Cognitive dysfunction in Nigerians with Parkinson's disease.

Despite the original description of Parkinson's disease (PD) as a disorder in which "the senses and intellect remain uninjured," there is now sufficient evidence that cognitive dysfunction does occur. This research determined the frequency, pattern, and predictors of cognitive dysfunction among 51 Nigerian patients with PD compared with 50 demographically matched controls using the modified Community Screening Instrument for Dementia (CSI'D') and selected items from the Ibadan Neuropsychological Battery (I-NB). In all, 21.6% patients with PD (4% of controls) exhibited cognitive impairment (P = 0.008) defined, for the purposes of this study, as total modified CSI'D' score below 2 SD of the mean score of the control group. Cognitive dysfunction in patients with PD encompassed memory, language, and executive dysfunction. Correlates of cognitive dysfunction included older age at PD onset (P = 0.001), older current age (P < 0.001), and higher UPDRS motor score (P = 0.005). After logistic regression, older age at onset of PD was the only independent predictor of cognitive dysfunction. (O.R = 1.29; 95% CI = 1.08-1.57, P = 0.006). Cognitive dysfunction occurs more frequently in Nigerians with PD compared to controls. Older age at disease onset is an important determinant of cognitive dysfunction in PD.