Arousal profiles are a method that we have developed for using data derived from time sampling to examine how behaviours such as the frequency with which the eyes are observed open, and the frequency of spontaneous movements, vary in the periods immediately before and immediately after sensory stimulation treatment. We believe changes in such behaviours reflect changes in arousal. The use of this new technique is illustrated with examples from a pilot study using data from 15-day treatment blocks, gathered for 10-minute periods immediately before and after sensory stimulation treatment from three patients using single-case research methods. The patients were diagnosed as being in vegetative state following traumatic brain injury. The possible significance of the differing characteristics of the profiles is discussed.