Bivariable Analysis of EEG Signals - Quantitative EEG Analysis Methods and Clinical Applications - page 115

c xx

0.1

Example A

Example B

0.08

Example C

0.06

R

0.04

0.02

0

0 5 10 15 20 25 30

(a)

c yy

0.1

0.08

0.06

L

0.04

0.02

0

0 5 10 15 20 25 30

(b)

Γ xy

1

0.8

0.6

0.4

0.2

0 5 10 15 20 25 30

(c)

ω (Hz)

Figure 4.3 (a-c) Power spectral estimation for the three signals of Figure 4.1 and the corresponding
coherence estimation as a function of frequency.

occurrence of X i after N samples. Note, however, that for a small number of sam-
ples this naïve estimate may not be appropriate and it may be necessary to introduce
corrections terms [8]. Given this set of probabilities, we can define the Shannon
entropy as follows:

M
=− = ∑

()

IX p log p (4.4)

i i

i 1