Dystonia is a neurological disorder that results in atypical uncontrolled motions or postures caused by either continuous or intermittent contractions of the muscles. Subtypes of dystonia vary in their symptoms and severity; they can affect people of all ages and cause significant disability and poor quality of life. Identifying genes responsible for single or mixed dystonia variants has improved our understanding of its pathogenesis. The mechanisms underlying several of the most prevalent genetic dystonias, including idiopathic dystonia, TOR1A, THAP1, and KMT2B mutations, involve anomalies in transcriptional regulation, striatal dopaminergic signaling, synaptic plasticity, and a loss of inhibition at neuronal circuits. Dystonia is mostly diagnosed based on clinical indicators, and the diagnosis and etiology of this illness remain a problem. In this review, we tried to summarize novel updates about genetic causes and treatment of focal dystonia.

Dystonias, characterized by excessive muscle contractions resulting in involuntary postures and movements, impact 3 million people globally, making them the third most common movement disorder. Often accompanied by tremors, dystonias have epidemiological links and non-motor features shared with isolated tremor, such as essential tremor. Both dystonia and tremor present with balance dysfunction and abnormal involuntary movements, potentially linked to abnormal cerebellar function. This study explores the perception of one’s own linear movement, heading, particularly discrimination of heading direction, in isolated cervical dystonia, isolated tremor, and their combination. The focus is on the perception of heading direction during isolated visual star-cloud movement (visual heading perception) and en bloc body movement (vestibular heading perception). Nineteen participants underwent a two-alternative forced-choice task in the vestibular and visual domains. Results reveal elevated vestibular heading perception thresholds in cervical dystonia with or without tremor, and isolated tremor compared to healthy controls. Vestibular heading perception threshold was comparable in cervical dystonia with tremor and isolated tremor, but it was even worse in isolated cervical dystonia. Visual heading perception, however, remained less affected all three conditions – isolated cervical dystonia, isolated tremor, and their combination. These findings indicate shared deficits and distinctions in the perception of linear translational heading across movement disorders, such as isolated cervical dystonia, tremor, or their combination, offering insights into their pathophysiology, particularly the involvement of cerebellum regions responsible for vestibular processing.

Dystonia and tremor are distinct movement disorders, but they overlap in certain circumstances. First, dystonia and tremor may co-exist in the same individual, in the same or different regions of the body. Second, dystonic movements are sometimes rapid and repetitive, and they may mimic tremor. The term dystonic tremor first appeared in the literature to describe a rapid and repetitive dystonic movement that mimicked tremor but could be discriminated from essential tremor. With the first consensus statement on tremor, the term dystonic tremor was instead used to describe any combination of dystonia with tremor in the same body region, a definition retained in the latest consensus statement. Both definitions continue to be used in the modern literature. To address this problem, a group of specialists in dystonia and tremor met to review the problem and develop recommendations for more consistent approach. The group agreed that a terminology that could be applied in the clinic was essential, even though laboratory-based measures may sometimes be required. The group also agreed that the term tremor should exclusively refer to rhythmic movements, and the establishment of boundaries for rhythmicity is needed. The group also agreed that repetitive movements that are grossly arrhythmic in the context of dystonia, should be called jerky dystonia, rather than terms that imply tremor. Moreover, when both tremor and dystonia coexist, they should be described according to affected body regions rather than given distinct labels.

AbstractIn the evolving modern era of neuromodulation for movement disorders in adults and children, much progress has been made recently characterizing the human motor network (MN) with potentially important treatment implications. Herein is a focused review of relevant resting state fMRI functional and effective connectivity of the human motor network across the lifespan in health and disease. The goal is to examine how the transition from static functional to dynamic effective connectivity may be especially informative of network-targeted movement disorder therapies, with hopeful implications for children.Impact StatementWhile functional connectivity has elucidated much MN properties with relation to age, disease, and behavior, effective connectivity has been shown to be useful in MN-informed therapies in adults. Thus, effective connectivity may have potential to impact childhood movement disorder therapies, given the lower to no patient demand.

Movement disorders encompass a diverse group of neurological conditions characterized by abnormal voluntary or involuntary movements. These disorders can be classified broadly into hyperkinetic and hypokinetic disorders. Excessive, involuntary movements, including tremors, dystonia, chorea, and myoclonus characterize hyperkinetic disorders. Tremors are rhythmic, involuntary movements occurring at rest or during movement. Dystonia involves sustained muscle contractions, leading to twisting and repetitive movements or abnormal postures. Chorea manifests as brief, irregular, involuntary movements that flow from one body part to another. Myoclonus consists of sudden, brief muscle contractions, either spontaneous or in response to a stimulus. Hypokinetic disorders are characterized by a lack of movement or difficulty initiating movement, as seen in Parkinson's disease and Parkinsonism. Parkinson's disease is a progressive neurological disorder that primarily affects movement, causing tremors, stiffness, and difficulty with balance and coordination. Parkinsonism refers to a group of disorders with similar symptoms to Parkinson's disease but with different underlying causes. Diagnosing movement disorders involves a thorough clinical evaluation, including a detailed medical history and physical examination. Neuroimaging studies such as MRI, CT scans, and functional imaging techniques may be used to assess brain structure and function. Additionally, laboratory tests, including genetic testing and biochemical markers, can help diagnose certain movement disorders.

Glucose is the primary energy fuel used by the brain and is transported across the blood-brain barrier (BBB) by the glucose transporter type 1 and 2.[1] A GLUT1 genetic defect is responsible for glucose transporter type 1 deficiency syndrome (GLUT1DS). Patients with GLUT1DS may present with pharmaco-resistant epilepsy, developmental delay, microcephaly, and/or abnormal movements, with tremendous phenotypic variability. Diagnosis is made by the presence of specific clinical features, hypoglycorrhachia and an SLC2A1 gene mutation. Treatment with a ketogenic diet therapy (KDT) is the standard of care as it results in production of ketone bodies which can readily cross the BBB and provide an alternate energy source to the brain in the absence of glucose. KDTs have been shown to reduce seizures and abnormal movements in children diagnosed with GLUT1DS. However, little is known about the impact of KDT on cognitive function, seizures and movement disorders in adults newly diagnosed with GLUT1DS and started on a KDT in adulthood, or the appropriate ketogenic diet therapy to administer. This case report demonstrates the potential benefits of using a modified Atkins diet (MAD), a less restrictive ketogenic diet therapy on cognition, seizure control and motor function in an adult with newly-diagnosed GLUT1SD.

Secondary movement disorders (SMDs) represent a heterogeneous group of neurological conditions characterized by abnormal, involuntary movements resulting from various underlying causes. This comprehensive review aims to thoroughly understand SMDs, including their epidemiology, pathophysiology, clinical manifestations, diagnostic approach, and management strategies. SMDs encompass a spectrum of movement abnormalities, including dystonia, chorea, athetosis, myoclonus, tics, and tremors. They can arise from a multitude of etiologies, such as drug-induced effects, post-infectious processes, metabolic disturbances, and structural brain lesions. The epidemiology of SMDs varies depending on the underlying cause, with some conditions being more prevalent in specific populations or age groups. Understanding the pathophysiology of SMDs is crucial for accurate diagnosis and targeted management. Diagnosing SMDs requires a comprehensive approach, including a detailed history, physical examination, laboratory investigations, neuroimaging studies, and sometimes electrophysiological studies. Management of SMDs is multifaceted and may involve pharmacological, non-pharmacological, and surgical interventions. Individualized treatment plans are essential, considering the underlying cause, severity of symptoms, and patient preferences. Emerging concepts in the field of SMDs include advancements in genetic research, identification of biomarkers, and development of novel therapeutic approaches. There is a growing focus on patient-centered care and improving the quality of life for individuals with SMDs. In conclusion, SMDs pose diagnostic and therapeutic challenges, requiring a multidisciplinary approach for optimal management. Continued research and collaboration are essential for advancing our understanding and treatment of these complex disorders.

Movement disorders can be associated with various drugs and systemic diseases, posing diagnostic challenges for clinicians. This review explores the spectrum of movement disorders associated with pharmacological agents and medical conditions. Drug-induced movement disorders encompass a broad range of conditions resulting from exposure to medications that affect several neurotransmitters. Neuroleptic medications can lead to tardive dyskinesia, characterized by involuntary, repetitive movements. Antipsychotics and antiemetics, including metoclopramide, may induce acute dystonic reactions. Other drugs, such as dopamine receptor-blocking agents, can contribute to drug-induced parkinsonism. Beyond medications, movement disorders can also arise secondary to systemic diseases. Metabolic disorders like Wilson's disease, characterized by copper accumulation, may manifest as chorea or dystonia. Inflammatory conditions such as rheumatoid arthritis and systemic lupus erythematosus can result in secondary movement disorders due to autoimmune-mediated processes affecting the central nervous system. Movement disorders linked to drugs or systemic diseases often necessitate a thorough clinical evaluation, including detailed medication histories and comprehensive systemic assessments. Neuroimaging, laboratory investigations, and, in some cases, cerebrospinal fluid analyses and electrodiagnostic studies help in establishing accurate diagnoses. Management involves addressing the underlying cause, modifying medications, and employing symptomatic treatments.