Introduction

A video electroencephalogram (video-EEG) is an advanced neurodiagnostic tool that combines continuous EEG recording with synchronized video monitoring. It is primarily used to evaluate patients with epilepsy and other seizure disorders. By capturing both electrical brain activity and behavioral manifestations, video-EEG provides a comprehensive assessment of neurological events.

Step-by-Step Explanation

1. Understanding EEG Basics

The electroencephalogram (EEG) is a diagnostic test that records the brain's electrical activity through electrodes placed on the scalp. It is a non-invasive, safe procedure widely used in neurology.

  • EEG signals are measured in microvolts (µV).
  • Normal EEG rhythms include alpha, beta, delta, and theta waves, each associated with specific brain states.

2. Why Combine Video with EEG?

While traditional EEG provides valuable data on brain activity, it lacks visual context. Video-EEG addresses this limitation by recording the patient's physical behaviors during neurological events, such as seizures. This integration aids in:

  • Correlating EEG changes with physical symptoms.
  • Distinguishing epileptic seizures from non-epileptic events.
  • Localizing seizure origins for surgical planning.

3. Procedure

The video-EEG procedure involves the following steps:

  1. Preparation:
    • The patient's scalp is cleaned, and electrodes are attached using conductive gel or adhesive.
    • The patient may be asked to avoid certain medications or substances (e.g., caffeine) before the test.
  2. Monitoring:
    • The patient is connected to an EEG machine, and video cameras record their behavior simultaneously.
    • The duration of monitoring can range from hours to several days, depending on clinical needs.
  3. Provocation Techniques:
    • Hyperventilation, photic stimulation, or sleep deprivation may be employed to provoke abnormal activity.
  4. Data Analysis:
    • Trained neurophysiologists review the EEG data alongside video recordings to identify and classify events.

4. Clinical Applications

Video-EEG is instrumental in diagnosing and managing various neurological conditions, including:

  • Epilepsy Diagnosis: Differentiates between seizure types and identifies seizure focus.
  • Non-epileptic Events: Identifies psychogenic non-epileptic seizures (PNES).
  • Surgical Evaluation: Guides pre-surgical planning in refractory epilepsy.
  • Sleep Disorders: Assesses parasomnias and other sleep-related phenomena.

5. Limitations and Risks

Despite its value, video-EEG has some limitations:

  • Prolonged monitoring can be inconvenient for patients.
  • Artifacts (e.g., muscle movement, environmental noise) may interfere with EEG interpretation.
  • There is a small risk of seizure provocation leading to injury, mitigated by close medical supervision.

Conclusion

Video-EEG is a vital tool in modern neurology, offering unparalleled insights into the interplay between brain activity and behavior. It is a cornerstone in the evaluation of epilepsy and related disorders, significantly enhancing diagnostic accuracy and treatment planning.