Myoclonus after Cardiac Arrest: Where Do We Go from Here?

Abstract

Prognostication after cardiac arrest often depends primarily on neurological function, and characterizing the extent of neurological injury hinges on neurophysiological testing and clinical neurological examination. The presence of early posthypoxic myoclonus (PHM) following cardiac arrest had been invariably associated with poor outcome, but more recent studies have shown that those with early PHM may survive with good neurological function. Electroencephalographic patterns suggestive of severe brain injury may be more valuable than the presence of PHM itself in portending poor functional status, and phenotyping PHM may also be useful in delineating benign and malignant forms. Patients with early PHM should be evaluated similarly to others who suffer cardiac arrest by using a multimodal approach in determining prognosis until further studies are performed that better characterize early PHM subtypes and their outcomes.

Targeted Temperature Management and Multimodality Monitoring of Comatose Patients After Cardiac Arrest

“…Its accuracy as a prognostic tool has had to be re-evaluated with the advent of TTM. Although early post-hypoxic myoclonus is associated with poor prognosis, since the publication of the 2006 American Academy of Neurology Guidelines on prognostication following CA ( 61 ), several authors have reported outcomes better than predicted in patients with myoclonic seizures ( 44 , 50 , 62 – 65 ). Cortical myoclonus or status myoclonus within 72 h from CA did not exclude a good neurologic recovery defined as Cerebral Performance Category (CPC) 1 or 2, with a 5% FPR ( 44 , 50 , 62 – 64 ).…”

“…Cortical myoclonus or status myoclonus within 72 h from CA did not exclude a good neurologic recovery defined as Cerebral Performance Category (CPC) 1 or 2, with a 5% FPR ( 44 , 50 , 62 – 64 ). Some have suggested that “benign” and “malignant” myoclonus or MSE can be differentiated by the background EEG pattern ( 65 , 66 ).…”

Neurophysiological and Clinical Correlates of Acute Posthypoxic Myoclonus

“…Neurophysiological studies are helpful in differentiating benign and malignant forms of acute PHM, 23 and recent guidelines have recommended ancillary neurophysiological testing. 18 Furthermore, some authors have found EEG correlates and background activity to best characterize and supplement the clinical PHM.…”

“…10 Since the 2006 practice parameter for determining prognosis after cardiac arrest was published, 10 others have found that some patients with acute PHM may survive with good neurological function. 12,13,15,16,[20][21][22][23][24] Some of these patients historically were referred to having "chronic" PHM because of its onset at times being delayed following cardiac arrest and persisting after the patient regained consciousness. 8 It has previously been referred to as Lance-Adams syndrome (LAS).…”

Visualisation of limb movements by accelerometers in sedated patients

“…As such, we are expanding the use and usability of accelerometric data from earlier studies which mainly focused on sedation and agitation levels [3,4]. In ICU patients, there are several known types of abnormal movements depending on the underlying pathophysiology of brain injury [5,6]. In this first study, we did not aim at doing any qualitative movement characterisation albeit we do believe this should be possible with the use of accelerometers in the future utilising the full time-resolution of the sensors.…”