Premotor diagnosis of Parkinson's disease

Introduction: Parkinson's disease is a neurodegenerative disorder characterized by bradykinesia, resting tremor and rigidity. Pathologically, Parkinson's disease is defined by the presence of Lewy bodies, which result from the aggregation of alpha-synuclein. Break, et al. have proposed that the aggregation of alpha-synuclein pathology in Parkinson's disease begins in the medulla oblongata and progresses predictably, reaching the substantia nigra in the midbrain after affecting the brain stem. Apart from the motor symptoms of the disease, non-motor symptoms may precede the evoked potentials, and these include cognitive dysfunction, psychiatric disorder, sleep disorders and autonomic dysfunction. Objective: To describe and discuss the non-motor symptoms and diagnostic tests and procedures which may provide a pre-motor diagnosis of Parkinson's disease. Conclusions: Non-motor symptoms are now accepted as an integral part of the clinical spectrum of Parkinson's disease and there is evidence to suggest that olfactory dysfunction and sleep disturbances may occur before motor signs. The presence of various non-motor symptoms in conjunction with imaging studies has the potential to detect patients with Parkinson's disease in the pre-motor phase. Nevertheless, a larger number of studies are required, in particular cohort design of subjects in risk.