Due to lacking energy stores, high energy consumption and dependency on a strict aerobic glycolysis, the brain is very dependent on an adequate blood supply of active neurons. Adequate regulation of the functionally induced local cerebral blood flow is assured by neurovascular coupling. Our understanding of its role in different disease processes has improved considerably in the last few years. Consequently, a diagnostic tool is needed which allows an easy and cost-effective investigation of the coupling in clinical conditions. A combined EEG and Doppler technique might be suitable in this regard. This review gives a short overview of the neurophysiological background and the techniques, before validation studies and first clinical applications are addressed.