The added value of neurophysiological investigations in post-hypoxic myoclonus.

Zijl, J.C. van (2014) The added value of neurophysiological investigations in post-hypoxic myoclonus. thesis, Medicine.

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Abstract

In this study we looked at the pathophysiology and outcome of the post-hypoxic myoclonus (PHM). PHM is a hyperkinetic movement disorder that can occur after anoxic brain damage. Based on its clinical manifestation PHM can be divided in generalised and (multi) focal PHM of which the former is associated with a subcortical aetiology and very poor prognosis, and the latter with a cortical aetiology and a better prognosis. However, it is not known how reliable this distinction can be made based on clinical criteria. To further differentiate between subcortical and cortical myoclonus, neurophysiological examinations can help. Examples of these neurophysiological examinations are electro-encephalography (EEG), electromyography (EMG), somatosensory evoked potentials (SSEP) and the combination of EEG and EMG from which “jerk-locked back averaging” (JLBA) and “coherence analysis” could be performed. However, the validation of neurophysiological examinations in different forms of myoclonus has only been established for non-comatose patients and not in patients with PAE. For this reason we analysed EEG/EMG data of 20 retrospective and prospective cases. The different modalities in which aetiology of myoclonus can be predicted, were mutually compared. More specific, the groups “clinical observed myoclonus”, “EEG and visual analysis”, “EEG/EMG”, “coherence analysis” and “JLBA” were compared in the ability to obtain a conclusion in aetiology of PHM. In summary, this study demonstrated an added value of analysis with EEG/EMG, JLBA and coherence analysis above physical examination and EEG alone in clarifying aetiology of PHM. EEG/EMG, JLBA and coherence analysis were able to identify the aetiology of PHM in most of cases. Therefore, application of these techniques on the ICU is a must. For illustration: in our population one patient with clinical generalized jerks, but cortical of origin following JLBA, survived. In other words, the life of this patient could be ended unnecessarily if the clinical based interpretation of PHM had been followed. Furthermore, this study revealed an interesting etiological phenomenon: cortical and subcortical PHM-jerks can co-exist. Moreover, the reticular formation could be the origin for both-type myoclonus, as it is presumed in subcortical myoclonus. Interestingly, the prognosis of both-type myoclonus and subcortical myoclonus is poor. Therefore, extra attention during electrophysiological analysis for non-cortical PHM is wise. Since analysis with advanced electrophysiological programs are time consuming, future research is needed to develop more automated methods, which can be applied at the ICU bedside.

Item Type:	Thesis (Thesis)
Supervisor name:	Koning-Tijssen, Prof. Dr. M.A.J. de and Beudel, Dr. M.
Faculty:	Medical Sciences
Date Deposited:	25 Jun 2020 11:04
Last Modified:	25 Jun 2020 11:04
URI:	https://umcg.studenttheses.ub.rug.nl/id/eprint/2437

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