The value of long term EEG monitoring in children: A comparison of ambulatory EEG and video telemetry

PURPOSE Outpatient ambulatory EEG may be followed by inpatient video telemetry EEG when investigating children for possible seizures and for classification of epilepsy. We investigated the value of ambulatory EEG and subsequent video telemetry recording in our centre. METHOD The departmental EEG database was interrogated retrospectively for children undergoing ambulatory recording followed by inpatient video telemetry within an 18-month period. RESULTS 30 patients fitted these criteria, 21 females, 9 males, age range 3-16 years. The mean interval between studies was 9 months. For ambulatory recordings 93% of studies were undertaken to ascertain if behaviours were epileptic. 66% of ambulatory recordings studies captured an event of interest and 63% were able to answer the question asked of the test. In video telemetry recording 80% of studies were aimed at ascertaining if events were epileptic or not, 20% were undertaken for classification of seizure type. 70% of recordings captured an ictus and were considered helpful in addressing the clinical question. Pooled together 90% of patients had a paroxysmal event captured and the clinical question answered by the recording techniques. In patients for whom ambulatory recording failed to capture an attack or answer the clinical question, 70% went on to have a successful video telemetry recording. CONCLUSION Both ambulatory EEG and inpatient video telemetry are effective tools for diagnosis of seizures. The majority of patients with failed ambulatory recordings go on to have successful video telemetry. Combining the two resources provides useful clinical information in nearly all instances.