title: Comparison of a row-column speller vs. a novel lateral single-character speller: assessment of BCI for severe motor disabled patients.
abstract: OBJECTIVE
  Non-invasive brain-computer interface (BCI) based on electroencephalography (EEG) offers a new communication channel for people suffering from severe motor disorders. This paper presents a novel P300-based speller called lateral single-character (LSC). The LSC performance is compared to that of the standard row-column (RC) speller.
  
  
  METHODS
  We developed LSC, a single-character paradigm comprising all letters of the alphabet following an event strategy that significantly reduces the time for symbol selection, and explores the intrinsic hemispheric asymmetries in visual perception to improve the performance of the BCI. RC and LSC paradigms were tested by 10 able-bodied participants, seven participants with amyotrophic lateral sclerosis (ALS), five participants with cerebral palsy (CP), one participant with Duchenne muscular dystrophy (DMD), and one participant with spinal cord injury (SCI).
  
  
  RESULTS
  The averaged results, taking into account all participants who were able to control the BCI online, were significantly higher for LSC, 26.11 bit/min and 89.90% accuracy, than for RC, 21.91 bit/min and 88.36% accuracy. The two paradigms produced different waveforms and the signal-to-noise ratio was significantly higher for LSC. Finally, the novel LSC also showed new discriminative features.
  
  
  CONCLUSIONS
  The results suggest that LSC is an effective alternative to RC, and that LSC still has a margin for potential improvement in bit rate and accuracy.
  
  
  CONCLUSIONS
  The high bit rates and accuracy of LSC are a step forward for the effective use of BCI in clinical applications.
authors.affiliation: Institute for Systems and Robotics, University of Coimbra, 3030-290 Coimbra, Portugal. gpires@isr.uc.pt
authors.forename: Gabriel
authors.initials: G
authors.lastname: Pires
authors.forename: Urbano
authors.initials: U
authors.lastname: Nunes
authors.forename: Miguel
authors.initials: M
authors.lastname: Castelo-Branco
mesh_terms: D001921:Brain / Q000503:physiopathology*; D003143:Communication Devices for People with Disabilities; D006233:Persons with Disabilities; D018913:Event-Related Potentials, P300 / Q000502:physiology; D006801:Humans; D009468:Neuromuscular Diseases / Q000534:rehabilitation*; D014584:User-Computer Interface; D014796:Visual Perception / Q000502:physiology*