Auxiliary Neurofeedback System for Diagnostic of Attention Deficit Hyperactivity Disorder

This paper describes a neurofeedback system for auxiliary diagnostic of attention deficit/hyperactivity disorder (ADHD). The design stresses ease of use and modification so that different interfaces can be added, and different signal processing procedures can be implemented as required. An isolated data acquisition system based on the MC68HC908GP32 microcontroller transfers the acquired EEG signals to a PC. The interface and signal processing procedures were implemented using the Labview (National Instruments) virtual instrumentation software. The software calculates the power density spectrum (PDS) of the signals using the Welch PDS estimation method and Kaiser-Bessel windowing functions, to determine the ratio beta-EEG/thetas-EEG. Two different screen layouts are available for carrying out the tests. A clinical study was conducted on 4 unmedicated young adults suspected of suffering from ADHD. The test consisted of 6 10-minute sessions, divided in two stages of 5 minutes, over a period of 12 days. The results obtained showed an increased beta/thetas ratio as sessions progressed.