Navigating the Complexity of Alternating Hemiplegia in Childhood: A Comprehensive Review.

Alternating hemiplegia of childhood (AHC) is a complex neurodevelopmental disorder characterized by paroxysmal and transient events of unilateral or bilateral paresis, usually occurring before 18 months of age. Mutations in the ATP1A3 gene, mainly p.Asp801Asn, p.Glu815Lys, and p.Gly947Arg at the protein level, are found in around 80% of the individuals with AHC. Interestingly, these mutations reflect the degree of severity of the neurological symptoms (p.Glu815Lys > p.Asp801Asn > p.Gly947Arg). Some channels involved in this disorder are N-type voltage-gated calcium channels, ATP-sensitive potassium channels, and the sodium/calcium exchanger. In this context, the management of AHC should be divided into the treatment of attacks, prophylactic treatment, and management of comorbidities commonly found in this group of individuals, including epilepsy, attention-deficit/hyperactivity disorder, aggressive behavior, cognitive impairment, movement disorders, and migraine. The importance of an integrated approach with a multidisciplinary team, such as neuropsychologists and dietitians, is worth mentioning, as well as the follow-up with a neurologist. In the present study, we propose new diagnostic criteria for AHC, dividing it into clinical, laboratory, supporting, and atypical features. Also, we review the location of the mutations in the ATP1A3 protein of individuals with AHC, rapid-onset dystonia-parkinsonism (RDP) variants, and early infantile epileptic encephalopathy (variants with hemiplegic attack). We also include a section about the animal models for ATP1A3 disorders.

Cocaine-induced Movement Disorder: A Literature Review.

This study aims to describe movement disorders secondary to cocaine use. To our knowledge, while these presentations have been previously reported in the literature, a comprehensive review has not been published yet. We searched six databases from 1986 to 2022 without language restriction. Case reports, case series, and literature reviews have been analysed to find associations between cocaine use and movement disorders. The present study encompasses epidemiology, clinical manifestations, pathophysiology, and diagnostic challenges of abnormal movements associated with cocaine use. This review highlights the importance of proper initial evaluation and investigation taking into account the broad spectrum of differential diagnoses and exclusion of primary movement disorders. The role of the dopaminergic system in movement disorders is reviewed. Cocaine use is associated with movement disorders such as dystonia, parkinsonism, akathisia, and tics. The complex interaction of multiple factors, including other neurological conditions, such as Tourette syndrome, and additional substances of abuse is discussed. The presentation of these manifestations is often heterogeneous and does not follow a specific pattern. In this way, future research is needed to improve our understanding of the pathophysiological mechanisms and develop novel drug targets for these disorders. Increased awareness among the general public and policymakers could translate into reduced stigma and improved care.

Herpes zoster ophthalmicus presenting with orbital myositis prior to the appearance of vesicular lesions: A case report and mini­review of the literature.

All orbital tissues, including extra-ocular muscles, can be affected by the varicella-zoster virus (VZV). However, only a minority of all individuals with herpes zoster infections present with herpes zoster ophthalmicus. The present study reports the case of a middle-aged male patient presenting with an acute intractable right-sided headache. His neurological examination yielded normal results. The analysis of cerebrospinal fluid by biochemistry and cultural analysis yielded normal results; however, the analysis of this fluid using polymerase chain reaction yielded a positive result for VZV. Thus, treatment with acyclovir was commenced. Brain magnetic resonance imaging revealed a bilateral intraorbital intraconal enhancement consistent with myositis. His symptoms evolved into a shock-like pain over the scalp associated with painful ocular movements. On the 2nd day of admission, he developed new vesicular lesions found on the right-side cranial nerve V1 dermatome. By the 6th day of admission, he was asymptomatic, and his physical examination revealed the resolution of the dermatologic manifestations of the VZV. The patient was stable for outpatient follow-up with ophthalmology and was discharged on an oral valacyclovir course for 7 days. To the authors' knowledge, there are four cases reported in the literature of herpes zoster ophthalmicus with orbital myositis prior to the appearance of vesicular lesions. Thus, it is suggested that VZV serology be investigated before a final diagnosis of idiopathic orbital myositis is made.

A Systematic Review of Oral Vertical Dyskinesia ("Rabbit" Syndrome).

Background and Objectives: Vertical rhythmic dyskinetic movements that are primarily drug-induced and affect solely the jaw, mouth, and lips without involving the tongue have been historically described as "rabbit" syndrome (RS). Evidence on the unique features and implications of this disorder remains limited. This literature review aims to evaluate the clinical-epidemiological profile, pathological mechanisms, and management of this movement disorder. Materials and Methods: Two reviewers identified and assessed relevant reports in six databases without language restriction published between 1972 and 2024. Results: A total of 85 articles containing 146 cases of RS were found. The mean frequency of RS among adults in psychiatric hospitals was 1.2% (range 0-4.4%). The mean age of affected patients was 49.2 (SD: 17.5), and 63.6% were females. Schizophrenia was the most frequent comorbidity found in 47.6%, followed by bipolar disorder (17.8%), major depressive disorder (10.3%), and obsessive-compulsive disorder (3.7%). Five cases were idiopathic. The most common medications associated with RS were haloperidol (17%), risperidone (14%), aripiprazole (7%), trifluoperazine (5%), and sulpiride (5%). The mean duration of pharmacotherapy before RS was 21.4 weeks (SD: 20.6). RS occurred in association with drug-induced parkinsonism (DIP) in 27.4% and with tardive dyskinesia (TD) in 8.2% of cases. Antipsychotic modification and/or anticholinergic drugs resulted in full or partial recovery in nearly all reported cases in which they were prescribed. Conclusions: RS occurs as a distinct drug-induced syndrome associated primarily but not exclusively with antipsychotics. Distinguishing RS from TD is important because the treatment options for the two disorders are quite different. By contrast, RS may be part of a spectrum of symptoms of DIP with similar course, treatment outcomes, and pathophysiology.

Unraveling belly dancer's dyskinesia and other puzzling diagnostic contortions: A narrative literature review.

Belly dancer's dyskinesia (BDD) is characterized by involuntary abdominal wall movements that are rhythmic, repetitive, and dyskinetic. The present study aims to review BDD's etiology, pathophysiology, and management. We searched six databases to locate existing reports on BDD published from 1990 to October 2023 in electronic form. A total of 47 articles containing 59 cases were found. The majority of the patients affected by BDD were female, accounting for 61.01% (36/59) of the cases. The mean and median ages were 49.8 (standard deviation: 21.85) and 52 years (range: 7-85), respectively. The BDD was unilateral in only 3.38% (2/59). The most commonly reported causes associated with BDD were 17 idiopathic, 11 drug-induced, 11 postsurgical procedures, 5 pregnancies, and 4 Vitamin B12 deficiencies. BDD is a diagnosis of exclusion, and other more common pathologies with similar presentation should be ruled out initially. Differential diagnostic reasoning should include diaphragmatic myoclonus, cardiac conditions, truncal dystonia, abdominal motor seizures, propriospinal myoclonus, and functional or psychiatric disorders.

Trazodone-induced parkinsonism in a middle-aged male: A case report.

Introduction: Trazodone is an antidepressant agent approved for treating major depressive disorders and is also prescribed for insomnia due to its sedative effect. In a few cases, trazodone was associated with parkinsonism. Herein, we describe a case of parkinsonism after a brief exposure to a moderate dose of trazodone. Objective: To describe a case of a patient with trazodone-induced parkinsonism in which the diagnosis was suspected after the exclusion of other common and serious causes. Methods: A case report of trazodone-induced parkinsonism. Clinical Case: A 58-year-old male with sleeping problems was prescribed trazodone 50 mg daily at bedtime. The subject doubled the dosage without medical advice a week later. After 14 days of trazodone treatment, he started to experience difficulty in moving his upper limbs and recurrent falling. Neuroimaging, electrodiagnostic studies, and laboratory exams were unremarkable. Trazodone was discontinued, and the patient fully recovered. Noteworthy, the patient developed a recurrence of the motor symptoms with trazodone-rechallenge. Conclusion: Our case showed reversibly induced parkinsonism after a short intake of a moderate dose of trazodone which was prescribed for insomnia. The patient had a complete recovery after trazodone withdrawal. Noteworthy, the symptoms recurred upon trazodone-rechallenge.

Pregabalin-Induced Parkinsonism: Case Report and Review of the Literature.

Pregabalin is an anti-epileptic drug approved for the treatment of neuropathic pain and focal-onset seizures. In a few cases, pregabalin was associated with parkinsonism. We present a case of a 48-year-old female who had hypertension and was on losartan 50 mg/daily. Her general practitioner prescribed pregabalin 150 mg/daily for fibromyalgia-related pain. The subject doubled the dosage without medical advice. After 5 days of the increased dosage, she started to experience difficulty and slowness in movement associated with resting tremors. Neuroimaging, electrodiagnostic studies, and laboratory exams were unremarkable. Secondary parkinsonism was suspected, so pregabalin was discontinued. The subject fully recovered within 7 days. To the authors' knowledge, only 6 cases of pregabalin-induced parkinsonism were reported in the literature. Pregabalin discontinuation was the most common management. All individuals fully recovered after pregabalin withdrawal. The mechanism of pregabalin-induced parkinsonism is not fully understood.

Isolated pseudo­abducens palsy and contralateral occipital headache with thalamic stroke: A case report and mini­review of the literature.

The abducens nerve (sixth cranial nerve) is essential for lateral eye movement, and its malfunction can cause a variety of issues with vision. Pseudo-abducens palsy is a rare neurological condition that causes a limitation in eye abduction, while the abducens nerve is still functioning. Thalamic pain syndrome, a severe complication of cerebrovascular events, presents as intense neuropathic pain provoked by temperature fluctuations. Although thalamic strokes are infrequently associated with ocular abnormalities, some studies suggest an association between isolated pseudo-abducens palsy and thalamic infarctions. The present study describes the case of a 38-year-old male patient with 1-day progressive diplopia and occipital headache who had abducens palsy on the left side as a result of a right thalamic infarction. The patient had a 10-year history of smoking and a 1-year history of hypertension, which was poorly controlled. The diagnosis was supported by a neurological examination, imaging and stroke etiology investigations. The patient recovered well within 5 days, highlighting the good prognosis of an acute thalamic presentation. In addition, a mini-review of the literature was performed and two similar reports were identified upon searching the literature using the Embase, Google Scholar, Lilacs, Medline, SciELO and ScienceDirect databases. On the whole, the present study demonstrates that understanding the complex neuronal connections inside the thalamus is critical for a proper diagnosis and appropriate intervention strategies in patients with thalamic stroke with oculomotor impairments. Further research is required to elucidate the underlying causes and develop treatment techniques for thalamic infarction consequences.

Flapping Tremor: Unraveling Asterixis-A Narrative Review.

Asterixis is a subtype of negative myoclonus characterized by brief, arrhythmic lapses of sustained posture due to involuntary pauses in muscle contraction. We performed a narrative review to characterize further asterixis regarding nomenclature, historical aspects, etiology, pathophysiology, classification, diagnosis, and treatment. Asterixis has been classically used as a synonym for negative myoclonus across the literature and in previous articles. However, it is important to distinguish asterixis from other subtypes of negative myoclonus, for example, epileptic negative myoclonus, because management could change. Asterixis is not specific to any pathophysiological process, but it is more commonly reported in hepatic encephalopathy, renal and respiratory failure, cerebrovascular diseases, as well as associated with drugs that could potentially lead to hyperammonemia, such as valproic acid, carbamazepine, and phenytoin. Asterixis is usually asymptomatic and not spontaneously reported by patients. This highlights the importance of actively searching for this sign in the physical exam of encephalopathic patients because it could indicate an underlying toxic or metabolic cause. Asterixis is usually reversible upon treatment of the underlying cause.

A Narrative Review of Stroke of Cortical Hand Knob Area.

The cortical hand knob region of the brain is a knob-like segment of the precentral gyrus, projecting into the middle genu of the central sulcus. This anatomic landmark is responsible for intricate control of hand motor movements and has often been implicated in motor weakness following stroke. In some instances, damage to this area has been mistaken for peripheral causes of hand weakness. Our article aims to consolidate clinically relevant information on the cortical hand knob area in a comprehensive review to guide clinicians regarding diagnosis and treatment strategies. We conducted a systematic search within the Medline/PubMed database for reports of strokes in the cortical hand knob region. All studies were published electronically up until December 2023. The search was conducted using the keyword "hand knob". A total of 24 reports containing 150 patients were found. The mean and median ages were 65 and 67 years, respectively. Sixty-two percent of the individuals were male. According to the TOAST criteria for the classification of the stroke, 59 individuals had a stroke due to large-artery atherosclerosis, 8 had small-vessel occlusion, 20 had cardioembolism, 25 were determined, and 38 were undetermined. The most common etiologies for stroke in the hand knob area can be attributed to large vessel occlusions, small vessel occlusions, or cardioembolism. Presentations following damage to this area can mimic ulnar, median, or radial neuropathy as well. Our comprehensive review serves as a resource for recognizing and managing stroke in the cortical hand knob area.

Catatonia as the Presentation of Encephalopathy Associated With Autoimmune Thyroiditis: A Case Report and Literature Review.

Encephalopathy can be associated with autoimmune disorders such as autoimmune thyroiditis, and it can present with a wide range of neuropsychiatric manifestations. However, it rarely presents with catatonia. We present the case of a middle-aged female with Hashimoto's thyroiditis presenting with catatonia. A literature review of previous similar cases highlighting significant points is also included. A 48-year-old female presented to the emergency department with catatonic symptoms that had worsened over the previous 5 days. A similar condition was reported to have occurred and resolved spontaneously 3 months earlier. On examination, the patient appeared uncooperative and unresponsive. She showed typical symptoms of catatonia, with a score of 21 points on the Bush-Francis Catatonia Rating Scale. Routine tests were within normal ranges except for an elevated level of C-reactive protein and an elevated erythrocyte sedimentation rate. Computed tomography, magnetic resonance imaging, and cerebrospinal fluid analysis were all normal. An electroencephalogram showed diffuse delta-theta range slowing with no epileptiform discharges. Lorazepam was initiated but did not control the catatonic symptoms. Re-evaluation revealed thyroid swelling and elevated levels of thyroperoxidase antibodies. IV methylprednisolone was therefore initiated and produced complete resolution of the catatonic symptoms in 4 hours. The patient was discharged and prescribed prednisone 1 mg/kg daily. At follow-up, the patient continued to show complete resolution of the catatonic symptoms. It is noteworthy that the patient developed hypothyroidism 6 months after this catatonic episode for which levothyroxine 50 mcg/d was prescribed. Encephalopathy associated with autoimmune thyroiditis can initially present with catatonic symptoms in euthyroid cases. The mainstay of treatment is steroids which result in complete resolution of the catatonic symptoms.

Action Myoclonus Secondary to Donepezil: Case Report and Literature Review.

Movement disorders associated with donepezil have been only rarely reported. Herein, we describe an older woman who developed myoclonus secondary to donepezil. A 61-year-old female presented with brief involuntary twitching. The patient reported that she consulted a general practitioner about 1 month before due to memory complaints. A diagnosis of mild cognitive impairment was made. Donepezil was started. After 4 weeks, she presented to our emergency department due to significant twitching. Multifocal myoclonus was observed. These movements occurred during rest and voluntary movement. Laboratory exams and cerebrospinal fluid analysis were normal. A cranial computed tomography and brain magnetic resonance imaging were unremarkable. Electroencephalography did not show epileptic activity. Electromyography revealed burst durations varying between 50 and 100 ms. Diazepam intravenous was started, which improved her abnormal movement within 1 hour. On the next day, she developed the same clinical symptoms of presentation. Donepezil was discontinued, and clonazepam was started. The patient had a complete recovery from her myoclonus. To the authors' knowledge, there are six reports of myoclonus secondary to donepezil/galantamine. There is no report of rivastigmine-induced myoclonus. The most frequent presentation was multifocal myoclonus. The management was the discontinuation of the acetylcholinesterase inhibitor. All the individuals recovered within 3 weeks.

Deep Brain Stimulation for the Management of Refractory Neurological Disorders: A Comprehensive Review.

In recent decades, deep brain stimulation (DBS) has been extensively studied due to its reversibility and significantly fewer side effects. DBS is mainly a symptomatic therapy, but the stimulation of subcortical areas by DBS is believed to affect the cytoarchitecture of the brain, leading to adaptability and neurogenesis. The neurological disorders most commonly studied with DBS were Parkinson's disease, essential tremor, obsessive-compulsive disorder, and major depressive disorder. The most precise approach to evaluating the location of the leads still relies on the stimulus-induced side effects reported by the patients. Moreover, the adequate voltage and DBS current field could correlate with the patient's symptoms. Implantable pulse generators are the main parts of the DBS, and their main characteristics, such as rechargeable capability, magnetic resonance imaging (MRI) safety, and device size, should always be discussed with patients. The safety of MRI will depend on several parameters: the part of the body where the device is implanted, the part of the body scanned, and the MRI-tesla magnetic field. It is worth mentioning that drug-resistant individuals may have different pathophysiological explanations for their resistance to medications, which could affect the efficacy of DBS therapy. Therefore, this could explain the significant difference in the outcomes of studies with DBS in individuals with drug-resistant neurological conditions.

Gabapentin-Associated Movement Disorders: A Literature Review.

BACKGROUND: Gabapentin (GBP)-induced movement disorders (MDs) are under-recognized adverse drug reactions. They are commonly not discussed with patients, and their sudden occurrence can lead to misdiagnosis. This literature review aims to evaluate the clinical-epidemiological profile, pathological mechanisms, and management of GBP-associated MD. METHODS: Two reviewers identified and assessed relevant reports in six databases without language restriction between 1990 and 2023. RESULTS: A total of 99 reports of 204 individuals who developed a MD associated with GBP were identified. The MDs encountered were 135 myoclonus, 22 dyskinesias, 7 dystonia, 3 akathisia, 3 stutterings, 1 myokymia, and 1 parkinsonism. The mean and median ages were 54.54 (SD: 17.79) and 57 years (age range: 10-89), respectively. Subjects were predominantly male (53.57%). The mean and median doses of GBP when the MD occurred were 1324.66 (SD: 1117.66) and 1033 mg/daily (GBP dose range: 100-9600), respectively. The mean time from GBP-onset to GBP-associated MD was 4.58 weeks (SD: 8.08). The mean recovery time after MD treatment was 4.17 days (SD: 4.87). The MD management involved GBP discontinuation. A total of 82.5% of the individuals had a full recovery in the follow-up period. CONCLUSIONS: Myoclonus (GRADE A) and dyskinesia (GRADE C) were the most common movement disorders associated with GBP.

Three Cases of Myoclonus Secondary to Ciprofloxacin: "Ciproclonus".

OBJECTIVES: Ciprofloxacin is a fluoroquinolone that is used for bacterial infections involving different systems. In some cases, ciprofloxacin was reported to induce myoclonus. METHODS: We performed a chart review of 3 patients with myoclonus secondary to ciprofloxacin and reviewed the literature for similar cases. Written consent for publication was obtained from each patient, and their identities were concealed for ethical reasons. RESULTS: We describe 3 cases of myoclonus secondary to ciprofloxacin, 2 males and a female aged 61, 26, and 48 years, respectively. The myoclonus appeared within 3 days of ciprofloxacin intake. In all 3 cases, ciprofloxacin was prescribed for urinary tract infection. Electroencephalogram and neuroimaging studies were normal and possible causes were excluded. Thus, ciprofloxacin was believed to be the underlying cause and hence it was withdrawn. The patients had complete recovery on follow-up. CONCLUSIONS: Although ciprofloxacin is widely prescribed for different infections, only 13 cases were reported to develop myoclonus secondary to ciprofloxacin. The mean age of patients was 62 years. Fifty-four percent of cases were males. Cessation of ciprofloxacin was the most common management course. All individuals fully recovered after ciprofloxacin withdrawal. The mechanism of ciprofloxacin-induced myoclonus is probably associated with γ-aminobutyric acid and glutamate pathways.

A 24-year-Old Male with Marden-Walker Syndrome and Epilepsy: Case Report.

We report a 24-year-old male with blepharophimosis, psychomotor retardation, brachycephaly, microstomia, immobile face, high arched palate, single palmar crease, kyphoscoliosis, talipes equinovarus, inguinal hernia, pyloric stenosis, recurrent infections, bilateral camptodactyly, wide-set eyes, decreased muscle mass, hypotonia, exotropia, and ptosis in the left eye, growth retardation, multiple congenital contractures, and hyporreflexia. Contractures improved with aging, but intellectual disability and blepharophimosis remained. He also presented epilepsy, outbursts of laughter, and predisposition to drug adverse effects (skin lesions with carbamazepine and secondary parkinsonism).

Overview of Movement Disorders Secondary to Drugs.

Drug-induced movement disorders affect a significant percentage of individuals, and they are commonly overlooked and underdiagnosed in clinical practice. Many comorbidities can affect these individuals, making the diagnosis even more challenging. Several variables, including genetics, environmental factors, and aging, can play a role in the pathophysiology of these conditions. The Diagnostic and Statistical Manual of Mental Disorders (DSM) and the International Statistical Classification of Diseases and Related Health Problems (ICD) are the most commonly used classification systems in categorizing drug-induced movement disorders. This literature review aims to describe the abnormal movements associated with some medications and illicit drugs. Myoclonus is probably the most poorly described movement disorder, in which most of the reports do not describe electrodiagnostic studies. Therefore, the information available is insufficient for the diagnosis of the neuroanatomical source of myoclonus. Drug-induced parkinsonism is rarely adequately evaluated but should be assessed with radiotracers when these techniques are available. Tardive dyskinesias and dyskinesias encompass various abnormal movements, including chorea, athetosis, and ballism. Some authors include a temporal relationship to define tardive syndromes for other movement disorders, such as dystonia, tremor, and ataxia. Antiseizure medications and antipsychotics are among the most thoroughly described drug classes associated with movement disorders.

Somatosensory Auras in Epilepsy: A Narrative Review of the Literature.

An aura is a subjective experience felt in the initial phase of a seizure. Studying auras is relevant as they can be warning signs for people with epilepsy. The incidence of aura tends to be underestimated due to misdiagnosis or underrecognition by patients unless it progresses to motor features. Also, auras are associated with seizure remission after epilepsy surgery and are an important prognostic factor, guiding the resection site and improving surgical outcomes. Somatosensory auras (SSAs) are characterized by abnormal sensations on one or more body parts that may spread to other parts following a somatotopic pattern. The occurrence of SSAs among individuals with epilepsy can range from 1.42% to 80%. The upper extremities are more commonly affected in SSAs, followed by the lower extremities and the face. The most common type of somatosensory aura is paresthetic, followed by painful and thermal auras. In the primary somatosensory auras, sensations occur more commonly contralaterally, while the secondary somatosensory auras can be ipsilateral or bilateral. Despite the high localizing features of somatosensory areas, cortical stimulation studies have shown overlapping sensations originating in the insula and the supplementary sensorimotor area.

Cenobamate (YKP3089) and Drug-Resistant Epilepsy: A Review of the Literature.

Cenobamate (CNB), ([(R)-1-(2-chlorophenyl)-2-(2H-tetrazol-2-yl)ethyl], is a novel tetrazole alkyl carbamate derivative. In November 2019, the Food and Drug Administration approved Xcopri®, marketed by SK Life Science Inc., (Paramus, NJ, USA) for adult focal seizures. The European Medicines Agency approved Ontozry® by Arvelle Therapeutics Netherlands B.V.(Amsterdam, The Neatherlands) in March 2021. Cenobamate is a medication that could potentially change the perspectives regarding the management and prognosis of refractory epilepsy. In this way, this study aims to review the literature on CNB's pharmacological properties, pharmacokinetics, efficacy, and safety. CNB is a highly effective drug in managing focal onset seizures, with more than twenty percent of individuals with drug-resistant epilepsy achieving seizure freedom. This finding is remarkable in the antiseizure medication literature. The mechanism of action of CNB is still poorly understood, but it is associated with transient and persistent sodium currents and GABAergic neurotransmission. In animal studies, CNB showed sustained efficacy and potency in the 6 Hz test regardless of the stimulus intensity. CNB was revealed to be the most cost-effective drug among different third-generation antiseizure medications. Also, CNB could have neuroprotective effects. However, there are still concerns regarding its potential for abuse and suicidality risk, which future studies should clearly assess, after which protocols should be changed. The major drawback of CNB therapy is the slow and complex titration and maintenance phases preventing the wide use of this new agent in clinical practice.

Myoclonus Secondary to Amantadine: Case Report and Literature Review.

The usual adverse events of amantadine are dizziness, dry mouth, and peripheral edema. Postmarketing experience has revealed abnormal movements such as tremors, involuntary muscle contractions, and gait abnormalities. Herein, we report a case of an elderly male who presented with generalized twitching associated with amantadine. A 64-year-old male presenting with jerking movements within one day of onset was admitted. Sudden and involuntary distal lower and upper limb muscle twitching was observed. The subject presented subsequent brief movements when attempting to stand or hold arms antigravity. He was diagnosed with Parkinson's disease three years ago. Eight days before the presentation to the emergency department, he consulted with his primary care physician, who prescribed amantadine to improve his motor symptoms. On the seventh day, he developed brisk abnormal movements. Laboratory exams, neuroimaging, and electroencephalogram were unremarkable. Amantadine was discontinued. After three days, the patient reported that his jerking movements had fully recovered. To the authors' knowledge, 22 individuals with amantadine-associated myoclonus had already been reported in the literature. The pathophysiology of amantadine-induced myoclonus is probably related to serotoninergic pathways. Myoclonus secondary to amantadine was slightly more common in men. The population affected was elderly, with a mean and median age of 67.7 and 64 years.