Vesper Fe Marie Llaneza Ramos

Tricks in dystonia: ordering the complexity

Sensory tricks are various manoeuvres that can ameliorate dystonia. Common characteristics are well known, but their variety is wide, sensory stimulation is not necessarily the critical feature, and their physiology is unknown. To enumerate the various forms of sensory tricks and describe their nature, research findings and theories that may elucidate their neurophysiologic mechanism, we reviewed the literature pertaining to sensory tricks, including variants like motor tricks, imaginary tricks, forcible tricks and reverse sensory tricks. On the basis of this information, we propose a new classification of sensory tricks to include its variants. We highlight neurophysiologic evidence suggesting that sensory tricks work by decreasing abnormal facilitation. We tie this with established dystonia pathogenesis and postulate that sensory tricks decrease abnormally increased facilitation to inhibition ratios in the dystonic brain. It appears worthwhile for patients to search for possible sensory tricks.

Intraoperative neurophysiology in deep brain surgery for psychogenic dystonia.

Psychogenic dystonia is a challenging entity to diagnose and treat because little is known about its pathophysiology. We describe two cases of psychogenic dystonia who underwent deep brain stimulation when thought to have organic dystonia. The intraoperative microelectrode recordings in globus pallidus internus were retrospectively compared with those of five patients with known DYT1 dystonia using spontaneous discharge parameters of rate and bursting, as well as movement‐related discharges. Our data suggest that simple intraoperative neurophysiology measures in single subjects do not differentiate psychogenic dystonia from DYT1 dystonia.

Inducing LTD-Like Effect in the Human Motor Cortex with Low Frequency and Very Short Duration Paired Associative Stimulation: An Exploratory Study.

Introduction. Paired associative stimulation (PAS) is an established technique to investigate synaptic plasticity in the human motor cortex (M1). Classically, to induce long-term depression- (LTD-) or long-term potentiation-like effects in the human M1, studies have used low frequency and long duration trains of PAS. In the present study, we explored an LTD-like effect using very short duration and low frequency of PAS10 ms protocols in human M1. Methods. Six protocols of low frequency PAS10 ms (ranging from 0.2 Hz to 1 Hz) were investigated with very short durations of 1 and 2 minutes stimulation. Six healthy volunteers were included in each protocol. We obtained motor-evoked potentials from right abductor pollicis brevis muscle before and after applying PAS10 ms up to 30 minutes. After we found PAS10 ms protocol which induced an LTD-like effect, we tested that protocol on additional 5 subjects. Results. One-way repeated-measures ANOVA showed that only the group of 1-minute stimulation of 0.25 Hz induced an LTD-like effect. When adding the additional subjects, the effect remained and lasted for 30 minutes. Conclusion. Low frequency and very short duration of PAS10 ms potentially induced an LTD-like effect in human M1. With further verification, this method might be useful for research relating to synaptic plasticity by reducing the duration of study and minimizing subject discomfort.

Head Accelerometry May be Useful as a Test of Psychogenic Head Tremor

Physiological studies of head tremor are challenging, and clinically relevant data to guide diagnosis in literature is sparse. Head accelerometry has been used as a quantitative assessment of botulinum toxin treatment in head tremor.1 Tremor studies rely on accelerometry to detect frequency and coherence for interpretation of test results.

Ultrasound as Diagnostic Tool for Diaphragmatic Myoclonus

Diaphragmatic myoclonus is a rare disorder of repetitive diaphragmatic contractions, acknowledged to be a spectrum that includes psychogenic features. Electromyography has been the diagnostic tool most commonly used in the literature.

Failed Attempt With Paired Associative Stimulation to Separate Functional and Organic Dystonia: Stimulation To Separate Functional and Organic Dystonia

can be used as a rescue drug for ALO when the effect of botulinum is not sufficient. In this study, the effect for truly disabling cases, such as COT >10 seconds, was not investigated because the maximum baseline COT was 7.0 seconds. The mechanisms of ALO have not been clearly understood. Previous studies have shown that reduced dopaminergic stimulation in the basal ganglia leads to reflex blink hyperexcitability in PD. Therefore, the corneal sensory input excessively induces reflex blink and produces abnormal contraction of the musculus orbicularis oculi in patients with ALO. As shown in this study, the effect of oxybuprocaine for ALO suggests that the hyperexcitability of reflex blink is an important part of the mechanism of ALO. In conclusion, we demonstrated the prompt effect of oxybuprocaine and the agent could possibly be an additional treatment as a rescue drug for ALO in PD.

Botulinum toxin injection following deep brain stimulation in generalized dystonia

1CNS, IRB, National Institutes of Health, Bethesda, MD-20892, USA 2Human Motor Control Section, National Institutes of Health, Bethesda, MD-20892, USA 3Functional and Applied Biomechanics Section, Rehabilitaion Medicine Department, National Institutes of Health, Bethesda, MD and Mount Washington Pediatric Hospital, Washington, DC, USA 4Office of the Clinical Director, National Institutes of Health, Bethesda, MD-20892, USA

Tremor in a Bassoonist: Tremor in Dystonia or Essential Tremor?

Dear Editor, Tremor is a common clinical feature in dystonia. It can be seen in both affected and unaffected body parts in patients with dystonia. Clinically, it may not be easily distinguishable from essential tremor, currently defined as a bilateral, largely symmetric postural or kinetic tremor involving the hands and forearms that is visible and persistent, with an associated or isolated head tremor in the absence of abnormal posturing [1]. Efforts to differentiate these types of tremor include using neurophysiological tests such as somatosensory temporal discrimination threshold (TDT) testing, electromyography, accelerometry and reciprocal inhibition [2,3]. In patients with dystonia, TDT values have been found to be prolonged, postulated to reflect abnormalities in the basal ganglia [2,4-6]. On the other hand, investigations on patients diagnosed with essential tremor have revealed TDT values to be normal in those with upper limb tremor [2,7]. To illustrate the use of TDT in tremor diagnosis, we report a case of tremor in a 48-year-old right-handed man. His symptoms began 12 years prior to consult, initially task-specific, beginning in the left hand while playing the bassoon. The tremor progressed to involve both hands, the head, voice and trunk, often simultaneously. Tremor and head pulling to the right would worsen with manual activities and emotional stress. He was seen by several neurologists and was given varying diagnoses of dystonia and essential tremor. Sodium oxybate dampened the tremor, but had to be discontinued due to side effects. Current medications included propranolol extended-release 60 mg daily, topiramate 100 mg twice daily, clonazepam 1 mg twice daily and escitalopram 20 mg daily. The patient’s past medical history was positive for depression, alcoholism (sober for the past eight years) and asthma. There was no family history of tremor, and both parents have a history of strokes. He is a smoker, works as a priest, is separated and lives alone. Exam revealed mildly depressed affect, bradyphrenia and intermittent word-finding difficulty. The Montreal Cognitive Assessment score was 23/30 with errors in the following domains; executive, attention, language, and delayed recall. A high-frequency, asymmetric postural and kinetic tremor was noted in both upper extremities and trunk, as well as a vocal tremor. Right head tilt was present, most prominent on playing the bassoon. There were no sensory tricks. Bilateral arm posturing was noted with walking, greater on the right (Supplementary Video in the Online-only Data Supplement). Magnetic resonance imaging of the brain and a dopamine transporter single photon emission computed tomography scan were performed, which were both unremarkable. He did not undergo DYT gene testing. Somatosensory TDT testing was performed at our institution, with the patient appropriately focusing his attention on the task (reporting one stimulus vs. two). The mean and range (215.83 ± 14.29 ms) of the thresholds for bilateral upper extremities were markedly prolonged, compatible with the results seen in patients with dystonia (110 ± 31.3 ms) [2]. Our case illustrates a tremor in a 48-year-old man that was first noticed to occur in the left hand when playing the bassoon, eventually involving both hands, the head, voice and trunk. Differentiating tremor in dystonia from essential tremor based on clinical criteria alone can be difficult, as both types of tremor are often symmetric, postural and kinetic and the dystonia may not be obvious on initial examination. TDT testing may be a useful tool for this purpose, along with other neurophysiological testing methods [2]. Prolonged thresholds have been found in various dystonia phenotypes, including cervical dystonia, writer’s cramp, blepharospasm, musician’s dystonia and spasmodic dysphonia [2,4]. The dramatically prolonged TDT results, the cervical dystonia noted on examination and the history of nearly simultaneous onset of tremor in the neck and upper extremities suggest that this is likely tremor in dystonia. We are ascribing his cognitive problems to depression, but this aspect will require continued attention. Differentiating tremor in dystonia from essential tremor is important in considering treatment options and further testing, including genetic counseling. Thus, TDT may be another useful neurophysiological tool in making this distinction.

Clinical Response to IncobotulinumtoxinA, after Demonstrated Loss of Clinical Response to OnabotulinumtoxinA and RimabotulininumtoxinB in a Patient with Musician's Dystonia.

Botulinum toxin is a mainstay therapy for dystonia. Formulations available are three types of botulinumtoxinA and one type of botulinumtoxinB.1 Antibodies can develop against the toxin, leading to treatment failure. IncobotulinumtoxinA (Xeomin; Merz Pharmaceuticals GmbH, Frankfurt, Germany) is differentiated from other types of botulinumtoxinA preparations by being free from complexing proteins, speculated to make the product less antigenic.2.

Supplementary motor area stimulation for Parkinson disease: A randomized controlled studyAuthor Response

Shirota et al.1 reported a large trial of repetitive TMS of the supplementary motor area (SMA) for PD. Stimulation was given weekly for 8 weeks, with a 3-arm design. The authors did not report baseline Unified Parkinsons Disease Rating Scale (UPDRS) scores and time of medication intake with respect to assessment times. Strong …