798
Electroencephalography and Clinical Neurophysiology, 1977, 43:798--801
© Elsevier/North-Holland Scientific Publishers, Ltd.
EEG SPECTRA IN XYY AND XXY MEN JAN VOLAVKA, SARNOFF A. MEDNICK, LEJF RASMUSSEN and JOSEPH SERGEANT Missouri Institute of Psychiatry, Department of Psychiatry, University of Missouri. St. Louis, Mo., 63139 (U.S.A.), Psychological Institute, Department of Psychiatry, Kommunehospitalet, 1399 Copenhagen, (Denmark) and The New School for Social Research, New York, N. Y., 10011 (U.S.A.)
(Accepted for publication : April 27, 1977 )
Sex c h r o m o s o m e anomalies present an opp o r t u n i t y to link a reliably detectable genetic factor with brain function and behavior. The most recent evidence (Witkin et al. 1976) shows that the XYY men have low intelligence, but no particular propensity for aggressive behavior as previously believed. The purpose o f our studies was to examine the effect o f an extra sex c h r o m o s o m e on the EEG. EEG slowing has been reported in institutionalized XYY and XXY men ( F e n t o n et al. 1971; Hamb er t and Frey 1964). Persons resident in mental-penal institutions are m or e likely than non-institutionalized persons to exhibit EEG slowing (Hill and Parr 1963); this bias has complicated the interpretation of their results. We have recently reported that the XYY men located in a non-institutionalized population had a slightly slower EEG alpha activity than their XY controls, but no increase o f EEG abnormality (Volavka et al. 1977). The alpha frequency was measured by hand in a 3-sec segment of 2 derivations. We now present the results of c o m p u t e r analyses o f EEGs in a subset o f subjects examined by Witkin et al. (1976) and Volavka et al. (1977).
Methods The subjects were selected from a c o h o rt o f 31,438 men in Copenhagen, mark. C h r o mo s o m e determinations made in 4,140 o f those men (selected
birth Denwere from
the c o h o r t because they were taller than 184 cm). Twelve XYY and 14 XXY men were identified and u n d e r w e n t an EEG examination. Control XY subjects were selected from the set o f 4,140 men. One group of controls (Control 1) was matched individually to the sex c h r o m o s o m e anomaly cases for age, height, and social class. A second control group (Control 2) was matched to the same cases for age, social class and performance on an intelligence test {This second group was included to control for the low intelligence o f the XY~; and XXY subjects). The subjects' age range at the time of the EEG was 26 31 years. Resting EEG with eyes closed was recorded on paper and magnetic tape for 4 min. The International 10-20 System was used for electrode placement {Jasper 1958). Coincidental EEG epochs of 2.5 sec duration were recorded from the following EEG leads: T3, T4, C3, C4, P3, P4, O1, O2. All leads were referred to joint ears (A12). Without knowledge o f the subject's group membership, EEG epochs affected by artifacts or drowsiness were identified and removed from furt her analyses. The average duration of the remaining artifact-free port i on was 80 sec. The minimal duration of the analyzed EEG was 7.5 sec (3 epochs). Subjects who failed to yield this minimal a m o u n t o f artifact-free EEG were dropped from c o m p u t e r analyses. These d r o p o u t s were approxi m at el y equally distributed among the 6 groups.
EEG IN XYY AND XXY MEN
799
TABLE I Average alpha frequency (in c/sec) n is the number of subjects contributing to t h e m e a n and SE is the standard error of the m e a n . Derivation
T3--A12 T4--A12 C3--A12 C4--A12 P3--A12 P4--A12 O1-A12 O2--A12
XYY
Control 1
Mean
n
SE
Mean
9.18 9.15 9.16 9.12 9.28 9.29 9.32 9.28
8 8 10 10 10 10 10 10
0.154 0.178 0.175 0.170 0.201 0.187 0.197 0.193
9.82 9.82 9.80 9.76 9.94 9.97 10.10 10.14
** ** ** ** ** ** ** **
Control 2 n
SE
Mean
8 8 10 10 10 10 10 10
0.076 0.070 0.112 0.086 0.114 0.112 0.127 0.129
9.73 9.69 9.69 9.64 9.88 9.85 9.96 9.97
** ** ** ** ** * * **
n
SE
8 8 11 11 11 11 11 11
0.164 0.180 0.160 0.156 0.169 0.161 0.147 0.167
* P < 0.05. ** P < 0.01.
The artifact-free segment was subjected to Fast Fourier Transform Analysis utilizing a PDP 11/40 system. The program yielded power values for the following frequency b a n d s : D e l t a 1, 0 . 5 - - 1 . 3 5 c / s e c ; D e l t a 2, 1.35--3.30 c/sec; Theta, 3.30--7.20 c/sec; A l p h a 1, 7 . 2 0 - - 9 . 6 0 c / s e c ; A l p h a 2 , 9 . 6 0 - 12.30 c/sec; Beta, 12.30--25.20 c/sec and Gamma, 25.20--40.00 c/sec. It also gave total p o w e r ( o v e r all f r e q u e n c y b a n d s ) . I n a d d i t i o n , t h e a v e r a g e f r e q u e n c y o f a l p h a a c t i v i t y (i.e., of the activity between 7.2 and 12.3 c/sec)
was computed. This computation used weighted sums of power coefficients for narrow frequency bands within the alpha range. The power coefficients for the above frequency bands were further transformed into power ratios. This was done by expressing the power within each of these frequency bands as a p e r c e n t a g e o f t h e t o t a l p o w e r . T h e r e s u l t i n g s c o r e s w e r e s u b j e c t e d t o a n a l y s e s o f variance. Separate analyses were done for each score for each derivation. Each analysis contrasted one of the chromosome deviation
TABLE II Relative p o w e r i n t h e t a band (3.3--7.2 c/sec) Derivation
T3--A12 T4--A12 C3--A12 C4--A12 P3--A12 P4--A12 O1--A12 O2--A12 *P< 0.05. ** P < 0.01.
XYY
Control 1
Mean
n
SE
Mean
0.229 0.203 0.245 0.244 0.205 0.191 0.160 0.165
8 8 10 10 10 10 10 10
0.044 0.035 0.031 0.028 0.024 0.024 0.019 0.019
0.147 0.132 0.155 0.168 0.141 0.140 0.112 0.104
** ** ** ** ** * * **
Control 2 n
SE
Mean
8 8 10 10 10 10 10 10
0.009 0.005 0.013 0.013 0.013 0.015 0.012 0.013
0.163 0.144 0.169 0.177 0.137 0.139 0.092 0.100
n *
* ** ** ** * ** **
SE 8
8 11 11 11 11 11 11
0.019 0.018 0.020 0.021 0.022 0.023 0.018 0.019
800
J. VOLAVKA ET AL.
TABLE III Relative power in alpha 1 band (7.2--9.6 c/sec) Derivation
T3--A12 T4--A12 C3--A12 C4--A12 P3--A12 P4--A12 O1--A12 O2--A12
XYY
Control 1
Mean
n
SE
Mean
0.271 0.255 0.273 0.279 0.305 0.311 0.343 0.339
8 8 10 10 10 10 10 10
0.045 0.044 0.036 0.034 0.044 0.049 0.056 0.058
0.121 0.117 0.138 0.147 0.146 0.146 0.137 0.135
** ** * * * * * *
Control 2 n
SE
Mean
8 8 10 10 10 10 10 10
0.018 0.017 0.020 0.016 0.023 0.021 0.024 0.024
0.152 0.172 0.167 0.167 0.177 0A75 0.193 0.180
* * * *
n
SE
8 8 11 11 11 11 11 11
0.028 0.034 0.024 0.024 0.036 0.033 0.043 0.040
* P ~< 0.05. ** P < 0.01.
g r o u p s ( X X Y a n d X Y Y ) against e a c h o f t h e 2 a p p r o p r i a t e c o n t r o l groups.
Results
T h e average alpha frequency was signific a n t l y l o w e r in t h e X Y Y g r o u p t h a n in e i t h e r o f t h e i r c o n t r o l groups. This was t r u e f o r e a c h o f t h e 8 d e r i v a t i o n s (Table I). T h e X Y Y s had t h e slowest average a l p h a f r e q u e n c y o f all the 6 g r o u p s in all t h e derivations. T h e relative p o w e r in t h e t a a n d a l p h a 1 b a n d s (i.e., 3 . 3 - - 9 . 6 c/sec) was g r e a t e r in t h e X Y Y g r o u p t h a n in e i t h e r o f t h e i r 2 c o n t r o l g r o u p s (Table II a n d III). T h e relative p o w e r in t h e b e t a b a n d was s o m e w h a t g r e a t e r in c o n trols t h a n in t h e X Y Y group. T h e o t h e r freq u e n c y b a n d s did n o t d i s c r i m i n a t e b e t w e e n t h e X Y Y and c o n t r o l s . N o significant differe n c e o n a n y E E G variable was f o u n d b e t w e e n t h e X X Y m e n and t h e i r X Y c o n t r o l s .
Discussion We have f o u n d an E E G slowing in a g r o u p o f X Y Y m e n d e t e c t e d in a b i r t h c o h o r t o f tall m e n ( n o n - i n s t i t u t i o n a l i z e d ) . T h e s e results c o n f i r m earlier findings on X Y Y m e n l o c a t e d
in m e n t a l - p e n a l i n s t i t u t i o n s a n d e x t e n d t h e i r generality. This is t h e first r e p o r t using c o m p u t e r i z e d E E G analysis w i t h X Y Y subjects. As m e n t i o n e d above, p r i o r to c o m p u t e r analysis t h e p o r t i o n s o f E E G c o n t a m i n a t e d b y a r t i f a c t or d r o w s i n e s s w e r e r e m o v e d . This editing had t w o effects. First, it d e c r e a s e d t h e d u r a t i o n o f the E E G s a m p l e a n a l y z e d b y t h e c o m p u t e r . S e c o n d , it increased t h e validity and reliability o f the a s s e s s m e n t o f the E E G . This p r o c e d u r e r e s u l t e d in e x t r e m e l y small w i t h i n - g r o u p inter-individual variability as reflected by the standard error of the group m e a n s (see T a b l e I). We o b s e r v e d this slowing o f w a k i n g a l p h a in t h e s e subjects b y t w o d i f f e r e n t m e t h o d s o f a s s e s s m e n t ( V o l a v k a et al. I 9 7 7 ) a n d consist e n t l y across all 8 d e r i v a t i o n s (Table I). As m e n t i o n e d above, this slowing has also b e e n r e p o r t e d in investigations o f i n s t i t u t i o n a l i z e d X Y Y m e n . Slowing o f w a k i n g a l p h a m u s t n o w be seen as a fairly reliable c h a r a c t e r i s t i c o f XYY men. In a previous p a p e r ( V o l a v k a et al. 1 9 7 7 ) we h a v e suggested t h a t this E E G slowing m i g h t r e p r e s e n t a d e v e l o p m e n t a l lag. It is possible t h a t t h e e x t r a Y c h r o m o s o m e i n t e r f e r e s with the development of brain functioning since s l o w e r E E G f r e q u e n c i e s n o r m a l l y pred o m i n a t e a t an earlier age ( L i n d s l e y 1 9 3 9 ;
801
EEG IN XYY AND XXY MEN
Matou§ek and Peters6n 1973). It is difficult to test this explanation without a longitudinal study. Generalized slowing is an unspecific EEG feature which can be produced by a variety of factors (e.g., hormonal and metabolic). The EEG is a part of an intensive assessment of these subjects which will provide the opport u n i t y to explore such possibilities.
Aucune difference significative n'a ~t~ observ~e entre les sujets XXY et les t~moins. This research was supported by Grants MH24872, MH23975, and MH21989 from the Center for the Study of Crime and Delinquency, NIMH. The study is being conducted in the context of a larger project directed by H.A. Witkin.
References Summary Ten XYY, 13 XXY, and 45 control XY men were located in a birth cohort of tall men (non-institutionalized), and their EEGs were subjected to computer analyses. The XYY men showed a significantly slower alpha activity and more power in the 3.3--9.6 c/sec band than their XY controls. There were no consistent EEG differences between the XXY men and their controls.
R~sum~ Spectres EEG chez des sujets de types X Y Y et XXY On a s~lectionn~ 10 individus XYY, 13 XXY et 45 t~moins XY, d ' u n ensemble de sujets de grande taille, d ' u n m~me groups d'~ge, non-intern~s, et proc~d~ ~ une analyse quantitative de leur EEG. Les sujets XYY ont pr~sent~ une activit~ alpha plus lente, avec une puissance spectrale plus grande dans la bande 3.3--9.6 c/sec, par rapport au groupe t6moin.
Fenton, G.W., Tennent, T.G., Cornish, K.A. and Rattray, N. The EEG and sex chromosome abnormalities. Brit. J. Psychiat., 1971, 119: 185--190. Hambert, G. and Frey, Sison, T. The electroencephalogram in the Klinefelter syndrome. Acta psychiat, scand. 1964, 40: 28--36. Hill, D. The EEG in psychiatry. In D. Hill and G. Parr (Eds.), Electroencephalography, Macmillan, London, 1963: 368--428. Jasper, H.H. Report of the committee on methods of clinical examination in electroencephalography. Electroenceph. clin. Neurophysiol., 1958, 10 : 370. Lindsley, D.G. A longitudinal study of the occipital alpha rhythm in normal children: Frequency and amplitude standards. J. genet. Psychol., 1939, 55: 197--213. Matou~ek, M. and Peters~n, I. Frequency analysis of the EEG in normal children and adolescents. In P. Kellaway and I Peters~n (Eds.), Automation of Clinical Electroencephalography, Raven Press, New York, 1973: 75--102. Volavka, J., Mednick, S.A., Sergeant, J. and Rasmussen, L. Electroencephalograms of XYY and XXY men. Brit. J. Psychiat., 1977, 130: 43--47. Witkin, H.A., Mednick, S.A., Schulsinger, F., Bakkestrom, E., Christiansen, K.O., Goodenough, D.R., Hirschhorn, K., Lundsteen, C., Owen, D.R., Philip, J., Rubin, D.B. and Stocking, M. Criminality in XYY and XXY men. Science, 1976, 193: 547-555.
Electroencephalography and Clinical Neurophysiology, 1977, 43:798--801
© Elsevier/North-Holland Scientific Publishers, Ltd.
EEG SPECTRA IN XYY AND XXY MEN JAN VOLAVKA, SARNOFF A. MEDNICK, LEJF RASMUSSEN and JOSEPH SERGEANT Missouri Institute of Psychiatry, Department of Psychiatry, University of Missouri. St. Louis, Mo., 63139 (U.S.A.), Psychological Institute, Department of Psychiatry, Kommunehospitalet, 1399 Copenhagen, (Denmark) and The New School for Social Research, New York, N. Y., 10011 (U.S.A.)
(Accepted for publication : April 27, 1977 )
Sex c h r o m o s o m e anomalies present an opp o r t u n i t y to link a reliably detectable genetic factor with brain function and behavior. The most recent evidence (Witkin et al. 1976) shows that the XYY men have low intelligence, but no particular propensity for aggressive behavior as previously believed. The purpose o f our studies was to examine the effect o f an extra sex c h r o m o s o m e on the EEG. EEG slowing has been reported in institutionalized XYY and XXY men ( F e n t o n et al. 1971; Hamb er t and Frey 1964). Persons resident in mental-penal institutions are m or e likely than non-institutionalized persons to exhibit EEG slowing (Hill and Parr 1963); this bias has complicated the interpretation of their results. We have recently reported that the XYY men located in a non-institutionalized population had a slightly slower EEG alpha activity than their XY controls, but no increase o f EEG abnormality (Volavka et al. 1977). The alpha frequency was measured by hand in a 3-sec segment of 2 derivations. We now present the results of c o m p u t e r analyses o f EEGs in a subset o f subjects examined by Witkin et al. (1976) and Volavka et al. (1977).
Methods The subjects were selected from a c o h o rt o f 31,438 men in Copenhagen, mark. C h r o mo s o m e determinations made in 4,140 o f those men (selected
birth Denwere from
the c o h o r t because they were taller than 184 cm). Twelve XYY and 14 XXY men were identified and u n d e r w e n t an EEG examination. Control XY subjects were selected from the set o f 4,140 men. One group of controls (Control 1) was matched individually to the sex c h r o m o s o m e anomaly cases for age, height, and social class. A second control group (Control 2) was matched to the same cases for age, social class and performance on an intelligence test {This second group was included to control for the low intelligence o f the XY~; and XXY subjects). The subjects' age range at the time of the EEG was 26 31 years. Resting EEG with eyes closed was recorded on paper and magnetic tape for 4 min. The International 10-20 System was used for electrode placement {Jasper 1958). Coincidental EEG epochs of 2.5 sec duration were recorded from the following EEG leads: T3, T4, C3, C4, P3, P4, O1, O2. All leads were referred to joint ears (A12). Without knowledge o f the subject's group membership, EEG epochs affected by artifacts or drowsiness were identified and removed from furt her analyses. The average duration of the remaining artifact-free port i on was 80 sec. The minimal duration of the analyzed EEG was 7.5 sec (3 epochs). Subjects who failed to yield this minimal a m o u n t o f artifact-free EEG were dropped from c o m p u t e r analyses. These d r o p o u t s were approxi m at el y equally distributed among the 6 groups.
EEG IN XYY AND XXY MEN
799
TABLE I Average alpha frequency (in c/sec) n is the number of subjects contributing to t h e m e a n and SE is the standard error of the m e a n . Derivation
T3--A12 T4--A12 C3--A12 C4--A12 P3--A12 P4--A12 O1-A12 O2--A12
XYY
Control 1
Mean
n
SE
Mean
9.18 9.15 9.16 9.12 9.28 9.29 9.32 9.28
8 8 10 10 10 10 10 10
0.154 0.178 0.175 0.170 0.201 0.187 0.197 0.193
9.82 9.82 9.80 9.76 9.94 9.97 10.10 10.14
** ** ** ** ** ** ** **
Control 2 n
SE
Mean
8 8 10 10 10 10 10 10
0.076 0.070 0.112 0.086 0.114 0.112 0.127 0.129
9.73 9.69 9.69 9.64 9.88 9.85 9.96 9.97
** ** ** ** ** * * **
n
SE
8 8 11 11 11 11 11 11
0.164 0.180 0.160 0.156 0.169 0.161 0.147 0.167
* P < 0.05. ** P < 0.01.
The artifact-free segment was subjected to Fast Fourier Transform Analysis utilizing a PDP 11/40 system. The program yielded power values for the following frequency b a n d s : D e l t a 1, 0 . 5 - - 1 . 3 5 c / s e c ; D e l t a 2, 1.35--3.30 c/sec; Theta, 3.30--7.20 c/sec; A l p h a 1, 7 . 2 0 - - 9 . 6 0 c / s e c ; A l p h a 2 , 9 . 6 0 - 12.30 c/sec; Beta, 12.30--25.20 c/sec and Gamma, 25.20--40.00 c/sec. It also gave total p o w e r ( o v e r all f r e q u e n c y b a n d s ) . I n a d d i t i o n , t h e a v e r a g e f r e q u e n c y o f a l p h a a c t i v i t y (i.e., of the activity between 7.2 and 12.3 c/sec)
was computed. This computation used weighted sums of power coefficients for narrow frequency bands within the alpha range. The power coefficients for the above frequency bands were further transformed into power ratios. This was done by expressing the power within each of these frequency bands as a p e r c e n t a g e o f t h e t o t a l p o w e r . T h e r e s u l t i n g s c o r e s w e r e s u b j e c t e d t o a n a l y s e s o f variance. Separate analyses were done for each score for each derivation. Each analysis contrasted one of the chromosome deviation
TABLE II Relative p o w e r i n t h e t a band (3.3--7.2 c/sec) Derivation
T3--A12 T4--A12 C3--A12 C4--A12 P3--A12 P4--A12 O1--A12 O2--A12 *P< 0.05. ** P < 0.01.
XYY
Control 1
Mean
n
SE
Mean
0.229 0.203 0.245 0.244 0.205 0.191 0.160 0.165
8 8 10 10 10 10 10 10
0.044 0.035 0.031 0.028 0.024 0.024 0.019 0.019
0.147 0.132 0.155 0.168 0.141 0.140 0.112 0.104
** ** ** ** ** * * **
Control 2 n
SE
Mean
8 8 10 10 10 10 10 10
0.009 0.005 0.013 0.013 0.013 0.015 0.012 0.013
0.163 0.144 0.169 0.177 0.137 0.139 0.092 0.100
n *
* ** ** ** * ** **
SE 8
8 11 11 11 11 11 11
0.019 0.018 0.020 0.021 0.022 0.023 0.018 0.019
800
J. VOLAVKA ET AL.
TABLE III Relative power in alpha 1 band (7.2--9.6 c/sec) Derivation
T3--A12 T4--A12 C3--A12 C4--A12 P3--A12 P4--A12 O1--A12 O2--A12
XYY
Control 1
Mean
n
SE
Mean
0.271 0.255 0.273 0.279 0.305 0.311 0.343 0.339
8 8 10 10 10 10 10 10
0.045 0.044 0.036 0.034 0.044 0.049 0.056 0.058
0.121 0.117 0.138 0.147 0.146 0.146 0.137 0.135
** ** * * * * * *
Control 2 n
SE
Mean
8 8 10 10 10 10 10 10
0.018 0.017 0.020 0.016 0.023 0.021 0.024 0.024
0.152 0.172 0.167 0.167 0.177 0A75 0.193 0.180
* * * *
n
SE
8 8 11 11 11 11 11 11
0.028 0.034 0.024 0.024 0.036 0.033 0.043 0.040
* P ~< 0.05. ** P < 0.01.
g r o u p s ( X X Y a n d X Y Y ) against e a c h o f t h e 2 a p p r o p r i a t e c o n t r o l groups.
Results
T h e average alpha frequency was signific a n t l y l o w e r in t h e X Y Y g r o u p t h a n in e i t h e r o f t h e i r c o n t r o l groups. This was t r u e f o r e a c h o f t h e 8 d e r i v a t i o n s (Table I). T h e X Y Y s had t h e slowest average a l p h a f r e q u e n c y o f all the 6 g r o u p s in all t h e derivations. T h e relative p o w e r in t h e t a a n d a l p h a 1 b a n d s (i.e., 3 . 3 - - 9 . 6 c/sec) was g r e a t e r in t h e X Y Y g r o u p t h a n in e i t h e r o f t h e i r 2 c o n t r o l g r o u p s (Table II a n d III). T h e relative p o w e r in t h e b e t a b a n d was s o m e w h a t g r e a t e r in c o n trols t h a n in t h e X Y Y group. T h e o t h e r freq u e n c y b a n d s did n o t d i s c r i m i n a t e b e t w e e n t h e X Y Y and c o n t r o l s . N o significant differe n c e o n a n y E E G variable was f o u n d b e t w e e n t h e X X Y m e n and t h e i r X Y c o n t r o l s .
Discussion We have f o u n d an E E G slowing in a g r o u p o f X Y Y m e n d e t e c t e d in a b i r t h c o h o r t o f tall m e n ( n o n - i n s t i t u t i o n a l i z e d ) . T h e s e results c o n f i r m earlier findings on X Y Y m e n l o c a t e d
in m e n t a l - p e n a l i n s t i t u t i o n s a n d e x t e n d t h e i r generality. This is t h e first r e p o r t using c o m p u t e r i z e d E E G analysis w i t h X Y Y subjects. As m e n t i o n e d above, p r i o r to c o m p u t e r analysis t h e p o r t i o n s o f E E G c o n t a m i n a t e d b y a r t i f a c t or d r o w s i n e s s w e r e r e m o v e d . This editing had t w o effects. First, it d e c r e a s e d t h e d u r a t i o n o f the E E G s a m p l e a n a l y z e d b y t h e c o m p u t e r . S e c o n d , it increased t h e validity and reliability o f the a s s e s s m e n t o f the E E G . This p r o c e d u r e r e s u l t e d in e x t r e m e l y small w i t h i n - g r o u p inter-individual variability as reflected by the standard error of the group m e a n s (see T a b l e I). We o b s e r v e d this slowing o f w a k i n g a l p h a in t h e s e subjects b y t w o d i f f e r e n t m e t h o d s o f a s s e s s m e n t ( V o l a v k a et al. I 9 7 7 ) a n d consist e n t l y across all 8 d e r i v a t i o n s (Table I). As m e n t i o n e d above, this slowing has also b e e n r e p o r t e d in investigations o f i n s t i t u t i o n a l i z e d X Y Y m e n . Slowing o f w a k i n g a l p h a m u s t n o w be seen as a fairly reliable c h a r a c t e r i s t i c o f XYY men. In a previous p a p e r ( V o l a v k a et al. 1 9 7 7 ) we h a v e suggested t h a t this E E G slowing m i g h t r e p r e s e n t a d e v e l o p m e n t a l lag. It is possible t h a t t h e e x t r a Y c h r o m o s o m e i n t e r f e r e s with the development of brain functioning since s l o w e r E E G f r e q u e n c i e s n o r m a l l y pred o m i n a t e a t an earlier age ( L i n d s l e y 1 9 3 9 ;
801
EEG IN XYY AND XXY MEN
Matou§ek and Peters6n 1973). It is difficult to test this explanation without a longitudinal study. Generalized slowing is an unspecific EEG feature which can be produced by a variety of factors (e.g., hormonal and metabolic). The EEG is a part of an intensive assessment of these subjects which will provide the opport u n i t y to explore such possibilities.
Aucune difference significative n'a ~t~ observ~e entre les sujets XXY et les t~moins. This research was supported by Grants MH24872, MH23975, and MH21989 from the Center for the Study of Crime and Delinquency, NIMH. The study is being conducted in the context of a larger project directed by H.A. Witkin.
References Summary Ten XYY, 13 XXY, and 45 control XY men were located in a birth cohort of tall men (non-institutionalized), and their EEGs were subjected to computer analyses. The XYY men showed a significantly slower alpha activity and more power in the 3.3--9.6 c/sec band than their XY controls. There were no consistent EEG differences between the XXY men and their controls.
R~sum~ Spectres EEG chez des sujets de types X Y Y et XXY On a s~lectionn~ 10 individus XYY, 13 XXY et 45 t~moins XY, d ' u n ensemble de sujets de grande taille, d ' u n m~me groups d'~ge, non-intern~s, et proc~d~ ~ une analyse quantitative de leur EEG. Les sujets XYY ont pr~sent~ une activit~ alpha plus lente, avec une puissance spectrale plus grande dans la bande 3.3--9.6 c/sec, par rapport au groupe t6moin.
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