Generalized periodic discharges and 'triphasic waves': A blinded evaluation of inter-rater agreement and clinical significance

for the Critical Care EEG Monitoring Research Consortium (CCEMRC)

Research output: Contribution to journalArticlepeer-review


Objectives: Generalized periodic discharges (GPDs) are associated with nonconvulsive seizures. Triphasic waves (TWs), a subtype of GPDs, have been described in relation to metabolic encephalopathy and not felt to be associated with seizures. We sought to establish the consistency of use of this descriptive term and its association with seizures. Methods: 11 experts in continuous EEG monitoring scored 20 cEEG samples containing GPDs using Standardized Critical Care EEG Terminology. In the absence of patient information, the inter-rater agreement (IRA) for EEG descriptors including TWs was assessed along with raters' clinical EEG interpretation and compared with actual patient information. Results: The IRA for 'generalized' and 'periodic' was near-perfect (kappa = 0.81), but fair for 'triphasic' (kappa = 0.33). Patients with TWs were as likely to develop seizures as those without (25% vs 26%, N.S.) and surprisingly, patients with TWs were less likely to have toxic-metabolic encephalopathy than those without TWs (55% vs 79%, p < 0.01). Conclusions: While IRA for the terms "generalized" and "periodic" is high, it is only fair for TWs. EEG interpreted as TWs presents similar risk for seizures as GPDs without triphasic appearance. GPDs are commonly associated with metabolic encephalopathy, but 'triphasic' appearance is not predictive. Significance: Conventional association of 'triphasic waves' with specific clinical conditions may lead to inaccurate EEG interpretation.

Original languageEnglish (US)
Pages (from-to)1073-1080
Number of pages8
JournalClinical Neurophysiology
Issue number2
StatePublished - Feb 1 2016


  • Critical care
  • EEG monitoring
  • Inter-rater agreement
  • Periodic discharges
  • Seizures
  • Triphasic waves

ASJC Scopus subject areas

  • Sensory Systems
  • Neurology
  • Clinical Neurology
  • Physiology (medical)


Dive into the research topics of 'Generalized periodic discharges and 'triphasic waves': A blinded evaluation of inter-rater agreement and clinical significance'. Together they form a unique fingerprint.

Cite this