H. Petsche et al., BRAIN ELECTRICAL MECHANISMS OF BILINGUAL SPEECH MANAGEMENT - AN INITIAL INVESTIGATION, Electroencephalography and clinical neurophysiology, 86(6), 1993, pp. 385-394
This exploratory study deals with EEG changes in 3 professional interp
reters while mentally interpreting from their mother language into for
eign languages and vice versa. EEGs were recorded while interpreting a
nd compared with the periods at rest between these periods of interpre
ting. Significant (P < 0.05) changes of coherence between all pairs of
electrodes with respect to the averaged EEG at rest were computed for
5 frequency bands between 4 and 32 Hz. The verbal tasks were control-
compared with comparable coherence measures for mental arithmetic and
listening to music. Interindividual differences predominated, but cert
ain common characteristics of the EEG measures were also found. The te
mporal regions were most involved in interpreting and particularly in
the uppermost beta band (24-32 Hz). More coherence increases - particu
larly in the right hemisphere - were found while interpreting into the
foreign than into the native language. Coherence changes were found t
o accumulate in certain regions of the scalp as pivots or focal areas
which apparently have functional significance for the task in question
as nodal points of information exchange and/or transfer. Such pivots
were found in T3 more than in T4 (in the right-handers) and vice versa
in a left-hander. Theta and alpha bands behaved differently and did n
ot show such clear-cut differences. The results during mental arithmet
ic and listening to music were different from the ones while interpret
ing. The results give support to the conception of the cortex as a net
work serving the greatest possible divergence and convergence of signa
ls.