Original Communication

Journal of Neurology

, Volume 260, Issue 4, pp 1087-1098

Clinical and imaging correlates of EEG patterns in hospitalized patients with encephalopathy

  • Raoul SutterAffiliated withDivision of Neurosciences Critical Care, Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine and Bayview Medical CenterDepartment of Neurology, Johns Hopkins University School of MedicineDepartment of Neurosurgery, Johns Hopkins University School of MedicineDepartment of Neurology, Johns Hopkins Bayview Medical Center Email author 
  • , Robert D. StevensAffiliated withDivision of Neurosciences Critical Care, Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine and Bayview Medical CenterDepartment of Neurology, Johns Hopkins University School of MedicineDepartment of Neurosurgery, Johns Hopkins University School of MedicineDepartment of Radiology, Johns Hopkins University School of MedicineDepartment of Neurology, Johns Hopkins Bayview Medical Center
  • , Peter W. KaplanAffiliated withDepartment of Neurology, Johns Hopkins University School of MedicineDepartment of Neurology, Johns Hopkins Bayview Medical Center

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Abstract

To identify the relationship between pathologic electroencephalographic (EEG) patterns, clinical and neuroradiological abnormalities, and outcome in hospitalized patients with acute encephalopathy. This 5-year cohort study was performed at an academic tertiary care center. EEGs in 154 patients with altered mental status were classified according to five predefined patterns: Isolated continuous slowing of background activity (theta, theta/delta, and delta activity) and patterns with slowing background activity with episodic transients [i.e., triphasic waves (TWs) or frontal intermittent delta activity (FIRDA)]. Clinical characteristics, blood tests and neuroimaging were compared among groups. Associations between EEG patterns and structural and non-structural abnormalities were calculated. Glasgow Outcome Score >3 at discharge was defined as favorable and 1–3 as unfavorable outcome. In multivariable analyses, theta was associated with brain atrophy (OR 2.6, p = 0.020), theta/delta with intracerebral hemorrhages (OR 6.8, p = 0.005), FIRDA with past cerebrovascular accidents (OR 2.7, p = 0.004), TWs with liver or multi-organ failure (OR 6, p = 0.004; OR 4, p = 0.039), and delta activity with alcohol/drug abuse with or without intoxication, and HIV infection (OR 3.8, p = 0.003; OR 9, p = 0.004). TWs were associated with death (OR 4.5, p = 0.005); theta/delta with unfavorable outcomes (OR 2.5, p = 0.033), while patients with FIRDA had favorable outcomes (OR 4.8, p = 0.004). In encephalopathic patients, well-defined EEG patterns are associated with specific pathological conditions and outcomes, suggesting that mechanistic hypotheses underlie these abnormal EEG patterns. To clarify the respective contributions of non-structural and structural abnormalities to encephalopathy reflected in specific EEG patterns, prospective studies using continuous EEG monitoring during the acute onset of encephalopathy are needed.

Keywords

Encephalopathy EEG patterns Triphasic waves FIRDA Theta activity Theta/delta activity Delta activity