Brain perfusion asymmetry in patients with oral somatic delusions

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

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.

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 ^99mTc-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 ^99mTc-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.

Asymmetrical atrophy of thalamic subnuclei in Alzheimer's disease and amyloid-positive mild cognitive impairment is associated with key clinical features

Introduction

Although widespread cortical asymmetries have been identified in Alzheimer's disease (AD), thalamic asymmetries and their relevance to clinical severity in AD remain unclear.

Methods

Lateralization indices were computed for individual thalamic subnuclei of 65 participants (33 healthy controls, 14 amyloid-positive patients with mild cognitive impairment, and 18 patients with AD dementia). We compared lateralization indices across diagnostic groups and correlated them with clinical measures.

Results

Although overall asymmetry of the thalamus did not differ between groups, greater leftward lateralization of atrophy in the ventral nuclei was demonstrated in AD, compared with controls and amyloid-positive mild cognitive impairment. Increased posterior ventrolateral and ventromedial nuclei asymmetry were associated with worse cognitive dysfunction, informant-reported neuropsychiatric symptoms, and functional ability.

Discussion

Leftward ventral thalamic atrophy was associated with disease severity in AD. Our findings suggest the clinically relevant involvement of thalamic nuclei in the pathophysiology of AD.

Oral dysesthesia associated with autistic traits: a retrospective chart review

Oral dysesthesia denotes a condition characterized by abnormal sensations in oral regions without a somatic basis, and is often seen in people with autistic traits, including those with autism spectrum disorder. This study aimed to examine the association between the symptoms of oral dysesthesia and the degree of autistic traits. A retrospective chart review was performed on 44 patients with oral dysesthesia, and associations among the subscales of the Oral Dysesthesia Rating Scale (Oral DRS), Autism Spectrum Quotient (AQ), and Glasgow Sensory Questionnaire (GSQ) were investigated. A Pearson correlation analysis revealed a significant, positive correlation between AQ scores and the A3 (squeezing or pulling) subscale of the Oral DRS (r = 0.37), but there were no significant correlations between the AQ and other subscale scores. There was a significant correlation between the AQ and GSQ score, but no correlation was detected between the GSQ and A3 scores or any other Oral DRS subscale scores. In conclusion, an abnormal squeezing or pulling sensation in oral regions without a somatic basis was associated with autistic traits and could be highlighted as a specific abnormality in sensory processing in autism spectrum disorder.

Clinical characteristics and course of oral somatic delusions: a retrospective chart review of 606 cases in 5 years

OBJECTIVE

Oral cenesthopathy is characterized by foreign body sensations without medical and dental evidence for them. It is thought to be a rare disease in psychiatry, but many patients are visiting dental clinics seeking treatment to remove a foreign body. Even though the features of oral cenesthopathy might be different between a psychiatric clinic and a dental clinic, there has been no clinic-statistical study from dentists. In this study, we report a clinico-statistical study of patients with oral cenesthopathy in dentistry.

METHODS

This is a retrospective chart review of 606 outpatients with oral cenesthopathy in Tokyo Medical and Dental University from April 2010 through to March 2015.

RESULTS

A total of 159 male and 447 female patients were included in this study. The mean age was 62.08 years, and female patients were older than male patients. The trigger of the dental treatment and the acute phase of depression at the onset were significantly related (p=0.037). Only 128 patients (36%) had clinically significant improvement after 6 months of pharmacotherapy. No history of psychiatric disorders (odds ratio [OR] 0.479 [95% confidence interval {CI}: 0.262-0.875], p=0.017) and longer duration of illness (>18 months) (OR 2.626 [95% CI: 1.437-4.799], p=0.002) were significant factors for clinical outcomes.

CONCLUSION

Patients with oral cenesthopathy in our clinic were predominantly elderly female patients. Dental treatment in the acute phase of depression might be a risk factor for oral cenesthopathy. Therefore, comprehending the situation of psychiatric disorder and obtaining adequate informed consent might be required to prevent the trouble concerning oral cenesthopathy.

Two Cases of Oral Somatic Delusions Ameliorated With Brain Perfusion Asymmetry: A Case Report

Background

Oral cenesthopathy is the complaint of abnormal oral sensation where no underlying organic cause can be identified. It is also called oral dysesthesia or oral somatic delusion and classified as delusional disorder, somatic type. The patients with oral cenesthopathy show right > left asymmetric regional cerebral blood flow (rCBF) in the broad brain region. However, the studies scrutinizing the rCBF change before and after the successful treatment are still a few so far.

Case

We present 2 cases of oral cenesthopathy, who responded well to aripiprazole. The asymmetric rCBF patterns were attenuated after successful treatment in both cases.

Conclusions

We found a marked improvement of oral cenesthopathy with aripiprazole. It is suggested that right > left rCBF asymmetry in the frontal and temporal lobes and thalamus, and the dopaminergic and serotonergic dysfunctions are involved in the pathology of oral cenesthopathy.

Oral cenesthopathy

Cenesthopathy is characterized by abnormal and strange bodily sensations and is classified as a ‘delusional disorder, somatic type’ or ‘somatoform disorder’ according to the DSM 5. The oral cavity is one of the frequent sites of cenesthopathy, thus the term ‘oral cenesthopathy.’ Patients with oral cenesthopathy complain of unusual sensations without corresponding abnormal findings in the oral area, such as excessive mucus secretion, a slimy sensation, or a feeling of coils or wires being present within the oral region. They usually visit multiple dentists rather than psychiatrists. Without a proper diagnosis, they repeatedly pursue unnecessary surgical procedures to remove their ‘foreign body’. This sometimes creates a dilemma between the dentists and patients. The nosography of oral cenesthopathy has been discussed in some case reports and reviews but is overlooked in mainstream medicine. This review focuses on the various aspects of oral cenesthopathy.

The estimated prevalence of cenesthopathy was 0.2 to 1.9 % in a study done at a Japanese university psychiatry clinic and 27 % in a study done at a Japanese psychosomatic dentistry clinic. Oral cenesthopathy do not have clear disposition, while some studies reported that elderly women were most commonly affected. Its pathophysiology has not been fully elucidated. However, recent studies have suggested a right > left asymmetrical pattern of the cerebral blood flow of patients with oral cenesthopathy. Antidepressants, antipsychotic drugs, electroconvulsive therapy, and psychotherapy might be effective in some cases, though it is known to be intractable.

To date, the epidemiology, pathophysiology, etiology, classification and treatment of oral cenesthopathy are unknown due to the few reports on the disorder, though there are a few case reports. To overcome this difficult medical condition, clinico-statistical and case–control studies done under rigorous criteria and with a large sample size are required.

Psychosomatic problems in dentistry

Many dental patients complain of oral symptoms after dental treatment, such as chronic pain or occlusal discomfort, for which the cause remains undetermined. These symptoms are often thought to be mental or emotional in origin, and patients are considered to have an "oral psychosomatic disorder". Representative medically unexplained oral symptoms/syndromes (MUOS) include burning mouth syndrome, atypical odontalgia, phantom bite syndrome, oral cenesthopathy, or halitophobia. With an increasing prevalence of these MUOS, dentists are being asked to develop new approaches to dental treatment, which include taking care of not only the patient's teeth but also the patient's suffering. Progress in the understanding of mind-body interactions will lead to investigations on the pathophysiology of MUOS and the development of new therapeutic approaches.

Comparison of cerebral blood flow in oral somatic delusion in patients with and without a history of depression: a comparative case series

BACKGROUND

A significant number of patients visit dental clinics because of unusual oral sensations for which no physical cause can be found. Such patients are recognized as having oral somatic delusion (OSD). OSD may be either primary (monosymptomatic) or secondary to another disease, such as depression or cerebral infarction. Although the presenting complaints of patients with primary and secondary OSD are nearly indistinguishable, symptoms in patients with secondary OSD seem to be resistant to treatment compared with those in patients with primary OSD. Moreover, right dominant cerebral blood flow (CBF) has been reported in patients with primary OSD, but the difference in CBF between patients with primary and secondary OSD remains unclear. The aim of this study was to assess the differences in clinical characteristics and CBF distribution between patients with monosymptomatic OSD (non-depression group) and OSD in conjunction with remitted depression (depression group).

METHODS

Participants were 27 patients of a psychosomatic dentistry clinic, all diagnosed with OSD. They were categorized into either the non-depression group (17 patients) or the depression group (10 patients) on the basis of assessments by their personal medical providers. CBF was examined using single-photon emission computed tomography.

RESULTS

There was no difference in clinical presentation between the two groups. A significant right dominant asymmetry in the temporal and posterior cerebral regions was observed in both groups. In the central region, a right dominance was seen in the non-depression group, while a left dominance was seen in the depression group. Moreover, the mean regional CBF values for patients in the depression group were significantly lower in several regions (including bilateral callosomarginal, precentral, angular, temporal, posterior cerebral, pericallosal, lenticular nucleus, thalamus, and hippocampus; and right central and cerebellum) than for patients in the non-depression group.

CONCLUSION

These results suggest that the temporal and posterior cerebral regions are involved in in the pathophysiology of OSD, regardless of depression history, and that widespread CBF reduction is a characteristic of remitted depression.

Oral Dysesthesia Rating Scale: a tool for assessing psychosomatic symptoms in oral regions

BACKGROUND

The concept of cenesthopathy was first introduced by Dupré and Camus in 1907 to describe clinically unexplainable bodily sensations mainly attributed to psychiatric pathology. If it occurs in oral regions, it is termed oral cenesthopathy and it has been of special interest to psychiatrists and dentists. While there is no independently defined criteria for this condition, which is classified as either a delusional or a somatoform disorder, clinical practice and research require a standard scale to measure and rate its symptoms. In this study, we included any types of psychosomatic symptoms in oral regions as oral dysesthesia, and developed an Oral Dysesthesia Rating Scale (Oral DRS) and evaluated its validity and reliability as an assessment tool.

METHODS

The scale was developed based on literature review and extensive clinical experience. Twelve reviewers assessed relevancy of each item to oral dysesthesia symptoms by 1-4 scoring scale and item content validity index was computed. To evaluate the inter-rater reliability of Oral DRS, pairs of raters administered the scale to 40 randomly selected patients with complaints of oral dysesthesia symptoms and Cohen's weighted kappa coefficient was determined for each item.

RESULTS

The scale assesses the severity of feelings of foreign body [A1], exudation [A2], squeezing-pulling [A3], movement [A4], misalignment [A5], pain [A6], and spontaneous thermal sensation or tastes [A7], and the degree of impairment in eating [B1], articulation [B2], work [B3], and social activities [B4] on a scale of 0-5. Items A1, A2, A3, A4, B3, and B4 demonstrated acceptable content validity. Inter-rater reliabilities were good or excellent for all items evaluated.

CONCLUSION

The Oral DRS can help define the nosography of clinically unexplainable oral dysesthesia through further case evaluation and clinical research and facilitate devising of treatment modalities.