ABSTRACT
Parkinson’s disease (PD) is a gradually progressive neurodegenerative disorder that is characterized clinically by bradykinesia, rigidity, tremor, postural instability, and gait dysfunction (Lang and Lozano, 1998a, b). While motor dysfunction is the hallmark of the disease, it is now well appreciated that nonmotor features (e.g., sleep disturbances, autonomic dysfunction, mood disorders, and dementia) also frequently develop in PD patients, especially during the advanced stages of the illness (Lang and Lozano, 1998a,b). The pathological hallmark of PD is degeneration of the neuromelanin-pigmented neurons of the substantia nigra pars compacta (SNc), coupled with characteristic proteinaceous inclusions known as Lewy bodies (Forno, 1996). Prominent neurodegeneration with Lewy bodies also occurs in other areas of the central nervous system (CNS), including the locus ceruleus (LC), dorsal motor nucleus of the vagus (DMN), nucleus basalis of Meynert (NBM), and the olfactory system (Forno, 1996; Braak et al., 2003; Zarow et al., 2003). Lewy pathology can also be detected in selected regions of the cerebral hemispheres, spinal cord, and peripheral autonomic nervous system such as the superior cervical ganglion and
the mesenteric plexus in the wall of the gut (Wakabayashi and Takahashi, 1997, #355].
