@article{DelVecchioHanafiPozzietal.2023,
  author    = {Del Vecchio, Jasmin and Hanafi, Ibrahem and Pozzi, Nicol{\´o} Gabriele and Capetian, Philipp and Isaias, Ioannis U. and Haufe, Stefan and Palmisano, Chiara},
  title     = {Pallidal recordings in chronically implanted dystonic patients: mitigation of tremor-related artifacts},
  series = {Bioengineering},
  volume    = {10},
  journal   = {Bioengineering},
  number    = {4},
  issn      = {2306-5354},
  doi       = {10.3390/bioengineering10040476},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-313498},
  year      = {2023},
  abstract  = {Low-frequency oscillatory patterns of pallidal local field potentials (LFPs) have been proposed as a physiomarker for dystonia and hold the promise for personalized adaptive deep brain stimulation. Head tremor, a low-frequency involuntary rhythmic movement typical of cervical dystonia, may cause movement artifacts in LFP signals, compromising the reliability of low-frequency oscillations as biomarkers for adaptive neurostimulation. We investigated chronic pallidal LFPs with the Percept\(^{TM}\) PC (Medtronic PLC) device in eight subjects with dystonia (five with head tremors). We applied a multiple regression approach to pallidal LFPs in patients with head tremors using kinematic information measured with an inertial measurement unit (IMU) and an electromyographic signal (EMG). With IMU regression, we found tremor contamination in all subjects, whereas EMG regression identified it in only three out of five. IMU regression was also superior to EMG regression in removing tremor-related artifacts and resulted in a significant power reduction, especially in the theta-alpha band. Pallido-muscular coherence was affected by a head tremor and disappeared after IMU regression. Our results show that the Percept PC can record low-frequency oscillations but also reveal spectral contamination due to movement artifacts. IMU regression can identify such artifact contamination and be a suitable tool for its removal.},
  language  = {en}
}
@article{PalmisanoKullmannHanafietal.2022,
  author    = {Palmisano, Chiara and Kullmann, Peter and Hanafi, Ibrahem and Verrecchia, Marta and Latoschik, Marc Erich and Canessa, Andrea and Fischbach, Martin and Isaias, Ioannis Ugo},
  title     = {A fully-immersive virtual reality setup to study gait modulation},
  series = {Frontiers in Human Neuroscience},
  volume    = {16},
  journal   = {Frontiers in Human Neuroscience},
  issn      = {1662-5161},
  doi       = {10.3389/fnhum.2022.783452},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-267099},
  year      = {2022},
  abstract  = {Objective: Gait adaptation to environmental challenges is fundamental for independent and safe community ambulation. The possibility of precisely studying gait modulation using standardized protocols of gait analysis closely resembling everyday life scenarios is still an unmet need. Methods: We have developed a fully-immersive virtual reality (VR) environment where subjects have to adjust their walking pattern to avoid collision with a virtual agent (VA) crossing their gait trajectory. We collected kinematic data of 12 healthy young subjects walking in real world (RW) and in the VR environment, both with (VR/A+) and without (VR/A-) the VA perturbation. The VR environment closely resembled the RW scenario of the gait laboratory. To ensure standardization of the obstacle presentation the starting time speed and trajectory of the VA were defined using the kinematics of the participant as detected online during each walking trial. Results: We did not observe kinematic differences between walking in RW and VR/A-, suggesting that our VR environment per se might not induce significant changes in the locomotor pattern. When facing the VA all subjects consistently reduced stride length and velocity while increasing stride duration. Trunk inclination and mediolateral trajectory deviation also facilitated avoidance of the obstacle. Conclusions: This proof-of-concept study shows that our VR/A+ paradigm effectively induced a timely gait modulation in a standardized immersive and realistic scenario. This protocol could be a powerful research tool to study gait modulation and its derangements in relation to aging and clinical conditions.},
  language  = {en}
}