Faculty Bibliography

OBJECTIVES/HYPOTHESIS: Spasmodic dysphonia (SD) is a task-specific laryngeal dystonia that affects speech production. Co-occurring voice tremor (VT) often complicates the diagnosis and clinical management of SD. Treatment of SD and VT is largely limited to botulinum toxin injections into laryngeal musculature; other pharmacological options are not sufficiently developed. STUDY DESIGN: Open-label study. METHODS: We conducted an open-label study in 23 SD and 22 SD/VT patients to examine the effects of sodium oxybate (Xyrem), an oral agent with therapeutic effects similar to those of alcohol in these patients. Blinded randomized analysis of voice and speech samples assessed symptom improvement before and after drug administration. RESULTS: Sodium oxybate significantly improved voice symptoms (P = .001) primarily by reducing the number of SD-characteristic voice breaks and severity of VT. Sodium oxybate further showed a trend for improving VT symptoms (P = .03) in a subset of patients who received successful botulinum toxin injections for the management of their SD symptoms. The drug's effects were observed approximately 30 to 40 minutes after its intake and lasted about 3.5 to 4 hours. CONCLUSIONS: Our study demonstrated that sodium oxybate reduced voice symptoms in 82.2% of alcohol-responsive SD patients both with and without co-occurring VT. Our findings suggest that the therapeutic mechanism of sodium oxybate in SD and SD/VT may be linked to that of alcohol, and as such, sodium oxybate might be beneficial for alcohol-responsive SD and SD/VT patients. LEVEL OF EVIDENCE: 4 Laryngoscope, 127:1402-1407, 2017.

Dystonic storm is a frightening hyperkinetic movement disorder emergency. Marked, rapid exacerbation of dystonia requires prompt intervention and admission to the intensive care unit. Clinical features of dystonic storm include fever, tachycardia, tachypnea, hypertension, sweating and autonomic instability, often progressing to bulbar dysfunction with dysarthria, dysphagia and respiratory failure. It is critical to recognize early and differentiate dystonic storm from other hyperkinetic movement disorder emergencies. Dystonic storm usually occurs in patients with known dystonia, such as DYT1 dystonia, Wilson's disease and dystonic cerebral palsy. Triggers such as infection or medication adjustment are present in about one-third of all events. Due to the significant morbidity and mortality of this disorder, we propose a management algorithm that divides decision making into two periods: the first 24 h, and the next 2-4 weeks. During the first 24 h, supportive therapy should be initiated, and appropriate patients should be identified early as candidates for pallidal deep brain stimulation or intrathecal baclofen. Management in the next 2-4 weeks aims at symptomatic dystonia control and supportive therapies.

In this review, we summarize recent advances in understanding the etiology, risk factors and pathophysiology of focal task specific dystonia (FTSD), movement disorders characterized by abnormal motor activation during the performance of specific, repetitive actions. We focus on two common FTSD, musician's dystonia and writer's cramp. FTSD may pose a threat to the patient's livelihood, and improved therapeutic treatments are needed.

BACKGROUND: Velopharyngeal dysfunction produces a nasal speech pattern because of the inability to close the nasal airway during speech, most often associated with anatomical abnormalities of the palate. CASE REPORT: We describe two cases of possible velopharyngeal dystonia, a task-specific movement disorder causing a speech pattern similar to velopharyngeal dysfunction. Both patients experienced treatment response with anticholinergic medication. DISCUSSION: Dystonia affecting speech via involvement of the pharyngeal musculature may be an unrecognized etiology of voice disorders.

BACKGROUND: Spasmodic dysphonia is a focal dystonia characterized by involuntary spasms in the laryngeal muscles that occur selectively during speaking. Although hereditary trends have been reported in up to 16% of patients, the causative etiology of spasmodic dysphonia is unclear, and the influences of various phenotypes and genotypes on disorder pathophysiology are poorly understood. In this study, we examined structural alterations in cortical gray matter and white matter integrity in relationship to different phenotypes and putative genotypes of spasmodic dysphonia to elucidate the structural component of its complex pathophysiology. METHODS: Eighty-nine patients with spasmodic dysphonia underwent high-resolution magnetic resonance imaging and diffusion-weighted imaging to examine cortical thickness and white matter fractional anisotropy in adductor versus abductor forms (distinct phenotypes) and in sporadic versus familial cases (distinct genotypes). RESULTS: Phenotype-specific abnormalities were localized in the left sensorimotor cortex and angular gyrus and the white matter bundle of the right superior corona radiata. Genotype-specific alterations were found in the left superior temporal gyrus, supplementary motor area, and the arcuate portion of the left superior longitudinal fasciculus. CONCLUSIONS: Our findings suggest that phenotypic differences in spasmodic dysphonia arise at the level of the primary and associative areas of motor control, whereas genotype-related pathophysiological mechanisms may be associated with dysfunction of regions regulating phonological and sensory processing. Identification of structural alterations specific to disorder phenotype and putative genotype provides an important step toward future delineation of imaging markers and potential targets for novel therapeutic interventions for spasmodic dysphonia. (c) 2017 International Parkinson and Movement Disorder Society.