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How Long Should Routine EEG Be Recorded to Get Relevant Information?
Hannah Doudoux1, Kristina Skaare2, Thomas Geay3
11 Clinical Neurophysiology Unit, Neurology Department, University Grenoble Alpes Hospital, Grenoble, France.
Clinical EEG and Neuroscience
|November 23, 2017
Summary
Routine electroencephalograms (EEGs) may be shortened. For patients with subacute cognitive impairment, a 10-minute routine EEG (rEEG) often provides sufficient diagnostic information, supporting individualized recording durations.
Area of Science:
- Neurology
- Clinical Neurophysiology
Background:
- The optimal duration for routine electroencephalograms (rEEGs) remains undetermined.
- Clinical decisions regarding rEEG length lack a standardized basis.
Purpose of the Study:
- To determine the necessary duration of rEEG to yield clinically relevant information.
- To correlate information acquisition time with specific clinical indications.
Main Methods:
- Retrospective analysis of 364 rEEGs from patients over 14 years old.
- Two independent blinded readers assessed the latency for relevant diagnostic information.
- Analysis stratified by clinical requests: cognitive impairment, spells, transient focal neurological events, and epileptologist referrals.
Main Results:
- 92% of pathological rEEGs showed abnormalities within the first 10 minutes.
- Background slowing was identified early; interictal epileptiform discharges emerged over time.
- Abnormalities in subacute cognitive impairment cases appeared within 10 minutes, unlike other groups.
Conclusions:
- Patients with subacute cognitive impairment show early EEG abnormalities, suggesting 10-minute rEEGs may suffice.
- Individualized rEEG durations are supported, but this finding excludes intensive care unit patients.
