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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2025-07-06 14:47 |
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Conference: Bucharest University Faculty of Physics 2025 Meeting
Section: Biophysics; Medical Physics
Title:
Time-frequency analysis of electroencephalographic data
Authors:
Adriana Denisa ENE, Constantin PISTOL
Affiliation:
Faculty of Physics, University of Bucharest
E-mail
adriana_k_2003@yahoo.com
Keywords:
time frequency analysis, Fourier Transform, Stereoelectroencephalography
Abstract:
The aim of this study is to highlight the utility of time-frequency analysis in interpreting stereoelectroencephalographic (sEEG) data recorded during epileptic seizures. The study focuses on two male subjects diagnosed with pharmacoresistant epilepsy who underwent stereoelectroencephalography. The first part of the paper presents a theoretical framework related to epilepsy and its investigative techniques, along with general information about the Fourier Transform and time-frequency analysis.
The core signal analysis was performed using AnyWave(Colombet et al., 2015) and MATLAB(Mathworks, Natick, MA). Initially, time-domain sEEG signals were imported and visually inspected in AnyWave. Subsequently, custom MATLAB scripts were developed to convert these signals into amplitude-time representations, followed by the application of the Fast Fourier Transform (FFT) to obtain their frequency-domain counterparts. Based on these transformed signals, time-frequency power maps were generated, clearly highlighting the seizure onset through color variations that reflect seizure intensity.
Additionally, a 3D brain model was constructed using MATLAB, allowing for accurate placement of the sEEG contacts on the brain surface. This provided a visual correlation between the anatomical location of the electrodes and the recorded signals.
In conclusion, the results confirm that time-frequency analysis is a valuable tool in evaluating ictal data, enabling precise identification of the seizure onset and the epileptogenic zone where it originated.
References:
1.L. Cohen. Time-frequency analysis, volume 778. Prentice Hall PTR New Jersey, 1995
2.Boashash. The time-frequency approach: Essence and terminology. Elsevier Inc., 2015.
3.K. Iida and H. Otsubo. Stereoelectroencephalography: indication and efficacy. Neurologia medico-chirurgica, 57(8):375–385, 2017.
4.W.H. Organization et al. Epilepsy: a manual for physicians. Technical report, WHO Regional Office for South-East Asia, 2004.
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