Comparison of Cerebral Blood Flow Patterns in Patients with Phantom Bite Syndrome with Their Corresponding Clinical Features

BACKGROUND: Phantom bite syndrome (PBS) is characterized by an uncomfortable sensation during occlusion without any evident abnormality. A recent case–control study with single-photon emission computed tomography (SPECT) using (99m)Tc-ethyl cysteinate dimer could not find the specific features of regional cerebral blood flow (rCBF), which might be due to the heterogeneity of PBS. We analyzed the brain images of PBS corresponding to the clinical features by studying PBS subgroups. METHODS: This study contributes to elucidating the pathophysiology of PBS by evaluating regional brain perfusion on SPECT and its clinical features. We performed SPECT using (99m)Tc-ethyl cysteinate dimer in 44 patients with PBS. The SPECT images were analyzed qualitatively and quantitatively. RESULTS: Asymmetrical rCBF patterns were detected, corresponding to symptom laterality. Patients with PBS with right-side symptoms showed right-side-predominant rCBF asymmetry in the parietal region and left-side-predominant rCBF asymmetry in the thalamus, and vice versa. Moreover, the analysis of the association between rCBF and patient behaviors revealed that patients who blamed their dentists for their symptoms tended to have a symmetrical rCBF pattern. CONCLUSION: Patients with PBS showed blood flow imbalance in the thalamus and parietal region corresponding to symptom laterality. There are two types of symmetrical and asymmetrical rCBF patterns in the pathophysiology of PBS despite similar clinical manifestations.