Clinical Characteristics of Predominantly Unilateral Oral Cenesthopathy With and Without Neurovascular Contact

Abstract

Oral cenesthopathy (OC) is characterized by unusual oral discomfort without corresponding evidence, and it has often been categorized as "delusional disorder, somatic type". Regarding possible causative factors of OC, involvement of neurovascular contact (NVC) of the trigeminal nerve, which transmits not only pain but also thermal, tactile, and pressure sensations, has never been observed yet. This study aimed to investigate the relationship between clinical characteristics of unilateral OC and the presence of trigeminal nerve NVC. This is a retrospective comparative study that involved 48 patients having predominantly unilateral OC who visited the Psychosomatic Dentistry Clinic of Tokyo Medical and Dental University between April 2016 and February 2019. Magnetic resonance imaging was performed to assess NVC presence. The Oral Dysesthesia Rating Scale (Oral DRS) was used to assess the various oral sensations and functional impairments besides psychometric questionnaires. Clinical characteristics were retrospectively obtained from the patients' medical charts. NVC was present in 45.8% (22/48) of the patients. There was no significant difference in sex, age, psychiatric history, oral psychosomatic comorbidity, and psychometric questionnaire scores between patients with and without NVC. However, compared to the patients with NVC, the patients without NVC had significantly higher scores for overall subjective severity of OC symptoms (p = 0.008). Moreover, patients having predominantly unilateral OC without NVC showed significantly higher scores in symptom severity and functional impairment of the following parameters: movement (p = 0.030), work (p = 0.004), and social activities (p = 0.010). In addition, compared with the patients with NVC, the patients without NVC showed significantly higher averages of the total symptom severity scale (SSS) and functional impairment scale (FIS) scores in the Oral DRS (p = 0.015 and p = 0.031, respectively). Furthermore, compared with the patients with NVC, the patients without NVC had significantly higher numbers of corresponding symptoms in both the SSS and FIS (p = 0.041 and p = 0.007, respectively). While NVC may be involved in the indescribable subtle OC symptoms, more complex mechanisms may also exist in OC patients without NVC, which yield varying and more unbearable oral symptoms.

Keywords: Oral DRS; burning mouth syndrome; delusional disorder somatic type; magnetic resonance imaging; neurovascular contact; oral cenesthopathy; trigeminal nerves; trigeminal neuralgia.

Figure 1

A flowchart of the patients' selection. Flowchart showing the selection of the patients having predominantly unilateral oral cenesthopathy for inclusion in the present study. OC, oral cenesthopathy; MRI, magnetic resonance imaging; NVC, neurovascular contact; BMS, burning mouth syndrome; PIFP, persistent idiopathic facial pain; PBS, phantom bite syndrome.

Figure 2

The MR images of NVC of the trigeminal nerves. A 57-year old man with NVC of the trigeminal nerves (arrowheads). The superior cerebellar artery was the responsible blood vessel (arrow). (A) Transverse view of the 3D-CISS image, (B) sagittal view, (C) coronal view, (D) MIP display of 3D-TOF MRA. Abbreviations: MR, magnetic resonance; NVC, neurovascular contact; 3D-CISS, 3D constructive interference in steady-stat; MIP, maximum intensity projection; 3D-TOF MRA, 3D time-of-flight magnetic resonance angiography.

Figure 3

The oral DRS scores in the patients having predominantly unilateral OC with and without NVC. (A) The overall subjective severity of OC symptoms: The patients without NVC presented significantly higher VAS scores that indicate overall subjective severity of OC symptoms according to Student's t-test. (B) The Oral DRS scores: The patients without NVC showed significantly higher scores in the parameters of movement, work, and social activities than patients with NVC. Mann–Whitney U-test was used for each parameter. (C) The total scores of corresponding categories in the SSS and FIS: The patients without NVC showed significantly higher averages of the total scores and the number of corresponding symptoms in both the SSS and FIS than the patients with NVC based on Student's t-test. (D) Total number of corresponding categories in the SSS and FIS: The patients without NVC showed significantly higher number of the total number of corresponding symptoms in both the SSS and FIS than the patients with NVC according to Mann–Whitney U-test. For the box-and-whisker plot in panels (A,C,D) the line in the middle indicates the median; the top and bottom lines show the first and third quartiles. The cross marks show the mean values, and the whiskers extend to 1.5 times the height of the box or, if no case/row has a value in that range, to the minimum or maximum values. The points are outliers. VAS, Visual Analog Scale; Oral DRS, Oral Dysesthesia Rating Scale; OC, oral cenesthopathy; NVC, neurovascular contact; SSS, symptom severity scale; FIS, functional impairment scale.