Cognitive Fluctuation Scale in Non-demented Patients with Parkinson's Disease

Cognitive fluctuations (CF) are spontaneous alterations in cognition, attention, and arousal, which are core clinical features in Lewy body dementia. A 4-item scale from the Dementia Cognitive Fluctuation Scale (4-item DCFS) is used in demented patients to identify CF. However, this has not been applied to non-demented patients with Parkinson's disease (PD).

We applied the 4-item DCFS in non-demented PD patients to evaluate its relationship to neuropsychological tests and to determine whether this score is associated with cognitive deterioration.

Fifty-one patients underwent prospective neuropsychological assessments. Those who scored ≥3 in the 4-item DCFS were recognized as CF positive. The Bayesian Kendall correlation test was applied to assess the relationship between the 4-item DCFS score, cognitive tests, and amyloid burden. Forty-five patients were followed up for 3 years.

Thirty-two patients scored 0 (62.7%, no positive answers), 11 (21.6%) scored 1, 4 (7.8%) scored 2, and 4 (7.8%) scored 3 points on the 4-item DCFS. Moderate or strong evidence showed that the 4-item-DCFS score correlated with worse performance on the Trail Making Test B (Bayes factor, BF₊₀ = 4), delayed visual recall test (BF_-0 = 12.9), and higher amyloid burden (BF₊₀ = 13.6). All patients who scored ≥3 converted to PD-mild cognitive impairment or dementia at follow-up, whereas only 29% without CFs had converted to a worse cognitive status.

A higher score on the 4-item DCFS is related to lower scores in executive and memory function, along with a potential connection to amyloid pathology. Patients with lower scores are less likely to develop a worse cognitive state, although larger sample sizes are needed to confirm this relationship.