A low‐cost, user‐friendly electroencephalographic recording system for the assessment of hepatic encephalopathy

Abstract

Electroencephalography (EEG) is useful to objectively diagnose/grade hepatic encephalopathy (HE) across its spectrum of severity. However, it requires expensive equipment, and hepatogastroenterologists are generally unfamiliar with its acquisition/interpretation. Recent technological advances have led to the development of low-cost, user-friendly EEG systems, allowing EEG acquisition also in settings with limited neurophysiological experience. The aim of this study was to assess the relationship between EEG parameters obtained from a standard-EEG system and from a commercial, low-cost wireless headset (light-EEG) in patients with cirrhosis and varying degrees of HE. Seventy-two patients (58 males, 61 6 9 years) underwent clinical evaluation, the Psychometric Hepatic Encephalopathy Score (PHES), and EEG recording with both systems. Automated EEG parameters were calculated on two derivations. Strong correlations were observed between automated parameters obtained from the two EEG systems. Bland and Altman analysis indicated that the two systems provided comparable automated parameters, and agreement between classifications (normal versus abnormal EEG) based on standard-EEG and light-EEG was good (0.6 < j < 0.8). Automated parameters such as the mean dominant frequency obtained from the light-EEG correlated significantly with the Model for End-Stage Liver Disease score (r 5 20.39, P < 0.05), fasting venous ammonia levels (r 5 20.41, P < 0.01), and PHES (r 5 20.49, P < 0.001). Finally, significant differences in light-EEG parameters were observed in patients with varying degrees of HE. Conclusion: Reliable EEG parameters for HE diagnosing/ grading can be obtained from a cheap, commercial, wireless headset; this may lead to more widespread use of this patientindependent tool both in routine liver practice and in the research setting. (HEPATOLOGY 2016;63:1651-1659 H epatic encephalopathy (HE) is a neuropsychiatric syndrome caused by liver disease and/or portal-systemic shunting, which manifests as a wide spectrum of mental and motor dysfunction.Patients with cirrhosis and HE exhibit electroencephalographic (EEG) alterations. These were first identified in 1950 by Foley and colleagues, who described highvoltage, slow waves in patients with hepatic coma.(1) A few years later, Parsons-Smith and colleagues reported that EEG alterations in patients with cirrhosis were related to the severity of overt HE (i.e., the more severe the clinical picture, the slower the EEG).(2) The same authors highlighted how mild EEG slowing could also be detected in patients without overt HE, thus already introducing the concept of latent or subclinical HE.(2) The visual classification of EEG changes proposed by ParsonsSmith and colleagues was descriptive in nature and thus prone to interobserver variability. In 1977, Conn and coworkers proposed a semiquantitative classification based Abbreviations: EEG, electroencephalography; HE, hepatic encephalopathy; MDF, mean dominant frequency; MELD, Model for End-Stage Liver Disease; MPZS, mean PHES z ...

Comparison of Medical and Consumer Wireless EEG Systems for Use in Clinical Trials

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Prediction of postoperative opioid analgesia using clinical‐experimental parameters and electroencephalography

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