Early and late components of the contingent negative variation prior to manual and speech responses in stutterers and non-stutterers.

The early and late components of the CNV were measured in 18 stutterers and 18 non-stutterers, all dextral, prior to a manual and 3 speech tasks. It was hypothesized that, due to a proposed deficit in articulatory timing, prior to the more complex speech tasks, stutterers would show reduced late CNV amplitudes over Broca's area when compared to the non-stutterers. This hypothesis was not confirmed. In both groups, there was a finding of greater late CNV activity over the right hemisphere prior to speech responses. Explanations for this finding in terms of (a) CNV polarity, and (b) right hemisphere involvement in the speech responses used, are proposed. It is suggested that attention be paid to the nature of the response when attempting to record slow brain potentials prior to speech.