Conditions

How is epilepsy diagnosed

Epilepsy is diagnosed clinically, from a detailed description of the episodes and evidence of a tendency for seizures to recur. EEG and imaging support the diagnosis and help classify it, but neither confirms nor excludes epilepsy on its own.

Quick answer

Epilepsy is diagnosed clinically, from a detailed description of the episodes and evidence of a tendency for seizures to recur. EEG and imaging support the diagnosis and help classify it, but neither confirms nor excludes epilepsy on its own.

The description carries the diagnosis

What happened before, during and after the episode is the single most important information, and the account of someone who witnessed it usually matters more than the patient's own, because awareness is frequently affected. Useful details include any warning sensation, whether the person responded when spoken to, what the movements looked like and in what order, how long it lasted, whether there was tongue biting or incontinence, and how long recovery took afterwards.

Distinguishing seizures from the mimics

Several things resemble seizures. Syncope, a faint from a drop in blood pressure or a cardiac cause, can produce brief jerking that looks convulsive. Functional or dissociative seizures produce genuine episodes without epileptic electrical activity. Sleep disorders, migraine with aura and transient ischaemic attacks can all be confused with seizures. Getting this wrong in either direction has real consequences, which is why an episode-by-episode history and, where doubt persists, prolonged EEG recording, matter.

What the investigations contribute

A routine EEG samples a short window and is often normal in people who genuinely have epilepsy, so a normal study settles little. Ambulatory EEG records over days and substantially raises the chance of capturing an infrequent event; both are performed at the CNS offices. Imaging looks for a structural cause and is arranged externally, since these offices have no imaging suite. Blood tests exclude metabolic provocations. Epileptology is represented within the group.

About this practice

Clinical Neurology Specialists has been physician-owned since 1998, when Leo Germin, M.D., FAANEM founded it. Five board-certified neurologists and four advanced practice providers see patients at the Las Vegas and Henderson offices, each with its own AANEM-accredited electrodiagnostic laboratory.

Clinical Neurology Specialists is an adult outpatient neurology practice for patients 18 and older. The practice performs no surgery and operates no imaging suite, infusion suite or interventional pain programme, and provides no emergency or inpatient care.

Emergency & crisis resources: Clinical Neurology Specialists is not an emergency service. For stroke symptoms, a seizure lasting more than five minutes or any medical emergency, call 911 or go to the nearest emergency room. For a mental health crisis, call or text 988 (Suicide & Crisis Lifeline).

Frequently asked

Questions about how is epilepsy diagnosed

How is epilepsy diagnosed?
Clinically, from a detailed description of the episodes and evidence that seizures have a tendency to recur. EEG helps classify seizure type and supports the diagnosis, and imaging looks for a structural cause, but neither test confirms nor excludes epilepsy by itself.
Why is a witness account so important?
Because awareness is frequently affected during a seizure, so the person having it often cannot report the part that matters most. What the movements looked like, whether they responded when spoken to, and how long recovery took are details usually only an observer can provide.
Does one seizure mean I have epilepsy?
Not necessarily. A single seizure with an identifiable provocation, such as extreme sleep deprivation, alcohol withdrawal or a metabolic disturbance, may not indicate epilepsy. The diagnosis rests on an enduring tendency for seizures to recur, and establishing that is the purpose of the assessment.
What else can look like a seizure?
Fainting from a blood pressure drop or cardiac cause, which can produce brief jerking. Functional or dissociative seizures, which are genuine episodes without epileptic electrical activity. Also sleep disorders, migraine with aura and transient ischaemic attacks. Distinguishing them properly matters in both directions.
What if my EEG is normal?
That is common and does not exclude epilepsy. A routine EEG records a short window between episodes, and many people with epilepsy have normal recordings in that window. Where suspicion remains, ambulatory EEG over several days is considerably more likely to capture something.

Physician-reviewed. Reviewed by the physicians of Clinical Neurology Specialists — board-certified neurologists, AANEM-accredited electrodiagnostic laboratories, physician-owned since 1998. Reviewed 1 August 2026. This article is general education for adults 18 and older and is not a substitute for a consultation.

Next step

Speak to a board-certified neurologist

Adults 18 and older, at the Las Vegas and Henderson offices. Call 702-804-1212 or request an appointment online.