Introduction: It was proposed to modify the Pfeffer questionnaire (PQ) for functional assessment in patients with Parkinson disease (PD).
Aim: To determine the cutoff score for diagnosis of functional impairment in patients with PD by modified PQ (mPQ).
Methods: A total of 110 patients with PD were enrolled into the study, and a neuropsychological test battery was performed to assess their cognitive status. Regarding functional assessment, the mPQ has been applied, and their results were compared to the functional assessment by Informant Questionnaire on Cognitive Decline in the Elderly adapted for use in Brazil (IQCODE-BR). The statistical analysis was accomplished through receiver operating characteristic (ROC) curve with evaluation of the area under the curve, sensitivity, and specificity of the new cutoff point.
Results: Eighty-nine patients with PD were evaluated with a mean age of 63.69 ± 9.14 years. Cognitive status categorization was 28.10% as normal, 44.94% as mild cognitive impairment, and 26.96% of patients as dementia associated with PD. The average score on PQ was 3.49 ± 4.79 and on the mPQ 2.56 ± 3.49. In IQCODE-BR, the average score was 6.75 ± 32.72. The ROC curve for the new cutoff point presented 47.4% sensitivity, 88.10% specificity, and 0.757 of area under the curve, with a standard deviation of 0.055 (95% confidence interval: 0.650-0.864).
Conclusion: 3.5 is proposed as the cutoff point to define functional impairment in patients with PD by mPQ.
Keywords: Parkinson disease; cognition; questionnaires.