Browsing by Author "Pais-Vieira, Carla"
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- Activation of a rhythmic lower limb movement pattern during the use of a multimodal brain-computer interface: a case study of a clinically complete spinal cord injuryPublication . Pais-Vieira, Carla; Figueiredo, José Gabriel; Perrotta, André; Matos, Demétrio; Aguiar, Mafalda; Ramos, Júlia; Gato, Márcia; Poleri, Tânia; Pais-Vieira, MiguelBrain–computer interfaces (BCIs) that integrate virtual reality with tactile feedback are increasingly relevant for neurorehabilitation in spinal cord injury (SCI). In our previous case study employing a BCI-based virtual reality neurorehabilitation protocol, a patient with complete T4 SCI experienced reduced pain and emergence of non-spastic lower limb movements after 10 sessions. However, it is still unclear whether these effects can be sustained, enhanced, and replicated, as well as the neural mechanisms that underlie them. The present report outlines the outcomes of extending the previous protocol with 24 more sessions (14 months, in total). Clinical, behavioral, and neurophysiological data were analyzed. The protocol maintained or reduced pain levels, increased self-reported quality of life, and was frequently associated with the appearance of non-spastic lower limb movements when the patient was engaged and not experiencing stressful events. Neural activity analysis revealed that changes in pain were encoded in the theta frequency band by the left frontal electrode F3. Examination of the lower limbs revealed alternating movements resembling a gait pattern. These results suggest that sustained use of this BCI protocol leads to enhanced quality of life, reduced and stable pain levels, and may result in the emergence of rhythmic patterns of lower limb muscle activity reminiscent of gait.
- Differential width discrimination task for active and passive tactile discrimination in humansPublication . Perrotta, André; Pais-Vieira, Carla; Allahdad, Mehrab K.; Bicho, Estela; Pais-Vieira, Miguel
- Embodiment comfort levels during motor imagery training combined with immersive virtual reality in a spinal cord injury patientPublication . Pais-Vieira, Carla; Gaspar, Pedro; Matos, Demétrio; Alves, Leonor Palminha; Cruz, Bárbara Moreira da; Azevedo, Maria João; Gago, Miguel; Poleri, Tânia; Perrotta, André; Pais-Vieira, MiguelBrain–machine interfaces combining visual, auditory, and tactile feedback have been previously used to generate embodiment experiences during spinal cord injury (SCI) rehabilitation. It is not known if adding temperature to these modalities can result in discomfort with embodiment experiences. Here, comfort levels with the embodiment experiences were investigated in an intervention that required a chronic pain SCI patient to generate lower limb motor imagery commands in an immersive environment combining visual (virtual reality -VR), auditory, tactile, and thermal feedback. Assessments were made pre-/ post-, throughout the intervention (Weeks 0–5), and at 7 weeks follow up. Overall, high levels of embodiment in the adapted three-domain scale of embodiment were found throughout the sessions. No significant adverse effects of VR were reported. Although sessions induced only a modest reduction in pain levels, an overall reduction occurred in all pain scales (Faces, Intensity, and Verbal) at follow up. A high degree of comfort in the comfort scale for the thermal-tactile sleeve, in both the thermal and tactile feedback components of the sleeve was reported. This study supports the feasibility of combining multimodal stimulation involving visual (VR), auditory, tactile, and thermal feedback to generate embodiment experiences in neurorehabilitation programs.
- Fronto-central changes in multiple frequency bands in active tactile width discrimination taskPublication . Ramos, Tiago; Ramos, Júlia; Pais-Vieira, Carla; Pais-Vieira, MiguelThe neural basis of tactile processing in humans has been extensively studied; however, the neurophysiological basis of human width discrimination remains relatively unexplored. In particular, the changes that occur in neural networks underlying active tactile width discrimination learning have yet to be described. Here, it is hypothesized that subjects learning to perform the active version of the width discrimination task would present changes in behavioral data and in the neurophysiological activity, specifically in networks of electrodes relevant for tactile and motor processing. The specific hypotheses tested here were that the performance and response latency of subjects would change between the first and the second blocks; the power of the different frequency bands would change between the first and the second blocks; electrode F4 would encode task performance and response latency through changes in the power of the delta, theta, alpha, beta, and low-gamma frequency bands; the relative power in the alpha and beta frequency bands in electrodes C3 and C4 (Interhemispheric Spectral Difference—ISD) would change because of learning between the first and the second blocks. To test this hypothesis, we recorded and analyzed electroencephalographic (EEG) activity while subjects performed a session where they were tested twice (i.e., two different blocks) in an active tactile width discrimination task using their right index finger. Subjects (n = 18) presented high performances (high discrimination accuracy) already in their first block, and therefore no significant improvements were found in the second block. Meanwhile, a reduction in response latency was observed between the two blocks. EEG recordings revealed an increase in power for the low-gamma frequency band (30–45 Hz) for electrodes F3 and C3 from the first to the second block. This change was correlated with neither performance nor latency. Analysis of the neural activity in electrode F4 revealed that the beta frequency band encoded the subjects’ performance. Meanwhile, the delta frequency band in the same electrode revealed a complex pattern where blocks appeared clustered in two different patterns: an Upper Pattern (UP), where power and latency were highly correlated (Rho = 0.950), and a sparser and more uncorrelated Lower Pattern (LP). Blocks belonging to the UP or LP patterns did not differ in performance and were not specific to the first or the second block. However, blocks belonging to the LP presented an increase in response latency, increased variability in performance, and an increased ISD in alpha and beta frequency bands for the pair of electrodes C3–C4, suggesting that the LP may reflect a state related to increased cognitive load or task difficulty. These results suggest that changes in performance and latency in an active tactile width discrimination task are encoded in the delta, alpha, beta, and low-gamma frequency bands in a fronto-central network. The main contribution of this study is therefore related to the description of neural dynamics in frontal and central networks involved in the learning process of active tactile width discrimination.
- Method for positioning and rehabilitation training with the ExoAtlet® powered exoskeletonPublication . Pais-Vieira, Carla; Khazraei, Mehrab; Neves-Amado, João; Perrotta, André; Morya, Edgard; Moioli, Renan; Shapkova, Elena; Pais-Vieira, MiguelExoskeletons for locomotion, support, or other uses are becoming more common. An increasing number of studies are demonstrating relevant results in rehabilitation. Here we describe the steps required to properly place and train patients in ExoAtlet ® powered exoskeletons (Moscow, Russia), for which there is currently limited information available. These steps combine actions related to the hardware, software, as well as safety, rehabilitation, and psycho-emotional state of the subject. Training starts with a general preparation of the environment, the equipment, and the patient. When the actual training program begins, the patient needs to gradually learn to perform the different actions that will be required to control the exoskeleton. Initially, training requires transferring weight between legs to guarantee adequate equilibrium control. Then, actions assisted by computer-controlled motors begin, namely: standing up, walking in place, moving small distances and sitting down. As the patient becomes comfortable with the exoskeleton and the cardiovascular system becomes adjusted to the upright position, training can then include walking over longer distances, inclined planes, opening doors, and climbing stairs.
- Neurophysiological correlates of tactile width discrimination in humansPublication . Pais-Vieira, Carla; Allahdad, Mehrab K.; Perrotta, André; Peres, André S.; Kunicki, Carolina; Aguiar, Mafalda; Oliveira, Manuel; Pais-Vieira, MiguelIntroduction: Tactile information processing requires the integration of sensory, motor, and cognitive information. Width discrimination has been extensively studied in rodents, but not in humans. Methods: Here, we describe Electroencephalography (EEG) signals in humans performing a tactile width discrimination task. The first goal of this study was to describe changes in neural activity occurring during the discrimination and the response periods. The second goal was to relate specific changes in neural activity to the performance in the task. Results: Comparison of changes in power between two different periods of the task, corresponding to the discrimination of the tactile stimulus and the motor response, revealed the engagement of an asymmetrical network associated with fronto-temporo-parieto-occipital electrodes and across multiple frequency bands. Analysis of ratios of higher [Ratio 1: (0.5–20 Hz)/(0.5–45 Hz)] or lower frequencies [Ratio 2: (0.5–4.5 Hz)/(0.5–9 Hz)], during the discrimination period revealed that activity recorded from frontal-parietal electrodes was correlated to tactile width discrimination performance between-subjects, independently of task difficulty. Meanwhile, the dynamics in parieto-occipital electrodes were correlated to the changes in performance within-subjects (i.e., between the first and the second blocks) independently of task difficulty. In addition, analysis of information transfer, using Granger causality, further demonstrated that improvements in performance between blocks were characterized by an overall reduction in information transfer to the ipsilateral parietal electrode (P4) and an increase in information transfer to the contralateral parietal electrode (P3). Discussion: The main finding of this study is that fronto-parietal electrodes encoded between-subjects’ performances while parieto-occipital electrodes encoded within-subjects’ performances, supporting the notion that tactile width discrimination processing is associated with a complex asymmetrical network involving fronto-parieto-occipital electrodes.
- Quality of life and therapeutic regimen management in onychomycosis patients and in vitro study of antiseptic solutionsPublication . Silva-Neves, Vasco; Hugo, Vitor; Alves, Paulo; Amado, João Costa; Pais-Vieira, Carla; Sousa, Fátima; Cerqueira, Fátima; Pinto, Eugénia; Pais-Vieira, MiguelOnychomycosis or tinea unguium (EE12.1) and Onychomycosis due to non-dermatophyte moulds (1F2D.5) (OM) is a fungal infection of the nail plates with a high prevalence that often affects vulnerable people with co-existing health problems. Gold standard pharmacological treatments for onychomycosis have been associated with low success rates and increasing antifungal resistance, suggesting that treatment outcome is dependent on multiple variables. Here, the prevalence of OM and quality of life were characterized in two vulnerable populations—Hospital patients and Homeless people. Comparing both groups, the most prevalent fungal species were identified in Hospital patients. Then, the in vitro fungicidal properties of the antiseptics povidone-iodine, polyhexamethylene biguanide-betaine, octenidine dihydrochloride, and a super-oxidized solution against two ATCC strains (Candida albicans and Aspergillus niger) and three clinical fungal isolates from Hospital patients (Candida parapsilosis, Trichophyton interdigitale, and Trichophyton rubrum) were tested. OM prevalence was high in both patient groups studied, who also reported a reduction in quality of life and concerns about the state of their feet. In addition, Hospital patients had a non-negligent therapeutic regimen management style. Antiseptics tested in vitro revealed antifungal properties. As antiseptics are low-cost and easy to apply and have few iatrogenic effects, the demonstration of fungicidal properties of these solutions suggests that they may constitute potential supportive therapeutics for OM.
- Sensorial feedback contribution to the sense of embodiment in brain-machine interfaces: a systematic reviewPublication . Tomas, Diogo João; Pais-Vieira, Miguel; Pais-Vieira, CarlaThe sense of embodiment (SoE) is an essential element of human perception that allows individuals to control and perceive the movements of their body parts. Brain–machine interface (BMI) technology can induce SoE in real time, and adding sensory feedback through various modalities has been shown to improve BMI control and elicit SoEe. In this study, we conducted a systematic review to study BMI performance in studies that integrated SoE variables and analyzed the contribution of single or multimodal sensory stimulation. Out of 493 results, only 20 studies analyzed the SoE of humans using BMIs. Analysis of these articles revealed that 40% of the studies relating BMIs with sensory stimulation and SoE primarily focused on manipulating visual stimuli, particularly in terms of coherence (i.e., synchronous vs. asynchronous stimuli) and realism (i.e., humanoid or robotic appearance). However, no study has analyzed the independent contributions of different sensory modalities to SoE and BMI performance. These results suggest that providing a detailed description of the outcomes resulting from independent and combined effects of different sensory modalities on the experience of SoE during BMI control may be relevant for the design of neurorehabilitation programs.
- Serious games as a tool for physical impairment rehabilitation: a reviewPublication . Vieira, Catarina; Perrotta, André; Novais, João; Pais-Vieira, Carla
- Serious games for physical rehabilitation: aesthetic discrepancies between custom-made serious games and commercial titles used for healthcarePublication . Vieira, Catarina; Perrotta, André; Pais-Vieira, CarlaSerious games are videogames that are used with purposes that go beyond the mere entertainment of the player. Among their many applications, healthcare is one of the most prominent ones, as serious games can have a wide range of uses within this field, namely physical rehabilitation of patients. For this purpose, both custom-made serious games and commercial entertainment titles, such as those for Nintendo Wii, can be used. However, while custom-made serious games appear to be more clinically effective, patients seem to prefer the gaming experience of playing a commercial title. This paper aims to compare the game goals and the aesthetics of Wii Sports (a commercial title used in the context of physical rehabilitation) with custom-made serious games that have obtained clinically significant results in upper limb rehabilitation, in order to try and understand what can be done to bridge the gap between these two approaches.