Successful magnetic resonance-guided focused ultrasound treatment of tremor in patients with a skull density ratio of 0.4 or less.

OBJECTIVE: The use of magnetic resonance-guided focused ultrasound (MRgFUS) for the treatment of tremor-related disorders and other novel indications has been limited by guidelines advocating treatment of patients with a skull density ratio (SDR) above 0.45 ± 0.05 despite reports of successful outcomes in patients with a low SDR (LSDR). The authors' goal was to retrospectively analyze the sonication strategies, adverse effects, and clinical and imaging outcomes in patients with SDR ≤ 0.4 treated for tremor using MRgFUS. METHODS: Clinical outcomes and adverse effects were assessed at 3 and 12 months after MRgFUS. Outcomes and lesion location, volume, and shape characteristics (elongation and eccentricity) were compared between the SDR groups. RESULTS: A total of 102 consecutive patients were included in the analysis, of whom 39 had SDRs ≤ 0.4. No patient was excluded from treatment because of an LSDR, with the lowest being 0.22. Lesioning temperatures (> 52°C) and therapeutic ablations were achieved in all patients. There were no significant differences in clinical outcome, adverse effects, lesion location, and volume between the high SDR group and the LSDR group. SDR was significantly associated with total energy (rho = -0.459, p < 0.001), heating efficiency (rho = 0.605, p < 0.001), and peak temperature (rho = 0.222, p = 0.025). CONCLUSIONS: The authors' results show that treatment of tremor in patients with an LSDR using MRgFUS is technically possible, leading to a safe and lasting therapeutic effect. Limiting the number of sonications and adjusting the energy and duration to achieve the required temperature early during the treatment are suitable strategies in LSDR patients.

An unusual case of deep brain stimulation-induced insomnia.

Cervical dystonia (CD) is the most common adult-onset focal dystonia. Non-motor symptoms, such as insomnia, can greatly impact the quality of life in CD patients. CD can be treated with deep brain stimulation (DBS) of the globus pallidus pars interna (GPi) although its effect on sleep is not yet fully understood. Here, we report a case of a 66-year-old female patient with cervical dystonia, who developed an unusual form of insomnia following her DBS surgery. Our patient reported recurrent episodes of visual symptoms (flashing lights), which would often wake her up at night. Following surgical revision of the extension wire, these visual symptoms completely resolved. This case provides an example of impedance oscillations caused by pressure on the pillow, which resulted in irregular delivery of current (according to Ohm's law) and recruitment of optic tract fibers secondary to excessive current.

Factors Influencing the Surgical Decision in Dystonia Patients Referred for Deep Brain Stimulation.

There is no available data on the journey of dystonia patients once referred to a tertiary center to undergo deep brain stimulation (DBS). We hypothesized that some patients might be incorrectly diagnosed while others might decline the procedure or experience significant benefit with switching to a different botulinum neurotoxin (BoNT). This is a single-center, retrospective study of dystonia patients who were referred to the DBS program between January 2014 and December 2018. We collected data on the surgical decision as well as factors influencing this decision. Sixty-seven patients were included (30 males, mean age: 48.3 ± 20.1 years, disease duration: 16.9 ± 15.3 years). Thirty-three (49%) patients underwent DBS. Four (6%) patients were awaiting the procedure while the remaining 30 patients (45%) did not undergo DBS. Reasons for DBS decline were patient refusal (17, 53%), functional dystonia (6, 20%), and successful use of AbobotulinumtoxinA (3, 10%) in patients who had failed other BoNTs. Our study highlights the importance of structured patient education to increase acceptance of DBS, as well as careful patient evaluation, particularly with respect to functional dystonia. Finally, changing BoNT formulation might be beneficial in some patients.

Myelopathies in patients older than 50: not to miss inflammatory etiologies.

BACKGROUND: Inflammatory myelopathies are primarily associated with younger age, and there are few studies in the elderly. Longitudinally extensive spinal cord lesions (LECL) are common in inflammatory myelopathies, but when the first event occurs in older age may have a broader differential diagnosis. OBJECTIVES: To identify all non-traumatic myelopathies' etiologies in patients older than 50 years in a tertiary care hospital and to evaluate characteristics that differentiate inflammatory from non-inflammatory etiologies, focusing on the late-onset (≥50 years old) longitudinally extensive spinal cord lesions (LO-LECL) group. METHODS: Retrospective study of patients admitted between 2008 to 2019. Demographic, clinical, laboratory, and magnetic resonance imaging (MRI) data of all patients were analyzed to identify predictors that could more easily identify inflammatory from non-inflammatory etiologies and further identify the etiologies of LO-LECL. RESULTS: One hundred and three patients 50 years or older diagnosed with non-traumatic myelopathy were included, despite the lesion extension. Five were vascular (5%), 10 spondylotic (10%), 16 other etiologies (16%), 22 inflammatory (21%) and 50 neoplastic myelopathies (49%). Among 23 LO-LECL, 3 were vascular (13%), 4 neoplastic (17%), 7 other etiologies (30%) and 9 inflammatory (39%). The inflammatory LO-LECL had the median time to nadir significantly different from the neoplastic and the other etiologies groups and had the median EDSS at last visit (3.5) significantly lower than the non-inflammatory LO-LECL (7.0-7.5). CONCLUSIONS: Inflammatory etiologies are not to be disregarded in older adults with non-traumatic myelopathies. The symptoms' temporal profile is critical to differentiate inflammatory LO-LECL from other etiologies and it has better functional recovery after adequate treatment.

Movement disorders in multiple sclerosis and neuromyelitis optica: A clinical marker of neurological disability.

INTRODUCTION: Movement disorders are not rare in demyelinating diseases but there are few studies comparing their frequency between multiple sclerosis and neuromyelitis optica spectrum disorder. Our aim was to determine the frequency and the related features of movement disorders in a cohort of patients with multiple sclerosis and neuromyelitis optica spectrum disorder. METHODS: It is a cross-sectional study of patients with multiple sclerosis and neuromyelitis optica spectrum disorder. Patients were evaluated by a movement disorder specialist. Data from a personal interview and neurological examination were collected. Fahn-Tolosa-Marin tremor rating scale was used for tremor evaluation. Health-related quality of life was assessed using EuroQol instrument. RESULTS: Two hundred fifty-three patients were included (mean [SD] age, 40 [12] years; 74.3% female; median [IQR] EDSS score 2.5 [1.0-6.0]); 26% presented with movement disorders. Paroxysmal dystonia (n = 32) and tremor (n = 27) were the most common movement disorders. Patients with multiple sclerosis and low Expanded Disability Status Scale score (below 4.0) have fewer movement disorders than patients with neuromyelitis optica spectrum disorder. The diagnosis of neuromyelitis optica spectrum disorder was strongly associated with paroxysmal dystonia (OR = 22.07, 95% CI = 2.56-189.78; p = 0.005). Patients with multiple sclerosis and patients without movement disorders have a slightly better quality of life. CONCLUSIONS: Paroxysmal dystonia was the most common movement disorder in demyelinating diseases and strongly associated with neuromyelitis optica spectrum disorder.