Correlation analysis between executive dysfunction and serum glial-derived neurotrophic factor level in children with attention deficit/hyperactivity disorder

Objective To explore the correlation between executive dysfunction and serum glial-derived neurotrophic factor (GDNF) levels in children with attention deficit hyperactivity disorder (ADHD). Methods 32 drug-free ADHD patients and 34 normal children matched in gender, age and IQ were included.The executive function was assessed using Digital Span Back Test (DSB-T), Trail Making Test (TMT), Semantic Fluency Test (SFT) and Stroop Color Word Test (SCW-T), and peripheral GDNF levels were measured by the enzyme linked immunosorbent assay (ELISA). The executive functional test scores and serum GDNF levels were compared between groups, and then the correlation between executive dysfunction and GDNF was analyzed by Spearman or pearson correlation analysis. Results (1) In the ADHD group, the DSB-T and SFT scores were lower than those in the normal control group(DSB-T4: (2) vs 5(1); SFT(13.66±2.34) vs (15.21±2.13)(Z=3.16, t=2.82, both P<0.05) and the TMT-A and TMT-B time-consuming were higher than those in the normal control group(TMT-A(61.12±19.03)s vs (48.76±21.06)s; TMT-B(158.66±63.78)s vs (123.62±45.24)s, t=2.50, 2.59, both P<0.05). The Word color consumption, word interference and word color errors of SCW-T in ADHD group were higher than those in the normal control group(Word color consumption(56.41±21.65)s vs (45.97±13.42)s; word interference 27(25)s vs 20(15)s; word color errors 4(3) vs 2(1)), and the differences were statistically significant(t=2.37, Z=2.31, 2.11, all P<0.05). (2) Serum levels of GDNF in the ADHD group were lower than that in the normal control group((481.59±68.74)pg/ml vs (552.47±110.13)pg/ml) , and the difference was statistically significant (t=3.11, P<0.05). (3) In the ADHD group, serum GDNF levels were negatively correlated with TMT-A, TMT-B and SCW-T word interference performance (r=-0.512, r=-0.578, r=-0.432, all P<0.05), and positively correlated with DSB-T performance(r=0.381, P<0.05). Conclusion Executive function is extensively damaged in ADHD patients, and GDNF may be involved in the pathophysiology of executive impairment. Key words: Attention deficit hyperactivity disorder; Glial-derived neurotrophic factor; Executive function; Children