Document Detail


The P300-based brain-computer interface (BCI): effects of stimulus rate.
MedLine Citation:
PMID:  21067970     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
OBJECTIVE: Brain-computer interface technology can restore communication and control to people who are severely paralyzed. We have developed a non-invasive BCI based on the P300 event-related potential that uses an 8×9 matrix of 72 items that flash in groups of 6. Stimulus presentation rate (i.e., flash rate) is one of several parameters that could affect the speed and accuracy of performance. We studied performance (i.e., accuracy and characters/min) on copy spelling as a function of flash rate.
METHODS: In the first study of six BCI users, stimulus-on and stimulus-off times were equal and flash rate was 4, 8, 16, or 32 Hz. In the second study of five BCI users, flash rate was varied by changing either the stimulus-on or stimulus-off time.
RESULTS: For all users, lower flash rates gave higher accuracy. The flash rate that gave the highest characters/min varied across users, ranging from 8 to 32 Hz. However, variations in stimulus-on and stimulus-off times did not themselves significantly affect accuracy. Providing feedback did not affect results in either study suggesting that offline analyses should readily generalize to online performance. However there do appear to be session-specific effects that can influence the generalizability of classifier results.
CONCLUSIONS: The results show that stimulus presentation (i.e., flash) rate affects the accuracy and speed of P300 BCI performance.
SIGNIFICANCE: These results extend the range over which slower flash rates increase the amplitude of the P300. Considering also presentation time, the optimal rate differs among users, and thus should be set empirically for each user. Optimal flash rate might also vary with other parameters such as the number of items in the matrix.
Authors:
Dennis J McFarland; William A Sarnacki; George Townsend; Theresa Vaughan; Jonathan R Wolpaw
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2010-11-09
Journal Detail:
Title:  Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology     Volume:  122     ISSN:  1872-8952     ISO Abbreviation:  Clin Neurophysiol     Publication Date:  2011 Apr 
Date Detail:
Created Date:  2011-03-09     Completed Date:  2011-05-17     Revised Date:  2014-09-17    
Medline Journal Info:
Nlm Unique ID:  100883319     Medline TA:  Clin Neurophysiol     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  731-7     Citation Subset:  IM    
Copyright Information:
Copyright © 2010 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.
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MeSH Terms
Descriptor/Qualifier:
Adult
Analysis of Variance
Communication Aids for Disabled*
Discriminant Analysis
Electroencephalography
Event-Related Potentials, P300 / physiology*
Feedback, Psychological / physiology
Female
Humans
Male
Middle Aged
Online Systems
Photic Stimulation
Psychomotor Performance / physiology
User-Computer Interface*
Grant Support
ID/Acronym/Agency:
EB00856/EB/NIBIB NIH HHS; HD30146/HD/NICHD NIH HHS; R01 EB000856/EB/NIBIB NIH HHS; R01 EB000856-09/EB/NIBIB NIH HHS; R01 HD030146/HD/NICHD NIH HHS; R01 HD030146-09/HD/NICHD NIH HHS
Comments/Corrections

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