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Mild cognitive impairment at time of Parkinson's diagnosis increased risk for early dementia

Patients with mild cognitive impairment when diagnosed with Parkinson’s disease appeared to be at an increased risk for early dementia, new research suggests.

“Cognitive testing should be performed in the early phase of [Parkinson’s disease], even at the time of [Parkinson’s disease] diagnosis, to detect patients with MCI who need to be more closely monitored for cognitive status during follow-up,” study researcher Kenn Freddy Pedersen, MD, of The Norwegian Centre for Movement Disorders, told Psychiatric Annals.

 

Kenn Freddy Pedersen

The population-based study included 182 patients with incident Parkinson’s disease monitored for 3 years. Standardized cognitive tests were performed at baseline and 1- and 3-year follow-up visits to test attention, executive function, verbal memory and visuospatial skills. Diagnoses of dementia and MCI were made according to published consensus criteria.

At baseline, 20.3% of participants had MCI. Researchers found that more patients with MCI at baseline (27%) than without (0.7%) progressed to dementia at follow-up (RR=39.2; 95% CI, 5.2-296.5).

However, researchers also found that 21.6% of participants with MCI at baseline had returned to normal cognition during follow-up.

Similar rates were found with MCI at the 1-year visit regarding progression to dementia (27.8%) and reversion to normal cognition (19.4%).

Of the 22 participants with persistent MCI at baseline and 1-year follow-up, 45.5% developed dementia and only 9.1% reverted to normal cognition at the end of the study.

Participants with MCI who developed dementia were older and showed more deficits of attention and verbal memory at baseline than participants with MCI who did not progress to dementia, but no significant differences were shown in other demographic, clinical or neuropsychological variables. Participants with MCI at baseline that reverted to normal cognition during follow-up were younger, had shorter disease duration, less severe Parkinson’s disease and better test performances on several cognitive tests at baseline vs. participants with MCI who developed dementia..

“Although long-term studies in [Parkinson’s disease] demonstrate that most patients will eventually develop dementia, the time of onset of dementia and less severe cognitive deficits is highly variable,” Pedersen and colleagues wrote. “Future interventions are likely to yield the most benefit if initiated early.”

Disclosure: Pedersen reports no relevant financial disclosures.