Dysautonomia and cognitive dysfunction in Parkinson's disease.

Nonmotor symptoms have recently become a focus of renewed clinical interest and research in Parkinson's disease (PD). Autonomic and cognitive dysfunction are among the most prevalent of these nonmotor aspects of the disease. Although exact clinico-pathological correlations have not been established, alpha-synuclein pathology with Lewy body formation in the central and peripheral autonomic nervous system as well as in neocortical areas are generally believed to be driving factors for autonomic failure and cognitive decline in PD. Recent pathological and clinical studies have suggested greater prevalence of clinical dysautonomia and cardiac sympathetic denervation in PD dementia and dementia with Lewy bodies as compared with PD without dementia. This raises the possibility that spread of synuclein pathology to involve neocortical areas producing cognitive decline could be somehow linked to involvement of the autonomic nervous system in PD.