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

Abstract

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.

Multisensory modulation of experimentally evoked perceptual distortion of the face

“…Descriptions of such distortion are commonly encountered in the dental clinic due to peripheral sensory deprivation of the region with local anaesthetics (LA) . Furthermore, distortion of corporal awareness has been documented for patients suffering from various psychological and neurological conditions, accounting non‐painful such as phantom sensations and anorexia nervosa, and painful conditions such as oro‐facial pain, complex regional pain syndrome and phantom limb pain . Factors underlying these disturbances remain elusive .…”

“…Factors underlying these disturbances remain elusive . In addition to pain, oro‐facial pain patients often suffer from somatosensory malfunctions and describe the region as “different”, “numb” or “rubber like” . Multisensory retraining therapies that target both the mechanical and visual systems have been shown to be effective in decreasing burdens associated with hypo‐aesthetic oro‐facial sensations and other unpleasant sensations in the face .…”

Effect of repetitive transcranial magnetic stimulation on altered perception of One’s own face

“…Distorted body image or PD has been extensively studied in many conditions such as phantom sensations, anorexia nervosa, chronic back pain and CRPS [6e9]. However, only a few studies have looked into such a phenomenon in the orofacial region [3,13,14], although a study reported that 55% of the chronic orofacial pain patients experienced PD [12]. Changes in the facial perception can be studied by employing LA, multisensory stimulation or by stimulating the peripheral sensory afferents, resulting in a striking illusion of a measurable changed perception as seen in the present study [5,11,14].…”

“…Thus, PD is considered as a multisensory phenomenon [11]. Orofacial pain patients often report that the painful facial area is "swollen" or "feels differently" [12,13]. There are often no clinical signs or physical differences present, hence such self-reported "illusions" may represent a sort of disrupted body image or a "perceptual distortion" of the face, and may contribute to the maintenance of facial pain [12e14].…”

Neuropathic orofacial pain: Facts and fiction

“…Paroxysmal pain may be spontaneous or initiated by touch or function (18,29). Patients may complain of swelling (not always verifiable clinically), a foreign body, heat or cold, local redness or flushing (20,29,35).…”