Difference between revisions of "Alpha rhythm"
From EEGpedia
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| + | Alpha rhythm of 9 Hz, posterior dominant with waxing and waning | ||
| − | + | [[File:Alpha rhythm average e.png|border|1400px|left]] | |
| − | [[File:Alpha rhythm average e.png|border|1400px|left | + | |
Revision as of 12:13, 14 February 2017
- Frequency: 8-13 Hz
- Posterior dominant
- 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
Alpha rhythm of 9 Hz, posterior dominant with waxing and waning
