Can an eeg detect tumors?

No: Eeg is mainly used to detect seizure. Other diseases including tumor can give abnormal eeg, but these abnormalities are nonspecific as to cause.

Indirectly: Eegs record electrical activity of all the neurons under the electrodes. If there is a tumor present, the normal brain cells are not present, so the eegs will record a decrease or absent activity. If the tumor is irritating the brain, it can cause the area to be hyperactive. Either way, the reading is abnormal, and patient should have an MRI to look for structural changes that would explain the ab.

Not directly: Eeg measures the activity of brain cells, not tumors. If the tumor is effecting a significant number of brain cells, the eeg may be abnormal. Some tumors cause enough irritation of the brain to cause seizures. These seizures can be located in the brain by eeg. Some tumors will have no effect on the eeg.