Imaging photoplethysmography for assessment of chronic pain patients

Abstract

In present pilot study application of multi-spectral imaging photoplethysmography for assessment of chronic pain patients during topical skin heating test was proposed. Photoplethysmography signal was recorded at 420nm, 530nm and 810nm illumination from the skin and corresponding perfusion indexes and perfusion maps were calculated. The novel parameter-PPGflare index was introduced and compared in neuropathic patients and healthy volunteers. Preliminary results suggest that neuropathic patients exhibited significantly lower PPGflare index, and that local heating substantially change PPG waveform at heat exposed skin region. Present study emphasizes advantages of imaging photoplethysmography as a simple and cost-effective alternative to Laser Doppler with promising clinical potential in assessment of neuropathic patients. In this respect, we believe that our study adds novel information to the field of existing chronic pain diagnostics.