Difference between revisions of "Alpha rhythm"

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

Alpha rhythm of 9 Hz, posterior dominant with waxing and waning

@@ Line 16: / Line 16: @@
 **7 years:	9 Hz
 **> 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
+|}