This document describes a number of inventions comprising of one or more wearable devices (i.e. attached or applied to limbs, body, head or other body extremities but also applicable to implanted or physiologically attachable systems). These systems have a means of enabling diagnostic or prognostic monitoring applicable to monitoring relevant parameters and corresponding analysis determination and characterisation applicable to the onset or detection of events or health conditions of interest. One application relates to sleep monitoring and associate EEG sensors.
