title: Development and initial testing of the Penn Parkinson's Daily Activities Questionnaire.
abstract: OBJECTIVE
  The aim of this work was to describe the development and psychometric analysis of the Penn Parkinson's Daily Activities Questionnaire. The questionnaire is an item response theory-based tool for rating cognitive instrumental activities of daily living in PD.
  
  
  METHODS
  Candidate items for the Penn Parkinson's Daily Activities Questionnaire were developed through literature review and focus groups of patients and knowledgeable informants. Item selection and calibration of item-response theory parameters were performed using responses from a cohort of PD patients and knowledgeable informants (n = 388). In independent cohorts of PD patients and knowledgeable informants, assessments of test-retest reliability (n = 50), and construct validity (n = 68) of the questionnaire were subsequently performed. Construct validity was assessed by correlating questionnaire scores with measures of motor function, cognition, an existing activities of daily living measure, and directly observed daily function.
  
  
  RESULTS
  Fifty items were retained in the final questionnaire item bank. Items were excluded owing to redundancy, difficult reading level, and when item-response theory parameters could not be calculated. Test-retest reliability was high (intraclass correlation coefficient = 0.97; P < 0.001). The questionnaire correlated strongly with cognition (r = 0.68; P < 0.001) and directly observed daily function (r = 0.87; P < 0.001), but not with motor impairment (r = 0.08; P = 0.53). The questionnaire score accurately discriminated between PD patients with and without dementia (receiver operating characteristic curve = 0.91; 95% confidence interval: 0.85-0.97).
  
  
  CONCLUSIONS
  The Penn Parkinson's Daily Activities Questionnaire shows strong evidence of reliability and validity. Item response theory-based psychometric analysis suggests that this questionnaire can discriminate across a range of daily functions.
authors.affiliation: Department of Psychiatry, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.|Philadelphia Veterans Affairs Medical Center, Philadelphia, Pennsylvania, USA.
authors.forename: Laura
authors.initials: L
authors.lastname: Brennan
authors.affiliation: Avid Radiopharmaceuticals, Philadelphia, Pennsylvania, USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Siderowf
authors.affiliation: American Institute of Certified Public Accountants, Ewing, New Jersey, USA.
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Rubright
authors.affiliation: Department of Neurology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Rick
authors.affiliation: Department of Neurology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
authors.forename: Nabila
authors.initials: N
authors.lastname: Dahodwala
authors.affiliation: Philadelphia Veterans Affairs Medical Center, Philadelphia, Pennsylvania, USA.|Department of Neurology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
authors.forename: John E
authors.initials: JE
authors.lastname: Duda
authors.affiliation: Department of Neurology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
authors.forename: Howard
authors.initials: H
authors.lastname: Hurtig
authors.affiliation: Department of Neurology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: Stern
authors.affiliation: Department of Biostatistics and Epidemiology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
authors.forename: Sharon X
authors.initials: SX
authors.lastname: Xie
authors.affiliation: Department of Biostatistics and Epidemiology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
authors.forename: Lior
authors.initials: L
authors.lastname: Rennert
authors.affiliation: Departments of Medical Ethics and Medicine, PENN-CMU Roybal Center on Behavioral Economics and Health, the LDI Center for Health Incentives, and Alzheimer's Disease Center.
authors.forename: Jason
authors.initials: J
authors.lastname: Karlawish
authors.affiliation: Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
authors.forename: Judy A
authors.initials: JA
authors.lastname: Shea
authors.affiliation: Department of Neurology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
authors.forename: John Q
authors.initials: JQ
authors.lastname: Trojanowski
authors.affiliation: Department of Psychiatry, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.|Philadelphia Veterans Affairs Medical Center, Philadelphia, Pennsylvania, USA.|Department of Neurology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Weintraub
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D003072:Cognition Disorders / Q000175:diagnosis / Q000209:etiology*; D015331:Cohort Studies; D003704:Dementia / Q000175:diagnosis / Q000209:etiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000150:complications* / Q000523:psychology*; D011594:Psychometrics; D011597:Psychomotor Performance / Q000502:physiology; D015203:Reproducibility of Results; D013223:Statistics as Topic; D011795:Surveys and Questionnaires
keywords: Parkinson's disease; cognition; instrumental activities of daily living; item response theory