ArticleClinical parkinsonism & related disorders2025
A single Center study of the Symbol Digit Modalities test as a screening tool for cognitive impairment in Parkinson's disease.
Article in Clinical parkinsonism & related disorders, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 2 papers.
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Who cites it
2 citing papers in PubMed.
- Cognitive Decline Preceding Incident Cardiovascular Events in Older Adults.JAMA network open · 2026Article
- Sex differences in depression in Parkinson's disease: cognitive dysfunction and female-specific associations.Frontiers in neuroscience · 2025Article
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Authors and funding
6 authors.
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Abstract
Background: Parkinson's Disease (PD) can include physical signs and possibly cognitive impairment, resulting from the convergence of pathological processes involving dopaminergic dysfunction, accumulation of alpha-synuclein, cholinergic deficits, and disruption of other neurotransmitter systems. We used screening tests to evaluate the characteristics of cognitive performance in patients with PD and to assess their validity compared to the Montreal Cognitive Assessment (MoCA). Methods: This is a natural history study of participants with PD and controls screened for possible cognitive impairment using the MoCA, Symbol Digit Modalities Test (SDMT), and King-Devick (KD). The groups were compared on performance and then factors associated with cognitive performance (age, diagnosis, and level of education) were analyzed to determine which best predicted test scores. Results: SDMT scores were lower in the PD group (Mean = 36.7 ± 12.4) compared to controls (Mean = 47.2 ± 11.0, p < 0.001), but the MoCA (PD = 23.8 ± 3.5; Control = 25.5 ± 3.6, p = 0.02) and KD (PD = 70.1 ± 23.4 s; Control = 61.6 ± 17.5, p = 0.048) did not differentiate between groups after controlling for multiple comparisons. Age and diagnosis predicted SDMT raw scores and, as expected, only diagnosis remained significant after calculating T-scores based on published test norms. Age, education, and diagnosis predicted MoCA scores. Conclusions: The SDMT emerged as a promising screening tool to detect cognitive impairment in PD. The test's age and education corrected norms controlled for those variables and left diagnosis as the only predictor of performance. The MoCA scores were predicted by age, education, and diagnosis suggesting the education correction of the MoCA did not fully account for the influence of demographic variables.
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