title: Screening for Cognitive Impairment in Parkinson's Disease: Improving the Diagnostic Utility of the MoCA through Subtest Weighting.
abstract: BACKGROUND
  Given the high prevalence of cognitive impairment in Parkinson's disease (PD), cognitive screening is important in clinical practice. The Montreal Cognitive Assessment (MoCA) is a frequently used screening test in PD to detect mild cognitive impairment (PD-MCI) and Parkinson's disease dementia (PD-D). However, the proportion in which the subtests are represented in the MoCA total score does not seem reasonable. We present the development and preliminary evaluation of an empirically based alternative scoring system of the MoCA which aims at increasing the overall diagnostic accuracy.
  
  
  METHODS
  In study 1, the MoCA was administered to 40 patients with PD without cognitive impairment (PD-N), PD-MCI, or PD-D, as defined by a comprehensive neuropsychological test battery. The new MoCA scoring algorithm was developed by defining Areas under the Curve (AUC) for MoCA subtests in a Receiver Operating Characteristic (ROC) and by weighting the subtests according to their sensitivities and specificities. In study 2, an independent sample of 24 PD patients (PD-N, PD-MCI, or PD-D) was tested with the MoCA. In both studies, diagnostic accuracy of the original and the new scoring procedure was calculated.
  
  
  RESULTS
  Diagnostic accuracy increased with the new MoCA scoring algorithm. In study 1, the sensitivity to detect cognitive impairment increased from 62.5% to 92%, while specificity decreased only slightly from 77.7% to 73%; in study 2, sensitivity increased from 68.8% to 81.3%, while specificity stayed stable at 75%.
  
  
  CONCLUSIONS
  This pilot study demonstrates that the sensitivity of the MoCA can be enhanced substantially by an empirically based weighting procedure and that the proposed scoring algorithm may serve the MoCA's actual purpose as a screening tool in the detection of cognitive dysfunction in PD patients better than the original scoring of the MoCA. Further research with larger sample sizes is necessary to establish efficacy of the alternate scoring system.
authors.affiliation: Department of Medical Psychology, Neuropsychology and Gender Studies, University Hospital Cologne, Cologne, Germany.|Institute of Gerontology & Center for Neuropsychological Diagnostics and Intervention (CeNDI), University of Vechta, Vechta, Germany.
authors.forename: Sophie
authors.initials: S
authors.lastname: Fengler
authors.affiliation: Department of Neurology, University Hospital Cologne, Cologne, Germany.
authors.forename: Josef
authors.initials: J
authors.lastname: Kessler
authors.affiliation: Department of Neurology, University Hospital Cologne, Cologne, Germany.
authors.forename: Lars
authors.initials: L
authors.lastname: Timmermann
authors.affiliation: Department of Medical Psychology, Neuropsychology and Gender Studies, University Hospital Cologne, Cologne, Germany.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Zapf
authors.affiliation: Department of Neurology, Center for Movement Disorders and Neuromodulation, University Hospital Düsseldorf, Düsseldorf, Germany.
authors.forename: Saskia
authors.initials: S
authors.lastname: Elben
authors.affiliation: Department of Neurology, Center for Movement Disorders and Neuromodulation, University Hospital Düsseldorf, Düsseldorf, Germany.
authors.forename: Lars
authors.initials: L
authors.lastname: Wojtecki
authors.affiliation: Department of Clinical and Developmental Neuropsychology, Faculty of Behavioural and Social Sciences, University of Groningen, Groningen, Netherlands.
authors.forename: Oliver
authors.initials: O
authors.lastname: Tucha
authors.affiliation: Department of Medical Psychology, Neuropsychology and Gender Studies, University Hospital Cologne, Cologne, Germany.|Institute of Gerontology & Center for Neuropsychological Diagnostics and Intervention (CeNDI), University of Vechta, Vechta, Germany.
authors.forename: Elke
authors.initials: E
authors.lastname: Kalbe
mesh_terms: D000368:Aged; D000465:Algorithms; D019540:Area Under Curve; D060825:Cognitive Dysfunction / Q000150:complications* / Q000175:diagnosis* / Q000503:physiopathology; D003710:Demography; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000150:complications* / Q000175:diagnosis* / Q000503:physiopathology