Prefrontal modulation during chewing performance in occlusal dysesthesia patients: a functional near-infrared spectroscopy study

Objectives: Neuropsychological associations can be considerable in occlusal dysesthesia (OD) patients who routinely complain of persistent occlusal discomfort, and somatization effects in the superior medial prefrontal cortex and the temporal and parietal regions are also present. However, the relationship between physical activity, i.e., chewing, prefrontal cognitive demand, and psychiatric states in OD patients remains unclear. We investigated this relationship in this study. Materials and methods: OD patients (n = 15) and healthy control (n = 15; HC) subjects were enrolled in this study. Occlusal contact, chewing activities of the masticatory muscles, prefrontal activities, and psychiatric states such as depression and somatization, of the participants were evaluated. Functional near-infrared spectroscopy was used to determine prefrontal hemodynamics and the Symptom Checklist-90-R was used to score the psychiatric states. Results: We observed a significant association between prefrontal deactivation during chewing and somatization subscales in OD patients. Further, there were no significant differences with regard to the occlusal state and chewing physical activities between the OD patients and HC subjects. Conclusions: Chewing-related prefrontal deactivation may be associated with somatization severity in OD patients. Clinical relevance: fNIRS is a functional imaging method that uses the principal of neuro-vascular couplings. It is applicable for evaluation of psychiatric state based on prefrontal cortex blood flow in patients with psychiatric disorders.