Additional overnight video EEG for the diagnosis of epilepsy: Experiences from Western Kenya

Objective

The prolonged video EEG monitoring is widely used for the diagnosis and management of epilepsy, especially during the presurgical evaluation. The routine practice in neurology is to order a prolonged recording like an overnight EEG when the initial routine EEG is normal or unrevealing. Only few studies have evaluated this sequential approach and we aimed in this study to evaluate the added diagnostic value of a relatively brief video EEG monitoring especially in developing nations where the history of seizure semiology may be harder to obtain, and the video EEG monitoring technology is scarce.

Methods

This study analyzed retrospectively 167 overnight video EEG records in one of the secondary healthcare facilities in Western Kenya between March 2018 and March 2021. The indications were mainly further diagnosis and seizure classification. All the patients had an unrevealing routine EEG and 162 of them were normal.

Results

Additional epileptiform discharges were recorded in 91 of those 162 with initial normal routine EEG. Further classification of seizure was achieved in 67 patients among 112 with initially unclassified seizure before the overnight recording. The improvement of 68% (97 out of 143 patients without a prior epilepsy diagnosis) for the diagnosis of epilepsy in those patients without initial final diagnosis is comparable to other similar studies but mostly with a longer duration of recording. The diagnosis was changed or at least improved in 142 (85%) patients out of the 167 patients who underwent the overnight video EEG. The treatment modification was immediately considered in 116 after the prolonged recording.

Conclusions

Adding an overnight video EEG to an unrevealing routine EEG can significantly increase the likelihood of detecting additional epileptiform discharges in patients with epilepsy, thereby improving diagnostic yield and aiding in treatment adjustment for all patients suspected of having epilepsy.

Significance

The sequential approach of adding a prolonged video EEG monitoring even as brief as an overnight video EEG to an unrevealing routine EEG has a very significant impact in further classification of seizure and diagnosis of epilepsy especially in a resource limited set up.