Which diagnostic tool records brain electrical activity?

• A. Electroencephalogram
• B. Otoscope
• C. Electrocardiogram
• D. Sphygmomanometer

Answer: (A)

Recording brain electrical activity is done with an electroencephalogram, which uses electrodes placed on the scalp to detect the small voltage changes produced by neuronal firing. These signals reflect different brain states and rhythms, helping identify things like seizures, sleep disorders, or brain injuries. The other tools measure other parts of the body: an otoscope examines the ear, an electrocardiogram records the heart’s electrical activity, and a sphygmomanometer measures blood pressure.