Pain-associated adaptive cortical reorganisation in chronic pancreatitis

In various chronic pain conditions cortical reorganisation seems to play a role in the symptomatology. The aims of this study were to investigate cortical reorganisation in patients with pain caused by chronic pancreatitis (CP) and to correlate putative cortical reorganisation to clinical pain scores.

24 patients suffering from CP and 14 healthy volunteers were included. Patients' daily experience of pain was recorded in a pain diary. The sigmoid was stimulated electrically with simultaneous recording of evoked brain potentials (EPs). The brain source localisations reflecting direct neuronal activity were fitted by a five-dipole model projected to magnetic resonance imaging of the individual brains.

Patients showed prolonged latencies of the EPs confined to the frontal region of the brain (p < 0.01). The corresponding brain sources were located in the bilateral insula, cingulate gyrus and bilateral secondary somatosensory area. The insular dipoles were localised more posterior in the patients than in healthy subjects (p < 0.01). The shift in insular dipole localisation was negatively correlated with the patients' clinical pain scores (p < 0.05).

The findings indicate that sustained pain in CP leads to functional reorganisation of the insular cortex. We suggest its physiological correlate to be an adaptive response to chronic pain. and IAP.