Abstract|Pain 1| Volume 357, SUPPLEMENT 1, e90, October 15, 2015

Contact heat evoked potentials (CHEPS) in patients with painful and non-painful polyneuropathies

      Background: CHEPS evaluate central and peripheral thermo-algesic pathways. There are few studies comparing CHEPS in polyneuropathies and central nervous system disorders with and without neuropathic pain.
      Objective: To compare CHEPS in controls and patients with polyneuropathies and central nervous system disorders(CNS) with and without neuropathic pain.
      Patients and methods: 58 M, 70 F. Mean age 52.5 years (range 21–83). 27 normal controls. 53 polyneuropathies with sensory involvement (16 small fibre), 39 painful. 25 had CNS disease, 17 painful. 21 had other peripheral conditions. CHEPS (Medoc, Israel) thermode was placed on the distal forearm and leg, baseline T° 37 °C, target T° 54 °C. Random interstimulus interval 10–15 seconds. 2 trains of 10 stimuli averaged and superimposed recorded from CZ-A1/A2. Filters 3–100 Hz. N2 latency and N2-P2 amplitude measured. Parametric and non-parametric statistics as appropriate.
      Results: The morphology of CHEPS was similar in central and peripheral lesions. CHEPS were absent in the legs significantly more in all groups than in controls. The mean amplitudes in lower limbs in painful and non-painful polyneuropathies and in CNS disease were smaller than in controls. Mean N2 latency was prolonged (compared to controls only) in the arm of CNS diseases and in the leg of painful polyneuropathies and non painful CNS diseases.
      Conclusions: CHEPS seems to be a reliable technique to assess the thermoalgesic pathway in sensory polyneuropathies and CNS disorders. The technique did not differentiate between painful and non-painful polyneuropathies nor between sensory polyneuropathies and CNS lesions.
      *Fondecyt 1120339: LAcevedo, GBarraza, MCampero, JLCastillo, GCavada, RGuiloff, JHoneyman, RHughes, JMMatamala EMullins, POrellana, CRamirez, HRojas, ISazunic, RVerdugo, YWang.