Slow potentials preceding vocalisation

Twenty-four subjects equally represented by males and females, and left- and right-handers, had slow potentials recorded prior to vocalisation of the same word 25 times ('Yes'), or a different word every sweep, chosen by the subject 5. Negativity on the scalp preceding generated words came earlier than preceding repetitions. Asymmetry in EEG was dependent on handedness, and occurred frontally in females, centrally in males. It is suggested that task-related differences in slow potentials preceding speech, and asymmetries associated with handedness, provide evidence that these potentials are not irretrievably contaminated by movement and respiratory artefacts.