title: Insulin-like growth factor-1 predicts cognitive functions at 2-year follow-up in early, drug-naïve Parkinson's disease.
abstract: OBJECTIVE
  Cognitive impairment is common in Parkinson's disease (PD), even in the early stages. We aimed to assess the relationship between insulin-like growth factor-1 (IGF-1) and cognitive functions in early, drug-naïve patients with PD.
  
  
  METHODS
  Serum IGF-1 was measured in 65 early, drug-naïve patients with PD that underwent a complete neuropsychological battery at baseline and after 2 years. Linear regression analysis was used to evaluate the relationships between neuropsychological scores and IGF-1. Repeated-measures anova was applied to assess changes in neuropsychological variables over time.
  
  
  RESULTS
  At baseline, IGF-1 levels were related to phonological fluency. At follow-up, IGF-1 levels were associated with the Rey auditory verbal learning test (RAVLT) - immediate and delayed recall, Frontal Assessment Battery, verbal span and Benton judgement of the line orientation test. Patients with low IGF-1 levels at baseline showed a significantly faster decline of performances than patients with high IGF-1 levels on immediate and delayed recall of the RAVLT and interference task of the Stroop test.
  
  
  CONCLUSIONS
  Low serum IGF-1 levels are related to poor performance on executive tasks in early, drug-naïve patients with PD, and may predict poor performance on attention/executive and verbal memory tasks after a 2-year follow-up.
authors.affiliation: Center for Neurodegenerative Diseases, University of Salerno, Salerno, Italy.
authors.forename: M T
authors.initials: MT
authors.lastname: Pellecchia
authors.forename: G
authors.initials: G
authors.lastname: Santangelo
authors.forename: M
authors.initials: M
authors.lastname: Picillo
authors.forename: R
authors.initials: R
authors.lastname: Pivonello
authors.forename: K
authors.initials: K
authors.lastname: Longo
authors.forename: C
authors.initials: C
authors.lastname: Pivonello
authors.forename: C
authors.initials: C
authors.lastname: Vitale
authors.forename: M
authors.initials: M
authors.lastname: Amboni
authors.forename: A
authors.initials: A
authors.lastname: De Rosa
authors.forename: M
authors.initials: M
authors.lastname: Moccia
authors.forename: R
authors.initials: R
authors.lastname: Erro
authors.forename: G
authors.initials: G
authors.lastname: De Michele
authors.forename: L
authors.initials: L
authors.lastname: Santoro
authors.forename: A
authors.initials: A
authors.lastname: Colao
authors.forename: P
authors.initials: P
authors.lastname: Barone
mesh_terms: D000161:Acoustic Stimulation; D000704:Analysis of Variance; D003072:Cognition Disorders / Q000175:diagnosis* / Q000209:etiology*; D005260:Female; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008137:Longitudinal Studies; D008297:Male; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000097:blood* / Q000150:complications*; D012044:Regression Analysis; D014706:Verbal Learning / Q000502:physiology
chemical_list: D007334:Insulin-Like Growth Factor I
keywords: cognitive functions; early Parkinson's disease; insulin-like growth factor-1