What does encephalogram mean?
An encephalogram is a record or image of the brain, produced either by tracing its electrical activity or by X-ray imaging. The term is built from Greek roots meaning 'within the head' combined with '-gram', meaning 'something written or recorded'. Historically, it covered two distinct procedures: the electroencephalogram, which records brainwaves through electrodes placed on the scalp, and the pneumoencephalogram, an early and uncomfortable X-ray technique in which air was introduced into the spaces around the brain to make it visible. Today the word survives chiefly in medical and historical writing, having been largely superseded by more specific terms such as EEG, CT scan, and MRI. It remains a useful word for understanding how medical vocabulary is assembled from classical elements, and it appears regularly in discussions of neurology, sleep research, and the diagnosis of epilepsy.
nounAn X-ray image or tracing of the brain, especially one produced by pneumoencephalography; more broadly, any record of the brain's electrical activity, as produced by an electroencephalograph.
- A record of the brain's electrical activity, especially as traced by an electroencephalograph.
- An X-ray photograph of the brain, historically produced by pneumoencephalography.
"The neurologist studied the encephalogram carefully, looking for abnormal patterns in the brain's activity."
"The technicians monitored the patient's encephalogram throughout the night to detect any seizure activity."
"In the mid-twentieth century, an encephalogram was among the few tools available for visualising tumours deep within the brain."
Regular plural formation, used when referring to multiple recordings or images.
"The researchers compared encephalograms taken before and after the treatment."
Before modern MRI scans, doctors sometimes replaced the fluid around the brain with air just to make it visible on an X-ray — and that startling image was called a pneumoencephalogram.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of encephalogram
Encephalogram derives from Greek: 'enkephalos' (ἐγκέφαλος), meaning 'brain' or literally 'that which is within the head' (from 'en-' meaning 'in' and 'kephale' meaning 'head'), combined with '-gram' from Greek 'gramma', meaning 'something written or drawn'. The word emerged in the late nineteenth or early twentieth century alongside the development of neurological imaging and recording techniques. It shares its root with related medical terms such as encephalitis (inflammation of the brain) and encephalon (the brain itself).
Related word forms
How encephalogram is actually used
A formal, technical term used mainly in medical contexts. In everyday clinical practice, more specific terms such as EEG (for electrical recordings) or CT/MRI scan (for imaging) have largely displaced it.
Easily confused with encephalogram
The encephalograph is the instrument that records brain activity, while the encephalogram is the record or image it produces.
An electroencephalogram (EEG) specifically records the brain's electrical activity via electrodes on the scalp, whereas encephalogram is a broader term that can also refer to X-ray images of the brain.