Correlation between neurological soft signs, executive functions and brain derived neurotrophic factor in male children with attention deficit/hyperactivity disorder

Aim and Hypothesis: Attention deficit hyperactivity disorder (ADHD), a neurodevelopmental disorder, is caused by structural disorders in the brain networks that affect cognitive, sensory and motor behaviors. Neurological soft signs (NSS), which are suggested to be central nervous system maturation delay, are also quite common in ADHD. In addition, executive functions are known to be impaired in patients with ADHD. However, it has been observed that the relationship between Brain-Derived Neurotrophic Factor (BDNF), which plays a key role in the regulation of neurogenesis and brain plasticity, and ADHD have been studied in many studies and there are wide discrepancies in the results. We predict that our study will contribute to the literature on whether there is a relationship between NSS in ADHD and BDNF, which is involved in the development and myelination of the central nervous system. Our aim in this study is to determine the relationship between the NSS, executive functions and serum BDNF levels in children with ADHD. Method: 87 randomly selected children with ADHD who were admitted to the outpatient clinic of Aydın Adnan Menderes University Department of Child and Adolescent Mental Health and Diseases, meeting the inclusion criteria and selected randomly were included in the study. Informed consent form was obtained from all children and their parents who volunteered to participate in the study. All cases were evaluated in terms of ADHD diagnosis and other psychiatric disorders by applying Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime Version, DSM-5 November 2016-Turkish Adaptation. In addition, all cases were evaluated by specialist pediatric neurologists for the exclusion of possible neurological diseases. The sociodemographic data form was completed by the clinician and Turgay DSM-IV-Based Child and Adolescent Disruptive Behavior Disorders Screening and Rating Scale parent form was completed by one of the parents. First, a biochemistry tube of blood was taken from the cases. Later, Stroop Test TBAG Form and Judgement of Line Orientation Test (JLOT) were used to evaluate the executive functions, and the Revised Physical and Neurological Examination of Subtle Signs (PANESS) to evaluate neurological soft signs. The data obtained were evaluated with appropriate statistical methods. Results: A negative correlation was found between the age of the cases and dysrhythmia, total time and total overflow in timed movements, Stroop 5th task time scores and serum BDNF levels. In cases with low socioeconomic status, JLOT score was lower and total time in timed movements was higher. Cases receiving neonatal intensive care have significantly lower in JLOT score. In addition, a negative correlation was found between total gait and station, total time and total overflow in timed movements with JLOT. Stroop 5th task time and error scores were found higher in cases born as a first child. There was a negative correlation between Stroop 5th task time score and total gait and station, total time and total overflow in timed movements. A negative correlation was found between Stroop 5th task time score and total gait and station score, total time and total overflow score in timed movements. A negative correlation was found between Stroop Difference 3 score and total overflow in timed movements. No significant correlation was found between Stroop 5th task error score and the PANESS subscores. In our study, a positive correlation was found between BDNF and dysrhythmia score. There was no relationship between BDNF levels and executive function tests. Conclusion: We think that being the first child in a family with low socioeconomic level is a risk factor for ADHD diagnosis and lower executive function performance. We predict that JLOT is more predictive in measuring executive functions in cases receiving neonatal intensive care. In addition, the relationship of the NSS with JLOT suggests that the NSS may be more related to the non-dominant cerebral hemisphere and cerebellum. In conclusion, neuroimaging studies are required to clarify the relationship between NSS and executive functions and BDNF in patients with ADHD and to evaluate the maturation difference of both cerebral hemispheres.