eprintid: 1494641 rev_number: 25 eprint_status: archive userid: 608 dir: disk0/01/49/46/41 datestamp: 2016-05-29 07:50:41 lastmod: 2020-02-13 08:18:13 status_changed: 2016-09-05 17:57:28 type: article metadata_visibility: show creators_name: Olesen, SS creators_name: Gram, M creators_name: Jackson, CD creators_name: Halliday, E creators_name: Sandberg, TH creators_name: Drewes, AM creators_name: Morgan, MY title: Electroencephalogram variability in patients with cirrhosis associates with the presence and severity of hepatic encephalopathy ispublished: pub divisions: UCL divisions: A01 divisions: B02 divisions: C10 divisions: D17 divisions: G91 keywords: Biological variability; Cirrhosis; Continuous wavelet transform; Electroencephalogram; Hepatic encephalopathy; Sample entropy; Spectral analysis note: Copyright © 2016 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ abstract: BACKGROUND & AIMS: The outputs of physiological systems fluctuate in a complex manner even under resting conditions. Decreased variability or increased regularity of these outputs is documented in several disease states. Changes are observed in the spatial and temporal configuration of the electroencephalogram (EEG) in patients with hepatic encephalopathy (HE), but there is no information on the variability of the EEG signal in this condition. The aim of this study was to measure and characterize EEG variability in patients with cirrhosis and to determine its relationship to neuropsychiatric status. METHODS: Eyes-closed, awake EEGs were obtained from 226 patients with cirrhosis, classified, using clinical and psychometric criteria, as neuropsychiatrically unimpaired (n=127) or as having minimal (n=21) or overt (n=78) HE, and from a reference population of 137 healthy controls. Analysis of EEG signal variability was undertaken using continuous wavelet transform and sample entropy. RESULTS: EEG variability was reduced in the patients with cirrhosis compared with the reference population (coefficient of variation: 21.2% [19.3-23.4] vs. 22.4% [20.8-24.5]; p<0.001). A significant association was observed between EEG variability and neuropsychiatric status; thus, variability was increased in the patients with minimal HE compared with their neuropsychiatrically unimpaired counterparts (sample entropy: 0.98 [0.87-1.14] vs. 0.83 [0.75-0.95]; p=0.02), and compared with the patients with overt HE (sample entropy: 0.98 [0.87-1.14] vs. 0.82 [0.71-1.01]; p=0.01). CONCLUSIONS: Variability of the EEG is associated with both the presence and severity of HE. This novel finding may provide new insights into the pathophysiology of HE and provide a means for monitoring patients over time. LAY SUMMARY: Decreased variability or increased regularity of physiological systems is documented in several disease states. Variability of the electroencephalogram was found to be associated with both the presence and severity of brain dysfunction in patients with chronic liver disease. date: 2016-09 date_type: published official_url: http://dx.doi.org/10.1016/j.jhep.2016.05.004 oa_status: green full_text_type: other language: eng primo: open primo_central: open_green article_type_text: Journal Article verified: verified_manual elements_id: 1130436 doi: 10.1016/j.jhep.2016.05.004 pii: S0168-8278(16)30189-1 lyricists_name: Morgan, Marsha lyricists_id: MYMOR45 full_text_status: public publication: Journal of Hepatology volume: 65 number: 3 pagerange: 517-523 issn: 1600-0641 citation: Olesen, SS; Gram, M; Jackson, CD; Halliday, E; Sandberg, TH; Drewes, AM; Morgan, MY; (2016) Electroencephalogram variability in patients with cirrhosis associates with the presence and severity of hepatic encephalopathy. Journal of Hepatology , 65 (3) pp. 517-523. 10.1016/j.jhep.2016.05.004 <https://doi.org/10.1016/j.jhep.2016.05.004>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/1494641/1/Olesen%20et%20al%20Electroencephalogram%20variability%20in%20patients%20with%20cirrhosis%20associates%20with%20the%20presence%20and%20severity%20of%20hepatic%20encephalopathy.pdf