title: Robustness of reliable change indices to variability in Parkinson's disease with mild cognitive impairment.
abstract: Ability to identify change is crucial for measuring response to interventions and tracking disease progression. Beyond psychometrics, investigations of Parkinson's disease with mild cognitive impairment (PD-MCI) must consider fluctuating medication, motor, and mental status. One solution is to employ 90% reliable change indices (RCIs) from test manuals to account for account measurement error and practice effects. The current study examined robustness of 90% RCIs for 19 commonly used executive function tests in 14 PD-MCI subjects assigned to the placebo arm of a 10-week randomized controlled trial of atomoxetine in PD-MCI. Using 90% RCIs, the typical participant showed spurious improvement on one measure, and spurious decline on another. Reliability estimates from healthy adults standardization samples and PD-MCI were similar. In contrast to healthy adult samples, practice effects were minimal in this PD-MCI group. Separate 90% RCIs based on the PD-MCI sample did not further reduce error rate. In the present study, application of 90% RCIs based on healthy adults in standardization samples effectively reduced misidentification of change in a sample of PD-MCI. Our findings support continued application of 90% RCIs when using executive function tests to assess change in neurological populations with fluctuating status.
authors.affiliation: a Mental Health Service , Ralph H. Johnson Veterans Affairs Medical Center , Charleston , SC , USA.|b Department of Psychiatry & Behavioral Sciences , Medical University of South Carolina , Charleston , SC , USA.
authors.forename: T H
authors.initials: TH
authors.lastname: Turner
authors.affiliation: c Department of Neurosciences , Medical University of South Carolina , Charleston , SC , USA.
authors.forename: J B
authors.initials: JB
authors.lastname: Renfroe
authors.affiliation: d Department of Public Health Science , Medical University of South Carolina , Charleston , SC , USA.
authors.forename: J
authors.initials: J
authors.lastname: Elm
authors.affiliation: c Department of Neurosciences , Medical University of South Carolina , Charleston , SC , USA.
authors.forename: A
authors.initials: A
authors.lastname: Duppstadt-Delambo
authors.affiliation: c Department of Neurosciences , Medical University of South Carolina , Charleston , SC , USA.|e Neurology Service , Ralph H. Johnson Veterans Affairs Medical Center , Charleston , SC , USA.
authors.forename: V K
authors.initials: VK
authors.lastname: Hinson
mesh_terms: D018759:Adrenergic Uptake Inhibitors / Q000627:therapeutic use; D000368:Aged; D000069445:Atomoxetine Hydrochloride / Q000627:therapeutic use; D003072:Cognition Disorders / Q000150:complications* / Q000188:drug therapy; D018450:Disease Progression; D004311:Double-Blind Method; D056344:Executive Function / Q000187:drug effects / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000150:complications*; D011594:Psychometrics; D015203:Reproducibility of Results; D016896:Treatment Outcome
chemical_list: D018759:Adrenergic Uptake Inhibitors; D000069445:Atomoxetine Hydrochloride
keywords: Problem solving; test construction; tests; treatment