title: Defining optimal cutoff scores for cognitive impairment using Movement Disorder Society Task Force criteria for mild cognitive impairment in Parkinson's disease.
abstract: The recently proposed Movement Disorder Society (MDS) Task Force diagnostic criteria for mild cognitive impairment in Parkinson's disease (PD-MCI) represent a first step toward a uniform definition of PD-MCI across multiple clinical and research settings. However, several questions regarding specific criteria remain unanswered, including optimal cutoff scores by which to define impairment on neuropsychological tests. Seventy-six non-demented PD patients underwent comprehensive neuropsychological assessment and were classified as PD-MCI or PD with normal cognition (PD-NC). The concordance of PD-MCI diagnosis by MDS Task Force Level II criteria (comprehensive assessment), using a range of standard deviation (SD) cutoff scores, was compared with our consensus diagnosis of PD-MCI or PD-NC. Sensitivity, specificity, and positive and negative predictive values were examined for each cutoff score. PD-MCI subtype classification and distribution of cognitive domains impaired were evaluated. Concordance for PD-MCI diagnosis was greatest for defining impairment on neuropsychological tests using a 2 SD cutoff score below appropriate norms. This cutoff also provided the best discriminatory properties for separating PD-MCI from PD-NC compared with other cutoff scores. With the MDS PD-MCI criteria, multiple domain impairment was more frequent than single domain impairment, with predominant executive function, memory, and visuospatial function deficits. Application of the MDS Task Force PD-MCI Level II diagnostic criteria demonstrates good sensitivity and specificity at a 2 SD cutoff score. The predominance of multiple domain impairment in PD-MCI with the Level II criteria suggests not only influences of testing abnormality requirements, but also the widespread nature of cognitive deficits within PD-MCI.
authors.affiliation: Department of Neurological Sciences, Rush University Medical Center, Chicago, Illinois, USA.
authors.forename: Jennifer G
authors.initials: JG
authors.lastname: Goldman
authors.forename: Samantha
authors.initials: S
authors.lastname: Holden
authors.forename: Bryan
authors.initials: B
authors.lastname: Bernard
authors.forename: Bichun
authors.initials: B
authors.lastname: Ouyang
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Goetz
authors.forename: Glenn T
authors.initials: GT
authors.lastname: Stebbins
mesh_terms: D000368:Aged; D060825:Cognitive Dysfunction / Q000145:classification / Q000175:diagnosis* / Q000209:etiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests / Q000592:standards; D010300:Parkinson Disease / Q000150:complications*; D011594:Psychometrics / Q000379:methods*; D012720:Severity of Illness Index
keywords: Parkinson's disease; executive function; memory; mild cognitive impairment; neuropsychological tests