Parkinson's Disease and Other Alzheimer's Disease and Related Dementia Pathologies and the Progression of Parkinsonism in Older Adults.

Background: The interrelationship of parkinsonism, Parkinson's disease (PD) and other Alzheimer's disease (AD) and Alzheimer's disease and related dementias (ADRD) pathologies is unclear.

Objective: We examined the progression of parkinsonian signs in adults with and without parkinsonism, and their underlying brain pathologies.

Methods: Annual parkinsonian signs were based on a modified Unified Parkinson's Disease Rating Scale.

Alzheimer's Disease Pathology Outside of the Cerebrum Is Related to a Higher Odds of Dementia.

Background: Assessments of Alzheimer's disease pathology do not routinely include lower brainstem, olfactory bulb, and spinal cord.

Objective: Test if amyloid-β (Aβ) and paired helical filament (PHF) tau-tangles outside the cerebrum are associated with the odds of dementia.

Methods: Autopsies were obtained in decedents with cognitive testing (n = 300).