Objective To study the relationship between subclinical epileptiformdischarge and transitory cognitive impairment, Methods BM800 AEEG Was used to analyse subclinical epileptiformdischarge of 8 patients from August, 1998 to March, 2002. Results The results indicate that 8 patients suffered from subclinical epilep- tiformdischange are all accompanied with TCI. Conclusion The result is show that subclinical epileptifor- mdischarge is connected with TCI. It is necessary to inspecte by AEEG the patients who have difficulties to study but have not obvious symptoms, subclinical.