CEPHALIC MEASURES I N NORMAL PRE-SCHOOL
CHILDREN 3 to 7-YEARS OF AGE
A . J. DlAMENT * F . W . RODRIGUES **
I n a study designed to d e t e r m i n e the n o r m a l standards f o r an E v o l u t i v e N e u r o l o g i c a l E x a m i n a t i o n7
certain measures of the head w e r e taken in o r d e r to study g r o w t h and shape o f children's heads.
METHODOLOGY A N D CASUISTICS
Head measures were taken in 200 children, half from each sex, with in each one of the five age groups 3-7 years consisting of 40 children.
This group was selected among 755 normal pre-school age children. The cri-teria for selection was both anamnestic and c l i n i c2
,7 .
The following measures were obtained: cephalic perimeter, biauricular and ante-rior-posterior distances following the sistematization already established2
, using a fiber-glass tape measure. The new cephalic index ( n C I ) was determined as the ratio of the biauricular distance by the anterior-posterior -.
For each one of those measures and within each category (sex, age) the mean ( X ) , standard deviation ( S ) and tolerance limits ( T L ) were calculated. For the new cephalic index ( n C I ) we used the Kruskal-Wallis t e s t1 0
and the differences among the ten groups were not significant. This indicates that, at least within those age limits, the nCI appears not to be associated with age or sex. Therefore we decided to use all 186 measures (14 were lost due to technical difficulties) to find a unique tolerance region for the 3-7 age group independently of sex.
RESULTS
The means, standard deviations (SD) and tolerance limits ( T L ) for each one of the measures can be found in tables 1, 2 and 3. Table 4 shows the same values for the nCI. Looking at these tables we can see that the largest values of S for the cephalic perimeter were found for five-years old boys and seven-years old girls.
* Assistant-Professor, Department of Neurology, School of Medicine, University of São Paulo (Brasil); ** Assistant-Professor of Statistics, Institute of Mathematic and Statistic, University of São Paulo (Brasil).
Since the sample size is practically the same for each group, those differences in variability are responsible for the different sizes of the tolerance intervals. This explains a larger letf-end point for 4-years old when compared with the 5-years old boys. For the 3 years old age group the mean of the cephalic perimeter is slightly larger for girls than for boys.
Although no statistical tests were made we believe this difference to be not significant. Discrepancies of the same type found in other measures (Tables 2 and 3) can probably be explained in the same w a y .
In table 4 we may observe that the nCI shows almost uniform variabUtiies the only exception being the 3-years old boys which shows a value slightly above the rest. This homogeneity of variances makes a stronger case for the hypothesis of no association of the nCI with age and sex (within the 3-7 l i m i t s ) . The tolerance interval for the nCI in the entire 3-7 age group is the interval 0,848-1,002. This means that we have 95% confidence that, independently of sex, this interval covers 90% of the population of normal children in this age group.
COMMENTS
F o r cephalic p e r i m e t e r s , in B r a z i l , an o t h e r r e f e r e n c e in the l i t e r a t u r e is M a r c o n d e s & c o l .8
w h e r e tolerance limits w e r e found f o r the cephalic p e r i m e t e r s of children up to three y e a r s of a g e . I n the 3-years o l d a g e g r o u p the means of the cephalic p e r i m e t e r w e r e 4 8 . 9 0 f o r boys and 47.87 c m f o r girls against our results of 49.90 and 50.16 r e s p e c t i v e l y . T h e i r tolerance intervals w e r e 45.77-52.04 c m f o r boys and 44.83-50.90 c m f o r girls 8
. T h o s e discrepancies can be explained b y the l a r g e r v a r i a b i l i t y of our e s t i m a t e of a2
since M a r c o n d e s & c o l .8
w o r k e d w i t h a much l a r g e r sample s i z e . W e decided n o t to discuss results obtained in o t h e r countries since the results a r e possibly n o t c o m p a r a b l e . F o r e x a m p l e w i t h respect to the N e l h a u s g r a f i c M a r c o n d e s & col. 8
o b s e r v e t h a t r i g o r o u s l y it should not be considered international and interracial since i t lacks observations f r o m both A f r i c a and L a tin- A m e r i c a . I n our cases the means of the cephalic p e r i m e t e r w a s s m a l l e r than in o t h e r c o u n t r i e s9
.1 2
. H o w e v e r t h e y a r e q u i t e close to the values r e p o r t e d b y W a t s o n & L o w r e y1 1
f o r north-american children of both s e x e s . F o r the 3-years old o u r means a r e l a r g e r than the ones r e p o r t e d by K a r l b e r g6
and a r e s i m i l a r to F a l k n e r5
. W i t h t h e excepction of B a r b e r & c o l .1
nobody else measured both anterior-posterior and biauricular dis-tances . B a r b e r & c o l .1
used an a n t h r o p o l o g i c a l compass and the biauricular distance f o r t h e m is the m a x i m a l distance b e t w e e n the p a r i e t a l e m i n e n c e s . T h e classical cephalic index ( C I ) w a s also obtained and a c c o r d i n g to it individuals w e r e classified as meso, b r a c h y and d o l y c h o c e p h a l i c s .
T h e C I also shows considerable differences according to a g e and s e x . I n o r d e r t o conciliate these differences w i t h the a l o m e t r i c l a w of g r o w t h of H u x l e y ( w h i c h is supposed to be valid f o r perpendicular distances) B a r b e r & c o l .1
used m a t h e m a t i c a l formulas e n v o l v i n g d e r i v a t i v e s of functions. T h e n C I expresses m o r e d i r e c t l y the h a r m o n y of g r o w t h of t w o perpendicular distances and constitutes a good e x a m p l e f o r an extension o f H u x l e y ' s pre-visions f o r C o e l e n t e r a t e s . T h e t o l e r a n c e r e g i o n f o r the n C I is l a r g e r than the one w e found b e f o r e f o r the first y e a r of a g e 2
a difference of 0,03616. O n e possible explanation could be t h a t heads of small children a r e m o r e u n i f o r m . A s t i m e passes the head starts to t a k e its definite f o r m a p p e a r i n g then a l a r g e n u m b e r of dolychocephalics due to a s l i g h t l y l a r g e r a t e o f g r o w t h of the antero-posterior distance. T h e n C I f o r the first y e a r w a s a l r e a d y used in a study of precocious craniostenosis 4
and it has p r o v e d to be v e r y e f f e c t i v e in d e t e c t i n g changes in h e a d - s h a p e3
. F o r all cases, b e l o w one y e a r the n C I w a s e i t h e r a b o v e the m a x i m u m o r b e l o w the m i n i m u m4
. A l s o as an indicator of changes in head shape it is m u c h simpler t o w o r k w i t h , than t h e measures suggested b y Z u c h o w i c z1 3
. W e a r e n o w w o r k i n g in a small ruler that w i l l a l l o w a p r a c t i c i o n e r g i v e n the t w o measures, to decide if a g i v e n individual has o r not alterations in head shape.
SUMMARY
I n a study designed to d e t e r m i n e standards f o r the D e v e l o p m e n t a l N e u r o -logical E x a m i n a t i o n ( D N E ) s e v e r a l measures o f the head w e r e also recorded. T h e study consisted in t h e e x a m i n a t i o n of 200 children, half f r o m each sex, 40 f r o m each a g e g r o u p ( 3 t o 7-years o f a g e ) . T h e s e children w e r e selected a m o n g 755 n o r m a l pre-school-age children, l i v i n g in the c i t y of S ã o P a u l o
( B r a z i l ) . T h e c r i t e r i a f o r selection w e r e both anamnestic and clinic. T h e f o l l o w i n g measures of the head w e r e r e c o r d e d : cephalic p e r i m e t e r , biauricular and antero-posterior distances ( D i a m e n t , 1967). A n e w cephalic index ( n C I ) w a s also d e t e r m i n e d ( D i a m e n t , 1968). T h i s index is useful in d e t e c t i n g changes in head shape m a i n l y in cases o f precocious cranioestenosis ( D i a m e n t , 1968; F a c u r e , 1 9 7 2 ) .
T h e statistical analysis consisted in d e t e r m i n i n g means and standard errors f o r each m e a s u r e . F o r the n e w cephalic index it w a s s h o w n t h r o u g h the K r u s k a l - W a l l i s test t h a t t h e r e w e r e no significant d i f f e r e n c e b e t w e e n a g e and sex. T h e r e f o r e w e considered a l l groups t o g e t h e r t o find out the t o l e r a n c e r e g i o n f o r t h e n e w index w h i c h turned out t o be g i v e n b y the i n t e r v a l : 0.848-1.002. T h i s result is based in 186 cases since 14 w e r e excluded because o f s o m e p r o b l e m s in the r e c o r d i n g p r o c e s s . T h e r e f o r e w e e x p e c t w i t h a confidence o f 95% t h a t t h e a b o v e i n t e r v a l c o v e r s 9 0 % of the popu-lation, in the 3 to 7 y e a r s a g e - g r o u p s independently of s e x .
RESUMO
Medidas cranianas em crianças pré-escolares normais de 3 a 7 anos
REFERENCES
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de crianças normais no primeiro ano de vida. São Paulo, 1967 (Tese, Facul-dade de Medicina da UniversiFacul-dade de São P a u l o ) . Rev. Bras. Def. Ment. 4:1, 1969.
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7. LEFÊVRE, A . B . — Exame Neurológico Evolutivo do Pré-Escolar Normal. Editora Sarvier, São Paulo, 1972.
8. MARCONDES, E . ; BERQUÒ, E . S . ; YUNES, J.; LUONGO, J.; MARTINS, J . S . ; ZACCHI, M . A . S . ; LEVY, M . S . F . A . & HEGG, R . — Estudo antropométrico de crianças brasileiras de zero a doze anos de idade. Anais Nestlé 84 (São Paulo), 1972.
9. NELHAUS, G. — Head circumference from birth to eighteen years. Practical composite international and interracial graphs. Pediatrics 41:106, 1968. 10. NOETHER, G. — Introduction to Statistics. Boston, Hougton Mifflin, Boston,
1971, p. 145.
11. WATSON, E H . & LOWREY, G . H . — Growth and Development of Children. 5.» ed. Year Book Pub., Chicago, 1967, p. 81-83.
12. WESTROP, C . K . & BARBER, C . R . — Growth of the skull in young children: I — Standards of head circumference. J. Neurol. Neurosurg. Psichyat. 19:52, 1956.
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bém se calculou médias, desvios-padrões e LT para cada idade e sexo. Pelo
teste de Kruskal-Wallis verificou-se não haver diferenças significantes entre
idade e sexo para o ICn. Então, considerou-se todo o grupo etário em
conjunto para achar uma única região de tolerância, dada pelo intervalo:
0,848-1,002, resultado baseado em 186 medidas (excluídas 14, por problemas
técnicos). Portanto, espera-se, com uma confiança de 95% de que o inter¬
valor cubra 90% desta população, independentemente do sexo. O mesmo
índice já havia sido determinado por um dos autores para crianças normais
no primeiro ano de vida, servindo para detectar precocemente alterações na
forma do crânio, principalmente cranioestenose precoce.
