Speech evoked potentials in response to grammatical structures

Abstract

The purpose of the present study was to monitor the electrophysiological responses to phrases varying in degree of grammaticality, congruity, and markedness. Eight English phrases were synthetically produced to control duration, amplitude, and alignment. These were composed of “I,” “She,” “A,” or “Three” followed by the nonsense word “wug” or its morphophonemically marked counterpart “wugs.” Cortical evoked potentials were monitored from F7, F8, and midway between Ta and P3, and midway between T4 and Px (International 10–20 Systems of the Electrode Placement), each referenced to the ipsilateral earlobe. Ten male, right-handed subjects between the ages of 20–30 years were solicited from among The University of Texas Health Science Center at Houston faculty and students. Ss were told to listen with eyes closed and to avoid movement. Evoked responses were averaged over 64 randomly ordered presentations of each stimulus, thus yielding a total of 512 presentations per S. Preliminary analysis indicates that the AEPs on the right were similar regardless of grammatical complexity, congruity, or markedness. AEPs on the left, however, were more variable depending on grammatical factors.