• No results found

INTELLIGENCE OF CHILDREN WITH DIABETES MELLITUS

N/A
N/A
Protected

Academic year: 2020

Share "INTELLIGENCE OF CHILDREN WITH DIABETES MELLITUS"

Copied!
9
0
0

Loading.... (view fulltext now)

Full text

(1)

INTELLIGENCE

OF CHILDREN

WITH

DIABETES

MELLITUS

Marvin Ack, Ph.D., Irving Miller, B.S., and William B. Weil, Jr., M.D.

Departments of Child Psychiatry, Preventive Medicine and Pediatrics, Western Reserve University

School of Medicine and University Hospitals of Cleveland

This study was supported in part by the National Institute of Arthritis and Metabolic Diseases, Public Health Service (Grant A-1317), the Foundation for the Study of Diabetes and Related Metabolic

Dis-orders, the Cleveland Diabetes Fund, and the Lorain (Ohio) United Health Foundation.

ADDRESS: (MA.) University Hospitals of Cleveland, 2065 Adelbert Road, Cleveland 6, Ohio.

PEDIATIIICS. November 1961

I

T IS WIDELY RECOGNIZED that an

under-standing of the intelligence and the

intellectual functioning of patients with

chronic diseases plays a critical role in the

management of such illnesses as diabetes

mellitus. The life expectancy for children

with diabetes is lengthening, so their future

as adults must be thoughtfully considered.

Their productivity as adult members of

society is contingent upon the enligiltelled

management of all aspects of their disease,

and in particular the physician needs to

un-derstand the effect of diabetes on

intellec-tual functioning and intellectual potential.

Although the need has long been

recog-nized as crucial and the problem of the

intellectual functioning of persons with

diabetes mellitus has been under

investi-gation since 1922, nonetheless our

knowl-edge of the intelligence of persons with

diabetes is extremely sketchy. Results of

previous investigations are contradictory.

Many of the studies have been based on

groups of patients in which unrecognized

bias occurred as a result of the method of

patient selection. The present

communica-tion is intended to indicate some of the

inconsistencies and misconceptions tilat

exist.

The study reported here is part of a

longitudinal study of diabetes mellitus in

children designed to investigate the

rela-tionship between the duration of tile

dis-ease process and the intellectual

function-ing of these children during a period of

10 to 15 years. The results reported here

represent findings of the initial phase of

the larger investigation. In this initial phase,

the authors were primarily interested in

\vilether certain factors could possibly

af-fect the level of intellectual functioning of

children with diabetes as measured by I.Q.

tests. These factors are age of onset of the

illness, duration of the illness at the time

of examination, and tile number of episodes

of hypoglycemia and acidosis.

PROCEDU RE

The subjects were 38 children with

dia-betes meliitus receiving their total medical

care at University Hospitals of Cleveland.

The age range of these cilildren was from

3 years 1 month to 18 years 6 months, with

a mean age of 10 years. The group of

chil-dren being followed is comprised of those

cllildren ordinarily followed in a University

Hospitals Outpatient Department plus all

tile diabetics referred as private patients to

one of us (W.B.W.). Thus a wide range of

socioeconomic levels is represented. In an

attempt to control factors such as

environ-mental background, educational

opportuni-ties and geographic location, one sibling

from each family was randomly selected

and tested.#{176} Tile age range of the siblings

was from 3 years 1 month to 17 ears 3

ITflOIltils, \Vitil a mean of 9 ‘ears 4 months.

Tile Stanford-Binet Intelligence Scale,

Form was administered individually to

each child. The variable used in testing all

0 The only factors not controlled by this popula-tion were age and sex. Previous investigations on intellectual functioning indicate that there is no

significant difference in intelligence between sexes.

To have used a population which would have con-trolled for the age factor would have meant

(2)

05

1

cv)

z

w

4 a

(0

z

0 a

MEANS OF GROUPS

+30 S ONSET UNDER 5,

S ONSET 5 AND OVER)

+20 C

+10

0 #{149}

-to .----. . . S S

-20 #{149} .

-30

I 2 3 4 5 6 7 8 9 0 II 12 3 4

AGE AT ONSET I YEARS

MEsNS OF PAIntED l.(. DIFFEI0ENCJ;s BY AGE AT

ONSET OF I)IABETES

.lge at Onset

<Syr >.ijr

Number of pairs of sil)hllgs

Average differenee iii I.Q. Sample \.ariafl(.e*

13

- loiS 115.3

‘2.5 ± 0.720

‘261.5

* Sample variance svas caictilated an:

(X)#{176}

52 101- 1

hypotheses was the difference in I.Q. score

between a diabetic and his sibling (diabetic

I.Q. minus sibling I.Q.). If a specific factor

has no effect upon the intellectual

func-tioning of children with diabetes, then the

differences, when classified according to

that factor, would tend to have an average

value of zero throughout, rather than a

trend with changing values of the factor.

With regard to age at onset, the I.Q.

differences were divided into two groups:

those for diabetics whose disease was

diag-nosed before tile age of 5 years and those

for diabetics who became ill at or after the

age of 5. A mean difference was computed

for eacil group and compared. Age 5 was

selected as a point of division for two

rea-sons. Experience in the treatment of

emo-tionally disturbed children has

demon-strated that traumatic experiences sHell as

hospitalizations, surgical procedures,

sepa-rations, etc., before the age of 5 are

infi-nitely more significant for future

develop-ment than are the same experiences after

this age. It is known that children under

5 years have only limited personality

re-sources available for the handling of such

disturbing events, and therefore the

possi-bility of pathologic sequalae is greatly

en-hanced. The second reason tilat led the

authors to choose this age is that the most

striking structural maturational cilanges in

the infantile brain are largely completed

during the first 5 postnatal years, and if any

disturbance in carbohydrate metabolism

occurs while the maturational process is

going on, the likelihood of irreversible

or-ganic damage occurring is increased.

Other factors were investigated as

cx-plained under the sections entitled

“Re-sults” and “Discussion”. The number of

episodes of hypoglycemia and acidosis were

obtained and quantified as follows. The

only hypoglycemic episodes enumerated

were those in which convulsions occurred

or those in which tile child was seen in a

Ilospital emergency ward or was admitted

to a hospital for this complaint. The

epi-sodes of acidosis tllat were counted were

limited to those in wilicil the child was

FIG. 1. I.Q. differences according to age at onset of diabetes.

admitted to tile hospital and analytic

docu-mentation of tile disturbance was

con-firmed.

RESULTS

Effect of Age at Onset

Detailed data on effect of age at onset of

diabetes are plotted in Figure 1 and are

summarized in Table I.

A t test on the differences shown in Table

I gave t=2.13, or a p value slightI’ less

thaii 0.05, indicating that age at onset does

Ilave an effect on the intellectual

function-ing of children Vitil diabetes.

It is also interesting to note that separate

(3)

+30

0

z

+20

(I)

I

‘:j#{149}

-. -tOe- o

Ui 0 0

U

z . 0

-20

w 0

a.

-30 OONSET UNDER FIVE

ci 0 #{149} YEARS OFAGE

0 I 2 3 4 5 6 7 8 9 10 II 2 3 4

TOTAL NO. OF EPISODES

Lengt/v of Illness at Time of

Examination

<‘2 yr ‘21110

>‘2 yr ‘2

10+

9

-8+ (9)

11-t 11-tes11-ts indicate that tile mean I.Q. difference

for the group Witil age of onset under 5

years is significantly different from zero

(p <0.02), and that for the other group is

not. Therefore, it appears that children who

become diabetic before the age of 5 years

suffer 5OIll intellectual illipairment, and

those who become diabetic after this age

show no such decrement.

Effect of Length of Illness

It is apparent that age of onset and

dura-tion of disease at time of testing could be

related. #{176}Accordingly, a more meaningful

test of the effect of length of illness would

be one in which tile sample was controlled

On age of onset. In order to do this a

so-called nonparametric technique1 was used.

The I.Q. difference for those with a total

duration of less than 2 years and those

with duration of more than 2 years in

each age group was compared with the

medians for the two age groups as to

whether they were above ( +

)

or below

( -)

the median. The data were then examined,

as shown in Table II. It is apparent

with-out a formal test that length of illness does

not affect the I.Q. differences.

Effect of Episodes of Hypoglycemia

and Acidosis

The data indicated a negative

relation-ship between I.Q. difference and the total

number of both types of episodes only for

patients in whom the onset occurred before

5 years of age (Fig. 2). The number of

epi-sodes of each type were generally too few

or too concentrated around a few values

to permit meaningful separate analysis.

Episodes occurring both before and after

the age of 5 were counted. Although the

data are suggestive, it turns out that the

negative linear regression coefficient (onset

before 5 years) of I.Q. difference on number

0 Patients with early onset (roughly before 7

years of age) tended to have a higher average

duration of illness and a much wider range of

dura-tion than patients with late onset, but these points

were not subjected to statistical test.

Ftc:. 2. 1.9. differences according to total number

of episodes of hypoglycemia and acidosis.

of episodes is not significantly different

from zero (p >0.10).

Because siblings were used as controls,

age, of course, could not be controlled. In

order to ascertain whether diabetic-sibling

age differences were affecting I.Q.

differ-ences, an analysis using the same method

145lfl Table II was undertaken.

It is apparent, without a formal test,

that diabetic-sibling age difference does not

affect I.Q. difference.

‘I’MiLE It

EFFECT OF LENGTH OF 1LI.NES ON I.Q.

DIFFER-ENCE,* WITH AGE OF ONSET CONTROLLED

Age at Onsetf

< 5 yr >5 Totals

7+(6.7)

‘2-

7-3+(3.7) 5+5.3)

.5-‘I’v)tal 13 ‘25 38

* I.Q. differences are compared with medians for each

age group (+ indicating above and - ,below). Figures in parentheses indicate expected number of

observa-tions above medians if length of illness had ISO relation-ship to I.Q. difference.

(4)

.)

-ARTICLES 767

‘I’ABLE Ill

EFFECT OF’ l)IABI;Tu-SIBLING AGE l)IF’rF:IF:NCF: ON I.Q. l)zFFEIIINeF:, V1TI1

AGE AT ONSET CONTROLLED

.lge at O,vset5

<5 r j >; IOt(lI

ihling older thou ulialvetir 4+ (4. ‘2 3+ (4.3) 9+ (8. .5)

4-

9-‘il)ling younger thou diabetic ‘2+ (1.8) 7+ (7.7i . 9+ (9..51

9-

11-lotal 13 ‘23 38

* I.xpecte(I ‘aliucs are given ill parcut leses.

COMMENT

As has been stated, though much

atten-tioll has been given to the problem of

intel-lectual functioning of diabetic children,

previously reported research presents

evi-dence to support contrary views. A review

of these studies indicates that there have

been three implicit ilypotilesis underlying

a majority of these studies. The first

as-sumes that children with diabetes are

prob-ably of lower than average intellectual

ability. Teagarden2 summarized the

rea-soning for this position by stating:

There are reasons for thinking that neurological and psychological functions may be impaired by diabetes and that insulin shock may produce neurological damage. Therefore, it seems unlikely that diabetic children as a group will be superior intellectually. There is no biological reason why they should be superior.

The second hypotilesis assumes that

dia-belie children possess higher than average

inteiligence.#{176}8 The underlying assumption

is that because of the physical limitations

often imposed upon these children, they

compensate for this by excessive emphasis

upon intellectual activities.

By far the largest group of

investiga-tors#{176}14 suggest that the intelligence of

children with diabetes is normally

distrib-itted and does not differ significantly, in

either direction, from that of the total

popu-lation.

\Vhen one reviews tile previous work

ac-complished in this area it is clear that many

of the factors known to affect intelligence

were not sufficiently controlled to rule out

tile possibility of bias. The major factor

ig-nored in almost all of the investigations

re-ported was socioeconomic standing. It is a

well-established fact that socioeconomic

background is positively correlated with

level of intelligence as measured by

stand-ard I.Q. tests. Yet of all the studies quoted,

only one9 achieved any measure of control

over this very important variable. Those

studies in which lower I.Q.’s were found

among diabetics, wllen compared with

na-tional norms, were based on samples drawn

from clinic populations and therefore from

lower socioeconomic backgrounds.” 0’

Those investigations indicating that diabetic

children are of higher than average

intelli-gence were based on samples from private

patients of higher socioeconomic levels.2 7. S

Because the number of diabetic patients

available to any one clinical investigator is

limited, it is nearly impossible to select a

sample that faithfully reflects the

socioeco-nomic distribution of the population and

other possibly important variables. It is

extremely doubtful, therefore, if the

under-standing of the intelligence of children with

diabetes can be furthered by simply

com-paring the mean I.Q. of randomly acquired

patients with published national norms. As

a result of this limitation, it becomes

(5)

768

all-or as many as is possible-of the

varia-bles known to affect the measurement of

intelligence. Unless one uses such a control

group and attempts to equalize the effects

of socioeconomic background, age,

educa-tional opportunities and sex, little can be

scientifically stated from the mere testing

of children with juvenile diabetes. Only

Brown and Thompson’ used an adequate

control group. In 28 of their cases the next

oldest sibling was also tested. White used

a control group matciled for age, but the

control of just this one variable is not

suffi-cient. In the present study, the use of

sib-hugs as control subjects served to take into

account socioeconomic, ethnic, geographic

aild environmental factors that could affect

I.Q.

Another serious limitatioll of the previous

studies is tile lack of any systematic attempt

to assess the relative importance of factors

such as age of onset, the duration of illness

at the time of examination and the nuflll)er

of episodes of hypoglycemia and/or

keto-acidosis. In light of the first hypothesis,

wilicil assumes that diabetes has a

degen-erative effect upon intelligence, it is

un-usual tllat more longitudinal studies

in-volving follow-up investigations and

retest-ing were not attempted. Fischer and

Dol-ger,” who also deplore the lack of

long-term investigations, did retest 10 patients;

but this, of course, is an extremely small

sample.

Although the studies mentioned were

concerned with the I.Q. status of diabetics

in general in relation to the total population,

in view of the finding that age at onset

may have some bearing on I.Q., tile

useful-ness aild validity of such an over-all verdict

is questionable. Such a verdict from tile

present sample, for purposes of comparison,

cOtil(l be done only if it is reasonable to

as-sume that this sample reflects tile general

population of child diabetics by age at

on-set. We have little evidence to make this

assumptioll, but if made, our sample

indi-cates an over-all judgment that there is no

I.Q. difference between diabetics and their

nondiseased siblings. A comparison of the

over-all Illd1l I.Q. differeilce of our sample

with zero produced a t value of - 1.18,

wilich is not significant.

The preponderance of children with

on-set after 5 years of age in our sample

ob-scured the importance of age of onset when

an over-all judgment was made. If the

im-portance of age at onset is borne out by

additional studies or by extension of our

OWIl series, it would seem imperative to

determine the etiology of this I.Q. loss.

The data on episodes of severe

hypogly-cemia and acidosis as related to loss of

in-tellectual capacity in the young diabetic

indicate that either or both of these

meta-boiic disturbances could be important. It is

intriguing that the one child witil three

episodes of loss of diabetic control, and

whose I.Q. is 33 points below that of her

sibling (Fig. 2), has an I.Q. of 109; tile

sib-1mg has an I.Q. of 142; another sibling (not

tile randomly selected one) has an I.Q. of

129. Furthermore, the child had a peculiar

episode of apnea at age 2 years (prior to

diabetes) in w’hich mouth-to-mouth

resusci-tation was required, and normal respiration

(lid not return for a period of about 30

minutes. If tilis value were not included,

tile slOi)e would be significant, with a p

value between 0.02 and 0.05. However. we

feel tllat we have no firnl basis for

exciud-ing tilis observation. Tile apneic episode

\V15 (liscOvere(1 accidentally, and there was

110 systematic search for events of this type

prior to tile Ollset of diabetes. While the

present data do not implicate hypoglycemia

and acidosis as possible causes of loss of intellectual functioning, the final resolution

of this question must await a larger sample

aild/Or tile development of a more precise

method of counting episodes.

Prolonged llypOglycenlia has been related

to mental deterioration, and whether the

relatively brief periods observed in diabetes

is important reIllaiIlS to be determined. Tile work of Ketv et (1l.’ on tile correlation of

de-crease in cerebral oxygen uptake with

in-crease of ketones in serum in diai)ctic

acidosis would indicate tilat episodes of

(6)

ARTICLES

769

in the decreased I.Q. of tile preschool

dia-betic as well.

It would have been more desirable to test

each of these types of metabolic

disturb-ances separately and to limit the episodes to

those that occurred prior to 5 years of age,

but the relative infrequency of these severe

aberrations in control and the small size of

the group made this impossible.

The amount of hypoglycemia and

acido-sis occurring after 5 years of age does not

appear to affect I.Q. in this group of

pa-tients. The data indicate no relationsilip

whatever between the diabetic-sibling I.Q.

differences and the number of episodes of

acidosis and hypoglycemia for the group

with onset after 5 years of age.

Other metabolic abnormalities are known

tilat lead to mental deterioration in the

early years of life but do not have such an

effect in older children. Galactosemia and

phenylketonuria do not produce continuing

loss of mental functioning after the

in-fancy period. Hypothyroidism is not

asso-ciated with permanent cerebral damage

when the onset is in later childhood, in

con-trast to the retardation associated with

crc-tinism. Severe jaundice is not a factor in the

production of mental deficiency in older

in-dividuals, but it certainly has an effect on

the newborn. Thus it does not seeni

un-reasonable that the young diabetic may

have some loss of I.Q. as a result of early

metabolic disturbances that do not produce

damage in later childhood.

An alternate hypothesis has already i)een

suggested, namely, that the impact of a

chronic illness on a child under 5 ‘ears

results in some degree of intellectual loss.

The critical factor appears to be tile

imma-turity of the personality. By the time the

average child reaches 5 years of age he has

matured sufficiently to handle successfully

many events that might have been upsetting

at an earlier age. This fact has been

recog-nized for years by educators, who have

established the age of 5 years as the critical

age for the beginning of school. The child

under 5, however, does not have tile

re-sources available to his older counterpart

and is mucil more Vulllerable to

environ-mental stress. Therefore, the onset of

dia-betes with all of its ramifications tends to

overwhelm the younger child. Much of his

mental energy that would normally be used

for sublimated intellectual activity remains

bound by the illness and unavailable for

Sucil pursuits.

The specific dynamics involved in tile

intellectual loss are not known, but two

possibilities have suggested themselves to

the authors during the course of this

in-vestigation. Because the child under 5 has

only an incomplete picture of himself, tile

onset of diabetes has an especiall’

disrupt-ing effect on this development. Tlle child

tends to feel himself damaged, different

and worthless, and this attitude becomes

translated into feelings of inadequacy in

intellectual endeavors. It also seems that

(liabetes disrupts the normal growth of

independence, both mental and physical, so

that tile child does not feel capable of

ade-quate, independent functioning.

Because of the small size of the present

sample, the findings must be considered

tentative. However, because of tile

import-ai#{236}ceof this finding, the authors hope other

investigators of childhood diabetes will

consider the collection of similarly

con-trolled data, so that the numbers of cases

could be expanded in an attempt to settle

tiliS important (luestion. For our part. we intend to retest the diabetics and their

siblings regularly to determine if tile above

difference persists, and to expand the study

to include children with other chronic

ill-nesses.

SUMMARY

I.Q. tests were administered to 38 pairs

of diabetic and nondiabetic children. In

each family the nondiabetic child was a

randomly selected sibling of the diabetic

cilild. No relation was found between 1.9.

difference (diabetic I.Q. - sibling 1.9.) and

duration of illness. Children in whom

dia-betes began before the age of 5 years had

significantly lower I.Q.’s than their

(7)

difference between the diabetic and his

sib-ling when the disease began after 5 years

of age. A suggestive relationship (but not

statistically significant) was found between

the number of episodes of hypoglycemia

and acidosis and the magnitude of the I.Q.

difference between diabetics and siblings

for those with onset of disease before 5

years of age.

REFERENCES

1. Mood, A. M. : Introduction to the Theory of

Statistics. New York, McGraw-Hill, 1950,

Chapt. 10.

2. Teagarden, F. M.: The intelligence of

dia-betic children with some case reports. j.

Appi. Psychol., 23:337, 1939.

3. Miles, P., and Root, H. F. : Psychologic tests

applied to diabetic patients. Arch. Intern.

Med., 30:767, 1922.

4. Dashieli, J. F. : Variations in psychomotor

efficiency in a diabetic with changes in

blood sugar level. J. Comp. Psychol., 10:187,

1930.

5. Shirley, H. F., and Greer, I. M.:

Environ-mental and personality problems in the

treatment of diabetic children.

J.

Pediat.,

16:775, 1940.

6.

White, P.: Diabetes in Childhood and

Adoles-cence. New York, Lea, 1952.

7. West, H., Richey, A., and Eyre, M. : Study

of the intelligence of juvenile diabetics

(Ab-stract). Psychiat Bull., Claremont College,

31:598, 1934.

8. Grishaw, W. H., West, H. F., and Smith, B.:

Juvenile diabetes mellitus. Arch. Intern.

Med., 64:787, 1939.

9. Brown, G. D., and Thompson, W. H. : The

diabetic child: an analytic study of his

development. Amer.

J.

Dis. Child., 59:238.

1940.

10. McGavin, A., et al.: The physical growth, the

degree of intelligence and the personality

adjustment of a group of diabetic children.

New Engi.

J.

Med., 223:119, 1940.

I 1. Fischer, A. E., and Dolger, H. : Behavior and

psychologic problems of young diabetic

pa-tients: 10-20 year survey. Arch. Intern. Med., 78:711, 1946.

12. Lisansky, E. S. : Convulsive disorders and per-sonality. J. Abnorm. Soc. Psychol., 43:29, 1948.

13.

Johannsen, D. E., and Bennett, E. N. : The

psychodynamics of the diabetic child.

Psychol. Monogr., 68:11, 1954.

14. Kubany, A. J., Danowski, T. S., and Moses, C.:

The personality and intelligence of diabetics.

Diabetes, 5:462, 1956.

15. Kety, S. S., et a!.: The blood flow and oxygen

consumption of the human brain in diabetic

acidosis and coma. J. Clin. Invest.,

27:500,

(8)

1961;28;764

Pediatrics

Marvin Ack, Irving Miller and William B. Weil, Jr.

INTELLIGENCE OF CHILDREN WITH DIABETES MELLITUS

Services

Updated Information &

http://pediatrics.aappublications.org/content/28/5/764

including high resolution figures, can be found at:

Permissions & Licensing

http://www.aappublications.org/site/misc/Permissions.xhtml

entirety can be found online at:

Information about reproducing this article in parts (figures, tables) or in its

Reprints

http://www.aappublications.org/site/misc/reprints.xhtml

(9)

1961;28;764

Pediatrics

Marvin Ack, Irving Miller and William B. Weil, Jr.

INTELLIGENCE OF CHILDREN WITH DIABETES MELLITUS

http://pediatrics.aappublications.org/content/28/5/764

the World Wide Web at:

The online version of this article, along with updated information and services, is located on

American Academy of Pediatrics. All rights reserved. Print ISSN: 1073-0397.

References

Related documents

Subsequent to receiving 1½ years of physiotherapy for post-surgical complications (decreased range of motion, pain, stiffness and tingling to the 4th and 5th fingers), the patient

Fifteen of 18 teachers reported that they had obtained information about their ELLs’ backgrounds from the students themselves and the same number reported that it had

CTO: chronic total occlusion; PCI: percutaneous transluminal coronary intervention; MT: medical therapy; MACE: major adverse cardiac event; MI: myocardial infarction; TVR:

The planting pattern comprised 40 cm spaced single rows, 60 cm spaced 2-row strips and 100 cm spaced 4-row strips while mashbean was intercropped in all the

This initiative has emerged following joint activities between the ESF and the US National Science Foundation (NSF) within the networking activities of “Smart Structural Sys-

In a study conducted by Johnson, Wilcox, Mankoff, &amp; Stricker (2014) using the Centers for Disease Control and Prevention (CDC) health-related quality of life (HRQoL)

This Cayley graph version of the zig-zag theorem raises the hope that, given a “seed” expander Cayley graph, one can obtain a sequence of expander Cayley graphs via an iterative

In the clinic, clinicians should consider the menstrual status of different breast cancer patients, especially in the case of low estrogen levels (postmenopausal),