What diagnostic tool is useful for measuring electrical activity in patients suspected of having epilepsy?

The Electroencephalogram (EEG) is the diagnostic tool that is most effective for measuring electrical activity in the brain, particularly for patients suspected of having epilepsy. The EEG provides real-time recordings of brain activity by placing electrodes on the scalp, which detect electrical impulses produced when neurons communicate. This tool is crucial for identifying abnormal electrical patterns that are characteristic of epilepsy, such as spikes or spike-and-wave discharges that occur during seizure activities.

In contrast, brain MRIs and CT scans are imaging techniques that visualize the brain's structure and can help identify underlying issues, such as tumors or structural abnormalities, but they do not directly measure electrical activity. X-rays, while useful for a variety of diagnostic purposes, offer no value in assessing brain electrical activity, particularly in the context of neurological disorders like epilepsy.