A spatial approach of magnitude-squared coherence applied to selective attention detection.
BACKGROUND
Auditory selective attention is the human ability of actively focusing in a certain sound stimulus while avoiding all other ones. This ability can be used, for example, in behavioral studies and brain-machine interface.


METHODS
In this work we developed an objective method - called Spatial Coherence - to detect the side where a subject is focusing attention to. This method takes into consideration the Magnitude Squared Coherence and the topographic distribution of responses among electroencephalogram electrodes. The individuals were stimulated with amplitude-modulated tones binaurally and were oriented to focus attention to only one of the stimuli.


RESULTS
The results indicate a contralateral modulation of ASSR in the attention condition and are in agreement with prior studies. Furthermore, the best combination of electrodes led to a hit rate of 82% for 5.03 commands per minute.


CONCLUSIONS
Using a similar paradigm, in a recent work, a maximum hit rate of 84.33% was achieved, but with a greater a classification time (20s, i.e. 3 commands per minute).


CONCLUSIONS
It seems that Spatial Coherence is a useful technique for detecting focus of auditory selective attention.
NIAS, Departamento de Engenharia Elétrica, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil.
Leonardo
L
Bonato Felix
Programa de Engenharia Biomédica - COPPE - Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de janeiro, Brazil.
Fernando
F
de Souza Ranaudo
Programa de Engenharia Biomédica - COPPE - Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de janeiro, Brazil.
Aluizio
A
D'affonseca Netto
Programa de Engenharia Biomédica - COPPE - Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de janeiro, Brazil. Electronic address: amflms@peb.ufrj.br.
Antonio Mauricio
AM
Ferreira Leite Miranda de Sá
D000161:Acoustic Stimulation; D000328:Adult; D001288:Attention / Q000502:physiology*; D001307:Auditory Perception / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D004566:Electrodes; D004569:Electroencephalography / Q000295:instrumentation / Q000379:methods*; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008297:Male; D012815:Signal Processing, Computer-Assisted; D055815:Young Adult
Auditory steady-state response; Selective attention; Spatial Coherence