Near infrared spectrometer combined with multichannel EEG for functional brain imaging

Clinical conditions such as epilepsy and stroke could benefit from portable functional brain evaluation systems for continuous online monitoring and to assist diagnostic. The combination of electroencephalography (EEG) and near infrared spectroscopy (NIRS) has the potential to provide useful information towards that task. Recent attempts at their combination in a single device have shown beneficial results but available instruments lack NIRS sensitivity and have low channel number. In this work, a portable EEG-NIRS prototype is developed having a large channel count to cover the whole head and a high NIRS sensitivity is obtained by the use of avalanche photodiodes. The system is demonstrated to be portable and its power consumption enables battery operation over long periods for continuous monitoring.