Difference between revisions of "Alpha rhythm"

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**7 years: 9 Hz
 
**7 years: 9 Hz
 
**> 60 years: Decrease by 0.08 Hz/year
 
**> 60 years: Decrease by 0.08 Hz/year
 +
 +
{| class="wikitable"
 +
|-
 +
! scope="col"| Age
 +
! scope="col"| Frequency
 +
|-
 +
|0-3 months
 +
|No posterior basic rhythm
 +
|-
 +
|4 months
 +
|3-4 Hz
 +
|-
 +
|5 months
 +
|5 Hz
 +
|-
 +
|1 year
 +
|6-7 Hz
 +
|-
 +
|3 years
 +
|8 Hz
 +
|-
 +
|7 years
 +
|9 Hz
 +
|-
 +
|> 60 years
 +
|Decrease by 0.08 Hz/year
 +
|}
 +
  
  

Revision as of 12:28, 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
Age Frequency
0-3 months No posterior basic rhythm
4 months 3-4 Hz
5 months 5 Hz
1 year 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

Alpha rhythm average e.png