IQ SCORES AND CRANIAL IRRADIATION

IQ SCORES AND CRANIAL IRRADIATION

512 Unfortunately even health authorities have been known to lack objectivity and their opinions, sometimes thinly veiled, may be equally political. ...

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Unfortunately even health authorities have been known to lack objectivity and their opinions, sometimes thinly veiled, may be equally political. It is therefore not unreasonable that their objections should carry little weight with the planning body. There good political arguments both for and against private to resort to spurious emotional allegations that the N.H.S. (with several thousand acute beds) might suffer competition with the proposed (1 00-bed) private hospital is not only farcical but also dishonest. Indeed, one wonders why Southampton, of all the cities in which private hospitals have been built, should be considered to need a public inquiry before its citizens are to be allowed the freedom to choose private or State medicine. There are plenty of papers and journals to provide political views; I take medical journals to read scientific articles on medical matters. are

doubtless

medicine, but

Shackleton Department of Anaesthetics, Level E, Centre Block, Southampton General Hospital, Shirley, Southampton SO9 4XY

JAMES M. B. BURN

**Not all editorials are written by editors, but this one was. It was based on inquiries in Southampton and many other places into the impact on the National Health Service of the growing private health market. The planned hospital in Southampton, for which outline planning permission was ratified earlier this month, is an example of the many enterprises by which the expansion of the private sector may impair the work of the N.H.S. When there is new competition for resources, doctors’ time may be divided in a way which is to the detriment of the N.H.S. We understand that -the new private hospital may have five resident doctors, but its consultants will all be members of the present staff of the Southampton General Hospital. The main question in this debate is how constructive competition (that is, competition which leads to more effective and efficient service in both institutions) may be established between a public monopoly and a private hospital which is not bound by national wage agreements and which can select its patients. Another point we made is that it is thoroughly unsound to grant or deny planning permission, as the law at present does for a private hospital of less than 120 beds, exclusively on such planning issues as traffic and disturbance to residents.-ED. L.

of IQs No mention is made of the inherent variability obtained before 5 years of ageand of high IQ scores.2 This lack of IQ stability during those years when most (72% of Meadows group II) new ALL patients are diagnosed is a problem in all prospective ALL studies. Additionally, the observed drop in high IQ scores may be explained by regression toward the mean, a possibility not discussed by Meadows et al. Again it is possible to observe change in a child’s IQ across time, but the quantification of such change (particularly if it is based on data obtained before age 5) is difficult or

both

impossible. Though the attempt to organise the neuropsychological data in terms of cognitive functions is an improvement over the simple reporting of tests results, normative data are not specified5and no explanation or definition of the functional categories is provided. This information is imperative if the contributions of this study are to be properly evaluated. Furthermore, Meadows et al. state that neuropsychological performance within the "impaired" range would not be expected of children with average to above average IQ. This is not true.5 The conclusion that the changes observed are secondary to CNS prophylaxis is unwarranted in light of the weakness of the control groups. The six solid tumour patients were of widely varying ages and were evaluated after only one year. The six non-irradiated ALL controls received only one evaluation several years post-therapy. Thus a legitimate comparison of intergroup differences is impossible. The problems described above are large enough to cast doubt on the strength of the conclusions drawn. Perhaps the real contribution of this study lies in its prospective approach and in its attempt to organise neuropsychological data in terms of functions. Departments of Leukemia/Lymphoma and Neurology/Psychology, St Jude Children’s Research Hospital, Memphis, Tennessee 38101, U.S.A.

IQ AND COGNITIVE FUNCTION IN CHILDREN TREATED WITH CRANIAL IRRADIATION

SiR,-We would like to respond to the letter from Gutjahr and Waltherand to the above comments from St Jude Children’s Research Hospital on our paper.7 Most of the tests in our battery were power rather than speed tests. Performance subtests on the WISC-R and the tactual performance test

IQ SCORES AND CRANIAL IRRADIATION SIR,-Meadows et al.lclaim to have detected a decline in both IQ scores and cognitive abilities in children with acute lymphocytic leukaemia (ALL) treated with cranial irradiation. We agree with Professor Gutjahr and Dr Walther (Dec. 5), that failure to standardise testing intervals and to match evaluation schedule with treatment phase limit the validity of the conclusions of Meadows and her

colleagues’ paper.

Meadows et al. directly compared different IQ measures without mentioning the degree of correlation. For example, in the initial evaluation seventeen patients received the Stanford-Binet, four the Wechsler intelligence scale for children (revised) (WISC-R), and two the McCarthy scales of childen’s abilities. Only the WISC-R was used in the final evaluation (eighteen patients). Because the correlation between Stanford-Binet and WISC-R is 0-822and that between the McCarthy and WISC-R is only 0 - 68,direct comparison is difficult and quantification should be viewed with caution. Inter-test comparison is further confounded by the varying contribution of verbal skills to overall IQ on a given measure as a function of age.3 Thus changes in the IQ of a child with verbal deficits may more accurately reflect changes in the test’s content than in the child’s skills. 1. Meadows acute

AT,

et

in IQ score and cognitive dysfunctions in children with leukaemia treated with cranial irradiation. Lancet 1981; ii:

al. Decline

lymphocytic

1015-18.

intelligence and special abilities, 2nd ed. Boston: Bacon, 1982. 3. Terman LM, Merrill MA. Stanford-Binet intelligence scale. Boston: Houghton Mifflin, 1973.

2. Sattler TM. Assessment of children’s

Allyn

and

MAURA L. CAMPBELL RICHARD A. BERG JUDITH J. OCHS

(Halstead-Reitan battery), a test of psychomotor function, were

timed. Of the five patients still on therapy at the third testing, four performed well on timed tests and three did poorly on more than one power function. The fourth child scored in the superior range on all tests and was the bright child whose IQ improved by 13 points. Of the remaining thirteen, eleven had discontinued therapy 3-26 months earlier and two had done so within a month of testing. We are testing these children annually and evaluating educational achievement. The children from Mainz,who were less than 4 years old at the time of treatment, also did not improve after discontinuation of therapy; we look forward to the complete report of these investigations. We cannot comment on social environment of our ALL patients but we have no reason to believe that it differs from that of children with Wilms’ tumour. For individual children the extent to which the pursuit of intellectual goals is encouraged may differ and this may account for some variations in school performance. Although the correlation between the Stanford-Binet and WISC-R is as noted by Campbell et al., these tests do yield essentially the same IQs in group comparisons.8,9 Moreover, the Bayley N. Development of mental abilities. In: Mursen PH, ed. Carmichael’s manual of child psychology. New York: John Wiley, 1970. 5. Reitan RM, Davison LA, eds. Clinical neuropsychology: Current status and applications. New York: John Wiley, 1974. 6. Gutjahr P, Walther B. IQ and cognitive function in long-term survivors of childhood acute lymphocytic leukaemia. Lancet 1981; ii: 1278. 7. Meadows AT, et al. Declines in IQ scores and cognitive dysfunctions in children with acute lymphocytic leukaemia treated with cranial irradiation. Lancet 1981; ii: 1015 8. Sattler TM. Assessment of children’s intelligence and special abilities, 2nd ed. Boston Allyn and Bacon, 1982. 9. Wechsler D. Manual for the Wechsler intelligence scale for children, revised New York: Psychological Corporation, 1974. 4.