A cochleovestibular investigation including tone audiometry, speech audiometry, impedance tests, stapedial reflex threshold, tone decay test, spontaneous nystagmus, tracking, caloric stimulation and visual suppression test, was performed in 13 patients affected by different types of progressive familial myoclonus epilepsy. The electronystagmographic study shows signs of lesion in the cerebellar system. In some cases the lesion seemed to be cerebellar, whereas in others there was also evidence of brainstem involvement.