Difference between revisions of "Alpha rhythm"
From EEGpedia
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'''Alpha rhythm''' | '''Alpha rhythm''' | ||
| + | |||
*Frequency: 8-13 Hz | *Frequency: 8-13 Hz | ||
*Posterior maximum | *Posterior maximum | ||
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*Most prominent with eyes closed and relaxed | *Most prominent with eyes closed and relaxed | ||
*Suppressed with eyes open, mental stress or sleep | *Suppressed with eyes open, mental stress or sleep | ||
| − | *Left-right difference < | + | *Left-right difference <1 Hz in frequency and <50% in amplitude (amplitude is usually higher on the right side) |
| − | * | + | *Alpha variants are normal sub- and supraharmonic frequencies of the alpha rhythm, particularly in children and young adults. |
| + | *The posterior basic rhythm frequency is age dependant: | ||
**0-3 months: No posterior basic rhythm | **0-3 months: No posterior basic rhythm | ||
**4 months: 3-4 Hz | **4 months: 3-4 Hz | ||
Revision as of 11:44, 14 February 2017
Alpha rhythm
- Frequency: 8-13 Hz
- Posterior maximum
- Amplitude: 10-80 microV
- Wax and wane in amplitude
- Most prominent with eyes closed and relaxed
- Suppressed with eyes open, mental stress or sleep
- Left-right difference <1 Hz in frequency and <50% in amplitude (amplitude is usually higher on the right side)
- Alpha variants are normal sub- and supraharmonic frequencies of the alpha rhythm, particularly in children and young adults.
- The posterior basic rhythm frequency is age dependant:
- 0-3 months: No posterior basic rhythm
- 4 months: 3-4 Hz
- 5 months: 5 Hz
- 1 years: 6-7 Hz
- 3 years: 8 Hz
- 7 years: 9 Hz
- > 60 years: Decrease by 0.08 Hz/year
