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Brain Waves (EEG) and ECG Waveform


Brain Waves (EEG) and ECG Waveform

Brain Waves (EEG)

Brain waves are electrical signals produced by the brain and measured using Electroencephalography (EEG).

Alpha Waves

  • Frequency: 8 – 13 Hz
  • Occurs when a person is awake but relaxed.
  • Examples: calm thinking, meditation, relaxed state.
  • Moderate frequency brain waves.

Beta Waves

  • Frequency: 13 – 30 Hz
  • Occurs during active thinking and concentration.
  • Examples: studying, problem solving, mental activity.
  • High frequency with low amplitude.

Gamma Waves

  • Frequency: 30 – 100 Hz
  • Associated with high-level brain functions.
  • Examples: learning, memory processing, perception.
  • Fastest brain waves.

Brain Wave Summary

Brain Wave Frequency Mental State
Delta 0.5 – 4 Hz Deep Sleep
Theta 4 – 8 Hz Light Sleep / Meditation
Alpha 8 – 13 Hz Relaxed Awake
Beta 13 – 30 Hz Active Thinking
Gamma 30 – 100 Hz High-Level Cognition

ECG Waveform

The electrical activity of the heart is measured using Electrocardiography (ECG).

P Wave

  • Represents atrial depolarization.
  • Electrical signal spreads through the atria causing them to contract.

QRS Complex

  • Represents ventricular depolarization.
  • Electrical signal spreads through ventricles causing contraction.
  • Normal duration: 0.06 – 0.10 seconds.

T Wave

  • Represents ventricular repolarization.
  • The ventricles relax and prepare for the next heartbeat.

ECG Wave Summary

ECG Wave Function
P Wave Atrial Contraction
QRS Complex Ventricular Contraction
T Wave Ventricular Relaxation

Easy Memory Tricks

  • Brain Waves (Slow → Fast): Delta → Theta → Alpha → Beta → Gamma
  • ECG Order: P → QRS → T

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