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Year : 2020  |  Volume : 2  |  Issue : 4  |  Page : 96

Unilateral Electroencephalography Discordance in a Patient with Subgaleal Air Collection

1 Critical Care, Regions Hospital, Saint Paul, MN, USA
2 Paracelsus Medical University, Salzburg, Austria; Latinamerican Council of Neurocritical Care, CLaNI; Department of Neurosurgery, Center of Biomedical Research (CIB), University of Cartagena, Cartagena de Indias, Colombia

Date of Submission23-Sep-2020
Date of Acceptance24-Nov-2020
Date of Web Publication25-Jun-2021

Correspondence Address:
Dr. Luis Rafael Moscote-Salazar
Department of Neurosurgery, University of Cartagena, Cra. 50 #24120, Cartagena De Indias

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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jtccm.jtccm_19_20

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How to cite this article:
Janjua T, Moscote-Salazar LR. Unilateral Electroencephalography Discordance in a Patient with Subgaleal Air Collection. J Transl Crit Care Med 2020;2:96

How to cite this URL:
Janjua T, Moscote-Salazar LR. Unilateral Electroencephalography Discordance in a Patient with Subgaleal Air Collection. J Transl Crit Care Med [serial online] 2020 [cited 2023 Mar 31];2:96. Available from: http://www.tccmjournal.com/text.asp?2020/2/4/96/319411

Dear Editor,

Electroencephalography (EEG) records are useful in various neurocritical pathologies. EEG records corresponding to low electric potential and may be affected by a wide range of factors.[1]

We present 64 years female who was in a store shopping when she lost balance and fell to the ground. On arrival to the neurocritical care unit, she was awake and alert. She did not remember how she fell. She developed left pariteo-occipital scalp laceration, which required suturing in the emergency department. Computed tomography (CT) – scan head showed small subarachnoid collection of blood in the left Sylvain fissure, which cleared in subsequent CT-scan. An emergent four vessels cerebral angiogram was negative for any cerebral aneurysm. The next day an EEG was done [Figure 1]a. This showed “higher” voltage on the right side as compared to the left side. There was question that patient might have right-sided skull defect. CT-scan head with the bone window was reviewed [Figure 1]b. The EEG amplitude was “low” on the left side due to subgaleal air collection from the fall. The patient left the intensive care unit to the cardiac floor for syncope workup, and no further neurological workup was requested.
Figure 1: (a) Top image with subgaleal air on bone window. (b) Bottom image is an electroencephalography epoch showing right-sided higher amplitude as compared to left, mostly posteriorly

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Two types of artifacts have been established, the physiological ones that come from the patient and the extra-physiological ones that correspond to environmental alterations or to the devices themselves. Muscle activity, heartbeat, and even eye movements give rise to biological signals; the latter are the most relevant because eye movements produce large amplitude signals that intermingle with brain activity. Artifacts of cardiac origin may appear as electrocardiographic-type signals. Muscle contraction also causes physiological artifacts, being observed preferentially in the electrodes at the temporal level. The electrodermal activity can also be a source of artifacts observed in areas of sweating. They are observed as waves of extremely low frequency and high amplitude. The subgaleal air collection acts as a source of contamination from nonphysiological artifacts. Our case clearly demonstrates that artifacts can provide wrong information if not fully interpreted. This EEG finding is highlighted because it is a potential cause of confusion if it is not known to the intensive care physicians and care team.

  References Top

Mari-Acevedo J, Yelvington K, Tatum WO. Normal EEG variants. Handb Clin Neurol 2019;160:143-60.  Back to cited text no. 1


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