Development of Stimulator Pneumatic for Realization of Evoked Potential Allodynic/Somatosensory

The stimuli used in the evoked potentials are electrical or laser. They are started and synchronized with the collection of the EEG by signals TTL (transistor-transistor logic). Investigators propose to validate a pneumatic stimulator delivering the compressed air sync with the EEG. It has two advantages over existing stimuli: Is capable of inducing in patients an allodynic response, excessive, painful, in response to a stimulation painless rarely obtained with laser or electrical stimuli. Therefore, the pneumatic stimulation is a means to study allodynic evoked potentials unknown to date. It must be possible with a single stimulator to explore non-painful sensations and allodynic sensation , compare them with one device. The differences are the abnormal responses. This validation assumes evoked potential recording 1. somatosensory (low stimulation) then 2. allodynic (only in patients). The study therefore provides for the registration 100 potential for each of these two modalities in patients and only for the painless pneumatic modality in volunteers.