Mental Retardation. Some Recent Developments in the Study of Causes and Social Effects of This Problem

44 Pages·1968·2.532 MB·English

by  Brian H. Kirman (Auth.)

MENTAL RETARDATION
Some recent developments in the study of causes
and social effects of this problem
BY
BRIAN H. KIRMAN, MD, DPM
CONSULTANT PSYCHIATRIST,
FOUNTAIN AND CARSHALTON HOSPITAL GROUP
DIRECTOR OF RESEARCH, FOUNTAIN UNIT
PUBLISHED FOR THE INSTITUTE FOR RESEARCH INTO
MENTAL RETARDATION BY
Üb
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Copyright © 1968 The Institute for Research into Mental Retardation
First Edition 1968
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Library of Congress Catalog Card No. 68-57159
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Foreword
THIS is the first of a series of Occasional Papers which are to be published
under the auspices of the Institute for Research into Mental Retardation
and is by the Chairman of the Institute's Research Committee. I am sure
it will be found to be of great value by all concerned with the problems
of mental retardation who are anxious to keep themselves fully informed.
The Institute has in mind a number of other Occasional Papers of
about this size and will also be sponsoring in due course the publication
of several important longer studies.
We are most grateful to Pergamon Press, our publishers, and to Mr.
Robert Maxwell personally for the advice and assistance they have so
generously given us in this matter.
LORD FRANCIS-WILLIAMS
Chairman
Vll
Preface
DOCTOR BRIAN KIRMAN has written a useful and simple paper on a
subject that is of immediate relevance to the people of all developed
countries, and that those who are concerned with the welfare of their
people in the developing countries cannot afford to ignore because the
lesson is clear: in respect to something that is obviously pertinent to
mental retardation, child life and health, Britain was an underdeveloped
country only at the turn of the century.
Doctor Kirman needs no introduction and this little book speaks for
itself. Aimed at an intelligent lay audience, it will be read with interest
and profit by workers in the field of mental retardation, by students of
the social sciences, education and medicine and by others who wish to
have a simple guide to a complex and common form of human impair-
ment. Written by a specialist who has spent a lifetime in the diagnosis,
management and care of the mentally handicapped and on thought and
research in this field, the book stresses from the start the problem of
definition and recognition, its relationship to frequency and to the
changes that have occurred in the natural history and prevalence of
mental handicap in general and of some of its specific constituent dis-
orders in particular. The realization was ever with us, not so many years
ago, of how little we knew about mental retardation and its causes, and
that not much could be done about it: books tended to be lists.
Today, thanks to knowledge that has accrued from research in many
directions—genetics, sociology, chemistry, education, cytology—we are
thinking more and more often in terms of specific disorders, their causes
and mechanisms and their prevention and treatment.
Thus, properly, Doctor Kirman emphasizes prevention, ranging from
such measures as rhesus antibody administration to prevent rhesus auto-
immunization of puerperae at risk, or the effect of a hypothetical restric-
tion of child-bearing age on trisomic chromosome disorders, to special
diets in the management of biochemical disorders whose impact on the
nervous system is postnatal. Prominence is equally rightly given to habi-
IX
X PREFACE
litation in the prevention of secondary handicap and to the importance
of minimizing cultural retardation. Genetic disorders and their detection,
and the detection of the carrier state in recessively inherited conditions
(useful also for counselling), are discussed, and one would remark on
the recent contributions of tissue culture methods to diagnosis in this
field. Genetic risks are being more clearly understood and empirical esti-
mates of risks become more accurate every day with increasing know-
ledge. We now think, for example, that a translocation-carrying mother
who has had a child with translocation Down's syndrome has a one in
ten risk of recurrence, an apparently five times greater risk than a trans-
location-carrying father, though the latter may produce more carriers
than expected.
The accent, throughout, is not only on what, in the field of mental
retardation, has been achieved and is known, but also on what is in-
sufficiently known or unknown and should be clarified or found out by
research.
In recommending this book I know that many will have reasons to be
grateful to Doctor Kirman for his very useful synthesis and the clear
presentation of many aspects of an important area of human biology.
London, PAUL E. POLANI
July, 1968.
Prince Philip, Professor of Paediatric
Research, Guy's Hospital Medical
School, University of London.
Mental Retardation
B. H. KlRMAN
MAN has survived and developed because he is quicker-witted than other
species. He is aware of this and attaches great importance to it. There-
fore, ever since speech developed there must have been words like "fool"
and "stupid". Social man must point out to others their folly and their
mistakes which may be costly for them and society as a whole. But from
early history it has been recognized that there are "natural fools" who
learn very little from their mistakes. In English law the notion of the
"natural fool" appears in a statute in the reign of Edward II. This
statute was primarily concerned with landed gentry who happened to be
idiots and dealt with the care of their property. From Elizabethan times
some provision was made for idiots and imbeciles through the Poor Law,
the responsibility being on the local parish.
To this day we know very little about the nature and cause of mental
backwardness though we realize that it is very common. Many children
find great difficulty in profiting from education in ordinary schools. Some
of them are excluded from school as "ineducable"; many more struggle
through school but leave, either completely illiterate or with so little
grasp of reading and writing that it is difficult for them to write a simple
letter or to read even the easiest newspaper. They may also find sums
difficult so that the reckoning of change or simple housekeeping budgets
is beyond them.
In 1959 the Mental Health Act replaced the Mental Deficiency Act of
1913. At that time there were some 150,000 people in England and Wales
under some form of care under the old Act, of which less than 60,000
were in hospital. These figures, however, represent only a small fraction
of those with difficulty in learning. The results of standard tests of intelli-
gence call for caution in interpretation, but they are the best guide
available in the circumstances. A survey of the intelligence of 11-year-
old school pupils was carried out in Scotland in 1947. This was the
1
2 MENTAL RETARDATION
second such survey, the previous one being in 1932. The Terman-Merrill
test was used as part of the survey and on this test 3% of the pupils
tested achieved an intelligence quotient of below 70 which may be taken
for some purposes as the upper limit of mental subnormality. On the
basis of this test result 3% of the citizens in a country with a 50 million
population, that is 1| million people, might be classed as having poor
learning ability. An example of the difficulty with such statistics is the
fact that when this test is "corrected" to make it comparable with the
revised version of the Binet test, known as the Stanford revision, the
percentage below I.Q. 70 falls to 1*4%, i.e. equivalent to roughly f
million people on a population of 50 million.
In fact, there is no sharp difference between people who are of "nor-
mal" intelligence and those who are mentally retarded or mentally
defective any more than there is in regard to height. If we get 100 people
to stand in a row in order of height we will get a gradual increase in size
throughout the line. This also applies to intelligence. The difference
between a helpless idiot and a person of average intelligence is very
striking but so is that between an "average" person and Einstein or
Newton. In fact there is a complete gradation in the general population
between these two extremes. Until recent times less attention has been
paid to the large number of people of relatively limited ability, the
feeble-minded or mentally subnormal. The idiots and imbeciles or
"severely subnormal" have always been obvious just as dwarfs are. It
was the introduction of compulsory general education which brought to
light the large numbers of children with special educational difficulty.
This led to the opening of special schools for mental deffectives, now
known as schools for the educationally subnormal. Penrose pointed out,
however, that the numbers of ascertained mental defectives were very
much greater relatively among children than in the adult population.
This is by no means entirely due to the fact that more mental defectives
die.
The main reason for the disappearance of mental defectives from the
official statistics was that many found jobs and integrated themselves
into the general community so that they were no longer in need of any
special help or supervision. From one angle the social problem of this
numerous group of people is thus solved satisfactorily. From another
angle it is clear that the social contribution of this group is limited if
only judged from the standpoint of economics. They are, in the main,
MENTAL RETARDATION 3
capable only of unskilled occupations at a time when there is an increas-
ing demand for technical skill and higher education. Anything which
could be done to reduce the total of mental retardation would reduce the
numbers of those who are dependent; the effects of any such measures
might be even more important in improving the learning capacity and
social efficiency of the less intelligent members of the general community.
No Immediate Danger of Decline of National Intelligence
One reason why the second Scottish survey was undertaken was be-
cause one school of thought considered that a decline in national intelli-
gence was inevitable. The argument ran that people of lower intelligence
tend to have more children: also, the improvement in material conditions
enables children of lower intelligence to survive and reproduce. Penrose
had suggested that there were many other factors which would make
for a balance in the population. In fact, the second Scottish survey pro-
duced no evidence of a decline in intelligence. The mean intelligence of
pupils born in 1936 was I.Q. 102*5 compared with I.Q. 101-5 for those
born in 1921. Difficulties of technical interpretation of the tests used,
however, make it unwise to assume that there has been a significant
improvement in the interval on the basis of these figures alone.
The Need for Information
The above example will serve to show how easily public opinion in
regard to such social problems as mental retardation can be based on
mistaken conclusions and how useful it is to have reliable information.
A variety of social, educational and medical measures may be necessary
to help to solve the problem but unless there is more knowledge as to
what is involved then these measures will not be taken or in some cases
inappropriate action may occur. In retrospect the Mental Deficiency Act
of 1913 appears to have been based largely on the view that it was desir-
able to detain the majority of mental defectives in institutions, whilst the
modern view is that they should be integrated as far as possible with
the general community.
We are badly in need of precise data about the incidence and preva-
lence of mental retardation of different degree. We would like to know
much more about the social, cultural and economic factors which are
concerned in its causation and also about the diseases which produce it.
4 MENTAL RETARDATION
More special study of the anatomy of the brain is needed in mentally
retarded patients, using the latest scientific methods. We need to apply
chemical methods to a study of the brain and there is a great need for a
study of chemical disorders which lead to mental defect. Much more
precise information about genetics is also needed. Modern developments
in understanding the nucleus of the cell have opened up fresh prospects
and a new science of microscopic or "cyto-" genetics has come into be-
ing. Detailed studies of child development with especial reference to the
retarded are still needed to form a proper basis for special education.
There is also a need for further pilot studies of employment and rehabili-
tation of the mentally retarded. Prospective studies are also needed of
social adaptation, marriage and parenthood among the mentally re-
tarded. Genetic counselling, marriage guidance and family planning, in
relation to the mentally handicapped, also call for much research if they
are to be based on reliable information.
Prevalence of Mental Retardation
One of the first questions asked about any abnormal condition is:
"How frequent is it?" We have seen already that this is a difficult ques-
tion for mental retardation since it merges with the general population
and, therefore, cannot be sharply defined. The situation is a little easier
with severe degrees of mental retardation, "severe subnormality". There
are fewer cases and they can be more easily recognized. For the research
worker it is relatively easy to trace and list cases of particular conditions
which cause mental retardation such as Down's syndrome or "mongol-
ism". This can be recognized at sight more or less easily and therefore
more precise information can be obtained about its prevalence. Carter
estimated that there had been something like a fourfold increase in the
prevalence of this condition at age 10 years. This was due to better
survival and does not necessarily imply that the condition is any com-
moner at birth.
There have been very few good surveys to find out the prevalence of
mental retardation and for this reason it is still common to refer back
to the study carried out by Lewis and reported in 1929. The methods
used at that time were, because of the limited resources allocated to the
survey, open to some criticism but, none the less, it provides the best
basis available for comparison with the present state of affairs. In 1962
MENTAL RETARDATION 5
Goodman and Tizard reported on their studies of prevalence and com-
pared these with Lewis's findings rather more than 30 years earlier. They
surveyed the counties of London and Middlesex in detail. They found
that there appeared to have been a decline in the prevalence of idiocy
and imbecility overall. On the other hand, they confirmed Carter's esti-
mate of a fourfold increase in the prevalence of Down's syndrome. They
admit the possibility that the apparent decline might be due to different
methods of assessment and classification but consider that this is not
very likely. They suggest that there is a real decline.
The infant mortality rate in England and Wales has fallen dramatic-
ally during the present century from 154 deaths in the first year of life
per 1000 live births in 1900 to 22 per 1000 in 1959. It might be thought
that on the principle of "survival of the fittest" this would lead to an
increase in the numbers of the mentally retarded surviving. In fact, there
is no evidence that this is so. The opposite may be true. For every child
who is ill and dies there are others who become ill but survive with some
permanent damage. In the case of meningitis an affected child may die
or may partially recover, only to remain at idiot or imbecile level of
intelligence because of a damaged brain.
Recent work by Lawson and Metcalfe has shown that with early
efficient treatment of septic meningitis the outcome can be extremely
satisfactory and no impairment of intelligence is likely to result. On the
other hand, meningitis is still a common cause of mental retardation.
Figures published by Berg in 1962 from the Fountain Hospital showed
that in 1800 consecutive admissions of severely mentally retarded
patients there were 175 cases of Down's syndrome and 22 whose defect
was due to meningitis, which was the next commonest diagnosis. The
decline in infant mortality is due to the improved standard of living and
to better measures to prevent and treat illnesses. The net result of these
will be that not only will less children die but also less will be ill and
less will suffer from long-term ill effects, including damage to the brain.
The main cause of the improvement in child health over the pas thalf-
century has been the improvement in the standard of living, better nutri-
tion, better housing and so forth. This will likewise result in healthier
children at birth, during early infancy and later childhood. It is easy to
demonstrate with animals that abnormalities of the brain can be caused
in offspring by giving defective diet to the mother during pregnancy. The
application of this work to humans is less clear, but on general principles