Direct comparison
EMG vs EEG: Devices, Electrodes, FDA Class
EMG vs EEG compared by what the FDA says each device does: muscle and nerve signals vs brain activity, electrode location, stimulation, Class II rules.
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How do EMG (diagnostic electromyograph), EEG (electroencephalograph) compare side by side?
The table below compares EMG (diagnostic electromyograph), EEG (electroencephalograph) across 10 procurement-relevant dimensions, from what the device is for (fda wording) through source.
Side-by-side comparison
| Dimension | EMG (diagnostic electromyograph) | EEG (electroencephalograph) |
|---|---|---|
| What the device is for (FDA wording) | A device intended for medical purposes to monitor and display the bioelectric signals produced by muscles, for the diagnosis and prognosis of neuromuscular disease. | A device used to measure and record the electrical activity of the patient's brain. |
| Tissue it records | Muscles, and also the electrical activity produced by nerves. | The brain. |
| Where electrodes are placed | Over the muscles and nerves being monitored; the definition covers muscle and nerve signals. | Two or more electrodes placed on the head. |
| Does the device stimulate? | Yes, the definition includes stimulating peripheral nerves, alongside monitoring the resulting nerve and muscle activity. | The definition describes measuring and recording only; it does not mention stimulation. |
| Clinical purpose stated in the regulation | Diagnosis and prognosis of neuromuscular disease. | Measuring and recording brain electrical activity (no disease named in the definition). |
| FDA device class | Class II (performance standards). | Class II (performance standards). |
| Regulation | 21 CFR 890.1375, in Part 890 (physical medicine devices). | 21 CFR 882.1400, in Part 882 (neurological devices). |
| FDA product code | IKN | GWQ |
| When to pick which | Pick the EMG definition when the subject is muscle or peripheral nerve signals, including nerve stimulation. | Pick the EEG definition when the subject is brain electrical activity recorded from the head. |
| Source | 21 CFR 890.1375 (diagnostic electromyograph), eCFR, read 2026-10-31: https://www.ecfr.gov/current/title-21/section-890.1375 | 21 CFR 882.1400 (electroencephalograph), eCFR, read 2026-10-31: https://www.ecfr.gov/current/title-21/section-882.1400 |
Common questions
Common questions about EMG (diagnostic electromyograph) vs EEG (electroencephalograph)
What is the difference between EMG and EEG?
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EMG devices monitor and display electrical signals from muscles and nerves, and the FDA definition includes stimulating peripheral nerves. EEG devices measure and record the electrical activity of the brain through electrodes placed on the head (21 CFR 890.1375 and 882.1400, read 2026-10-31).
Does EEG record muscle activity or EMG record the brain?
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Per the FDA definitions, an EEG records brain electrical activity and a diagnostic EMG records muscle and nerve activity. The regulations describe each device by that target tissue.
Are EMG and EEG devices regulated the same way by the FDA?
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Both are Class II (performance standards), but they sit in different parts of 21 CFR: the diagnostic electromyograph in 890.1375 and the electroencephalograph in 882.1400.
Which one is used for neuromuscular disease?
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The FDA definition of the diagnostic electromyograph names diagnosis and prognosis of neuromuscular disease. The electroencephalograph definition names no disease. Which test a person needs is a decision for a clinician, not this page.
Going deeper
