小児脳波の発達に関するスペクトル分析的研究 健常児及び精神薄弱児脳波の変動性

堅田 明義; 鈴木 宏哉; 寿原 健吉

doi:10.4992/jjpsy.49.318

SPECTRAL ANALYTICAL STUDY ON THE DEVELOPMENTAL PROPERTIES OF EEG IN CHILDREN

VARIABILITY OF EEG IN NORMAL AND MENTALLY RETARDED CHILDREN

AKIYOSHI KATADA, HIROYA SUZUKI, KENKICHI SUHARA

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JOURNAL FREE ACCESS

1979 Volume 49 Issue 6 Pages 318-325

DOI https://doi.org/10.4992/jjpsy.49.318

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Published: March 20, 1979 Received: June 12, 1978 Available on J-STAGE: July 16, 2010 Accepted: - Advance online publication: - Revised: -
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Date of correction: July 16, 2010 Reason for correction: - Correction: ABSTRACT Details: Wrong : The most important data on the EEG during maturation are the findings on the temporal changes or variabilities of EEGs in a short period as well as the averaged frequency power spectra over a long period.
The purpose of this paper is mainly concerned with the problems of variability of the resting arousal EEGs in normal and mentally retarded children, and includes a discussion of the development of their brain in relation to the results obtained.
The subjects used were 53 normal and 63 mentally retarded children without any exogenous factors and especially proxysmal waves in their EEGs. Their ages ranged from 3 to 15 years in the normal and from 7 to 18 in the retarded. The EEG was recorded monopolarly from six regions of the scalp: Frontal, central, parietal and occipital regions along the midline and bilateral temporal ones referred to the indifferent leads on both ears.
The spontaneous resting EEGs of approximately 4min were sectioned into successive epochs of 10 sec and an auto-power spectrum was obtained for each epoch by a multi-purpose digital computer. Then, we calculated from 50 auto-power spectra an averaged power spectrum and a coefficient of variation of nower spectra at each frequency. The frequency resolution of the spectrum was 1/3Hz.
The results obtained were as follows:
1. In both normal and retarded, the variability of power at the peak frequency appeared at 6-7Hz was remarkable in the frontal region (Table 2).
2. The frequency component at the theta frequency band, especially 6-7Hz in the normal and the retarded showed a notable higher value of variability compared with the other frequency bands in all regions. The variability of 3-5Hz component in all regions was more conspicuous than alpha frequency component in both groups of children (Table 3).
3. It was found that the difference of power variability between the normal and retarded put on the alpha frequency component, that is, the coefficient of variation of power in the retarded was higher than that in the normal (Table 3).
4. It was difficult to find a certain relation between the age and the variability of power spectra (Fig. 2).
From the facts described above, it is most unlikely that the remarkable variability of power in the theta frequency band as compared with the alpha is a peculiarity of the retarded's EEG. Therefore, we assume that the upper facts are a characteristic of EEG during maturation of the children's brain. Finally, we discussed some of the problems of treating this variability of power as a general characteristic of theta wave or as a developmental one. For example, we pointed out that it was necessary for quantification of variability of EEG to reveal the statistical properties of theta and alpha rhythms shown by the higher moment of power spectra.
Right : The present study aimed at clarifying the characteristics of variability of the resting arousal EEGs in normal and mentally retarded children. Their ages ranged from 3 to 15 years in 58 normal and from 7 to 18 in 63 retarded. The EEG was recorded monopolarly from six regions of the scalp. The data analysed by a multipurpose digital computer comprised auto-power spectra and a coefficient of variation of power at each frequency. The variability of power at peak within the theta frequency band in both groups of children showed a notably higher value as compared with other frequency bands in all regions. We discussed some of the problems of treating this variability of power as a general characteristic of theta waves or as a developmental one.

Abstract

The present study aimed at clarifying the characteristics of variability of the resting arousal EEGs in normal and mentally retarded children. Their ages ranged from 3 to 15 years in 58 normal and from 7 to 18 in 63 retarded. The EEG was recorded monopolarly from six regions of the scalp. The data analysed by a multipurpose digital computer comprised auto-power spectra and a coefficient of variation of power at each frequency. The variability of power at peak within the theta frequency band in both groups of children showed a notably higher value as compared with other frequency bands in all regions. We discussed some of the problems of treating this variability of power as a general characteristic of theta waves or as a developmental one.

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