NEUROFIBRILLARY TANGLES AND NEUROPIL THREADS AS A CAUSE OF DEMENTIA IN PARKINSONS-DISEASE

Alzheimer's disease (AD) and Parkinson's disease (PD) are the most com mon age-related degenerative disorders of the human brain. Both diseas es involve multiple neuronal systems and are the consequences of cytos keletal abnormalities. In AD susceptible neurons produce neurofibrilla ry changes, while in Parkinson's disease, they develop Lewy bodies. In AD six developmental stages can be distinguished on account of the pr edictable manner in which the neurofibrillary changes spread across th e cerebral cortex. During the course of PD numerous limbic determined parts of the brain undergo specific lesions regulating endocrine and a utonomic functions. In general, the extranigral destructions are in th emselves not sufficient to produce overt intellectual deterioration. F ully developed Parkinson's disease with concurring incipient Alzheimer 's disease is likely to cause impaired cognition.