Palatal myoclonus: an unusual presentation

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.

Botulinum Toxin in Movement Disorders: An Update

Since its initial approval in 1989 by the US Food and Drug Administration for the treatment of blepharospasm and other facial spasms, botulinum toxin (BoNT) has evolved into a therapeutic modality for a variety of neurological and non-neurological disorders. With respect to neurologic movement disorders, BoNT has been reported to be effective for the treatment of dystonia, bruxism, tremors, tics, myoclonus, restless legs syndrome, tardive dyskinesia, and a variety of symptoms associated with Parkinson's disease. More recently, research with BoNT has expanded beyond its use as a powerful muscle relaxant and a peripherally active drug to its potential central nervous system applications in the treatment of neurodegenerative disorders. Although BoNT is the most potent biologic toxin, when it is administered by knowledgeable and experienced clinicians, it is one of the safest therapeutic agents in clinical use. The primary aim of this article is to provide an update on recent advances in BoNT research with a focus on novel applications in the treatment of movement disorders. This comprehensive review of the literature provides a critical review of evidence-based clinical trials and highlights recent innovative pilot studies.

Palatal Tremor - Pathophysiology, Clinical Features, Investigations, Management and Future Challenges

Background:

Palatal tremor is involuntary, rhythmic and oscillatory movement of the soft palate. Palatal tremor can be classified into three subtypes; essential, symptomatic and palatal tremor associated with progressive ataxia.

Methods:

A thorough Pubmed search was conducted to look for the original articles, reviews, letters to editor, case reports, and teaching neuroimages, with the keywords “essential”, “symptomatic palatal tremor”, “myoclonus”, “ataxia”, “hypertrophic”, “olivary” and “degeneration”.

Results:

Essential palatal tremor is due to contraction of the tensor veli palatini muscle, supplied by the 5^th cranial nerve. Symptomatic palatal tremor occurs due to the contraction of the levator veli palatini muscle, supplied by the 9%^th and 10%^th cranial nerves. Essential palatal tremor is idiopathic, while symptomatic palatal tremor occurs due to infarction, bleed or tumor within the Guillain-Mollaret triangle. Progressive ataxia and palatal tremor can be familial or idiopathic. Symptomatic palatal tremor and sporadic progressive ataxia with palatal tremor show signal changes in inferior olive of medulla in magnetic resonance imaging. The treatment options available for essential palatal tremor are clonazepam, lamotrigine, sodium valproate, flunarizine and botulinum toxin. The treatment of symptomatic palatal tremor involves the treatment of the underlying cause.

Discussion:

Further studies are required to understand the cause and pathophysiology of Essential palatal tremor and progressive ataxia and palatal tremor. Similarly, the link between tauopathy and palatal tremor associated progressive ataxia needs to be explored further. Oscillopsia and progressive ataxia are more debilitating than palatal tremor and needs new treatment approaches.

Essential palatal myoclonus following dental surgery: a case report

Introduction

Various presentations of essential palatal myoclonus, a condition characterized by clicking noises and palatal muscle spasm, have been reported in the literature. We are reporting the first case of essential palatal myoclonus following dental treatment.

Case presentation

A 31-year-old Caucasian man presented to our Ear, Nose and Throat department complaining of objective clicking tinnitus occurring immediately after he had undergone root canal treatment on his right lower third molar 3 months ago. Magnetic resonance imaging of his head revealed no abnormalities in the cerebrum, cerebellum or brainstem making the diagnosis essential palatal myoclonus. He returned a week later, and 20 units of botulinum toxin A (Allergan) were injected into his left tensor veli palatine muscle. He reported an immediate improvement; however, symptoms recurred 6 months later.

Conclusions

Dental treatment can be a trigger of essential palatal myoclonus. Botulinum toxin injections are an effective treatment for short-term relief of symptoms.

Early Parkinson's disease and non-motor issues

Non motor symptoms (NMS) of PD are a key determinant of health, quality of life and societal cost of PD. Contrary to common perception, many NMS of PD occur early in PD and some may even predate the diagnosis of PD which is based on motor signs. These include olfactory deficit, sleep problems such as REM behaviour disorder, contipation and the more recently described male erectile dysfunction. The non motor quesionnaire (NMSQuest) and the recently validated NMS scale allow falgging and quantification of NMS of PD and therefore are important tools to comprehensively assess symptom load in PD.

Parkinson's disease: a dual-hit hypothesis

Accumulating evidence suggests that sporadic Parkinson's disease has a long prodromal period during which several non-motor features develop, in particular, impairment of olfaction, vagal dysfunction and sleep disorder. Early sites of Lewy pathology are the olfactory bulb and enteric plexus of the stomach. We propose that a neurotropic pathogen, probably viral, enters the brain via two routes: (i) nasal, with anterograde progression into the temporal lobe; and (ii) gastric, secondary to swallowing of nasal secretions in saliva. These secretions might contain a neurotropic pathogen that, after penetration of the epithelial lining, could enter axons of the Meissner's plexus and, via transsynaptic transmission, reach the preganglionic parasympathetic motor neurones of the vagus nerve. This would allow retrograde transport into the medulla and, from here, into the pons and midbrain until the substantia nigra is reached and typical aspects of disease commence. Evidence for this theory from the perspective of olfactory and autonomic dysfunction is reviewed, and the possible routes of pathogenic invasion are considered. It is concluded that the most parsimonious explanation for the initial events of sporadic Parkinson's disease is pathogenic access to the brain through the stomach and nose - hence the term 'dual-hit'.

Neurolaryngologic evaluation of the performer

Numerous neurologic diseases affect voice production either through direct effects on the larynx or by affecting muscles involved with support or resonation of the voice. Voice changes can be the initial presenting symptoms of neurodegenerative disorders, especially in patients who have increased awareness of their vocal quality. Some patients present to the otolaryngologist before the neurologist. The otolaryngologist must have an understanding and familiarity with laryngeal manifestations of neurodegenerative diseases to make the appropriate diagnosis in a timely fashion. Moreover, the otolaryngologist can play a significant role in the care of patients who have neurodegenerative disease. Video procedures for neurolaryngologic evaluation accompany this content online.

Non-motor symptoms in Parkinson's disease: an underdiagnosed problem

Parkinson's disease results from degeneration of the substantia nigra pars compacta and the consequent dysfunction of the dopaminergic nigrostriatal pathway. Serotonergic and noradrenergic pathways are also affected. However, It has been recognized that nondopaminergic and non-motor symptoms are sometimes present prior to diagnosis and these inevitably emerge with disease progression, impacting on morbidity, quality of life and mortality. The non-motor symptoms of Parkinson's disease continue to be poorly recognized and inadequately treated in contrast with motor symptoms, and a modern holistic approach to treatment of Parkinson's disease should therefore include recognition and assessment of non-motor symptoms. Certain aspects of the non-motor symptoms complex of Parkinson's disease can be improved with currently available treatments, but other features may be more refractory and require research into effective nondopaminergic drug therapies for the future.

The 'essentials' of essential palatal tremor: a reappraisal of the nosology

Essential palatal tremor (EPT) is an uncommon disorder, distinct from symptomatic palatal tremor (SPT), but characterized by superficially similar rhythmic movements of the soft palate. While the pathophysiology of SPT has been relatively well defined, this is not the case in EPT. Based on an analysis of 103 published cases, we reviewed EPT in the context of other movement disorders with similar features and outline possible pathophysiological mechanisms. Phenomenologically it remains best classified as a tremor. Four major causes, including a central generator, peripheral/mechanical, voluntary/special skill and psychogenic, appear to account for the majority of cases of EPT, although there is considerable overlap in the pathogenic mechanisms underlying these categories. Among the cases reviewed, a large proportion fit into the latter two categories, although there are others where multiple mechanisms are likely at play. Based on our reappraisal, we suggest a change in designation to 'isolated palatal tremor', with primary and secondary subtypes. This retains the distinction from SPT and emphasizes the non-uniform, heterogeneous nature of the disorder.