Treatable ataxias are a group of ataxic disorders with specific treatments. These disorders include genetic and metabolic disorders, immune-mediated ataxic disorders, and ataxic disorders associated with infectious and parainfectious etiology, vascular causes, toxins and chemicals, and endocrinopathies. This review provides a comprehensive overview of different treatable ataxias. The major metabolic and genetic treatable ataxic disorders include ataxia with vitamin E deficiency, abetalipoproteinemia, cerebrotendinous xanthomatosis, Niemann-Pick disease type C, autosomal recessive cerebellar ataxia due to coenzyme Q10 deficiency, glucose transporter type 1 deficiency, and episodic ataxia type 2. The treatment of these disorders includes the replacement of deficient cofactors and vitamins, dietary modifications, and other specific treatments. Treatable ataxias with immune-mediated etiologies include gluten ataxia, anti-glutamic acid decarboxylase antibody-associated ataxia, steroid-responsive encephalopathy associated with autoimmune thyroiditis, Miller-Fisher syndrome, multiple sclerosis, and paraneoplastic cerebellar degeneration. Although dietary modification with a gluten-free diet is adequate in gluten ataxia, other autoimmune ataxias are managed by short-course steroids, plasma exchange, or immunomodulation. For autoimmune ataxias secondary to malignancy, treatment of tumor can reduce ataxic symptoms. Chronic alcohol consumption, antiepileptics, anticancer drugs, exposure to insecticides, heavy metals, and recreational drugs are potentially avoidable and treatable causes of ataxia. Infective and parainfectious causes of cerebellar ataxias include acute cerebellitis, postinfectious ataxia, Whipple’s disease, meningoencephalitis, and progressive multifocal leukoencephalopathy. These disorders are treated with steroids and antibiotics. Recognizing treatable disorders is of paramount importance when dealing with ataxias given that early treatment can prevent permanent neurological sequelae.

Objective: This study aims to identify the demographic, clinical, and therapeutic characteristics of four patients with hemimasticatory spasm (HMS) seen in our outpatient department over a period of 20 years. Methods: We performed a retrospective chart review of four patients with HMS who visited outpatient services in the Department of Neurology from 2001 to 2020. Results: The follow-up for all patients ranged from 2 years to 9 years. Three patients had facial or bucco-oral morphea. Two patients maintained long-term improvements in symptoms after being treated with botulinum toxin for 4–7 years, while one patient reported improvement in symptoms with treatment of carbamazepine that subsequently remitted after pregnancy. Conclusion This report highlights the long-term outcome of HMS in our patients. Our patients reported a significant reduction or complete resolution of symptoms after treatment, and eventually, two patients were asymptomatic while off treatment.

Objective: Joubert syndrome (JS) is a rare syndrome characterized by ataxia and the molar tooth sign (MTS) on imaging. The present study aims to explore the clinical and radiological features in a cohort of patients with JS. Methods: This was a retrospective chart review of patients with JS evaluated by movement disorder specialists. Results: Nine patients were included in the study. All patients had facial dysmorphism and ocular abnormalities, and 4 patients had dystonia. Ocular tilt reaction and alternate skew deviation (66%) were the most common ocular abnormalities. Horizontally aligned superior cerebellar peduncles were observed in all four patients with diffusion tensor imaging, with a lack of decussation in three. Exome sequencing performed in four patients revealed novel variants in the MKS1, CPLANE1, and PIBF1 genes. Conclusion Facial dysmorphism, ocular abnormalities and classical imaging findings were observed in all patients with JS. Apart from ataxia, dystonia and myoclonus are other movement disorders observed in JS.

Sialidosis is an inborn error of metabolism due to a defect in the NEU1 gene and manifests as two phenotypes: mild type I and severe type II. The cherry red spot (CRS) is a characteristic feature in both types of sialidosis; reports of sialidosis without a CRS are rare. We report two cases of genetically confirmed sialidosis type I with a typical presentation of progressive cortical myoclonus and ataxia but without the CRS. A previously reported homozygous pathogenic variant p.Arg294Cys was detected in the first case, and a novel homozygous pathogenic variant p.Arg305Pro was detected in the second case. Additionally, we reviewed the literature describing cases with similar mutations to find a genetic basis for the absence of a CRS. Milder mutation of both alleles detected in both patients may be the reason for the absence of a CRS.

Objective: Willingness to undergo deep brain stimulation (DBS) among patients with Parkinson’s disease (PD) and their overall satisfaction with the procedure is highly dependent upon expectations, which are based on the core concepts of knowledge, attitude and perceptions. The present study aims to evaluate these factors in patients and caregivers with PD from a single tertiary care hospital in India. Methods: A structured questionnaire designed to assess the knowledge, attitude and perceptions about DBS in PD was administered to 400 patients with PD and their caregivers. Results: A very small proportion of patients and caregivers were aware of DBS. Even those who claimed to be aware of DBS were inadequately informed and had incorrect knowledge, which led to wrong attitudes and perceptions. Conclusion There are very significant knowledge gaps and misconceptions regarding DBS among patients with PD and caregivers. Adequate and appropriate education is necessary to clarify these misconceptions to avoid the development of unrealistic expectations and poor satisfaction.

Occasionally, movement disorders can occur following interventional procedures including but not limited to radiotherapy, dental procedures, and cardiac, cerebral and spinal surgeries. The majority of these disorders tend to be unexpected sequelae with variable phenomenology and latency, and they can often be far more disabling than the primary disease for which the procedure was performed. Owing to poor knowledge and awareness of the problem, delays in diagnosing the condition are common, as are misdiagnoses as functional movement disorders. This narrative review discusses the phenomenology, pathophysiology, and potential treatments of various movement disorders caused by interventional procedures such as radiotherapy and neurological and non-neurological surgeries and procedures.

Objective: Joubert syndrome (JS) is a rare syndrome characterized by ataxia and the molar tooth sign (MTS) on imaging. The present study aims to explore the clinical and radiological features in a cohort of patients with JS. Methods: This was a retrospective chart review of patients with JS evaluated by movement disorder specialists. Results: Nine patients were included in the study. All patients had facial dysmorphism and ocular abnormalities, and 4 patients had dystonia. Ocular tilt reaction and alternate skew deviation (66%) were the most common ocular abnormalities. Horizontally aligned superior cerebellar peduncles were observed in all four patients with diffusion tensor imaging, with a lack of decussation in three. Exome sequencing performed in four patients revealed novel variants in the MKS1, CPLANE1, and PIBF1 genes. Conclusion Facial dysmorphism, ocular abnormalities and classical imaging findings were observed in all patients with JS. Apart from ataxia, dystonia and myoclonus are other movement disorders observed in JS.

Objective: The novel coronavirus disease (COVID-19) pandemic and public health measures to control it have resulted in unique challenges in the management of patients with deep brain stimulation (DBS). We report our experience with the management of acute worsening of symptoms due to battery exhaustion in 3 patients with DBS. Methods: Patients with DBS for movement disorders who visited the emergency room due to battery exhaustion during the nationwide lockdown from April to May 2020 were included. Results: Two patients with subthalamic nucleus-DBS for Parkinson’s disease (PD) and one with globus pallidus interna-DBS for generalized dystonia presented with acute worsening of symptoms due to battery exhaustion. Urgent battery replacement was performed in both patients with PD. The patient with generalized dystonia was managed with medication adjustment as he chose to defer battery replacement. Conclusion DBS battery replacement can be an emergency. Decisions regarding DBS battery replacement should be individualized during this COVID-19 pandemic.