There are only few reports in the literature on isolated episodes of speech arrest as first symptom of a tumour in the supplementary motor area. These episodes of speech arrest are due to seizure activity and must be distinguished from speech arrest due to transient ischaemic attacks. The diagnosis may be difficult because the tumour may erroneously be suspected in the lower portion of the sensorimotor strip and may, hence, be missed on CT if apical sections of the regions are not performed. Clinical and experimental aspects of this problem are discussed on the basis of a case report and a review of the literature.