Short questionnaire for Parkinson's disease as a screening instrument

Objective

To validate and simplify a screening questionnaire for the determination of PD.

Methods

The screening questionnaire for PD was developed with the permission of the author. Reliability of the questionnaire was tested. To validate the questionnaire, 40 patients with PD and 93 controls completed the questionnaire. Multiple logistic regression analysis was used to determine the questions independently associated with PD and a risk score was calculated. The predictive performance of the risk score was evaluated via the area under the curve (AUC) of a receiver operating characteristics (ROC) curve.

Results

The questionnaire showed a Cronbach's alpha coefficient of 0.73 with no difference between the initial and follow up scores. The mean content validity was 0.86. Of the 11 questions, 4 were independently associated with PD and were used to calculate the risk score. The scores of these questions were 2 (clumsiness) + 4 (tremor) + 2 (masked face) + 2 (loss of balance while turning). The AUC of a ROC curve for the sum of risk score was 0.95. With a cutoff score of 5 or higher, the sensitivity and specificity were 0.88 and 0.95, respectively.

Conclusions

The screening questionnaire for PD is a reliable and valid instrument. The predictive performance of the simplified questionnaire is as good as the original.