Absence of P300 Amplitude Laterality in Persons Who Stutter

Abstract

Objective: This study investigated differences in P300 auditory-evoked potentials between Persons Who Stutter (PWS) and Persons Who Do Not Stutter (PWNS). Methods: Responses to tonal and synthetic speech stimuli were recorded from electrodes over the right and left parietal locations and amplitude and latency measures were analyzed. The speech stimuli /bA/-/pA/ and /bA/-/dA/ were two sets of syllables contrasting across and within categorical boundaries on the first phoneme. Results: PWS demonstrated different inter-hemispheric activity in response to the stimuli than PWNS. Whereas PWNS had significantly greater P300 amplitudes over the left than the right parietal location, PWS did not demonstrate significantly greater P300 amplitudes over either location. Conclusion: This lack of laterality for PWS is discussed in the light of cerebral dominance theories and speech development.