P300 Evocated Potential

“Detection and analysis of the P300 Evocated Potential” by Diogo Barreiros, FCT, 2008

Diogo Barreiros
Manuel Ortigueira

This thesis consist in the study of electroencephalografic signals of an Alzheimer
disease person and on other Healthy subject in order to analyse and study the evoked potential
P300, which allows to extract indicators that can explain how is an Alzheimer disease
individual affected on its auditory system and what are the differences to an Healthy.
It was performed a spectral analysis through the application of several tecniques such
as the Empirical Mode Decompotition (EMD) and Wavelets, which decompose the signal into
different components in the frequency domain, allowing to filter the frequency range of
interest and therefore reconstruct the “optimized” signal, detect the P300 and collect its
latency values.
On the other hand, it was performed a time-frequency analysis of that same signals,
applying four methods: (1) AR demodulation and its graphics observation, (2) a developed
algorithm (explanation in chapter 3, section 3.6), (3) AR demodulation making a correlation
with its output data and one last method (4) the Espectrogram. From the first three methos,
information regarding frequency and signal amplitude were pulled out showing how these
parameters influence each other and how theyalternate/vary along time.
Having those methods in concern, their data was evaluated and examined through the
creation of several tables and graphics, correlating data in order to discover and detect a
specific behaviour (frequency, amplitude and latency) between an Alzheimer disease and a
Healthy subject.
Auditory Evoked Potential, P300, Spectral Analysis, EMD, Wavelets, Spetrogram.
Theses Here9.38 MB