Distinguishing Alzheimer's disease from Parkinson's disease dementia using Enhanced Cued Recall test subscores

Objectives: This study aimed to investigate the utility of differences in Enhanced Cued Recall (ECR) subscores in distinguishing cognitive impairment associated with Alzheimer's disease (AD) and Parkinson's disease (PD). Patients and methods: The prospective study included 50 patients (34 females, 17 males; mean age: 71.3±8.6 years; range, 51 to 82 years) with AD and 25 patients (13 females, 12 males; mean age: 70.0±9.3 years; range, 53 to 93 years) with PD with associated cognitive impairment between January 2023 and June 2023. The counts of items within the free recall segments of the three ECR test trials were individually assessed and compared as repeated measurements between the respective groups. The difference between the number of items in the third and the first free recall trials was calculated and evaluated as a prospective predictive instrument. Results: In addition to the total ECR score, the number of items in each of the three free recall trials was significantly lower in the AD group compared to the PD group. While these scores remained relatively consistent across trials in the AD group, the PD group progressively recalled more item names. The increasing positive difference between the third trial and the first trial, when subtracted, was found to be a significant predictor in favor of the PD group, with a sensitivity of 84% and specificity of 68%. Conclusion: The examination of the trajectory of ECR test subscores, in addition to the total score, can be a useful method for the differential diagnosis of cognitive impairment associated with AD and PD.