[Eeglablist] Question about EEG Power

[Simon Finnigan]

Hi Carla

On face value, absolute power values as high as 400 μV2 may not necessarily
seem too unusual .... however based on my various experiences analysing EEG
power spectra - these are unusual (unless they are observed at the very
lowest frequencies, i.e. less than 0.5-1Hz). Generally speaking, power
values (across approx 1-30Hz, at least) shoudl generally be more in the
range of tens rather than hundreds (μV2).

[By the way - in general I think it's often preferable to analyse relative,
rather than absolute, band-power.]

You can feel free email me if you'd like further info.

Regards,
Simon Finnigan

On Tue, Aug 11, 2015 at 1:19 AM, Carla Barros <carla.88.barros at gmail.com>
wrote:

> Dear all,
>
> We have been trying to calculate total, evoked and induced power related
> to auditory processing in an oddball task.
>
> Power has been calculated as the squared magnitude of the EEG (μV2),
> followed by baseline correction, following Roach and Mathalon (2008) and
> others. However, the resulting values have been intriguing us, since they
> vary between 0 and 400 μV2. Based on the existing studies, it is difficult
> to get a sense of what should be the right range, since many do not report
> the measurement unit and others refer to power as μV and not as μV2.
>
> Based on your experience, what would be your recommendation for the
> baseline correction method (we are using the subtraction method)?
>
>
> Thank you very kindly in advance.
>
> Best regards,
> Carla Barros, MS.C., Biomedical Engineer
>
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