Test results indicated that no abnormalities were found in the brain's electrical activity and patterns are normal. Which test was used?

• A. MRI
• B. EEG
• C. CT scan
• D. PET scan

Answer: (B)

Electrical activity in the brain is measured with an electroencephalogram (EEG). An EEG records voltage changes from neurons using scalp electrodes, producing brain wave patterns that show normal or abnormal activity. When results indicate that brain electrical activity is normal, it means the EEG found typical waveforms and no abnormal discharges. The other tests image structure or metabolism—MRI and CT reveal anatomy, PET shows metabolic activity—so they don’t assess electrical activity. Thus, the test that directly evaluates the brain’s electrical activity and yields a “normal” pattern is EEG.