What EEG findings are characteristic of adrenal conditions?

Updated: Oct 09, 2019
  • Author: Eli S Neiman, DO, FACN; Chief Editor: Selim R Benbadis, MD  more...
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Adrenal disease

EEG pattern is nonspecific.

Cushing disease

EEG changes are uncommon.

Addison disease

Nonspecific slowing and diffuse theta and delta may be seen in a disorganized manner.


No particular EEG pattern has been noted.


The EEG resembles changes described with hypoxia; hyperventilation response is exaggerated and FIRDA may be observed. If prolonged coma ensues, the EEG changes persist and may become permanent. In most cases of hypoglycemia, a generalized disorganization of record occurs; in patients with long-term diabetes, the EEG is usually mildly to moderately diffusely disorganized and slow.


Similar slowing is the rule; however, epileptic activity may be observed with clinical seizure.

Wang et al described hyperglycemia with occipital seizures. They described acute and follow-up visual evoked potential (VEP) and magnetic resonance imaging (MRI) findings of a patient with hyperglycemia-related visual SE of occipital origin. Occipital seizures and hemianopsia can be caused by hyperglycemia and may be accompanied by special MRI and VEP findings. [65]

Glutaric aciduria type I

Neurophysiologic abnormalities are frequently seen in organic acidemias. Yalnizoglu et al studied EEG, VEP, and brain-stem auditory evoked response (BAER) in 7 children with glutaric aciduria type I (GA1). [66] Three of the 7 patients showed abnormal EEG findings; 2 showed asymmetry with intermittent occipital delta slowing in 1 hemisphere. This finding probably indicates underlying cerebral dysfunction and is not a specific feature. One patient showed high amplitude bursts of beta in the occipital regions with left predominance while on clonazepam and baclofen.


This has a nonspecific pattern, including slowing and FIRDA. Depending on the severity of the thyroid dysfunction, seizures and epileptiform discharges can be seen. [39]


Low-voltage theta is the rule with reduced photic driving response.

Nutritional deficiency syndromes

Pyridoxine deficiency causes severe, and at times, fatal convulsions in infants. The underlying metabolic problem has been suggested to be insufficient gamma-aminobutyric acid (GABA) synthesis. Thiamine deficiency causes diffuse slowing in Wernicke encephalopathy. Malnutrition results in EEG slowing, proportional and corresponding to the clinical alertness of the patient.

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