Clinical and Phenomenological Characteristics of Patients with Task-Specific Lingual Dystonia: Possible Association with Occupation

Peripherally induced movement disorders in the stomatognathic system after oral surgical or dental procedures

OBJECTIVES

Peripherally induced movement disorders (PIMD) are hyperkinetic movement disorders that can occur after injury to a part of the body. This study aimed to identify PIMD in the stomatognathic system following dental or oral surgical procedures.

MATERIALS AND METHODS

A total of 229 patients with PIMD (144 women and 85 men; mean age: 53.4 years) triggered by oral surgical or dental interventions were evaluated retrospectively.

RESULTS

The average latency between the procedures and onset of PIMD was 14.3 days. Oral surgery (40.2%), including tooth extraction, trauma treatment, and other surgical procedures, was the most frequent trigger of PIMD. This was followed by general dental treatment, including periodontal, endodontic, and restorative procedures (36.7%), prosthetic treatment (19.7%), and orthodontic treatment (3.5%). PIMD consisted of oromandibular dystonia (73.8%), functional (psychogenic) movement disorders (11.4%), orolingual dyskinesia (7.9%), and hemimasticatory spasms (5.7%).

CONCLUSIONS

These results suggest that even minor alterations in normal anatomy or physiology after dental procedures may result in PIMD in predisposing patients.

CLINICAL RELEVANCE

Dental professionals should be aware that although infrequently, PIMD can develop after various dental treatments. If such symptoms precipitate, the attending physician should properly explain them to the patient and provide appropriate treatment or consultation with a movement disorder specialist.

Task-Specific Lingual Dystonia During Japanese Religious Services

INTRODUCTION

Lingual dystonia is a subtype of oromandibular dystonia characterized by involuntary contractions of the tongue muscles, often provoked by speaking or eating.

METHODS

This study reports six Japanese cases (four female and two male, mean age at onset of 49.5 years) with task-specific lingual dystonia during praying. In the early phase, all patients experienced lingual protrusion exclusively during Japanese religious services. When the patients start speaking, the tongues protrude forward, making it difficult to pronounce words. The patients were treated with multimodal treatment, including muscle afferent block (MAB) therapy comprising local anesthetic injection, botulinum toxin (onabotulinumtoxinA) injection, and a sensory trick splint.

RESULTS

MAB therapy was conducted in five patients (mean time: 5.8), and botulinum toxin injection was administered in four patients (mean time: 8). The injected muscles were the genioglossal muscles and, in one case, the lateral pterygoid muscle. Sensory trick splints were inserted in three patients. After the multimodal therapy, the patients were able to pronounce words smoothly and clearly. Oromandibular Dystonia Rating Scale scores improved significantly (P<0.005) from baseline (187 points) to endpoint (47 points) with a mean follow-up of 4.7 years.

CONCLUSION

Although this entity is rare, medical and dental professionals should be aware of this peculiar symptom. Multimodal therapy is required to ensure effective treatment of praying-induced lingual dystonia.

Task-specific oromandibular dystonia secondary to chewing Khat (Catha edulis)- A series of 35 cases

BACKGROUND

The leaves of "Khat" (Catha edulis), an indigenous shrub of Yemen and Arabian Peninsula are habitually chewed by the inhabitants for psychostimulant properties.

OBJECTIVE

To describe a unique task specific Oro-mandibular dystonia (OMD) in Yemenese men, with a temporal association with chewing "Khat".

METHODS

Multicentric, retrospective analysis (2009-2020) of patients with OMD associated with "Khat" chewing, evaluating clinical features and response to Onabotulinum toxin A.

RESULTS

35 Yemenese men with a negative family history, normal neuroimaging mean age of 44.31(±3.21) years and prolonged (20.31 ± 3.27 years) history of chewing Khat, around 5.16(±0.80) hours/day presented with OMD-20 jaw opening, 13 jaw closing and 2 mixed affecting chewing (n = 6), speech (n = 3), or both (n = 26). Additional lingual dystonia was seen in five.

CONCLUSIONS

Chewing of khat is a repetitive task involving the jaw musculature and may be one of the causative factors of this task specific OMD. Recognition can prevent disability in these regions.

Botulinum Toxin Therapy for Oromandibular Dystonia and Other Movement Disorders in the Stomatognathic System

Various movement disorders, such as oromandibular dystonia, oral dyskinesia, bruxism, functional (psychogenic) movement disorder, and tremors, exist in the stomatognathic system. Most patients experiencing involuntary movements due to these disorders visit dentists or oral surgeons, who may be the first healthcare providers. However, differential diagnoses require neurological and dental knowledge. This study aimed to review scientific advances in botulinum toxin therapy for these conditions. The results indicated that botulinum toxin injection is effective and safe, with few side effects in most cases when properly administered by an experienced clinician. The diagnosis and treatment of movement disorders in the stomatognathic system require both neurological and dental or oral surgical knowledge and skills, and well-designed multicenter trials with a multidisciplinary team approach must be necessary to ensure accurate diagnosis and proper treatment.

[Therapeutic strategies for oromandibular dystonia]

Oromandibular dystonia is characterized by tonic or clonic involuntary spasms of the masticatory, lingual and / or muscles in the stomatognathic system. It is often misdiagnosed as craniomandibular dysfunction or psychiatric disease. According to clinical features, the oromandibular dystonia is classified into 6 subtypes (jaw closing-, jaw opening-, tongue-, jaw deviation-, jaw protrusion-, and lip dystonia). There are several treatment methods like botulinum toxin injection, muscle afferent block (injection of lidocaine and alcohol into the masticatory or tongue muscles for blocking muscle afferents from muscle spindle), occlusal splint, and oral surgery (coronoidotomy). Most of patients can be treated successfully according to subtype by combination of these treatments. Special treatment recommendations for each subtype were described in this focus article. Accurate diagnosis and treatment of oral dystonia requires comprehensive knowledge and skills of both oral and maxillofacial surgery and neurology. Therefore, collaboration among these departments is very important.

Development and Validation of a Disease-Specific Oromandibular Dystonia Rating Scale (OMDRS)

Background: Oromandibular dystonia manifests with sustained or task-specific contractions of the masticatory, tongue, and/or other muscles in the stomatognathic system. Since its symptoms can vary, it has been difficult to objectively measure disease severity and post-treatment changes. Objective: To develop and validate a comprehensive measurement tool for oromandibular dystonia. Methods: An examiner-rated scale included three subscales for severity, disability, and pain, modified specifically for oromandibular dystonia from the Toronto Western Spasmodic Torticollis Rating Scale-2. To evaluate the severity of each subtype of oromandibular dystonia, four of the six items were selected according to the subtype (jaw closing dystonia, tongue dystonia, jaw opening dystonia, jaw deviation [protrusion] dystonia, and lip dystonia). A patient-administered questionnaire based on clinical features and other relevant aspects associated with oromandibular dystonia was developed, which included five subscales: general, eating, speech, cosmetic, and social/family life. The questionnaire, examiner-rated scale, and four subscales (sleep, annoyance, mood, and psychosocial functioning) of the Cervical Dystonia Impact Profile-58 were combined to construct the oromandibular dystonia rating scale (OMDRS). The reliability and validity of the scale were assessed using clinimetric testing. Results: Six hundred and eighteen patients with oromandibular dystonia (394 women and 224 men; mean age, 51.7 years) were evaluated by the OMDRS. The overall OMDRS showed high-level internal consistency measured by Cronbach's alpha (0.95) with a logical factor structure. Cronbach's alpha for the subscales was satisfactory to excellent, ranging from 0.72 to 0.94. All items revealed acceptable inter-rater reliability (kappa > 0.4, interclass correlation coefficient > 0.6). Repeated ratings of videotapes revealed acceptable intra-rater reliability for all items (kappa > 0.76, interclass correlation coefficient > 0.86). Test-retest reliability showed a significant (p < 0.001) correlation efficiency. The OMDRS showed significant (p < 0.001) convergent and discriminant validity and significant (p < 0.001) sensitivity to changes after botulinum toxin therapy. Conclusion: The OMDRS can be useful for the comprehensive evaluation of disease severity, disability, psychosocial functioning, and impact on the quality of life as well as therapeutic changes in patients with oromandibular dystonia.

Prevalence and clinical characteristics of patients with oromandibular dystonia seen in the orofacial pain clinic: a retrospective study

OBJECTIVE

The aim of this study was to describe the prevalence and clinical characteristics of patients with oromandibular dystonia (OMD) presenting to an academic orofacial pain clinic. OMD diagnosis was based on clinical signs and symptoms, presenting in varied forms and severities. Knowledge of clinical characteristics would help in early diagnosis and treatment of OMD.

STUDY DESIGN

In this retrospective study, we identified patients with OMD (International Classification of Diseases [ICD]-9 diagnostic code 333.82 and ICD-10 code G24.4) who presented at the clinic from October 2012 to December 2017. Additional selection criteria were age greater than 18 years and confirmation of OMD diagnosis with at least 1 follow-up visit.

RESULTS

Over a 5-year period, 22 patients with OMD were identified according to the ICD diagnostic codes, and of those, 6 patients met the selection criteria corresponding to a prevalence of 170 per 100,000 (95% confidence interval [CI] 70-390). The most common chief complaint was jaw pain (67%), and all patients had associated diagnosis of myofascial pain of masticatory muscles.

CONCLUSIONS

The prevalence of patients with OMD in an academic orofacial pain clinic is higher than previously reported in population-based studies. The presentation of OMD often includes temporomandibular disorders (TMDs), with involvement of various masticatory muscles.

Case Report: Isolated Lingual Dystonia

Oromandibular dystonia is defined as a focal dystonia that manifests as forceful contractions of the face, jaw, and/or tongue. Lingual dystonia is a rare subtype of oromandibular dystonia that specifically affects the tongue. Multiple etiologies are thought to attribute to oromandibular dystonia, including brain damage, the use of neuroleptic medications, neurodegenerative disorders, metabolic disorders, neurodevelopmental disorders, and viral infections. Idiopathic cases of isolated lingual dystonia are rare and seldom reported in the literature. This report describes a 35-year-old female patient with lingual dystonia that was present at rest and aggravated during speech. Despite detailed history taking and a thorough examination, along with multiple imaging and laboratory studies, no cause could be established and her case was classified as being that of an idiopathic etiology.

Clinical Characteristics of Functional Movement Disorders in the Stomatognathic System

Background: Functional (psychogenic) movement disorders often have distinguishable clinical features in the orofacial region. Tonic mandibular deviation accompanying ipsilateral downward and lateral lip pulling is the most common phenotype seen in patients with facial functional movement disorders. However, functional movement disorders in the stomatognathic system are underrecognized. Objective: This study aimed to evaluate clinical characteristics and phenomenology in patients with functional movement disorders in the stomatognathic system. Methods: Ten-item inclusion criteria (point range: 0-10) for functional movement disorders in the stomatognathic system was produced, based on previously established criteria for functional movement disorders and general signs of functional facial dystonia, to determine subject inclusion. The criteria included inconsistency, incongruence, and paroxysm in symptoms; rapid onset; distractibility; suggestibility; static course; spreading to multiple sites; spontaneous remission; and lack of sensory tricks. Fifty-eight patients [42 women (72.4%), 16 men (27.6%); mean age: 46.2 years] scored over 7 points on the criteria and were included in further analyses. Characteristic features, including the pattern and site of abnormal movements, were assessed in clinical examination. Results: Frequent items in the scale were inconsistent symptoms (93.1%), incongruous symptoms (91.4%), spreading to multiple sites (89.7%), paroxysmal symptoms (86.2%), and lack of sensory tricks (81%). Sixty percent of patients exhibited a pattern resembling dystonia. Some patients had a combination of organic and functional disease. Common involuntary movements included jaw deviation (74.1%), jaw closing (50%), lip pulling (34.5%), and tongue movement (31%). A functional dystonia phenotype (unilateral lower lip pulling and jaw deviation) was observed in 26 patients (44.8%). Characteristic features of functional stomatognathic movement disorders were rapidly repeating mandibular (lateral or tapping) and tongue movements (27.6%), which fluctuated in speed and direction. Conclusion: In 58 patients with functional movement disorders in the stomatognathic system, the functional dystonia phenotype was observed in 44.8%. Furthermore, 27.6% of patients showed the most characteristic type of functional stomatognathic movement disorders: very fast repeated jaw and/or lingual movements.

Factors Associated with Untreated Decayed Teeth in Male Sales Workers: An Internet Survey

The purpose of this study was to identify factors associated with untreated decayed teeth (DT) in male sales workers. The participants were recruited by screening a pool of Japanese registrants in an online database for eligibility for inclusion in the study. Between 20 February 2015 and 11 March 2015, those deemed eligible were asked to complete a questionnaire on the status of their oral health. Responses from a total of 142 male sales workers aged between 30 and 49 years were analyzed. Of these, 40 reported DT and 102 no untreated decayed teeth (NDT). The percentage of participants with DT was higher than that with NDT among night shift workers (p<0.001). A higher percentage of participants with DT reported pain when eating or drinking something cold (p=0.041), pain in the teeth or gingiva (p<0.001), or frequent stomatitis (p=0.030). A higher percentage of participants with DT reported eating between meals (p=0.027) and a lower percentage visiting a dental clinic in the past 6 months (p=0.017) compared with among participants with NDT. Those with NDT were more likely to report an inability to visit a dental clinic when they wanted to (p=0.033), but those with DT were more likely to report that their reasons for not visiting a dental clinic were that multiple visits were required for treatment (p=0.012) or that they did not like the treatment (p=0.005). Working the night shift (Odds Ratio [OR], 3.492; 95% Confidence Interval [CI], 1.347-8.725) and visiting a dental clinic in the past 6 months (OR, 0.084; 95%CI, 0.010-0.733) were identified as independent variables correlated with leaving DT untreated. Requiring oral health education and dental checkups at least once every 6 months may have a positive effect on oral health among male sales workers, especially those doing night shifts.

Botulinum Neurotoxin Therapy for Lingual Dystonia Using an Individualized Injection Method Based on Clinical Features

Lingual dystonia is a debilitating type of oromandibular dystonia characterized by involuntary, often task-specific, contractions of the tongue muscle activated by speaking or eating. Botulinum neurotoxin (BoNT) has been used to treat lingual dystonia; however, it is known to cause serious complications, such as dysphasia and aspiration. The purpose of this study was to evaluate the efficacy and adverse effects of individualized BoNT therapy for lingual dystonia. One-hundred-and-seventy-two patients (102 females and 70 males, mean age: 46.2 years) with lingual dystonia were classified into four subtypes based on symptoms of involuntary tongue movements: protrusion (68.6%), retraction (16.9%), curling (7.6%), and laterotrusion (7.0%). Patients were treated with BoNT injection into the genioglossus and/or intrinsic muscles via individualized submandibular and/or intraoral routes. Results were compared before and after BoNT therapy. Botulinum neurotoxin was injected in 136 patients (mean: 4.8 injections). Clinical sub-scores (mastication, speech, pain, and discomfort) in a disease-specific rating scale were reduced significantly (p < 0.001) after administration. Comprehensive improvement after BoNT injection, assessed using the rating scale, was 77.6%. The curling type (81.9%) showed the greatest improvement, while the retraction type showed the least improvement (67.9%). Mild and transient dysphasia occurred in 12.5% of patients (3.7% of total injections) but disappeared spontaneously within several days to two weeks. No serious side effects were observed. With careful diagnosis of subtypes and a detailed understanding of lingual muscle anatomy, individualized BoNT injection into dystonic lingual muscles can be effective and safe.

Botulinum Neurotoxin Injection for the Treatment of Recurrent Temporomandibular Joint Dislocation with and without Neurogenic Muscular Hyperactivity

The aim of this study was to compare treatment outcomes following intramuscular injection of botulinum neurotoxin (BoNT) in patients with recurrent temporomandibular joint dislocation, with and without muscle hyperactivity due to neurological diseases. Thirty-two patients (19 women and 13 men, mean age: 62.3 years) with recurrent temporomandibular joint dislocation were divided into two groups: neurogenic (8 women and 12 men) and habitual (11 women and 1 man). The neurogenic group included patients having neurological disorders, such as Parkinson’s disease or oromandibular dystonia, that are accompanied by muscle hyperactivity. BoNT was administered via intraoral injection to the inferior head of the lateral pterygoid muscle. In total, BoNT injection was administered 102 times (mean 3.2 times/patient). The mean follow-up duration was 29.5 months. The neurogenic group was significantly (p < 0.001) younger (47.3 years) than the habitual group (84.8 years) and required significantly (p < 0.01) more injections (4.1 versus 1.7 times) to achieve a positive outcome. No significant immediate or delayed complications occurred. Thus, intramuscular injection of BoNT into the lateral pterygoid muscle is an effective and safe treatment for habitual temporomandibular joint dislocation. More injections are required in cases of neurogenic temporomandibular joint dislocation than in those of habitual dislocation without muscle hyperactivity.

Multilingual website and cyberconsultations for oromandibular dystonia

Oromandibular dystonia is a focal dystonia that manifests as involuntary masticatory and/or tongue muscle contractions. This movement disorder is frequently misdiagnosed as a temporomandibular disorder. Hence, it would be useful to establish a method that makes it possible for patients with the condition to find appropriate medical institutions by themselves. The author produced a website Involuntary movements of the stomatognathic region (https://sites. google.com/site/oromandibulardystoniaenglish/) for patients with oromandibular dystonia, which is available in twenty languages. It has been viewed more than 1,000,000 times by individuals from all over the world. The visitors to the site have completed questionnaires and/or sent images or videos of their involuntary movements over the internet. Cyberconsultations (remote diagnosis) were also performed via Skype^™. Approximately 1000 patients with involuntary stomatognathic movements visited our department. Only 12.5% of the patients had previously been diagnosed with or were suspected to have dystonia. The findings of this study suggest that the multilingual website has contributed to increasing awareness of oromandibular dystonia and that the provision of basic telemedicine via the internet can aid the diagnosis and treatment of oromandibular dystonia.

Sensory trick splint as a multimodal therapy for oromandibular dystonia

PURPOSE

Many patients with oromandibular dystonia, which is characterized by involuntary masticatory, lower facial, and/or tongue muscle contractions, experience relief of symptoms through sensory tricks such as eating chewing gum or candy. The aim of this study was to identify the factors influencing the effects of splints in patients with oromandibular dystonia.

METHODS

Occlusal splints were inserted in 128 patients (89 women, 39 men) with oromandibular dystonia (102 with jaw closing dystonia, 20 with lingual dystonia, 5 with jaw deviation dystonia, 4 with jaw opening dystonia, 3 with lip dystonia, and 2 with jaw protrusion dystonia). Patients who showed improvement with the use of splints and continued to wear them for at least 3 months were defined as responders. In contrast, patients who showed little or no effect and/or were unable to insert splints were defined as non-responders. Differences in demographic and clinical data were statistically compared between responders and non-responders.

RESULTS

Ninety-eight patients (76.6%) were responders (subjective improvement: 30.5%). Thirty patients (23.4%) were non-responders (subjective improvement: 7.2%). The responders were significantly older than the non-responders (53.8 years vs 47.0 years; p<0.05). Patients with jaw closing dystonia showed the most favorable results. The proportion of patients with sensory tricks was significantly higher in responders than in non-responders (66.3% vs 26.7%; p<0.05).

CONCLUSIONS

The sensory trick splint is especially helpful for patients with jaw closing dystonia. It is useful, although partially effective, as an alternative therapy in patients for whom other therapies have been unsatisfactory.