mu rhythm
Pronunciation: MYOO rhythm
A normal EEG rhythm of 8-13 Hz over central regions that blocks with contralateral hand movement, generated by sensorimotor cortex.
Full Definition
Mu rhythm is a normal variant EEG pattern characterized by arciform (arch-shaped) waves of 8-13 Hz frequency located over the central (C3, C4) electrode positions. This rhythm is generated by the sensorimotor cortex and has a distinctive morphology that often resembles the Greek letter mu (μ). The key identifying feature is its reactivity to movement or the intention to move: mu rhythm blocks or attenuates with contralateral hand movement, touching, or even the thought of movement. Unlike alpha rhythm, mu rhythm is not affected by eye opening or closing. This pattern is present in approximately 20% of normal individuals and should not be confused with pathological activity.
Usage
Usage note: Always test reactivity with movement to confirm mu rhythm identification.
In Context
- "Bilateral mu rhythm was present and blocked appropriately with hand movement." — Normal EEG report
- "The arciform waves over central regions represented normal mu rhythm, not spike activity." — EEG interpretation correction