The purpose of this paper is to report the speech and hearing disorders of myoclonus epilepsy in 24-year-old male with photosensitive covulsion. Myoclonus epilepsy is characterized clinically by the onset in adolesence of myoclonus, convulsion and progressive dementia. We recently have studied a patient with speech and hearing impairments as a sign of dementia. He had suffered from photosensitive epilepsy which had its onset at age 18. Birth and development history was normal. He had done average work in school. As for speech and hearing, his chief complaint was difficulty in copy-writing and understanding of spoken words. With neurological examination, the brain damage including thalamus and visual fields in occipital and frontal was suspected. Speech and hearing test was carried out at ages 23 and 24. The result was as follows: Pure tone audiometry was normal, but auditory discrimination was poor. As for speech function, copy-writing was disturbed at first. Later, understanding of spoken words became difficult and amnesia appeared. Dictation and spontaneous writing were also poor at first and later became impossible. IQ was 64 at age 23 and was under 60 next year. During one year, speech and hearing impairments had been deteriorating progressively.