[wineeg] Re: Drop in amplitude right hemisphere?

  • From: Jay Gunkelman <qeegjay@xxxxxxxxxxxxx>
  • To: wineeg@xxxxxxxxxxxxx
  • Date: Thu, 21 Aug 2003 12:35:17 -0800

You are reporting focal low amplitude across the frequencies for a specific
region. The EEG can be seen with areas of decreased amplitude, not just a
beta deficit, but an area of general amplitude minima. This phenomenon is
seen well in topographic EEG mapping and has been reported in areas of
cortical dysfunction (Brownback and Mason, 1998).  The area is effectively
shut down and is not functioning.  These areas have been observed frontally
in attentional and affective disorders (Gunkelman, 1997).

The functional areas you describe would suggest hyperactive/impulsive
behavior (fight frontal) with poor social environment awareness (right
temporal)... is this seen clinically... if not, the effect is likely an

You are right about the subdural doing this attenuation pattern... a chronic
subdural attenuates the EEG... but a tumor would generally show as a slow
focus in addition to this attenuation.


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