Audit of EEG reporting temporal abnormalities.
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).


CONCLUSIONS
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.
Service de neurologie, Centre hospitalier de l'Université de Montréal - Hôpital Notre-Dame, Montréal, Québec, Canada.
Dang Khoa
DK
Nguyen
Marie-Eve
ME
Girard
Patrick
P
Cossette
Jean-Marc
JM
Saint-Hilaire
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D054869:Clinical Audit / Q000706:statistics & numerical data; D004569:Electroencephalography / Q000592:standards*; D004827:Epilepsy / Q000473:pathology* / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D012189:Retrospective Studies; D013702:Temporal Lobe / Q000503:physiopathology*; D055815:Young Adult