EEG Simulator

Lead Placement Practice

Practice placing EEG electrodes according to the International 10-20 System. Select electrodes from the list and place them on the head model, then check your accuracy. You can also view different montage configurations to see how electrodes are arranged.

How to Use This Tool

Select an electrode from the list on the left (Fp1, F3, etc.)
Click on the head model where you think it should be placed
Continue until you've placed all the electrodes
Click Check Placement to see your accuracy
Use the montage dropdown to visualize different EEG montages

Select Montage

Difficulty Level

Standard tolerance for correct placement

Practice Mode

Place all leads at your own pace

EEG Leads

Accuracy

0 / 0 correct

Nasion

Inion

Left

Right

Understanding Phase Reversal in EEG

Phase reversal is a key concept in interpreting EEG recordings and localizing the source of electrical activity. It occurs when adjacent electrode pairs in a bipolar montage display deflections in opposite directions.

How Phase Reversals Work

In a bipolar montage, each channel records the voltage difference between two electrodes. When an electrical discharge occurs beneath an electrode:

The voltage at that electrode changes relative to surrounding electrodes

The electrode sees the highest voltage when directly over the source

In bipolar recordings, this creates opposite deflections in adjacent channels

Interactive Phase Reversal Simulator

Fp1

Fp2

Montage:

Voltage Intensity:

120 μV

50 μV 100 μV 150 μV 200 μV

Click or tap on any location on the head to simulate an electrical discharge and observe the resulting phase reversal.

Mathematical Foundation of EEG Montages

Bipolar Montage Calculation

V_channel = V_electrode1 - V_electrode2

Example: For channel F3-C3

V_F3-C3 = V_F3 - V_C3

If V_F3 = +60μV and V_C3 = +100μV, then V_F3-C3 = -40μV (downward deflection)

Referential Average Montage

V_avg = (V₁ + V₂ + ... + V_n) / n
V_channel = V_electrode - V_avg

The average reference is calculated as the mean of all electrode voltages, then each electrode is referenced to this average.

Example: If we have electrodes F3, C3, P3 with voltages +60μV, +100μV, +80μV:

V_avg = (60 + 100 + 80) / 3 = 80μV

V_F3-avg = 60 - 80 = -20μV (downward deflection)

V_C3-avg = 100 - 80 = +20μV (upward deflection)

Phase Reversal Criterion

V_channel1 × V_channel2 < 0

A phase reversal occurs when two adjacent channels that share an electrode have opposite polarities (one positive, one negative).

Example: If F3-C3 = -40μV and C3-P3 = +40μV, then -40 × 40 = -1600 < 0, indicating a phase reversal at C3.

The International 10-20 System

Content coming soon...

Understanding EEG Montages

Content coming soon...

EEG Lead Placement Tutorial

Welcome to the EEG Lead Placement Practice!

Fp1

Fp2

The International 10-20 System places electrodes at specific locations on the scalp.

This tool will help you learn and practice the International 10-20 System for EEG electrode placement.

How to Place Leads

Drag and drop leads from the list onto the head model. Position them where you think they should go according to the 10-20 system.

Fp1

Each lead has a specific location based on cranial landmarks.

Checking Your Placement

When you've placed all the leads, click the "Check Placement" button to see how accurate you are.

Fp1

Correct placements will turn green, incorrect ones will turn red.

Different Practice Modes

Try different practice modes to challenge yourself:

Standard: Place all leads at your own pace
Timed: Place leads within a time limit
Random: Place specific requested leads
Guided: Follow step-by-step instructions

Visualizing Montages

Use the montage selector to see how different EEG montages connect the electrodes. This helps you understand how the leads relate to each other in clinical practice.

Fp1

Montages show how leads are connected for EEG interpretation.