Different movement disorders are reported in association with infectious diseases. In addition, myoclonus can be associated with different types of viral and bacterial infections. We screened three electronic databases for cases of myoclonus as a feature of different infections and collected cases and series describing myoclonus associated with infections. Data regarding study design, sample size, neurological assessment, and diagnostic workup including brain imaging and cerebrospinal fluid analysis were extracted from the identified studies. In this narrative review, we review different infections associated with myoclonus and discuss their salient features. The infections presenting with myoclonus include predominantly subacute sclerosing panencephalitis due to measles. In addition, we describe other viral infections that are reported to associated with myoclonus. Recently, coronavirus disease 2019 infections have been reported to be increasingly associated with myoclonus. The hypothesized mechanisms of infection-related myoclonus are vasculopathy, autoimmune reactions, and inflammation. Although myoclonus is considered to be a result of heredodegenerative, metabolic, or autoimmune disorders, infections may present with myoclonus, especially in tropical and developing countries. In this review, we describe the infections that are associated with myoclonus.

Sialorrhea is a common disabling nonmotor symptom of Parkinson’s disease. It can lead to several ill effects such as poor orodental hygiene, speech and feeding difficulty, depressive symptoms, poor quality of life, and aspiration pneumonia. It most likely occurs secondary to swallowing dysfunction due to a combination of factors such as lingual bradykinesia, oropharyngeal dysphagia, and esophageal dysmotility, leading to impaired salivary clearance. Various tools are available for its objective assessment to assess drooling in patients with Parkinson’s disease. The treatment options include use of anticholinergic medications and optimization of dopaminergic therapy. However, their use is limited due to the occurrence of adverse effects. Botulinum toxin injections into the parotid and submandibular glands is the most effective and safest treatment available at present.

Writer’s cramp (WC) is a focal task-specific dystonia that affects the fingers, hands, and forearms. It interferes with an individual’s ability to write, causing professional disability. In this systematic review, we discuss the epidemiology, pathophysiology, clinical features, and management of WC. In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we included publications until February 5, 2022, from the PubMed database. In addition, we elaborate on the clinical assessment and selection of appropriate muscles for botulinum neurotoxin therapy through pictorial illustrations. The prevalence of WC is underestimated because medical attention is only sought by those with professional disability. The clinical presentation of WC is heterogeneous. In some patients, dystonia is manifested only during writing tasks (simple WC), while in others, several manual tasks are affected in addition to writing (complex WC). Some patients have semirhythmic movements of the hand with no apparent postural abnormality during writing (writing tremor). The assessment of the pattern of dystonia is confounded by the compensatory movements a patient adopts while writing. There are several pharmacological, nonpharmacological, and surgical options for the management of WC. However, there are no randomized controlled trials supporting the efficacy of oral medications. The efficacy of physiotherapy, occupational therapy, and noninvasive brain stimulation is debatable. Neurosurgical procedures, although reportedly effective, are seldom justified in focal task-specific dystonia. Botulinum neurotoxin is considered an effective treatment option based on several prospective studies and few randomized controlled trials. However, WC may be the most challenging indication for this therapy because writing is a complex manual task. Furthermore, given the heterogeneity, clinicians often face difficulties in discerning the exact abnormality and selecting the appropriate muscles for treatment.

Objective: To evaluate and compare the effect of “super” high-frequency (SHF; >130 Hz) stimulation and conventional high-frequency (CHF; 100–130 Hz) stimulation on patients with dyskinesia. Methods: The patients were evaluated using the Abnormal Involuntary Movement Scale (AIMS) with SHF and CHF after levodopa infusion. The secondary outcomes included the Burke–Fahn–Marsden dystonia rating scale and the Unified Parkinson’s Disease Rating Scale part III scores. Result: Six patients were enrolled in this study. The AIMS scores were not significantly different between SHF and CHF (p=0.89, paired t-test). Three out of six patients (50%) had better AIMS scores when SHF was applied, the scores of two patients remained unchanged, and one patient had a score worse than that with CHF. No short-term adverse effects were observed. Conclusion: The results of our pilot study show that SHF is safe and tolerable. We believe that in appropriate cases SHF can be used for managing dyskinesia after conventional methods yield unfavorable results.

Introduction: Middle latency auditory evoked potentials (MLAEPs) allow the assessment of the function of the central part of the auditory pathway. MLAEP abnormalities have been demonstrated in patients with Alzheimer’s and Parkinson’s disease with dementia. Objective: The objective of our study was to assess the MLAEP findings in patients with idiopathic Parkinson’s disease (IPD) and atypical parkinsonism (AP) and to determine whether MLAEPs could contribute to the differential diagnosis of IPD and AP. Methods: We included 75 participants (25 IPD patients, 25 AP, and 25 age-matched healthy control subjects). MLAEPs were recorded in all patients and control subjects as per the standard procedure for MLAEP recordings. Absent waveforms (Na and Pa waves) and prolonged latencies of individual waves were considered as abnormal MLAEP readings. Results: The Pb waveform was significantly absent in the patients with IPD and AP compared to control subjects (p = 0.02). The Pb waveform was significantly absent in the AP group compared to the IPD group (p = 0.03). The Pb waveform was significantly absent in the AP group without cognitive impairment compared to the IPD group without cognitive impairment (p = 0.003). There was no statistically significant difference between the patients with IPD with and without cognitive impairment (p = 0.07). There was no significant difference among the groups with respect to Na and Pa wave latencies. Other parameters such as Na–Pa amplitude and Nb–Pb amplitudes were not significant among the groups. Conclusion: The absence of Pb potential in AP is an electrophysiological clue for the diagnosis of AP in patients presenting with parkinsonism. MLAEPs can act as an electrophysiological adjunct to the clinical imaging markers in differentiating IPD from AP.

Opsoclonus–myoclonus–ataxia syndrome (OMAS) is an inflammatory neurological disordercharacterized by chaotic uncontrolled movements of the eyes and involuntary jerk-like movements of the body. We report the case of a 45-year-old man who presented with fever without any seizures or focal deficits. On examination, he had opsoclonus in his eyes and cortical myoclonus in his hands and body. On evaluation, he tested positive for the dengue NS1 antigen. Furthermore, he had low platelets, normal metabolic workup, normal brain imaging, and normalcerebrospinal fluid analysis. He was managed conservatively and showed improvement in opsoclonus–myoclonus by day 7 of his illness and complete recovery in 2 weeks. Although dengue is primarily considered to be a hematotropic virus, it can involve the nervous system and manifest with OMAS. To the best of our knowledge, OMAS has been reported in only four cases of dengue infection in adults to date.

Duchenne Muscular Dystrophy (DMD) is an X-linked recessive muscular dystrophy that presents in the first decade of life. Neurodevelopmental disorders are increasingly recognized features in DMD including autistic spectrum disorder, attention-deficit– hyperactivity disorder, and obsessive-compulsive disorder. The presence of Gilles De La Tourette Syndrome (GTS) in DMD patients is extremely rare. GTS in DMD patients supports the hypothesis that disruption of different dystrophin isoforms may play a role in brain development and function.

Paraneoplastic syndromes are a heterogeneous group of disorders that present with varied symptoms in the presence of a tumor but are unrelated to the growth of primary malignancies, invasiveness, or metastases. Paraneoplastic neurological syndromes are estimated to affect <1% of the patients with cancer. They are commonly associated with small-cell lung carcinoma and hematologic and gynecologic malignancies and are rarely observed in head and neck malignancies. The diagnosis of paraneoplastic neurological syndromes may precede, be concurrent with, or follow the diagnosis of a malignant tumor. In this report, we present the case of a 55-year-old man who presented with rapidly progressive spastic ataxia and neurobehavioral symptoms with a background of longstanding cervical dystonia, which subacutely progressed to generalized dystonia. The patient was diagnosed with oral squamous cell carcinoma.

Opsoclonus myoclonus syndrome (OMS) is a rare autoimmune condition occurring due to Purkinje cell degeneration due to remote aetiology. Most often it occurs as a paraneoplastic syndrome. Here we report a case of opsoclonus-myoclonus–ataxia tremor syndrome in a 60-year-old woman that occurred due to hyperammonemia and she recovered completely with immunotherapy and correction of hyperammonemia. OMS is the first in literature associated with hyperammonemia.

Hemifacial spasm is a common peripheral movement disorder that usually results from neurovascular conflict involving the facial nerve motor root exit zone. Although it is a sporadic disease, some cases of familial clustering have been reported. In this case report, we present a case of familial occurrence of hemifacial spasm with dolichoectasia of the vertebrobasilar system in three siblings. The patients responded well to botulinum toxin therapy. A genetic mechanism predisposing them to vascular abnormalities is likely to be responsible for the clinical–radiological picture in our patients.