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Audit of EEG Reporting Temporal Abnormalities

Published online by Cambridge University Press:  23 September 2016

Dang Khoa Nguyen ,
Marie-Eve Girard ,
Patrick Cossette  and
Jean-Marc Saint-Hilaire
Dang Khoa Nguyen*
Affiliation:
Service de neurologie, Centre hospitalier de l'Université de Montréal – Hôpital Notre-DameMontréal, Québec, Canada
Marie-Eve Girard
Affiliation:
Service de neurologie, Centre hospitalier de l'Université de Montréal – Hôpital Notre-DameMontréal, Québec, Canada
Patrick Cossette
Affiliation:
Service de neurologie, Centre hospitalier de l'Université de Montréal – Hôpital Notre-DameMontréal, Québec, Canada
Jean-Marc Saint-Hilaire
Affiliation:
Service de neurologie, Centre hospitalier de l'Université de Montréal – Hôpital Notre-DameMontréal, Québec, Canada
*
Service de neurologie, Hôpital Notre-Dame du CHUM, 1560 rue Sherbrooke Est, Montréal, Québec, H2L 4M1, Canada
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Abstract

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Background:

To ensure the overall quality of our electroencephalogram (EEG) laboratory, we decided to perform an audit of EEGs interpreted at our institution, focusing initially on EEGs reporting temporal abnormalities.

Methods:

Reports of all EEGs performed between January 1st and June 30th, 2006 were reviewed in order to identify tracings mentioning abnormalities in the temporal regions. These records were then independently reviewed by two epileptologists on two distinct occasions, separated by an interval of at least six months. If the recording was considered normal after this process, the cause for misinterpretation was identified and the patient's chart was reviewed to determine if he was epileptic or not based on available evidence until June 2009.

Results:

In the first half of 2006,143 out of 773 EEGs mentioned temporal abnormalities (18.5%). In general, intra- and interrater agreement ratios between our two epileptologists were moderate to substantial for normality, presence of epileptic activity and presence of slowing. Forty-five recordings (31.5%) were reported as normal independently by them on two distinct sittings six months apart. The most common causes for misinterpretation were the presence of benign epileptiform variants, normal sharply contoured patterns of somnolence or hyperventilation. Chart review confirmed that most were non-epileptic patients (60% non-epileptic, 27% epileptic, 13% unknown).

Conclusion:

Moderate to substantial intra- and interrater agreement as well as frequent misinterpretation of physiological variants indicate that some corrective measures need to be implemented to improve the consistency of EEG interpretation amongst our group of electroencephalographers.

Résumé

RésuméContexte:

Nous avons décidé de procéder à la vérification des EEG interprétés à notre institution afin de nous assurer de la qualité globale de notre laboratoire d'EEG, en ciblant initialement les EEG qui rapportaient des anomalies temporales.

Méthodologie:

Tous les rapports d'EEG effectués entre le premier janvier et le 30 juin 2006 ont été révisés pour identifier les tracés mentionnant des anomalies dans les régions temporales. Ces dossiers ont ensuite été révisés par deux épileptologues à deux reprises, à six mois d'intervalle. Si l'enregistrement était considéré normal après cette étude, la cause de la mésinterprétation était identifiée et le dossier du patient était révisé afin de déterminer s'il était épileptique ou non, selon les données disponibles acquises jusqu'en juin 2009.

Résultats:

Au cours de la première moitié de 2006, 143 des 773 EEG mentionnaient des anomalies temporales (18,5%). En général, le taux de concordance intra et inter observateurs entre nos deux épileptologues était de modéré à élevé en ce qui concerne la normalité, la présence d'activité épileptique et la présence de ralentissement. Quarante-cinq enregistrements (31,5%) ont été rapportés comme normaux par chacun d'eux indépendamment, lors des deux lectures à six mois d'intervalle. Les causes les plus fréquentes de mésinterprétation étaient la présence de variantes épileptiformes bénignes, de tracés normaux de somnolence ou d'hyperventilation à l'aspect accentué. La revue de dossiers a confirmé que la plupart des patients n'étaient pas épileptiques (60% non épileptiques, 27% épileptiques, 13% état inconnu).

Conclusion:

Une concordance modérée à élevée intra et inter observateurs ainsi qu'une mésinterprétation fréquente de variantes physiologiques indiquent que des mesures correctrices doivent être mises en place pour améliorer la cohérence des interprétations EEG au sein de notre groupe d'électroencéphalographistes.

Type
Original Articles
Information
Canadian Journal of Neurological Sciences , Volume 37 , Issue 6 , November 2010 , pp. 819 - 825
Copyright
Copyright © The Canadian Journal of Neurological 2010

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