Factor analysis-derived cognitive profile predicting early dementia conversion in PD

OBJECTIVES: To investigate which baseline neuropsychological profile predicts the risk of developing dementia in early-stage Parkinson disease (PD). METHODS: We retrospectively reviewed detailed medical records of 350 drug-naive patients with early-stage PD (follow-up >3 years) who underwent a detailed neuropsychological test at initial assessment. Factor analysis was conducted to determine cognitive profiles that yielded 4 cognitive function factors: factor 1, visual memory/visuospatial; factor 2, verbal memory; factor 3, frontal/executive; and factor 4, attention/working memory/language. Subsequently, we assessed the effect of these cognitive function factors on the risk for dementia conversion. We also constructed a nomogram to calculate the risk for developing dementia over a 5-year follow-up period based on these cognitive profiles. RESULTS: Cox regression analysis demonstrated that a higher composite score of factor 1 (hazard ratio [HR] 0.558, 95% confidence interval [CI] 0.427-0.730), factor 2 (HR 0.768, 95% CI 0.596-0.991), and factor 3 (HR 0.425, 95% CI 0.305-0.593) was associated with a lower risk for dementia conversion, while factor 3 had the most predictive power. The nomogram had a fair ability (Heagerty integrated area under the curve 0.763) to estimate the risk for dementia conversion within 5 years. The composite scores of factor 3 contributed more to the occurrence of dementia in PD than those of the other cognitive function factors. CONCLUSIONS: These findings suggest that these factor analysis-derived cognitive profiles can be used to predict dementia conversion in early-stage PD. In addition, frontal/executive dysfunction contributes most to the occurrence of dementia in PD.