Document Detail

Time-frequency analysis of the electrocortical activity during maturation using wavelet transform.
MedLine Citation:
PMID:  8068778     Owner:  NLM     Status:  MEDLINE    
In this study, we introduce the wavelet transform (WT) as a method for characterizing the maturational changes in electrocortical activity in 24 fetal lambs ranging from 110-144 days gestation (term 145 days). The WT, based on multiresolution signal decomposition, is free of assumptions regarding the characteristics of the signal. The approximation of the electrocortical activity at resolutions varying from 2j+1 to 2j can be extracted by decomposing the signal on a wavelet orthonormal basis of L2(R). We performed multiresolution decomposition for four sets of parameters D2j, where -1 < j < -4. The four series WT represent the detail signal band-widths: (1) 16-32 Hz, (2) 8-16 Hz, (3) 4-8 Hz, (4) 2-4 Hz. The data were divided into three groups according to gestational age: 110-122 days (early), 123-135 days (middle), and 136-144 days (late). In the early group, the power was highest in the fourth signal bandwidth, with relatively low power in the other bands. Increase in gestational age was characterized by increased power in all four bandwidths. Comparison of the cumulative distribution function of the power in the four wavelet bands confirmed the presence of two statistically different patterns in all three age groups. These two patterns correspond to the visually identified patterns of HVSA (high-voltage slow activity) and LVFA (low-voltage fast activity). The earliest development change occurred in HVSA, with progressive increase in power in the 2-8 Hz band. Later changes occurred in LVFA, with a significant increase in power in the 16-32 Hz band.(ABSTRACT TRUNCATED AT 250 WORDS)
M Akay; Y M Akay; P Cheng; H H Szeto
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Biological cybernetics     Volume:  71     ISSN:  0340-1200     ISO Abbreviation:  Biol Cybern     Publication Date:  1994  
Date Detail:
Created Date:  1994-09-29     Completed Date:  1994-09-29     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  7502533     Medline TA:  Biol Cybern     Country:  GERMANY    
Other Details:
Languages:  eng     Pagination:  169-76     Citation Subset:  IM    
Department of Biomedical Engineering, Rutgers University, Piscataway, NJ 08855.
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MeSH Terms
Central Nervous System / embryology,  physiology*
Electroencephalography / methods*,  statistics & numerical data
Fetus / physiology*
Fourier Analysis
Gestational Age
Grant Support
DA-00100-10/DA/NIDA NIH HHS; DA-02475-13/DA/NIDA NIH HHS

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