Parkinson's disease: an epidemiologic method for distinguishing between symptomatic and neuroprotective treatments

Recent studies have suggested that deprenyl may exert a neuroprotective influence and thus retard progression of Parkinson's disease (PD). On the other hand, the data do not disprove that deprenyl is primarily another form of symptomatic therapy like levodopa. Longitudinal Gompertzian analysis demonstrates the absence of beneficial alteration of intrinsic or environmental influences on the epidemiology of PD mortality after the introduction of levodopa. Moreover, this method demonstrates the basis for the enhanced survival in PD that resulted from the efficacy of levodopa as symptomatic therapy. If deprenyl becomes standard therapy in PD and exerts a beneficial (neuroprotective) influence on intrinsic and environmental pathogenic mechanisms, this will become evident by a decrease in the PD mortality rate in the United States in men at age 73.4 years and in women at age 79.1 years. The ability to accurately assess the overall impact of new therapies on the general population is increasingly important in an era of upward spiraling health care costs. Longitudinal Gompertzian analysis is a simple method of detecting and distinguishing between symptomatic (competitive) and protective (intrinsic and environmental) influences on disease mortality at the population level after the introduction of new therapies.