title: ERD-based online brain-machine interfaces (BMI) in the context of neurorehabilitation: optimizing BMI learning and performance.
abstract: Event-related desynchronization (ERD) of sensori-motor rhythms (SMR) can be used for online brain-machine interface (BMI) control, but yields challenges related to the stability of ERD and feedback strategy to optimize BMI learning.Here, we compared two approaches to this challenge in 20 right-handed healthy subjects (HS, five sessions each, S1-S5) and four stroke patients (SP, 15 sessions each, S1-S15). ERD was recorded from a 275-sensor MEG system. During daily training,motor imagery-induced ERD led to visual and proprioceptive feedback delivered through an orthotic device attached to the subjects' hand and fingers. Group A trained with a heterogeneous reference value (RV) for ERD detection with binary feedback and Group B with a homogenous RV and graded feedback (10 HS and 2 SP in each group). HS in Group B showed better BMI performance than Group A (p < 0.001) and improved BMI control from S1 to S5 (p = 0.012) while Group A did not. In spite of the small n, SP in Group B showed a trend for a higher BMI performance (p = 0.06) and learning was significantly better (p < 0.05). Using a homogeneous RV and graded feedback led to improved modulation of ipsilesional activity resulting in superior BMI learning relative to use of a heterogeneous RV and binary feedback.
authors: National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD 20892, USA. surjo@soekadar.com
authors: Surjo R
authors: SR
authors: Soekadar
authors: Matthias
authors: M
authors: Witkowski
authors: Jürgen
authors: J
authors: Mellinger
authors: Ander
authors: A
authors: Ramos
authors: Niels
authors: N
authors: Birbaumer
authors: Leonardo G
authors: LG
authors: Cohen
mesh_terms: D000223:Adaptation, Psychological; D000328:Adult; D000465:Algorithms; D001921:Brain / Q000502:physiology; D003344:Cortical Synchronization / Q000502:physiology*; D003627:Data Interpretation, Statistical; D004569:Electroencephalography / Q000379:methods*; D025461:Feedback, Physiological; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007092:Imagination / Q000502:physiology; D007858:Learning / Q000502:physiology*; D015225:Magnetoencephalography; D008297:Male; D009989:Orthotic Devices; D011434:Proprioception / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology*; D012201:Reward; D012984:Software; D000071939:Stroke Rehabilitation; D014584:User-Computer Interface; D055815:Young Adult