedback of the effector when touching that pa...
Article
Full-text available
The Rehabilitation Gaming System (RGS) has been designed as a flexible, virtual-reality (VR)-based device for rehabilitation of neurological patients. Recently, training of visuomotor processing with the RGS was shown to effectively improve arm function in acute and chronic stroke patients. It is assumed that the VR-based training protocol related...
Chapter
Full-text available
In this study, a Virtual Reality system for stroke rehabilitation was left in the homes of chronic stroke patients to monitor the progress of the patients after constant and extended use of the system. The frequency of use indicated that patients were able to use the system independently. We also found an improvement on the Chedoke Arm and Hand Act...
Article
Full-text available
This paper studies the reliability of the Rehabilitation Gaming System (RGS) on the evaluation of motor function in stroke patients. We developed a virtual reality (VR) scenario for motor function assessment and we tested it in 18 stroke patients. We found strong correlations between the parameters obtained from the virtual reality scenario (work a...
Article
The Rehabilitation Gaming System (RGS) is a Virtual Reality system giving patients augmented multimodal feedback on their goal-directed movements. This paradigm is neurologically grounded and proven effective for motor recovery [1]. The RGS allows sustained independent use by automatically adapting training tasks to a patient’s skill level. In the...
Conference Paper
Experimental research on decision making has been mainly focused on binary perceptual tasks. The generally accepted models describing the decision process in these tasks are the integrator models. These models suggest that perceptual evidence is accumulated over time until a decision is made. Therefore, the final decision is based solely on recent...
Article
The Rehabilitation Gaming System (RGS) has been designed as a flexible, virtual-reality (VR)-based device for rehabilitation of neurological patients. Recently, training of visuomotor processing with the RGS was shown to effectively improve arm function in acute and chronic stroke patients. It is assumed that the VR-based training protocol related...
Article
Foraging can be described as goal-oriented exploration for resources. It exemplifies how animals coordinate complex sensory and effector systems under varying environmental conditions. To emulate the foraging capabilities of natural systems is a major goal for robotics. Therefore, foraging is an excellent paradigm to benchmark novel autonomous cont...
Conference Paper
We introduce affordance gradients (AGs), continuous sensorimotor structures that allow to predict the consequences of the agent's actions on the state of the environment. AGs allow to generalize among never performed actions and compress all possible consequences of the action state space. AGs also provide a way of estimating the world state after...
Article
Full-text available
The effects of stroke differ considerably in degree and symptoms for different patients. It has been shown that specific, individualized and varied therapy favors recovery. The Rehabilitation Gaming System (RGS) is a Virtual Reality (VR) based rehabilitation system designed following these principles. We have developed two algorithms to control the...
Article
Intelligence depends on the ability of the brain to acquire and apply rules and representations. At the neuronal level these properties have been shown to critically depend on the prefrontal cortex. Here we present, in the context of the Distributed Adaptive Control architecture (DAC), a biologically based model for flexible control and planning ba...
Chapter
Full-text available
The eXperience Induction Machine (XIM) is one of the most advanced mixed-reality spaces available today. XIM is an immersive space that consists of physical sensors and effectors and which is conceptualized as a general-purpose infrastructure for research in the field of psychology and human–artifact interaction. In this chapter, we set out the epi...
Conference Paper
Sequence learning tasks depend on the ability to acquire and control the order of actions and their proper timing. Several studies have shown that in sequence learning different areas of the brain are involved when recalling the order of actions and their proper interval. One hypothesis proposes that two separate areas of the brain interact with ea...
Article
For an animal to survive it has to excel in a twofold task: It has to perceive the world and execute adequate actions. These skills are acquired and adapted through perceptual and behavioral learning, respectively. Perceptual and behavioral learning are tightly interwoven, choosing the adequate action is only possible in the presence off accurate p...
Chapter
Full-text available
In behavioral motor coordination and interaction it is a fundamental challenge how an agent can learn to perceive and act in unknown and dynamic environments. At present, it is not clear how an agent can – without any explicitly predefined knowledge – acquire internal representations of the world while interacting with the environment. To meet this...
Conference Paper
Full-text available
We present a novel biomimetic approach to mapless autonomous navigation based on insect neuroethology. We implemented and tested a real-time neuronal model based on the Distributed Adaptive Control framework. The model unifies different aspects of insect navigation and foraging including landmark recognition, chemical search, path integration and o...
Conference Paper
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We synchronize cameras and analog lighting with high speed projectors. Radiometric compensation allows displaying flexible blue screens on arbitrary real world surfaces. A fast temporal multiplexing of coded projection and flash illumination enables ...
Article
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We present a virtual reality (VR)-based motor neurorehabilitation system for stroke patients with upper limb paresis. It is based on two hypotheses: (1) observed actions correlated with self-generated or intended actions engage cortical motor observation, planning and execution areas ("mirror neurons"); (2) activation in damaged parts of motor cort...
Conference Paper
Full-text available
In order to understand the general principles along which sensory processing is organized, several recent studies optimized particular coding objectives on natural inputs for different modalities. The homogeneity of neocortex indicates that a sensitive objective should be able to explain response properties of different sensory modalities. The temp...
Article
Full-text available
Humans and animals are able to make near optimal use of their knowledge to achieve their goals. This ability is seen as a hallmark of intelligent behavior [1]. Rule learning describes a main subset of intelligent behavior. On a neuronal level rule learning has been shown to critically depend on the pre-frontal cortex (PFC) [2]. Two main properties...
Article
Full-text available
The process of developing a successful stroke rehabilitation methodology requires four key components: a good understanding of the pathophysiological mechanisms underlying this brain disease, clear neuroscientific hypotheses to guide therapy, adequate clinical assessments of its efficacy on multiple timescales, and a systematic approach to the appl...
Chapter
Full-text available
Stroke is a debilitating condition with major costs for patients and their care-givers. Here we present a novel virtual reality (VR) based cognitive neurorehabilitation system for improving the rehabilitation of stroke patients with arm and hand paresis. Using a custom, low-cost kinematic tracking system designed for clinical or home use, patients...

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