Aim Compare the value of ambulatory EEG and video telemetry in Diagnosis and Classification of seizures.
Method The EEG department database was interrogated retrospectively for children having both ambulatory EEG and video telemetry recording during the period March 1998 to August 2011. Only patients referred for purposes of diagnosis of attacks and classification of epilepsy were included. Patients admitted for pre-surgical evaluation of epilepsy were excluded. 48 patients were included in the study; M:F ratio 0.7:1, mean age 11.5 years, range 2 to 21 years.
All patients had only 1 telemetry but 9 patients had more than 1 ambulatory recording. For the purposes of the study the result from the ambulatory recording preceding the video telemetry was used.
Information regarding reason for referral and result of the long term EEG investigations was obtained.
Results The reason for request was for Diagnosis of attacks in 77% of ambulatory EEGs and 52% of video telemetries. Classification of epilepsy in 16% of ambulatories and 43% of telemetries. Recording length for ambulatory EEG was: 24 h (68%) 48 h (25%) and 72 h (6%). Recording length for video telemetry was 1–3 days (60%) and 4–5 days (40%).
Typical attacks were recorded in 68% of ambulatory EEGs and 56% of telemetry recordings. The EEG helped in Diagnosis in 66% of ambulatory EEG’s and 62% of telemetries. The EEG helped in Classification in 21% of ambulatory EEG’s and 56% of telemetries.
62% of patients where ambulatory EEG was inconclusive (21% of the total) went on to have a valuable telemetry. The combined yield of the investigations was 89%.
Conclusion Ambulatory EEG is an effective tool for diagnosing seizures in two thirds of children. Where ambulatory EEG is inconclusive, videotelemetry improves the diagnosis in a further fifth. Video telemetry is superior to ambulatory EEG in classifying seizures.