A monitoring or predicting system to detect the onset of a neurological episode and a method of detecting the onset of a neurological episode are disclosed. The system comprises a neurological electrical input, a converter, a pattern analyser and a monitor. The input is a digital representation of a neurologically derived signal. The converter is adapted to convert the digital signal into a digital data string and the pattern analyser is adapted to identify recurring patterns in the digital data string. The monitor is adapted to measure a pattern-derived parameter related to one or more of: a count of the recurring patterns in the digital data string； a proportion of recurring patterns in the digital data string； a rate of change of a count of the recurring patterns in the digital data string； and a rate of change of a proportion of recurring patterns to anomalies in the digital data string. An output from the monitor gives an indication of the onset or occasion of a neuronal activity in dependence on the pattern-derived parameter.
