Already the duration of the various perceptions of vertigo and dizziness may help to reach diagnosis:Attacks for 1-2 seconds indicate central disturbances of functional and also of vascular origin.Attacks lasting for 30-60 seconds are most frequently caused by peripheral disturbances, often benign positlonal vertigo, occasionally also functional disturbances.Attacks for 2-5 hours are of peripheral or at least somatic origin, frequently Ménière's disease.Fluctuating vertigo or dizziness indicates functional origin. Continuous vertigo or dizziness may be expected to be of central origin, mainly functional but peripheral origin must be excluded (caloric test).In a previous paper (12) was accounted for a material of 338 dizzy and vertiginous patients. Characters in the vertiginous perceptions were related to other symptoms and also to objective findings. Characteristics in perceptions helped to differentiate between peripheral and central and between functional and non functional disturbance.In the present paper the interest will be directed towards the duration patterns of various perceptions of vertigo and dizziness with the ambition to map out the clinical significanceof these patterns.