Distinct theta and alpha electrophysiological dynamics during audiovisual semantic processing in healthy aging and mild cognitive impairment.

Orofacial pain is a global term that comprises a category of disorders that include neuropathic pain, neurovascular disorders, and musculoskeletal disorders such as temporomandibular disorders (TMD) (). Musculoskeletal pain affecting the masticatory muscles, known as orofacial musculoskeletal pain (OMP), is considered a painful TMD subtype and represents one of the leading causes of pain in the orofacial region. It is characterized by hypersensitivity in the masseter and/or temporalis muscles and this condition can impair essential functions of the stomatognathic system, such as chewing and speech. The development and severity of this condition can be influenced by different situations, like anatomical or biomechanical factors, sleep disturbances, sedentarism, and stress (). According to Svensson (), painful TMD is typically chronic, bilateral, diffuse, and associated with jaw movement, aligning with the criterion for nociplastic pain addressed by Kosek et al. (). Nociplastic pain is characterized by altered nociception without clear evidence of tissue damage or dysfunction of the somatosensory system and is often associated with central sensitization, a process involving amplification of the central nervous system's response to painful stimuli. Generalized pain sensitization, as seen in conditions such as fibromyalgia, chronic headaches, and TMDs, highlights the role of dysfunction in central inhibitory and facilitatory pathways in pain processing. Patients with nociplastic pain often experience multiple widespread pain, fatigue, sleep disturbances, cognitive difficulties, and various somatic symptoms, in addition to high levels of emotional distress, anxiety, depression, and pain catastrophizing (,). Clinical trials on orofacial nociplastic pain conditions, such as painful TMD, identify stress as a predictor factor for pain, suggesting that psychosocial factors interact with other variables, worsening pain in the facial region (). Emotional stress (ES) is a prevalent medical condition that provokes adaptive reactions controlled by neurohormonal processes aimed at maintaining physiological integrity. Increasing evidence indicates that ES can influence both the onset and maintenance of orofacial pain. This interplay between psychosocial stressors and pain highlights the involvement of central neural mechanisms, supporting hypotheses centered on sensitization processes (,,).