Background and aims: Central sensitization is a major factor contributing to the development and persistence of neuropathic pain. The lack of quantitative measures to objectively assess sensitization hampers the development of effective treatment options. As hyperexcitability is observed in both somatosensory and autonomic nervous systems, the aim was to investigate modulation of sensory-autonomic interactions in response to noxious pinprick stimulation after experimentally induced central sensitization. 
Methods: Twenty healthy individuals underwent 3 blocks of 15 pinprick stimuli (256mN) to the volar forearm before (PRE) and after (POST) an experimental and control intervention, separated by 2 weeks. A repetitive phasic heat pain model was applied to induce secondary hyperalgesia to pinprick in the experimental, but not in the control intervention. The adjacent skin was stimulated to capture the effect of experimentally induced central sensitization on PEP and sympathetic skin response (SSR) habituation. QST was performed prior to the PRE and POST condition. 
Results: PEP amplitudes (p=0.003) and pain ratings (p=0.0004) to pinprick were increased in the area of secondary hyperalgesia, whereas no changes were observed in the control intervention. PEP habituation from the PRE to the POST assessment did not differ between the experimental and control interventions. Preliminary analysis showed increased amplitudes and reduced habituation of SSR. 
Conclusions: PEP amplitudes in combination with SSR habituation may represent a useful tool to objectively quantify mechanical hyperalgesia in experimentally and pathology-induced central sensitization. This approach might contribute towards a comprehensive phenotyping of neuropathic pain patients and ultimately provide mechanism-based treatment options.

SENSORY-AUTONOMIC INTERACTION: A READOUT OF CENTRAL SENSITIZATION