Neurology

Diagnostic Testing: Video-EEG and Clinical Correlation

At a Glance

Perioral myoclonia with absences is evaluated by matching a child’s mouth movements with generalized, approximately 3-Hz spike-and-wave activity on Video-EEG. A usually normal background and expert clinical correlation help distinguish PMA from other seizure types.

Because Perioral Myoclonia with Absences (PMA) is so often mistaken for other conditions, getting a definitive diagnosis requires careful evaluation. The cornerstone of this evaluation is the Video-EEG, which may sometimes be paired with an EMG.

These tests support the diagnosis by showing that what is happening in your child’s brain is closely linked with what is happening to their mouth ^[1]^[2].

The Two Halves of the Evaluation

To evaluate PMA, doctors often look at two different signals:

The Video-EEG: This records your child’s brain waves while a camera captures their physical movements. In PMA, the EEG shows a generalized rhythmic approximately 3-Hz spike-and-wave discharge ^[1]. “3-Hz” means the brain “spikes” three times every second during the seizure. “Generalized” means these patterns involve broad networks across the brain, rather than starting in one isolated spot ^[1]^[3].
The Perioral EMG (Optional but Useful): EMG (electromyography) uses small stickers on the face—specifically near the orbicularis oris muscle around the mouth—to measure muscle activity. When used, it can show that the muscle twitch on the EMG is closely and consistently time-locked to the spike on the EEG ^[2]. They happen in a linked rhythm. Note that specialized facial EMG is a useful adjunct but is not strictly required; a Video-EEG with expert clinical correlation is often sufficient.

What the Doctor Looks For

When the neurologist reviews the results, they are looking for a very specific “normal” background. Unlike some other forms of epilepsy, the EEG background (the brain waves between seizures) in children with PMA is usually normal ^[1]^[3]. If the background shows significant “slowing” or other irregularities, the doctor may investigate whether the condition is a different or more complex type of epilepsy ^[3].

The Hyperventilation Procedure

During the EEG, the technician will likely ask your child to blow on a pinwheel or pretend to blow out birthday candles for about three minutes. This is called hyperventilation (overbreathing).

Overbreathing is an activation procedure often used during medical tests. In clinical studies, this exercise successfully provoked a seizure in about 63% of children with PMA ^[1]. Capturing an episode this way allows the medical team to see the “time-locking” in action, making the diagnosis clearer. However, if your child does not have a seizure during overbreathing, it does not mean they don’t have PMA ^[1].

Discussing Your EEG Report

When you receive the written report from your child’s EEG, you may see highly technical wording. Families should not self-diagnose from the presence of keywords, because focal seizures can sometimes produce misleading bilateral patterns. Instead, you can use these concepts to guide questions for the clinician:

Background Organization: Ask if the report states the background is “normal” or “well-organized” for your child’s age ^[1].
Discharge Frequency: Ask if the seizure activity was described as “approximately 3-Hz” ^[1].
Distribution: Ask if the activity was described as “generalized” ^[2]^[3].
Clinical Correlation: Ask if the clinician felt the mouth movements were “time-locked” or consistently linked to the brain wave spikes ^[1]^[2].
Activation Procedures: Ask what the report says about the results of hyperventilation and photic (flashing light) stimulation ^[1].

Rely on your epileptologist’s expert interpretation of these combined findings to ensure your child is on the right treatment path.

Common questions in this guide

What does a Video-EEG show in perioral myoclonia with absences?

A Video-EEG records brain waves and a video of the child at the same time. In PMA, clinicians look for generalized rhythmic activity at approximately 3 Hz that occurs with the mouth movements, while the EEG background between seizures is usually normal.

Is a facial EMG needed to diagnose PMA?

No. A facial EMG can measure activity in the orbicularis oris muscle and show that mouth twitching is time-locked to EEG spikes, but it is an optional supporting test. Expert review of the Video-EEG and the child’s movements is often sufficient.

Can hyperventilation trigger a PMA seizure during an EEG?

Yes, overbreathing during the EEG can provoke an episode in some children; clinical studies reported this in about 63% of children with PMA. If no seizure occurs during hyperventilation, that result alone does not rule out PMA.

What does a normal EEG background mean for my child?

Children with PMA usually have a normal, well-organized EEG background between seizures. If the background is significantly slowed or otherwise abnormal, the neurologist may look for a different or more complex epilepsy condition.

Why does a specialist need to interpret a generalized EEG pattern?

A generalized-looking pattern is not enough to diagnose PMA because some focal seizures can produce bilateral EEG patterns. The specialist compares the EEG with the video, the timing of mouth movements, and responses to activation procedures such as hyperventilation and flashing lights.

Could eyelid fluttering or flashing lights point to a different epilepsy syndrome?

Eyelid fluttering, eye-closure triggers, or photosensitivity may prompt the clinician to consider other epilepsy syndromes, including Jeavons syndrome. These findings need to be interpreted alongside the EEG and video rather than used alone for diagnosis.

Get notified when new evidence is published on Perioral myoclonia with absences.

We monitor PubMed for new peer-reviewed studies on this topic and email a short summary when something meaningful changes.

References (3)

1
Clinical and EEG-EMG characteristics of perioral myoclonia with absence seizures.
Yang H, Liu X, Lu J, et al.
Seizure 2025; (130()):51-55 doi:10.1016/j.seizure.2025.03.011.
PMID: 40359772
2
Perioral myoclonia with absences in children: a case report and literature review.
Jin M, Yang F, Qu Y, et al.
BMC pediatrics 2026; (26(1)).
PMID: 42351044
3
Unmasking the entity of 'drug-resistant' perioral myoclonia with absences: the twitches, darts and domes!
Rudrabhatla PK, Er S, Radhakrishnan A, Menon RN
Epileptic disorders : international epilepsy journal with videotape 2021; (23(2)):313-324 doi:10.1684/epd.2021.1265.
PMID: 33851919

This page explains how Video-EEG and optional facial EMG may support evaluation of perioral myoclonia with absences in a child. It is for informational purposes only, does not constitute medical advice, and cannot replace interpretation by your child’s neurologist or epileptologist.