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A pilot evaluation of a brief non-verbal executive function assessment in Parkinson's disease




Screening for cognitive impairment in the clinical or community setting is often hampered by the lack of a suitable assessment that is not overburdened with complex administration and scoring methods. We have developed non-verbal cognitive screening instrument: the Weigl Token Test (WTT) from two existing instruments, the Weigl's Colour-Form Sorting Test (WCFST) and the Token Test. The aim of this investigation is to compare the modified WTT with a battery of ‘Gold Standard’ cognitive assessments, to determine its utility, sensitivity and specificity as a brief cognitive screen in a cohort of Parkinson's disease (PD) patients.


A total of 50 PD patients consented to participate in this investigation. All participants were assessed with a battery of cognitive screening instruments including the WCFST, Mini Mental Status Examination, Addenbrooke's Cognitive Examination—Revised and Delis Kaplan Executive Function Systems. The sensitivity and specificity of the WTT to detect cognitive impairment were based upon psychiatric interview, neuropsychological assessment and application of DSM-IV criteria.


The optimal cut-point of the WTT was 116/120, and its sensitivity and specificity to detect cognitive impairment were 88% and 89%, respectively. The diagnostic accuracy of the WTT as calculated by the area under the receiver operating curve was 0.83 (95% CI 0.76–0.95), suggesting that this instrument has acceptable psychometric properties to discriminate between case and non-cases of cognitive impairment.


The WTT demonstrated excellent concurrent validity with existing ‘Gold Standard’ assessments of cognitive impairment. We believe that this instrument will prove to be a valuable additional screening assessment in epidemiological, primary care, specialist mental health or clinical investigations. Copyright © 2013 John Wiley & Sons, Ltd.