Light up ADHD: II. Neuropharmacological effects measured by near infrared spectroscopy: is there a biomarker?

Background: Attention deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by deficits in self-controlling attention, behavior, and emotions. In recent years, noninvasive optical techniques, such as near infrared spectroscopy (NIRS), have been used to measure the neural correlates of pharmacologicaltherapy outcomes in children and adolescents with ADHD. Methods: We reviewed a short series of articles that investigated the results of functional NIRS (fNIRS) on developmental-age ADHD. The review was limited to fNIRS studies that investigated the cortical responses that occurred during neuropsychological tasks in ADHD patients who received methylphenidate or atomoxetine. Results: The majority of the reviewed studies revealed the presence of increased oxygenated hemoglobin concent-rations in the prefrontal cortex following pharmacotherapy in ADHD samples. A higher frequency of right-lateralized results was found. Limitations: The considered studies are characterized by substantial methodological heterogeneity in terms of the patients' medication status and washout period, explored cerebral regions, and neuropsychological tasks. Conclusions: fNIRS seems to be a promising tool for the detection of pharmacological-treatment biomarkers in samples of children and adolescents with ADHD