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Background: MR-guided focused ultrasound (MRgFUS) thalamotomy has been shown to be a safe and effective treatment for essential tremor (ET).Objective: To investigate the effects of MRgFUS in patients with ET with an emphasis on ipsilateral-hand and axial tremor subscores.Methods: Tremor scores and adverse effects of 100 patients treated between 2012 and 2018 were assessed at 1 week, 3, 12, and 24 months. A subgroup analysis of ipsilateral-hand tremor responders (defined as patients with ≥30% improvement at any time point) and non-responders was performed. Correlations and predictive factors for improvement were analysed. Weighted probabilistic maps of improvement were generated.Results: Significant improvement in axial, contralateral-hand and total tremor scores was observed at all study visits from baseline (p<0.0001). There was no significant improvement in ipsilateral subscores. A subset of patients (n=20) exhibited group-level ipsilateral-hand improvement that remained significant through all follow-ups (p<0.001). Multivariate regression analysis revealed that higher baseline scores predict better improvement in ipsilateral-hand and axial tremor. Probabilistic maps demonstrated that the lesion hotspot for axial improvement was situated more medially than that for contralateral improvement.Conclusion: MRgFUS significantly improved axial, contralateral-hand and total tremor scores. In a subset of patients, a consistent group-level treatment effect was observed for ipsilateral-hand tremor. While ipsilateral improvement seemed to be less directly related to lesion location, a spatial relationship between lesion location and axial and contralateral improvement was observed that proved consistent with the somatotopic organisation of the ventral intermediate nucleus.Trial Registration Numbers: NCT01932463, NCT01827904, and NCT02252380. [ABSTRACT FROM AUTHOR]

Background: Celiac disease is associated with motor cortex hyperexcitability and neurological manifestations including cortical myoclonus. Electroencephalography abnormalities have been described, but no distinct pattern has been reported. Methods: We describe the neurophysiological characteristics of 3 patients with celiac‐associated cortical myoclonus using electroencephalography, magnetoencephalography, and transcranial magnetic stimulation. Results: Electroencephalography in all cases demonstrated lateralized low‐amplitude, electropositive beta‐frequency polyspike activity over the central head region, corresponding to motor cortex contralateral to the myoclonic limb. Jerk‐locked back‐averaging demonstrated a preceding cortical potential; magnetoencephalography source localization revealed a cortical generator in the posterior wall of the precentral gyrus for the back‐averaged potential and oscillatory abnormality. In 1 patient, cerebellar inhibition of the motor cortex was physiologically normal. Conclusions: Central head oscillatory, low‐amplitude, electropositive electroencephalography polyspike activity may be a distinct marker of celiac‐related cortical myoclonus and is consistent with celiac‐related motor cortex hyperexcitability, which may not necessarily result from cerebellar disinhibition. © 2020 International Parkinson and Movement Disorder Society [ABSTRACT FROM AUTHOR]

Deep brain stimulation (DBS) depends on precise delivery of electrical current to target tissues. However, the specific brain structures responsible for best outcome are still debated. We applied probabilistic stimulation mapping to a retrospective, multidisorder DBS dataset assembled over 15 years at our institution (ntotal = 482 patients; nParkinson disease = 303; ndystonia = 64; ntremor = 39; ntreatment‐resistant depression/anorexia nervosa = 76) to identify the neuroanatomical substrates of optimal clinical response. Using high‐resolution structural magnetic resonance imaging and activation volume modeling, probabilistic stimulation maps (PSMs) that delineated areas of above‐mean and below‐mean response for each patient cohort were generated and defined in terms of their relationships with surrounding anatomical structures. Our results show that overlap between PSMs and individual patients' activation volumes can serve as a guide to predict clinical outcomes, but that this is not the sole determinant of response. In the future, individualized models that incorporate advancements in mapping techniques with patient‐specific clinical variables will likely contribute to the optimization of DBS target selection and improved outcomes for patients. ANN NEUROL 2021;89:426–443 [ABSTRACT FROM AUTHOR]

Introduction: Gait impairment is a very common problem in clinical practice. Multiple classifications of gait disorders are available based on anatomy, etiology, pathology and phenomenology. These classifications provide a diagnostic guide but do not clearly explain the pathophysiology of some gait disorders, which can sometimes hinder the diagnostic process. In this context, unusual gait disorders become an even more difficult clinical challenge. Areas covered: The scientific and non-scientific literature contains illustrative descriptions of unusual gait disorders based on their predominant signs and/or comparisons with normal and abnormal zoological and folkloric patterns. Unusual gait disorder phenomenology can be carefully deconstructed in order to achieve an integral approach. We present a pragmatic, phenomenological approach to various unusual gait disorders and highlight key features underlying their phenotypes. We also propose unifying terminology to facilitate diagnosis and academic communication. Expert commentary: Advanced gait analysis, neurophysiological and neuroimaging techniques have allowed for us to recognize that locomotion is a complex motor behavior that requires simultaneous integration of multiple neurological and non-neurological systems. A phenomenological approach such as the one proposed in this review could be useful while those objective techniques become more widely available in clinical practice. [ABSTRACT FROM AUTHOR]