Reports of perceptual distortion of the face are common in patients with different types of chronic oro-facial pain

Anecdotally, chronic oro-facial pain patients may perceive the painful face area as 'swollen'. Because there are no clinical signs, these self-reported 'illusions' may represent perceptual distortions and can be speculated to contribute to the maintenance of oro-facial pain. This descriptive study investigated whether chronic oro-facial pain patients experience perceptual distortions - a kind of body image disruption. Sixty patients were consecutively recruited to fill in questionnaires regarding i) pain experience, ii) self-reports of perceptual distortion and iii) psychological condition. Perceptual distortions were examined in the total group and in three diagnostic subgroups: i) painful post-traumatic trigeminal neuropathy (PPTN), ii) painful temporomandibular disorder (TMD) or iii) persistent idiopathic facial pain (PIFP). A large proportion of oro-facial pain patients reported perceptual distortions of the face (55.0%). In the diagnostic subgroups, perceptual distortions were most pronounced in PPTN patients (81.5%) but with no significant group differences. In the total group of chronic oro-facial pain patients, the present pain intensity explained 16.9% of the variance in magnitude of the perceptual distortions (R-2 = 16.9, F(31) = 6.3, P = 0.017). This study demonstrates that many chronic oro-facial pain patients may experience perceptual distortions. Future studies may clarify the mechanisms underlying perceptual distortions, which may point towards new complementary strategies for the management of chronic oro-facial pain.