Slow alpha variant

• Two types of alpha variants
  • Slow or sub-harmonic alpha rhythm
  • Fast or harmonic alpha rhythm

• Slow alpha variant is usually half of the normal background rhythm
• Higher amplitude than the normal background rhythm
• Posterior dominant
• Suppressed with eyes open, mental stress or sleep, like the normal background rhythm (see Alpha rhythm)
• Normal in healthy adults

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Slow or subharmonic alpha variant in a 29 year old male(average).

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