Electroencephalogram (EEG)

Electroencephalogram (EEG)

Advanced Brain Monitoring & Diagnostics at Ruby Hospital Kampala

What is an EEG?

An Electroencephalogram (EEG) is a safe, non-invasive, and painless diagnostic test that measures and records the brain’s electrical activity. The brain communicates through electrical impulses, and this test helps visualize these patterns, offering valuable insights into brain function and possible abnormalities.

During an EEG, small metal electrodes connected to thin wires are gently placed on your scalp using a special conductive paste. These electrodes detect electrical signals produced by the brain’s nerve cells (neurons). These signals are extremely small and require amplification to be read properly. Once collected, the brain’s electrical activity is displayed as a series of waveforms on a computer screen or printed out for detailed review by a neurology specialist.

EEG readings can vary depending on a person’s age, level of consciousness (awake or asleep), medications, and neurological health. Our specialists analyze various patterns in the waveforms—such as spikes, slowing, and rhythms—to help diagnose specific conditions.

In addition to the standard EEG, we may also conduct evoked potential studies, which assess how the brain responds to specific sensory stimuli like flashes of light, sound tones, or touch. These responses can reveal more subtle or deeper neurological issues that aren’t visible in resting brain wave activity.

Why Might You Need an EEG?

Your neurologist may recommend an EEG for a range of medical reasons, particularly when symptoms suggest a disruption in brain function. EEGs are valuable in diagnosing or monitoring:

• Epilepsy and seizure disorders: EEGs help detect abnormal brain activity or pinpoint seizure origins.

• Brain tumors or stroke: May show areas of slowed or disrupted activity due to lesions or damaged tissue.

• Alzheimer’s disease and dementia: Certain EEG patterns can reflect cognitive decline or brain degeneration.

• Psychiatric conditions: Used alongside other assessments in cases of psychosis, schizophrenia, or mood disorders.

• Sleep disorders: Including narcolepsy, sleep apnea, or insomnia, especially when sleep stages need evaluation.

• Head injuries or brain trauma: To assess functional impairment after accidents or concussions.

• Drug effects or intoxication: EEGs can reflect the impact of certain substances or medications on brain activity.

• Surgical monitoring: In some procedures, EEGs are used to observe brain activity and monitor blood flow in real time.

• Coma assessment and brain death determination: Helps measure remaining brain function or lack thereof in critically ill patients.

Is the EEG Safe?

Absolutely. EEGs are considered one of the safest neurological tests available. The procedure is:

• Non-invasive – no needles or surgery involved.

• Painless – the electrodes only record signals; they do not send electricity into your body.

• Low risk – most people complete the test with no issues at all.

In rare cases, people with a history of seizures may experience one during the test, particularly if the EEG includes flashing lights or controlled breathing exercises. If this happens, our medical team is fully equipped to manage it immediately.

Preparing for Your EEG at Ruby Hospital

To ensure accurate and reliable results, we advise the following preparations:

• Hair preparation: Wash your hair the night before the test. Avoid conditioners, oils, gels, or sprays, as these can interfere with electrode contact.

• Caffeine restriction: Avoid caffeinated drinks such as coffee, tea, soda, and energy drinks for 8 to 12 hours before the test.

• Medication disclosure: Inform your doctor of any medications, herbal supplements, or treatments you’re taking. Some may need to be paused.

• Sleep instructions: If you’re scheduled for a sleep EEG, you may be advised to reduce your sleep the night before. For example, adults may be limited to 4–5 hours of sleep.

• Avoid fasting: Eat normally unless instructed otherwise. Low blood sugar can affect brain activity and the accuracy of the results.

Your healthcare provider will give you personalized instructions depending on the type of EEG you’re scheduled for.

What to Expect During the EEG

Your EEG will be conducted in a calm and quiet environment to help ensure a quality recording. Here’s what typically happens:

• You’ll be seated or asked to lie down comfortably in a reclined chair or bed.

• Between 16 and 25 electrodes will be attached to your scalp using conductive gel or a cap.

• The test begins while you’re relaxed with your eyes closed. You’ll be asked to remain still to minimize interference.

• The technician may ask you to perform simple tasks such as opening/closing your eyes, breathing deeply, or responding to flashing lights.

• The recording may last 45 minutes to 2 hours, depending on the reason for the test.

• For sleep-related assessments, you may be asked to sleep during the EEG. In some cases, you may undergo 24-hour prolonged EEG monitoring or be given an ambulatory EEG device for at-home recording.

After the EEG

Once your test is complete:

• The electrodes will be gently removed, and any remaining gel or paste will be cleaned off. You may be asked to wash your hair afterward at home.

• If you were sedated for the test, you’ll rest until the effects wear off, and someone will need to accompany you home.

• Some people may experience mild skin redness or irritation where the electrodes were applied. This usually disappears quickly.

• You can resume normal activities immediately unless instructed otherwise by your provider.

• Your doctor will inform you when you can resume any medications that were paused for the test.

The EEG results will be reviewed by our neurology specialists, and a detailed report will be shared with your doctor. Based on the findings, your care team will discuss the next steps for diagnosis, treatment, or follow-up care.