The electroencephalography (EEG) is primarily used to aid in diagnosis of seizures and epilepsy to differentiate between focal and generalized types and at times to differentiate epileptic events from non epileptic paroxysms that can be mistakenly taken for epileptic seizures and treated inappropriately.
Lately, the EEG has been used for prognostication of the outcome of anoxic brain injuries, traumatic brain injuries, and severe cerebrovascular disorders.
- In primary care EEG can be ordered as:
- 1. 95819 EEG awake and asleep, 20-40 min
- 2. 95812 EEG extended monitorjng, 41-60 min
- 3. 95813 EEG extended monitoring, greater than 1 hr
The role of the primary care physician is to suspect an epileptic event and order a neurologist consult or a routine EEG for 30 min followed by a neurologist consult if suspicion for seizures remains or confirmed. Majority of insurances require a 30 min EEG before approving a study of longer duration that can be 24, 48, or 72 hrs and done as outpatient (ambulatory EEG) or as inpatient (long term video EEG monitoring) procedure.
Please note, a diagnosis of epilepsy remains clinical in most cases. Sensitivity of routine EEG to capture epileptic discharges is low. A neurologist consultation is a gold standard when seizures are suspected.
Please note, diagnosis of a headache on an EEG order is not a proper indication for it. But headache can frequently be seen in the postictal period or upon awakening in the morning after night time seizure with no witnesses. If headache is suspected to be postictal, then EEG is indicated to rule out ongoing epileptic activity and the proper diagnosis on the order form would be seizures.
Commonly used ICD 10 codes to order electroencephalogram include but not limited to:
R56.9 Unspecified convulsions
Convulsions can be epileptic and non epileptic like in conversion disorder. Epileptic discharges on EEG make epileptic nature of the disorder more likely and warrant further evaluation and treatment.
R41.82 Altered mental status
Brief alteration of consciousness, especially if repetitive and stereotypic, might be a dyscognitive seizure. EEG might reveal epileptiform discharges and aid in management of a patient.
R55 Syncope and collapse
Loss of consciousness can be due to a seizure. Epileptiform discharges on EEG following an episode might signify a high risk of repetitive events and the patient’s management needs to be further optimized with antiepileptic medications and long term regular follow up.
F03.90 Unspecified dementia with behavioral disturbance
Seizures are very common in many types of dementia, especially in the advanced stages. Paroxysmal behavioral changes can be a non convulsive seizure that needs to be further evaluated for proper management. EEG might provide further information.