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Introduction to EEG[edit | edit source]
Preface
This primer is written as a brief introduction to EEG that can be read on the first day as someone is exposed to an EEG for the first time. It is not meant to be a comprehensive text. There are many textbooks available that go into much more detail. The goal is to review the principles of EEG and give examples of EEG findings encountered on a routine day of EEG reading. Therefore, subjects such as neonatal EEG and full treatment of EEG interictal and ictal patterns are not included.
It is easy to read EEG, but difficult to read EEG well.
For Neurology Residents:
These are the Neurology Residency Milestones for EEG.
| Level | Description |
| Level 1 | Identifies patients for whom EEG is appropriate |
| Level 2 | Recognizes normal EEG features, including common artifacts, in children and adults |
| Level 3 | Recognizes patterns of status epilepticus, normal EEG variants, and common abnormalities in children and adults |
| Level 4 | Interprets common EEG abnormalities and patterns that could represent status epilepticus |
| Level 5 | Interprets uncommon EEG abnormalities and creates a report |
“Must Know” EEG findings for Adult and Child Neurology Residents
| Normal findings | Normal variants | Abnormal findings |
| Awake, adult PDR | Wickets | Generalized epileptiform discharge, 3 Hz |
| Awake, pediatric PDR | Hyperventilation-induced slowing | Generalized epileptiform discharge, 3–5 Hz polyspike |
| Drowsiness, slowing of PDR | Small sharp spikes | Focal seizure |
| Stage 2 sleep, sleep spindles | Breach | Focal epileptiform discharge, spike |
| Stage 2 sleep, K complexes | Rhythmic mid-temporal theta of drowsiness | Focal epileptiform discharge, sharp |
| Drowsiness, diffuse irregular delta-theta slowing of background | Hypnopompic hypersynchrony | Generalized seizure, absence |
| Stage 1/2 sleep, vertex waves | Hypnagogic hypersynchrony | Generalized epileptiform discharge, <2.5 Hz |
| Drowsiness, slow roving lateral eye movements | Photic driving | Focal epileptiform polyspike |
| Stage 1/2 sleep, POSTS | Mu rhythm | Generalized seizure, tonic |
| Stage 3 sleep, diffuse irregular delta slowing | Posterior slow waves of youth | Infantile spasm |
| REM sleep, erratic eye movements | Photomyogenic response | Hypsarrhythmia |
| REM sleep, sawtooth waves | Lambda waves | Focal irregular/polymorphic slowing |
| Temporal slowing of the elderly | Focal regular/rhythmic slowing | |
| Artifacts | Slow alpha variant | Diffuse irregular/polymorphic slowing |
| EKG | 6 Hz phantom spikes | Diffuse regular/rhythmic slowing |
| Eye blinks | Frontal arousal rhythm | Abnormal PDR, slow for age |
| Electrode pop | 14- and 6-Hz positive spikes | Abnormal PDR, asymmetric |
| Myogenic | Increased frontal beta activity | Asymmetric sleep spindles |
| Eye fluttering | Subclinical rhythmic electrographic discharges in adults | |
| Lateral eye movements | Fast alpha variant | |
| 60/50-Hz artifact | Midline central theta (Ciganek rhythm) | |
| Pulse | Occipital needle-like spikes of blindness | |
| Lateral rectus spikes | Slow fused transient | |
| Chewing/bruxism | Fronto-central rhythm (texting rhythm) | |
| Sweat | ||
| Glossokinetic | ||
| Nystagmus | ||
| Respiration/breathing |