(Photo: Getty Images)
People who were diagnosed with Parkinson’s disease in their 80s had a higher likelihood of showing evidence of brain buildup of amyloid beta, a protein linked to cognitive decline in Alzheimer’s disease, than those diagnosed at a younger age. That is according to an August study published in Aging.
“Amyloid-beta plays a pivotal role in cognitive decline in Lewy body (LB) disease,” authors said. “Neuropathological studies have shown that the amyloid burden in the central nervous system is more strongly correlated with the development of dementia than α-synuclein pathology both in PD with dementia (PDD) and dementia with Lewy bodies (DLB). Marked amyloid deposition in patients with PDD is associated with a rapid rate of cognitive decline.”
Researchers retrospectively evaluated 89 patients who had been diagnosed with PD based on the UK Parkinson’s Disease Society Brain Bank clinical diagnostic criteria at the Tokyo Metropolitan Institute for Geriatrics and Gerontology between April 2013 and December 2022. All patients had been diagnosed within five years of their first motor symptoms and were divided into two groups based on their age at diagnosis: 73 or older, or under 73 years — or the HIGH and LOW groups, respectively.
Evidence of amyloid buildup was found in 30.6% of people in the HIGH group, nearly three times the rate of those in the LOW group (10%). The HIGH group, on average, had fewer years of education and scored slightly lower on memory and thinking tests.
Researchers hypothesized that once amyloid appears, PD patients could move more quickly from normal cognition to dementia. They also assert that the study is the first study to demonstrate the presence of amyloid positivity using cerebrospinal fluid profiles of patients with early PD without dementia.