Improvement of "Bouncy Gait" in Lance-Adams Syndrome with Perampanel

Negative Myoclonus: Neurophysiological Study and Clinical Impact in Progressive Myoclonus Ataxia

INTRODUCTION

Negative myoclonus (NM) is an involuntary movement caused by a sudden interruption of muscular activity, resulting in gait problems and falls.

OBJECTIVE

To establish frequency, clinical impact, and neurophysiology of NM in progressive myoclonus ataxia (PMA) patients.

METHODS

Clinical, neurophysiological, and genetic data of 14 PMA individuals from University Medical Centre Groningen (UMCG) Expertise Center Movement Disorder Groningen were retrospectively collected. Neurophysiological examination included video-electromyography-accelerometry assessment in all patients and electroencephalography (EEG) examination in 13 individuals. Jerk-locked (or silent period-locked) back-averaging and cortico-muscular coherence (CMC) analysis aided the classification of myoclonus.

RESULTS

NM was present in 6 (NM+) and absent in 8 (NM-) PMA patients. NM+ individuals have more frequent falls (100% vs. 37.5%) and higher scores on the Gross Motor Function Classification System (GMFCS) (4.3 ±0.74 vs. 2.5 ±1.2) than NM- individuals. Genetic background of NM+ included GOSR2 and SEMA6B, while that of NM- included ATM, KCNC3, NUS1, STPBN2, and GOSR2. NM was frequently preceded by positive myoclonus (PM) and silent-period length was between 88 and 194 ms. EEG epileptiform discharges were associated with NM in 2 cases. PM was classified as cortical in 5 NM+ and 2 NM- through EEG inspection, jerk-locked back-averaging, or CMC analysis.

DISCUSSION

Neurophysiological examination is crucial for detecting NM that could be missed on clinical examination due to a preceding PM. Evidence points to a cortical origin of NM, an association with more severe motor phenotype, and suggests the presence of genetic disorders causing either a PMA or progressive myoclonus epilepsy, rather than pure PMA phenotype. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Cervical Osteomyelitis, Cardiac Arrest, and Lance-Adams Syndrome: A Case Report

Lance-Adams syndrome (LAS) is a rare complication of successful cardiopulmonary resuscitation, often accompanied by action myoclonus. Myoclonus may occur as generalized, focal, or multifocal movements and can include the face, trunk, and/or extremities. Only 100 cases of LAS have been reported worldwide. Here, we present the case of a 53-year-old female who had a cardiac arrest event after being admitted for posterior cervical wound dehiscence management following a posterior cervical fusion from C3-T1. The patient was successfully resuscitated but developed action myoclonus in all extremities shortly after. Anoxic brain injury and myoclonus led to debilitation and prolonged hospital stay. During her inpatient stay, she was treated with clonazepam, levetiracetam, and sodium valproate with mild improvement.

Lance-Adams Syndrome Treated by Perampanel in the Acute Term

Lance-Adams syndrome (LAS) is chronic post-hypoxic myoclonus after a hypoxic encephalopathy. Recently, the report on LAS in the chronic term treated by perampanel (PER) is increasing. However, PER’s efficacy in the “acute term” has not been reported. Here, we report an LAS patient who markedly improved when PER was added to his existing treatment regime in the acute term. The 65-year-old patient presented with a return of spontaneous circulation after cardiopulmonary arrest. He developed myoclonus on the admission day, and it led to tonic-clonic convulsion. We started levetiracetam 3000 mg/day, lacosamide 400 mg/day, general anesthesia using midazolam 180 mg/day, dexmedetomidine 1000 μg/day, and fentanyl 1.2 mg/day. We could stop the convulsions after 18 h from the onset. We tried to reduce sedatives, but his convulsion recurred. We added PER 2 mg/day for three days, PER 4 mg/day for next four days, then used PER 8 mg/day and we could gradually reduce the sedatives. Single-photon emission computed tomography on day 40 showed cerebral blood flow (CBF) increase at the bilateral anterior lobes of the cerebellum, medial temporal lobes, and supplementary motor and premotor areas, while CBF decrease at the brain surface of the frontal, parietal, and temporal lobes. The myoclonus disappeared since day 12, and he was transferred to another rehabilitation hospital on day 56. The optimal treatment strategy has not been established for LAS, but our case suggested that PER could be one of the choices to treat LAS in the acute term.

[A case of the successful treatment of severe myoclonus with Lance-Adams syndrome by add-on perampanel showing long term effects]

Perampanel is an α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor antagonist that has been marked as an antiepileptic drug for partial-onset and primary generalized tonic-clonic seizures. There have been some recent reports of perampanel being effective against cortical myoclonus by Lafora disease and Unverricht-Lundborg disease. We herein report a 49-year-old man who presented with myoclonus due to Lance-Adams syndrome (LAS) after cardiopulmonary arrest caused by a severe bronchial asthma attack. Perampanel was very effective against myoclonus induced by LAS even in the chronic state, over 10 years after the remote onset. Perampanel should be considered for the treatment of extremely refractory myoclonus due to LAS.