title: Evaluation of Neuropsychiatric Function in Phenylketonuria: Psychometric Properties of the ADHD Rating Scale-IV and Adult ADHD Self-Report Scale Inattention Subscale in Phenylketonuria.
abstract: BACKGROUND
  Previous qualitative research among adults and parents of children with phenylketonuria (PKU) has identified inattention as an important psychiatric aspect of this condition. The parent-reported ADHD Rating Scale-IV (ADHD RS-IV) and the Adult ADHD Self-Report Scale (ASRS) have been validated for measuring inattention symptoms in persons with attention-deficit/hyperactivity disorder (ADHD); however, their psychometric attributes for measuring PKU-related inattention have not been established.
  
  
  OBJECTIVE
  The primary objective of this investigation was to demonstrate the reliability, validity, and responsiveness of the ADHD RS-IV and ASRS inattention symptoms subscales in a randomized controlled trial of patients with PKU aged 8 years or older.
  
  
  METHODS
  A post hoc analysis investigated the psychometric properties (Rasch model fit, reliability, construct validity, and responsiveness) of the ADHD RS-IV and ASRS inattention subscales using data from a phase 3b, double-blind, placebo-controlled clinical trial in those with PKU aged 8 years or older.
  
  
  RESULTS
  The Rasch results revealed good model fit, and reliability analyses revealed strong internal consistency reliability (α ≥ 0.87) and reproducibility (intraclass correlation coefficient ≥ 0.87) for both measures. Both inattention measures demonstrated the ability to discriminate between known groups (P < 0.001) created by the Clinical Global Impression-Severity scale. Correlations between the ADHD RS-IV and the ASRS with the Clinical Global Impression-Severity scale and the age-appropriate Behavior Rating Inventory of Executive Function Working Memory subscale were consistently moderate to strong (r ≥ 0.56). Similarly, results of the change score correlations were of moderate magnitude (r ≥ 0.43) for both measures when compared with changes over time in Behavior Rating Inventory of Executive Function Working Memory subscales.
  
  
  CONCLUSIONS
  These findings of reliability, validity, and responsiveness of both the ADHD RS-IV and the ASRS inattention scales, in addition to content validation results, support their use for the assessment of inattention symptoms among persons with PKU aged 8 years or older in both clinical and research settings.
authors.affiliation: Evidera, Bethesda, MD, USA. Electronic address: kathy.wyrwich@evidera.com.
authors.forename: Kathleen W
authors.initials: KW
authors.lastname: Wyrwich
authors.affiliation: Evidera, Bethesda, MD, USA.
authors.forename: Priscilla
authors.initials: P
authors.lastname: Auguste
authors.affiliation: Evidera, Bethesda, MD, USA.
authors.forename: Ren
authors.initials: R
authors.lastname: Yu
authors.affiliation: BioMarin Pharmaceutical, Inc., Novato, CA, USA.
authors.forename: Charlie
authors.initials: C
authors.lastname: Zhang
authors.affiliation: BioMarin Pharmaceutical, Inc., Novato, CA, USA.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Dewees
authors.affiliation: BioMarin Pharmaceutical, Inc., Novato, CA, USA.
authors.forename: Barbara
authors.initials: B
authors.lastname: Winslow
authors.affiliation: BioMarin Pharmaceutical, Inc., Novato, CA, USA.
authors.forename: Shui
authors.initials: S
authors.lastname: Yu
authors.affiliation: BioMarin Pharmaceutical, Inc., Novato, CA, USA.
authors.forename: Markus
authors.initials: M
authors.lastname: Merilainen
authors.affiliation: BioMarin Pharmaceutical, Inc., Novato, CA, USA.
authors.forename: Suyash
authors.initials: S
authors.lastname: Prasad
mesh_terms: D000293:Adolescent; D000328:Adult; D001289:Attention Deficit Disorder with Hyperactivity / Q000175:diagnosis* / Q000523:psychology; D002648:Child; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010661:Phenylketonurias / Q000175:diagnosis* / Q000523:psychology; D011569:Psychiatric Status Rating Scales / Q000592:standards*; D011594:Psychometrics; D057566:Self Report / Q000592:standards*; D012720:Severity of Illness Index; D055815:Young Adult
keywords: attention deficit/hyperactivity disorder; inattention; metabolic disorder; phenylketonuria; psychometrics