Faculty Bibliography

BACKGROUND: Many patients with lower cranial dystonia (LCrD) are misdiagnosed, and recognition of this condition by general practitioners and dental health professionals is limited. METHODS: We define the phenomenology and natural history of idiopathic LCrD, presenting in 41 patients with the disorder, the largest series of these patients reported to date. RESULTS: Phenomenology of dystonia included lower cranial and pharyngeal involvement, jaw opening and jaw closing dystonia, and tongue dystonia. Of 25 newly described patients, 72% (18) were female, average age at onset was 56 years, and delay before correct diagnosis was 3.8 years (0-25 years, median 2 years). Eleven patients (44%) reported a precipitating event, the most common of which was recent dental work. Geste antagonistes were found in 18 patients (72%). Response to treatment was mixed, indicating an unmet therapeutic need. CONCLUSIONS: Idiopathic LCrD is often missed and institution of effective therapy is often delayed. The clinical features and natural history of LCrD are similar to other forms of focal dystonia.

BACKGROUND: The sensory trick or geste antagoniste is a cardinal feature of cervical dystonia. Patients are often aware of their tricks, using them to their advantage to temporarily improve dystonic symptoms. The typical sensory trick must be internally generated by the patient in order to be effective, and external mechanical pressure alone may not be sufficient. METHODS: We present a case description. We present and demonstrate a new clinical phenomenon in patients with cervical dystonia, which we call "closing the loop". DISCUSSION: We discuss the possible mechanisms underlying this finding.

BACKGROUND: Vivid descriptions of the phenomenology of focal task-specific dystonia (FTSD) date back to the late nineteenth century. METHODS: In this review, I summarize the natural history, phenomenology, and treatment of FTSD, focusing on nineteenth-century neurologists' descriptions of the phenomenology, etiology, treatment, and mechanism. RESULTS: Examining these texts through a twenty-first-century lens, the "modern" ideas of a dystonic endophenotype, disordered physiology, and dystonic metabolic networks actually appeared in these texts more than a century ago. DISCUSSION: By incorporating these ideas with recent investigations, I present a new conceptual model for understanding this mysterious malady.

L-2-hydroxyglutaric aciduria (L2HGA) is a neurometabolic disorder characterized by macrocephaly, seizures, progressive mental retardation, pyramidal signs, ataxia and tremor. Dystonia is an under-recognized feature of this entity in the literature. We report two siblings with L2HGA, one of whom presented with writer's cramp followed by dystonia of the other hand. An elevated plasma lysine, highly elevated urine 2-hydroxyglutaric acid, and MRI with characteristic findings (leukoencephalopathy of bilateral subcortical white matter sparing central white matter) suggested the diagnosis, which was confirmed by genetic testing.

Aspiration risk from dysphagia increases with central and peripheral neurologic disease. Stroke, microvascular ischemic disease, a spectrum of neurodegenerative diseases, and advancing dementia all have unique aspects. However, there are distinct commonalities in this population. Increasing nutritional requirements to stave off oropharyngeal muscular atrophy and a sedentary lifestyle further tax the patient's abilities to safely swallow. This article reviews stroke, muscular dystrophy, myasthenia gravis, multiple sclerosis, amyotrophic lateral sclerosis, Parkinson's disease, and advanced dementia. Approaches to screening and evaluation, recognizing sentinel indicators of decline that increase aspiration risk, and options for managing global laryngeal dysfunction are also presented.

Musician's dystonia (MD) is a focal adult-onset dystonia most commonly involving the hand. It has much greater relative prevalence than non-musician's focal hand dystonias, exhibits task specificity at the level of specific musical passages, and is a particularly difficult form of dystonia to treat. For most MD patients, the diagnosis confirms the end of their music performance careers. Research on treatments and pathophysiology is contingent upon measures of motor function abnormalities. In this review, we comprehensively survey the literature to identify the rating scales used in MD and the distribution of their use. We also summarize the extent to which the scales have been evaluated for their clinical utility, including reliability, validity, sensitivity, specificity to MD, and practicality for a clinical setting. Out of 135 publications, almost half (62) included no quantitative measures of motor function. The remaining 73 studies used a variety of choices from among 10 major rating scales. Most used subjective scales involving either patient or clinician ratings. Only 25% (18) of the studies used objective scales. None of the scales has been completely and rigorously evaluated for clinical utility. Whether studies involved treatments or pathophysiologic assays, there was a heterogeneous choice of rating scales used with no clear standard. As a result, the collective interpretive value of those studies is limited because the results are confounded by measurement effects. We suggest that the development and widespread adoption of a new clinically useful rating scale is critical for accelerating basic and clinical research in MD.

The definition of dystonia has been a subject of much debate and controversy for the last century. In this paper, a practical definition of dystonia for the movement disorders expert is presented, based on a new algorithm. (c) 2013 Movement Disorder Society.