What is the significance of an electroencephalogram (EEG) showing a few sharp waves in the left temporal region, indicating a relatively inactive discharging epileptiform focus?

From the Guidelines

The patient's EEG findings of sharp waves in the left temporal region with a relatively inactive epileptiform focus, confirmed by digital spike analysis, suggest focal epilepsy originating from the left temporal lobe, and treatment with antiepileptic medications such as levetiracetam (Keppra) or carbamazepine (Tegretol) may be considered, as there is indirect evidence from case series suggesting sedatives such as propofol are effective in suppressing clinical seizures and electrographic seizures 1. The definition of electrographic seizure, as outlined by the American Clinical Neurophysiology Society, is epileptiform discharges averaging >2.5 Hz for ≥10 s (>25 discharges in 10 s) or any pattern with definite evolution and lasting ≥10 s, which does not apply to this patient's case, as the EEG findings do not meet these criteria 1. However, the patient's EEG pattern may be classified as an ictal-interictal continuum, which is a pattern on the ictal-interictal continuum that is present for ≥10 continuous min or for a total duration of >20% of any 60-min period of recording, which shows EEG improvement with a parenteral antiseizure medication but without clinical improvement 1. The treatment approach for this patient should be individualized, taking into account the potential benefits and risks of antiepileptic medications, as well as the patient's overall clinical condition and medical history. Some key points to consider in the management of this patient include:

• The use of antiepileptic medications such as levetiracetam (Keppra) or carbamazepine (Tegretol) may be considered, as there is indirect evidence from case series suggesting sedatives such as propofol are effective in suppressing clinical seizures and electrographic seizures 1.
• Regular follow-up EEGs are recommended every 6-12 months to monitor the epileptiform activity.
• Patients should avoid sleep deprivation, excessive alcohol, and maintain medication compliance.
• The left temporal focus suggests possible involvement of memory and language functions, so neuropsychological testing may be beneficial.
• These sharp waves represent abnormal, synchronous electrical discharges from neurons in the temporal region that can lower the seizure threshold, though not all epileptiform discharges lead to clinical seizures.

From the Research

EEG Findings

• The EEG shows few sharp waves in the left temporal region, indicating a discharging relatively inactive discharging epileptiform focus within this region, as confirmed by digital spike analysis 2, 3.
• This finding suggests that the patient may be experiencing epileptiform discharges, which are abnormal electrical impulses in the brain that can be associated with epilepsy 4, 5.

Epileptiform Discharges

• Epileptiform discharges are transient waveforms that can be divided into seven types, and are often used to diagnose and localize seizure activity in the brain 3.
• The presence of epileptiform discharges in the EEG can be an indicator of underlying epilepsy or seizure activity, and can be used to guide treatment and management decisions 2, 6.

Diagnostic Considerations

• The diagnosis of epilepsy or seizure activity requires a combination of clinical evaluation, EEG findings, and other diagnostic tests 4, 5.
• The use of digital spike analysis and other advanced EEG techniques can help to improve the accuracy of diagnosis and localization of seizure activity 3.
• Further evaluation and monitoring may be necessary to determine the underlying cause of the epileptiform discharges and to guide treatment decisions 2, 6.