title: Association of peripheral BDNF level with cognition, attention and behavior in preschool children.
abstract: BACKGROUND
  Brain-derived neurotrophic factor (BDNF) has been reported to affect development, cognition, attention and behavior. However, few studies have investigated preschool children with regard to these areas. We evaluated the relationship between cognition, attention and peripheral blood concentration of BDNF in preschool children.
  
  
  METHODS
  Twenty-eight children (mean age: 6.16 ± 0.60 years) were recruited. For all subjects, serum and plasma BDNF levels were assessed; intelligence was assessed using the Korean standardisation of the Wechsler Intelligence Scale for Children (KEDI-WISC); attention was assessed using the computerised continuous performance test (CCPT), the children's color trails test (CCTT), the Stroop color-word test for preschool children, and the attention-deficit/hyperactivity disorder rating scale (K-ARS); and finally emotional and behavioral problems were assessed using the child behavior checklist (K-CBCL). We confirmed the previously reported correlations between the various psychometric properties assessed and serum and plasma levels of BDNF in our sample.
  
  
  RESULTS
  Serum BDNF levels were negatively correlated with both KEDI-WISC full scale IQ (FSIQ, r = -0.39, p = 0.04) and verbal IQ (VIQ, r = -0.05, p = 0.01), but not with the performance IQ (PIQ, r = -0.12, p = 0.56). There were no significant relationships between plasma BDNF level and VIQ, PIQ or FSIQ. No correlations were found between either serum or plasma level of BDNF and any of the attentional measures (CCPT, ARS, CCTT or Stroop color word test). The CBCL total behavioral problem and attention problem sections were positively correlated with plasma BDNF level (r = 0.41, p = 0.03), (r = 0.44, p = 0.02), however, no relationship was found between the serum BDNF and any of the composite CBCL measures.
  
  
  CONCLUSIONS
  Our results suggest that high peripheral BDNF may be negatively correlated with intelligence, behavioral problems and clinical symptoms of neuro-developmental disorders such as intellectual disability in preschool children. A high peripheral BDNF concentration may, if these findings are further replicated, prove to be a useful biomarker for such issues in preschool children.
authors.affiliation: Department of Psychiatry, Bugok National Hospital, Changnyeong-gun, Gyeongsangnam-do South Korea.
authors.forename: Chan-Woo
authors.initials: CW
authors.lastname: Yeom
authors.affiliation: Department of Internal Medicine, Ulsan University Hospital, Ulsan, South Korea.
authors.forename: Young-Ja
authors.initials: YJ
authors.lastname: Park
authors.affiliation: Korea Institute on Behavioral Addictions, Easy Brain Clinic, Seoul, South Korea ; Health Care and Information Research Institute, Namseoul University, Cheonan, South Korea.
authors.forename: Sam-Wook
authors.initials: SW
authors.lastname: Choi
authors.affiliation: Department of Psychiatry, Eulji University School of Medicine, Eulji General Hospital, 68 Hangeulbiseok-Ro, Nowon-Gu, Seoul, 139-711 South Korea.
authors.forename: Soo-Young
authors.initials: SY
authors.lastname: Bhang
keywords: ADHD; BDNF; Brain-derived neurotrophic factor; Cognition; Neurodevelopment