(
Received April 5; revision accepted for publication July 19, 1971.)Presented, in part, to the American Pediatric Society-Society for Pediatric Research meeting, May 2, 1970.
Presented, in part, at the meeting of the XIII International Congress of Pediatrics in Vienna,
Sep-tember 1, 1971.
This study was supported by grants from the U.S. Public Health Service A1-06110, NIH Vanderbilt
University General Research Grant #96, in part by the U.S. Office of Education Grant OEG 0 8
070644-1753.
ADDRESS FOR REPRINTS: (S.H.W.S.) Department of Pediatrics, Vanderbilt University School of
Medi-cine, Nashville, Tennessee 37203.
PELwrnxcs, Vol. 49, No. 2, February 1972
PSYCHOLOGICAL
SEQUELAE
TO
BACTERIAL
MENINGITIS:
TWO
CONTROLLED
STUDIES
Sarah H. W. Sell, M.D., Warren
W. Webb,
Ph.D.,
John E. Pate, Ed.D.,and Emanuel 0. Doyne,
M.D.
From the Departments of Pediatrics and Psychiatry, Vanderbilt University School of Medicine,
Nashville, Tennessee
ABSTRACT. Two controlled studies concern the
results of standardized psychological test assess-ment of long-term sequelae of bacterial meningitis
inschool age children who were ill before age 3. In the first group, each survivor was matched
with a near-age, nonmeningitic sibling. Results of
the Wechsler Intelligence Scale for Children indi-cated that the mean IQ of the post-meningitic chil-dren was 86; control children, 97 (p = <.05).
Comparison of each subject with his control
re-vealed that six (29%) were 15 IQ points (1
stan-dard deviation) below the control. In two (10%)
the difference exceeded 30 IQ points (2 standard deviations). There were six subjects with IQ scores higher than controls but none by 15 points.
The second investigation compared survivors
who were considered to be entirely normal with
matched peers in the same classroom. Results of
the dependent measures-Illinois Test of Psycholin-guistic Abilities, the Frostig Developmental Test of Visual Perception, and the Peabody Picture Vocab-ulary Test-all indicated that the post-meningitic children functioned at significantly lower levels
than their nonmeningitic peers.
It was concluded that both groups of survivors
were damaged by the disease. The evidence
sup-ports the need for prevention rather than reliance upon cure of meningitis. Pediatrics, 49:212, 1972, MENINGITIS, SEQUELAE, PSYCHOLOGICAL TEST
ASSESS-MENT.
T
HE dramatic reduction of mortality from meningitis due to Hemophilus in-fluenzae, Neiseria meningitic, andDiplo-coccus penumoniae, by the use of
antibiot-ics, is one of the great achievements of the
past two decades. However, now that
bac-terial antigens have been developed for possible prevention of serious infections due to these microorganisms,15 there is need for data concerning the results of the long-term effects of meningitis in patients who
survived under the present regime of
treat-ment. Such information would be useful in
evaluating the need for prevention by
im-munoprophylaxis.
Two recent reports concerned the
long-term, overall functioning of survivors of H. influenzae meningitis.6’7 Both studies found that less than half of the children escaped detectable sequelae. However, there were no control subjects for either study, which was considered a weakness by both groups
of authors.
This report presents the results of
stan-dardized psychological test assessment of long-term sequelae of bacterial meningitis
in two controlled studies. The first investi-gation concerns the Wechsler Intelligence
TABLE I AGES OF SIBLING PAIRS AT TESTING
TABLE II
ARTICLES
were considered to be entirely normal with matched peers in the same classroom. De-pendent measures included the Illinois Test
of Psycholinguistic Abilities, the Frostig Developmental Test of Visual Perception, and the Peabody Picture Vocabulary Test.
FIRST STUDY
Selection of Subjects
From the records of the Pediatric Bacte-riologic Laboratory of the Vanderbilt Uni-versity Medical Center, patients were
iden-tified who had cerebrospinal fluid or blood cultures from which Hemophilus influenzae
was grown during the period June 1960,
through June 1964. Information from their clinical charts determined survivors of
pu-rulent meningitis who were 2 months to 3
years of age at the time of onset of the ill-ness. All such patients who had a near-age
sibling to act as control were invited to
re-turn to Vanderbilt University Medical Center during the summer of 1969 for a
se-ries of tests. Travel costs were paid for those who indicated need. When there was a choice, the sibling of same sex and nearest
age was selected as control. Twenty-one
pairs of children accepted the invitation. All
except two subjects returned to Vanderbilt
for the evaluation. One severely retarded
child was tested at his special residential fa-cility. One nearest age, same sex sibling
control was congenitally deaf, and was tested at her special school.
PSYCHOLOGICAL TESTING: Each child was
appraised by a skilled psychological
tech-nician who did not know which was con-trol (C) or post-meningitic (PM). The
Age at Testing Sex
Test Groups
Mean Sid.
Des. M F
Post-meningitic (PM) (N=1) 8.4 ±1.5 13 8
Controls (C) (N=1) 10.8 ±.5 1 9
Wechsler Intelligence Scale for Children (WISC)8 was selected for the evaluation of intellectual functioning since it covers a
variety of tasks with 10 subtests each of
which is standardized for age. The I.Q.
scores allow direct comparisons of children at different ages and can be related to some of the other standardized tests such as Stan-ford-Binet.9
STATISTICAL METHODS: The data were
analyzed by the t-test and by the sign test.1#{176}
Results
Table I presents the composition of the subject population. Males predominated in both groups.
Table II presents the basic results from
this study. It will be noted that the mean I.Q. score for the PM subjects was 86 while
C was 97, a significant difference.
Figure 1 is a graphic representation of I.Q. results of each subject with his control.
It shows that there was a wide variation in
the I.Q. scores of the nonmeningitic controls,
ranging from 148 to 62, with nine below 90 and four below 80. There were 14 PM chil-dren who were functioning below their
INTELLIGENCE TmT RIBTJLTS
N Mean I.Q.
test Wilcoxson’s Si gn Test
t p Lower Rank Total p
Post-Meningitic (P.M.) 1 86
.16 .04 5.5 <.05
#{149}posi MENINGITIC OCONTROL
214
Ui -J U Cl)
a
Fic. 1. Representation of I.Q. results of each subject with his control (21 sibling pairs).
controls. The difference for six pairs
(
29%)was 15 I.Q. points
(
1 standard deviation) below while in two pairs(
10%) the differ-ence exceeded 30 I.Q. points (2 standard deviations). There were six PM subjects who had I.Q. scores higher than controls but none by 15 points.No statistically significant correlation was
found between the difference in I.Q.’s and the patients’ length of hospitalization or age at onset of illness or difference in age from his sibling at the time of the testing.
SECOND STUDY
Selection of Subjects
From the records of hospitals and prac-ticing pediatricians in Nashville, Tennessee,
25 PM subjects were identified who had
pu-rulent meningitis, 15 due to H. influenzae,
five to meningococcus, and five to pneu-monococcus. Each child received adequate
therapy for the illness, survived, and ap-peared to be free from sequelae. Of those
who were considered to be normal at school age, the 25 were selected from enrollees in
the first three grades in regular public
school classes of the Nashville Metropolitan
School System in 1969. Those who had ob-vious sequelae, or who were
institutional-ized, or who required special educational
services were excluded from the sample.
Each child was matched by age, sex, social
class,h1 and classroom membership with a
nonmeningitic peer. To select the controls, all students in the classroom of the same sex
as an index subject were given a personal
TABLE III AGES OF PEER PAIRS AT TESTING
ARTICLES
One child was selected at random from those that matched. The parents were inter-viewed to obtain written informed consent
for participation in the study.
PSYcHOLOGICAL TESTING: Although the
pairs of subjects were assessed along a wide
spectrum of parameters, of primary import
for this report were three standardized psychological tests:
(
1)
The Illinois Test of Psycholinguistic Abffities,IS which is di-vided into 10 subtests, evaluates the abilityof the subject to receive, integrate and
ex-press language. A raw score and a
psy-cholinguistic age can be calculated from the results. (2) The Frostig Developmental Test of Visual Perception,13 evaluates five facets of visual perceptual development, and the results are expressed as a perceptual
quotient. (3) The Peabody Picture
Vocab-ulary Test,14 is a relatively simple means of
testing word knowledge. At the sound of a
test word, the subject merely points to one of four pictures, the one he believes is most appropriate. The result is expressed as a vocabulary quotient.
PROCEDURE: The children were
trans-ported in pairs from their school to the Vanderbilt University Medical Center for
evaluation. A skilled psychological
techni-cian administered the tests without knowl-edge of which individual was survivor or
control.
Results
Table III represents the subject
popula-tion, matched for age and sex. With each of the tests for instructional receptivity the survivor subjects had lower mean scores than the peer controls.
Table IV shows the results of the Illinois Test of Psycholinguistic Abilities. The mean psycholinguistic raw score of the sur-vivors was 225.48 while controls scored 327.00. This difference is significant at the
.004 level (t-test two tailed).
Table V indicates results of the Frostig Test. The mean perceptual quotient of the
survivor subjects was
92.36
while that for controls was 101.84; the probability for thisAge at Testing Sex
Test Groups
-Mean S.D. Al F
Post-meningitic (PM) (N = 5) 7. 1 ± .9 16 9
Controls (C) (N=25) 7.8 ±1.0 16 9
difference in means was .084 which is not
quite significant, (t-test, two tailed). How-ever, the mean difference for the subject,
position in space, was signfficant
(
t = 2.19,p = .031).
Table VI presents the results for the
Pea-body Picture Vocabulary Test. The mean
vocabulary quotient of the survivors was
90.96 while that for controls was 102.60. This difference is significant at the .035
level (t-test, two tailed).
DISCUSSION
The sibling controls, as a whole, had a wide range of I.Q. scores. The differences
between the pairs gave indication of what
the PM’s might have been. Both groups of
survivors of bacterial meningitis, despite
acceptable therapy received during the
ill-ness at early ages, were functioning
intel-lectually below their controls. In the second study the children were specifically selected because they were thought to be entirely undamaged by their experience with
men-ingitis. That these were having learning
TABLE IV
ILLINOIS TEST OF PSYCHOLINGUISTIC ABILITIES*t
Al ean Psycho-linguistic Raw Score Standard Deviation t-te st -p
Post-meningitic 5 .48 116.89 3.055 .004
(N=5)
Control (N=5) 37.00 118.05
* Both distributions are normally distributed. t There is homogeneity of variance.
TABLE V
FROSTIG DEVELOPMENTAL TEST OF
VISUAL PERcEp’nout
Mean 1-test
Standard ____________
Perceptual
Deviation -__________
Quotient t p
Post-meningitic
(N=5) 9.36
1.74 .084
Control (N=5) 101.84 15.70
* Both distributions are normally distributed.
t There is heterogeneity of variance, but with ap-propriate formula, t is still 1.74.
problems which were undetected
prey-ously is especially significant.
The selection of controls for children is
always controversial. It can be argued that
siblings have their individual differences. Matched peers certainly differ in many
ways. But the important fact is that the
ex-perimental results with both classes of
con-trols led to the same general conclusion that survivors were damaged by their illness.
The weight of evidence points to the need for prevention rather than reliance upon cure of the disease.
The differential influences of child-rear-ing practices and the differential reactions
of families to serious illness in their
chil-dren were not examined in this report, but these factors should be of substantial conse-quence. For example, it is interesting to speculate that within families, social
pres-TABLE VI
PEABODY PICTURE VOCABULARY TERT*t
Mean Vocabulary Quotient Standard Deviation t-test I p
Post-meningitic 90.96 Qi .24
(N=25) 2.139 .035
Control
(N=25) 102.60 17.00
sures on the relatively slow child
(
even though his I.Q. be above 90) but whosesib-lings were very bright, might be greater than that experienced by a child with a
be-low
average
I.Q. whose family members were also functioning in the below average range.SUMMARY
Two groups
of survivors
of proven
bacte-rial meningitis before age 3 years were
tested for intellectual functioning after school age. In the first group, each survivor was matched with a near-age sibling. Re-suits of the Wechsier Intelligence Scale for Children indicated that the mean I.Q. of these children was significantly lower than that of the controls. The second group
con-sisted of survivors considered to be entirely free of sequelae who were enrolled in the
first three grades in public school classes.
Each was matched by age, sex, social class, and classroom membership with a
nonmen-ingitic peer. Results of tests for instructional
receptivity indicated that the survivors
functioned at significantly lower levels than
their nonmeningitic peers. It was
con-cluded that both groups of survivors of bacterial meningitis were damaged by the disease. The evidence supports the need for prevention rather than reliance upon cure.
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