Time-frequency characterization of interdependencies in nonstationary signals: application to epileptic EEG.
IEEE Trans Biomed Eng
; 52(7): 1218-26, 2005 Jul.
Article
em En
| MEDLINE
| ID: mdl-16041985
ABSTRACT
For the past decades, numerous works have been dedicated to the development of signal processing methods aimed at measuring the degree of association between electroencephalographic (EEG) signals. This interdependency parameter, which may be defined in various ways, is often used to characterize a functional coupling between different brain structures or regions during either normal or pathological processes. In this paper, we focus on the time-frequency characterization of the interdependency between signals. Particularly, we propose a novel estimator of the linear relationship between nonstationary signals based on the cross correlation of narrow band filtered signals. This estimator is compared to a more classical estimator based on the coherence function. In a simulation framework, results show that it may exhibit better statistical performances (bias and variance or mean square error) when a priori knowledge about time delay between signals is available. On real data (intracerebral EEG signals), results show that this estimator may also enhance the readability of the time-frequency representation of relationship and, thus, can improve the interpretation of nonstationary interdependencies in EEG signals. Finally, we illustrate the importance of characterizing the relationship in both time and frequency domains by comparing with frequency-independent methods (linear and nonlinear).
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Algoritmos
/
Encéfalo
/
Diagnóstico por Computador
/
Eletroencefalografia
/
Epilepsia
/
Modelos Neurológicos
Tipo de estudo:
Diagnostic_studies
/
Evaluation_studies
/
Prognostic_studies
/
Risk_factors_studies
Limite:
Humans
Idioma:
En
Revista:
IEEE Trans Biomed Eng
Ano de publicação:
2005
Tipo de documento:
Article
País de afiliação:
França