Difference between revisions of "Alpha rhythm"

Latest revision as of 15:45, 30 March 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 (Slow alpha variant and Fast alpha variant)
2-5% of healthy people does not have a detectable alpha rhythm

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

@@ Line 1: / Line 1: @@
-Alpha rhythm
-Frequentie: 8-13 Hz
+*Frequency: 8-13 Hz
-Posterior dominant
+*Posterior dominant
-Amplitude: 10-80 microV
+*Amplitude: 10-80 microV
-Suppressed with eyes open or mental tension
+*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 ([[Slow alpha variant]] and [[Fast alpha variant]])
+*2-5% of healthy people does not have a detectable alpha rhythm
+*The posterior basic rhythm frequency is age dependent:
+{| 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
+|}
+----
+'''''Alpha rhythm of 9 Hz, posterior dominant with waxing and waning (source)'''''
+[[File:Alpha rhythm average e.png|border|1500px|left]]
+----