This invention provides an EEG-based method of determining whether a test subject is sufficiently alert to perform a predefined task. The non-invasive method permits continuous monitoring of the individual's EEG signal, producing a set of real time frequency bands that indicate their state of wakefulness. When the frequency bands begin to skew towards the lower end, indicating the onset of drowsiness and eventual sleep, the system optionally sounds an acute alarm tone to alert the individual back to attention. The method also provides remotely monitoring the alertness of an individual and can be used, for example, to monitor productivity. In addition, the technology monitors self-recognized errors through the utilization of the ERN waveform. The remote or in-person monitoring can be continuous for any period of time.