Makindo Medical Notes

An EEG (Electroencephalogram) is a non-invasive test that measures electrical activity in the brain. It records brain waves through electrodes placed on the scalp. EEGs are primarily used to detect abnormalities in brain function and diagnose various neurological conditions.

Uses of EEG

• Seizure Disorders: EEG is commonly used to diagnose epilepsy and other seizure disorders by detecting abnormal electrical activity in the brain.
• Sleep Disorders: It helps in diagnosing conditions like sleep apnea, narcolepsy, and other sleep-related issues.
• Brain Tumors: EEG can aid in detecting abnormal brain activity associated with brain tumours or structural brain abnormalities.
• Head Injuries: EEG may be used to assess brain function after head trauma or to determine the extent of brain injury.
• Encephalopathy: It helps in diagnosing metabolic or toxic encephalopathies that affect brain function.
• Monitoring During Surgery: EEG is sometimes used intraoperatively to monitor brain activity during certain surgical procedures, like neurosurgery.
• Coma or Brain Death Evaluation: EEG is utilized to assess brain activity in patients with coma and to determine brain death.

How EEG is Done

• Preparation: The patient is asked to avoid consuming caffeine and certain medications that may affect brain activity. The scalp is cleaned, and electrodes are placed on specific areas using a conductive gel or paste.
• Electrode Placement: About 16 to 25 electrodes are attached to the scalp. These electrodes are connected to the EEG machine, which amplifies the brain's electrical signals and records them as wave patterns.
• Recording the EEG: The patient is asked to remain still, relax, and close their eyes during the test. In some cases, the EEG may include tasks such as breathing deeply, looking at flashing lights, or even being asked to sleep.
• Duration: A standard EEG test typically takes around 20-40 minutes, though longer EEGs (24-hour or ambulatory EEGs) may be required to capture data over an extended period.
• Post-Test: The electrodes are removed, and the patient can resume normal activities. The EEG data is then analyzed by a neurologist.

Interpretation of EEG Results

• Normal Brain Waves: A normal EEG shows consistent patterns of brain waves that correspond to various states such as waking, relaxation, and sleep.
• Abnormal Brain Waves: Abnormal waveforms such as sharp waves, spikes, or slowing may indicate specific conditions:
  • Epileptic Seizures: Spikes or sharp waves are commonly seen in individuals with epilepsy.
  • Tumors or Brain Injury: EEG may show focal slowing or abnormalities near the site of the lesion.
  • Sleep Disorders: Abnormal sleep patterns or disruptions in normal sleep architecture may indicate a sleep disorder.
  • Coma or Brain Death: An absence of brain waves (flatline) can indicate brain death, while slow wave activity may suggest coma.
• Clinical Relevance: EEG results must be interpreted in the context of the patient's clinical symptoms, history, and other diagnostic findings.