Thesis defence « Psychophysical, neurophysiological and morphological studies of small fibre neuropathies » presented by M. Michaël Rage.

As he has mentioned in his abstract, "lesions to the contingent of thin peripheral afferents cause small fibre neuropathies (SFN), a large and heterogeneous class of peripheral neuropathies with a great variety of etiological factors and pathophysiological mechanisms. As these small calibrated afferents (lightly myelinated Aδ- and unmyelinated C-fibres) mainly participate to the thermonociceptive system, lesions of the pathways are responsible for disorders of thermal sensitivity and often cause severe chronic intractable neuropathic pain and might significantly affect the quality of life. Unfortunately, somatosensory thermo-nociceptive pathways cannot be investigated by conventional electrophysiological methods for multiple technical reasons. Conventional non-invasive methods to investigate the peripheral nervous system in early stages of SFN are difficult because of the lack of validity and sensitivity. Another limitation of standard tests can result from the difficulty to stimulate selectively the thermonociceptive system and to avoid the co-activation of non-nociceptive somatosensory afferents.

 

In the present thesis, we explored and determined the validity and reliability of nociceptive tests for the psychophysical and electrophysiological assessment of SFNs based mainly on CO2-laser technology, whose stimulation characteristics make it possible to activate selectively the free Aδ- and C-nociceptors located above the dermo-epidermal junction, and on the contact thermode (quantitative sensory testing, QST). Functional assessments of the nociceptive system were also correlated to the data with morphometric measures of the density of intraepidermal nerve fibres estimated from a skin punch biopsy."

 

The results of his studies are available in the current abstract . For more detail, you are warmly welcomed at his public defence.