Neurophysiological observation of the nociceptive system using electrocutaneous stimulation

Adequate observation techniques are required to explore changes in the nociceptive system in pain patients. In this thesis neurophysiological observation methods of nociceptive system are explored. The focus is to explore the merits of electrocutaneous single pulse (SP) and pulse train (PT) stimulation as observation techniques of the nociceptive system. It is shown that in healthy subjects both SP and PT influence evoked potentials (EPs) and subjective ratings; however not all EP components were changed by both methods. For both SP and PT the amplitude of several EP components were inhibited by a heterotopic noxious conditioning stimulus. Results of lumbosacral radicular patients showed that similar EP components were modulated by SP and PT in both patients and healthy subjects. However EP amplitudes were larger or smaller in patients. In this thesis we showed that both SP and PT methods influence EP components and subjective ratings differently. The results shed some light on the link between neurophysiology of nociception and the recorded EPs. We concluded that different ways of processing are involved in both SP and PT method. PT is less dependent on stimulus location, which can be of interest for further research to changes in the nociceptive system of pain patients. Results of patients suggest that the methods can be used to measure changes in the central pain processing in patients. To further analyse changes in the nociceptive system in pain patients different measurement protocols can be formulated based on the SP and PT methods depending on the research question.