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Publications

Publications by Elodie Múrias Lopes

2019

Automated measures of gait dynamics and camptocormia angle in Parkinson's disease before and after subthalamic deep brain stimulation

Authors
Soares, C; Vilas Boas, MDC; Lopes, EM; Choupina, H; Soares Dos Reis, R; Fitas, D; Cunha, JPS; Monteiro, P; Linhares, P; Rosas, MJSL;

Publication
EUROPEAN JOURNAL OF NEUROLOGY

Abstract

2019

iHandU: Towards the Validation of a Wrist Rigidity Estimation for Intraoperative DBS Electrode Position Optimization

Authors
Lopes, EM; Sevilla, A; Vilas Boas, MD; Choupina, HMP; Nunes, DP; Rosas, MJ; Oliveira, A; Massano, J; Vaz, R; Cunha, JPS;

Publication
2019 9TH INTERNATIONAL IEEE/EMBS CONFERENCE ON NEURAL ENGINEERING (NER)

Abstract
DBS surgery is considered for Parkinson's Disease patients when motor complications and consequent quality of life is no longer acceptable on optimal medical therapy prescribed by neurologists. Within the operating room, the electrode placement with the best clinical outcome for the patient is quantitatively assessed via the wrist rigidity assessment. A subjective scale is used, influenced by the neurologists' perception and experience. Our research group has previously designed a novel, comfortable and wireless system aiming to tackle this subjectivity. This system comprised a gyroscope sensor in a textile band, placed in the patients' hand, which communicated its measurement to a Smartphone via Bluetooth. During the wrist rigidity evaluation exam, a signal descriptor was computed from angular velocity (omega) and a polynomial mathematical model was used to classify the signals using a quantitative scale of rigidity improvement. In this present work, we aim to develop models that consider the 3-gyroscope-axes to acquire the omega and the cogwheel rigidity. Our results showed that y-gyroscope-axis remains the best way to classify the rigidity reduction, showing an accuracy of 78% and a mean error of 3.5%. According to previous results, the performance was similar and the decrease of samples to extract the omega features did not compromise system performance. The cogwheel rigidity did not improve the previous model and other gyroscope-axis beyond the y-axis decreased system performance.

2016

Synchronization in the random-field Kuramoto model on complex networks

Authors
Lopes, MA; Lopes, EM; Yoon, S; Mendes, JFF; Goltsev, AV;

Publication
PHYSICAL REVIEW E

Abstract
We study the impact of random pinning fields on the emergence of synchrony in the Kuramoto model on complete graphs and uncorrelated random complex networks. We consider random fields with uniformly distributed directions and homogeneous and heterogeneous (Gaussian) field magnitude distribution. In our analysis, we apply the Ott-Antonsen method and the annealed-network approximation to find the critical behavior of the order parameter. In the case of homogeneous fields, we find a tricritical point above which a second-order phase transition gives place to a first-order phase transition when the network is either fully connected or scale-free with the degree exponent gamma > 5. Interestingly, for scale-free networks with 2 < gamma <= 5, the phase transition is of second-order at any field magnitude, except for degree distributions with gamma = 3 when the transition is of infinite order at K-c = 0 independent of the random fields. Contrary to the Ising model, even strong Gaussian random fields do not suppress the second-order phase transition in both complete graphs and scale-free networks, although the fields increase the critical coupling for gamma > 3. Our simulations support these analytical results.

2019

Automated and objective measures of gait dynamics in camptocormia Parkinson's Disease subthalamic deep brain stimulation

Authors
Soares, C; Vilas Boas, MD; Lopes, EM; Choupina, H; Soares dos Reis, R; Fitas, D; Silva Cunha, JPS; Monteiro, P; Linhares, P; Rosas, MJ;

Publication
CLINICAL NEUROLOGY AND NEUROSURGERY

Abstract
Objective: Axial motor features are common in Parkinson's disease (PD). These include gait impairment and postural abnormalities, such as camptocormia. The response of these symptoms to deep brain stimulation (DBS) is variable and difficult to assess objectively. For the first time, this study analyzes the treatment outcomes of two PD patients with camptocormia that underwent bilateral subthalamic nucleus (STN)-DBS evaluated with disruptive technologies. Patients and methods: Two patients with PD and camptocormia who underwent STN-DBS were included. Gait parameters were quantitatively assessed before and after surgery by using the NeuroKinect system and the camptocormia angle was measured using the camptoapp. Results: After surgery, patient 1 improved 29 points in the UPDRS-III. His camptocormia angle was 68 degrees before and 38 degrees after surgery. Arm and knee angular amplitudes (117.32 +/- 7.47 vs 134.77 +/- 2.70; 144.51 +/- 7.47 vs 169.08 +/- 3.27) and arm swing (3.59 +/- 2.66 vs 5.40 +/- 1.76 cm) improved when compared with his pre-operative measurements. Patient 2 improved 22 points in the UPDRS-III after surgery. Her camptocormia mostly resolved (47 degrees before to 9 degrees after surgery). Gait analysis revealed improvement of stride length (0.29 +/- 0.03 vs 0.35 +/- 0.03 m), stride width (18.25 +/- 1.16 vs 17.9 +/- 0.84 cm), step velocity (0.91 +/- 0.57 vs 1.33 +/- 0.48 m/s), arm swing (4.51 +/- 1.01 vs 7.38 +/- 2.71 cm) and arm and hip angular amplitudes (131.57 +/- 2.45 degrees vs 137.75 +/- 3.18; 100.51 +/- 1.56 vs 102.18 +/- 1.77 degrees) compared with her preoperative results. Conclusion: The gait parameters and camptocormia of both patients objectively improved after surgery, as assessed by the two quantitative measurement systems. STN-DBS might have a beneficial effect on controlling axial posturing and gait, being a potential surgical treatment for camptocormia in patients with PD. However, further studies are needed to derive adequate selection criteria for this patient population.

2020

IHandU: A novel quantitative wrist rigidity evaluation device for deep brain stimulation surgery

Authors
Murias Lopes, E; Vilas Boas, MD; Dias, D; Rosas, MJ; Vaz, R; Silva Cunha, JP;

Publication
Sensors (Switzerland)

Abstract
Deep brain stimulation (DBS) surgery is the gold standard therapeutic intervention in Parkinson’s disease (PD) with motor complications, notwithstanding drug therapy. In the intraoperative evaluation of DBS’s efficacy, neurologists impose a passive wrist flexion movement and qualitatively describe the perceived decrease in rigidity under different stimulation parameters and electrode positions. To tackle this subjectivity, we designed a wearable device to quantitatively evaluate the wrist rigidity changes during the neurosurgery procedure, supporting physicians in decision-making when setting the stimulation parameters and reducing surgery time. This system comprises a gyroscope sensor embedded in a textile band for patient’s hand, communicating to a smartphone via Bluetooth and has been evaluated on three datasets, showing an average accuracy of 80%. In this work, we present a system that has seen four iterations since 2015, improving on accuracy, usability and reliability. We aim to review the work done so far, outlining the iHandU system evolution, as well as the main challenges, lessons learned, and future steps to improve it. We also introduce the last version (iHandU 4.0), currently used in DBS surgeries at São João Hospital in Portugal. © 2020 by the authors.

2020

SnapKi—An Inertial Easy-to-Adapt Wearable Textile Device for Movement Quantification of Neurological Patients

Authors
Oliveira, A; Dias, D; Lopes, EM; Vilas Boas, MD; Silva Cunha, JPS;

Publication
Sensors

Abstract
The development of wearable health systems has been the focus of many researchers who aim to find solutions in healthcare. Additionally, the large potential of textiles to integrate electronics, together with the comfort and usability they provide, has contributed to the development of smart garments in this area. In the field of neurological disorders with motor impairment, clinicians look for wearable devices that may provide quantification of movement symptoms. Neurological disorders affect different motion abilities thus requiring different needs in movement quantification. With this background we designed and developed an inertial textile-embedded wearable device that is adaptable to different movement-disorders quantification requirements. This adaptative device is composed of a low-power 9-axis inertial unit, a customised textile band and a web and Android cross application used for data collection, debug and calibration. The textile band comprises a snap buttons system that allows the attachment of the inertial unit, as well as its connection with the analog sensors through conductive textile. The resulting system is easily adaptable for quantification of multiple motor symptoms in different parts of the body, such as rigidity, tremor and bradykinesia assessments, gait analysis, among others. In our project, the system was applied for a specific use-case of wrist rigidity quantification during Deep Brain Stimulation surgeries, showing its high versatility and receiving very positive feedback from patients and doctors.