QST is a method for accurately determining sensory thresholds in human skin and is particularly useful for determining dysfunction in the nociceptive smaller diameter nerve fibres, although the precise utility of QST in routine clinical neuropathic pain management perhaps requires some further evaluation. There is also increasing interest in using QST in combination with assessment of pain descriptors to give insights into the underlying pathophysiological mechanisms of chronic pain. For example, the presence of brush evoked dynamic allodynia indicates sensitisation at the spinal level. The investigators will use a standardized protocol developed by the german neuropathic pain consortium in which they have great experience. Only limited studies have been performed on inherited painful channelopathies in assessing sensory function. The investigators will correlate findings in QST with pain symptoms and quality of life. The investigators would like to see if specific abnormalities of sensory processing are associated with particular channelopathies.