CLINICAL OBSERVATIONS ON THE RATE OF PROGRESSION OF IDIOPATHIC PARKINSONISM

The time course of evolution of clinical deficits has been a tradition al guide to the nature of the aetiopathogenesis of neurological diseas e. We studied the influence of ageing and duration of disease on the n atural history of idiopathic parkinsonism (IP). Two hundred and thirty -eight patients with IP were examined while off medication. Bradykines ia scores were analysed against patients' age and duration of disease by multiple regression. There was no significant interaction between t he effects of age and of duration (P = 0.923). We conclude that age an d duration of symptoms influence the natural history of IP additively and independently. Furthermore, the rate of neuronal death is more rap id in the earlier stages of evolution of the pathology; subsequently, the velocity of progression slows down to approach the rate of attriti on produced by normal ageing. This time course has implications for po ssible models of pathogenesis.