Develop. Med. Child Neurol. 1975, 17, 320-324

A Longitudinal Psychophysiological Study of Three-year-old Mauritian

Children: Preliminary Report Brian Bell Sarnoff A . Mednick Abdul C. Raman

Fini Schulsinger Brian Sutton-Smith Peter H. Venables

Introduction Mednick and McNeil (1968), in their

review of the methodological problems encountered in research into the aetiology of schizophrenia, advocate the use of the high-risk-group research design which had been employed previously by Mednick and Schulsinger (1968). Essentially, since ethical and other considerations preclude direct manipulative experimentation with human subjects, the authors propose that any intervention should be beneficial in that experimental manipulation of an identified high-risk group should be of a supportive nature. However, this approach depends on whether individuals at high risk for schizophrenia can in fact be identified before the onset of their illness.

The studies by Mednick and Schulsinger (1968) and Mednick (1973) indicate that the speed with which skin conductance returns to baseline value after response to stimulation may be a reliable predictor of later psychopathology. During 1962, those authors gave a variety of psychological and psychophysiological tests to 207 ‘normally functioning’ children with chronically schizophrenic motheis, and to 104 control

children. By 1967, 20 of the index children were manifesting severely abnormal beha- viour, and analysis of the 1962 data indicated that these children had differed from the control children in several respects. This was especially so in the case of their electrodermal function during a conditioning experiment, the index child- ren having shown a characteristically fast recovery rate. A later analysis of skin- conductance data from individuals sub- sequently diagnosed as schizophrenic has confirmed this characteristic pre-morbid fast recovery following stimulation. Other studies of patients already schizophrenic have confirmed Mednick and Schulsinger’s original results (Ax and Bamford 1970, Gruzelier and Venables 1972).

Since it seemed possible that a reliable indicator of psychopathology could be identified by psychophysiological measures, we decided to use this experimental tech- nique in a prospective study of young children. The study was planned to intro- duce intervention procedures for children identified psychophysiologically as being at high risk later in life.

With the active support of the World

Correspondence to Brian Bell, Ph.D., Psykologisk Institut, Kommunehospitalet, 1399 Copenhagen, Denmark.

320

B. BELL S. A. MEDNlCK A. C. RAMAN F. SCHULSINGER R . SUTTON-SMITIf P. H. VENABLES

-risk

Health Organisation, a research pro- gramme was instituted on the island of Mauritius during the summer of 1972.

Data analyses tor' se lec t io~i of High-

011 p s y c l i ~ ~ ~ i h y s ~ ~ i l ~ ~ ~ y test and L u w - r ~ s k children - Insed -

Method of Study A total of 1800 three-year-old children

were tested on a number of psychophysio- logical and psychological measures. In addition to comprehensive information about the family environment and living conditions of each child, data were

obtained about the pregnancy and birth, current medical status and cognitive development. The method of study is shown diagrammatically in Fig. 1. The central part ot the testing programme was a 30-minute psychophysiological examina- tion, during which recordings were made of the child's electrodermal and cardiac activity. The physiological recording was carried out in a specially constructed laboratory under controlled conditions and

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Children attend laboratory for

I SOCIAL BEHAVIOUR OBSERVATION

PSYC HOLOGlC A L EXAMINATION 1 Bloud and urine samples for susar , a l l ~ u m i ~ i and HI) t es t s at Cent ra l Patholocv Laboratorv

PEDlATRIC EXAMINATION

ELECTROENCE I'HALOGRAPHY TEST I PSYCHOPHYSIO1,OGY TEST I I , !

S u i ~ p l e i i ~ e n t a i y ~ ~ i f o r i ; i a t ~ o i i t o I I PARENT INTERVIEW 4

+ 4 TWO COMMLKITY TWO KINDERGARTEN

GROUPS GROUPS

Fig. 1. Flow-chart indicating experimental procedures employed in the psychophysiological examination of 1800 three-year-old Mauritian children.

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DEVELOPMENTAL MEDICINE AND CHILD NEUROLOGY. 1975, 17

the records were scored by trained Mauritian personnel.

The psychophysiological data were stored on punched cards and then sub- jected to an initial analysis, which identified thiee groups of children on the basis of their electrodermal responses. (We were unable to include the data from about 5 per cent of the children tested because their records were incomplete.) We selected a total of 200 children as representative of the three different patterns of‘electrodermal response: those with short recovery and high-amplitude responses (the ‘short re- coverers’) ; those with medium recovery and medium amplitudes (the ‘lcw-risk’ children); and those with minimal electro- dermal activity, i.e. no significant response and low basal levels (the ‘non-responders’). We were thus identifying two high-risk groups-the short recoverers (Mednick 1973) and the non-responders (Gruzelier and Venables 1972)-and a low-risk group of medium recoverers and responders. Within each group we attempted to reflect the ethnic composition of the island population, Hindu children being the largest group and Tamil the smallest. The children in each risk-group were then assigned at random to a control or an experimental group within their residential areas, the original sample having been drawn from two urban areas. The propor- tion of short-recoverers, non-responders and Icw-risk children were equal between the control and experimental groups. Within each group there were approx- imately 50 per cent who evidenced fast skin-conductance recovery and 20 per cent who were classed as non-responders; the remaining 30 per cent consist of children with medium amplitudes and recovery times.

The initial intervention method was the provision of extensive and intensive nursery-school education and day-care. As a result, we now have two schools in

Mauritius (financed by the Danish Inter- national Development Agency and sup- ported by the Government of Mauritius) which cater for a total of 100 children. The other 100 children remain in the com- munity as a control group. In both schools a number of young Mauritians are being trained in modern kindergarten methods by three resident Danish teachers. The children in the schools are being assessed on a range of behavioural ratings, based on the study by Bell et al. (1971). Assess- ments are made weekly and monthly. The children in the nursery schools, and the control children, have undergone two further physiological examinations during 1974, and we intend to repeat this testing for a number of years in order to obtain an indication of the reliability of the measurements, as well as an assessment of the effects of intervention.

An additional cross-sectional, longi- tudinal, psychophysiological study has recently been completed on the island (with the support of the Medical Research Council of Great Britain), in which samples of the population aged between five and 25 years have been studied. During the last two years this research has been extended to include samples of hospital populations and has also included the examination of the parents of children selected for the project.

Obviously, the final outcome of this research will not be determined for many years. However, we feel that there have been a number of short-term gains. We have a considerable amount of normative data on the physiological and psycho- logical status of young Mauritian children to form the basis of a longitudinal study. During the original testing in 1972 and 1973, direct medical aid was given to many of the children, especially those suffering from scabies and parasitic worm infections (when necessary, they were referred to the appropriate hospital department). The

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B. BELL S. A. MEDNICK A. C. RAMAN F. SC‘IlULSINCiER B. SUTTON-SMITH P. H. VENABLES

are now trained to carry out later para- medical investigations, and the establish- ment of nursery schools will ensure that there is a nucleus of trained kindergarten

with the testing programme. Mr. Regis Rose provided invaluable liaison between the Project and various government departments. The paper was prepared during the tenure of a fellowship grant from the Royal Society to the senior author.

teachers on the island.

possible causes of schizophrenia-cannot be assessed until the children have reached the age of maximum risk about 20 years from now. ~~~i~~ the intervening period the project will be concerned with ~ 0 1 1 - Bassin. Mauritius.

AUTHORS’ APPOINTMENTS The long-term Of Brian Bell, Ph,D., Research Fclloa, psykologisk

Institut. Copenhagen, Denmark. SarnolF A. Mednick, Ph.D., Professor, Psykologisk Institut. Copenhagen, and Ne\c School for Social Research, New York. Abdul C. Raman, D.P.M., F.R.C.Psych., Chief Psychiatrist. Brown Sequard Hospital, Beau

. .

tinuing the assessment procedures. Fini Schulsinger, M.D.. Professor, Psykologisk Institut. Copenhagen. and University of Copen- hagen, Denmark.

,4cknoUled~emer1/s: This work is supported by Brian Sutton-Smith, Ph.D.. Professor, Teachers’ grants from the Medical Research Council of College, Columbia University, New York. Great Britain, the Danish International Develop- Peter H. Venables, Ph.D.. Professor. Department nient Agency and the Ford Foundation. The of Psychology, University of York, England, and authors would like to express their thanks t o the Psykologisk Institut, Copenhagen.

SUMMARY

The rationale for using the high-risk-group research design in the search for the aetiology of schizophrenia is described. A longitudinal study is being made of three-year-old Mauritian children who underwent a variety of physiologid and psychological tests. Groups of these children, selected on the basis of their responses to electrodermal stimulation, are now attending nursery schools established on the island as part of this study. A control group of children do not attend nursery school. I t is intended to follow-up these children over the next two decades. Mention is made of the benefits of this research to the development of para-medical and educational services in a developing country.

KGSUME

Etude psychophysiologique loiigituciiiitrle de jeunes niauritietis de trois ails

Les dispositions prises pour mettre en place une recherche sur un groupe h risque eleve dans I’Ctude d’une Ctiologie de la schizophrenie sont dicrites. Des details sont fournis concernant une Ctude A long terme de jeunes mauritiens de trois ans ayant subi des tests psychologiques et physiologiques. Des groupes choisis de ces enfants ont PtC pris en charge par deux jardins d’enfants de I’ile Maurice et i l est prCvu de suivre ces enfants durant les vingt ans li venir. Les binifices de cette recherche pour le diveloppenlent d’une pratique para-medicale et educative dans un pays en voie de dCveloppenient sont soulignis.

ZUSAMMENFASSUNG

Eke psychopliysiologisclie Latigzeitsludie an 3-Jalire-alten niauritanisrheii Kitidern Es wird die Anwendung des Untersuchungsmusters fur eine Gruppe von Risikokindern

zur Klarung der Diagnose schizophrenie erkliirt. Uber eine Langzeitstudie an 3-Jahre-alten mauritanischen Kindern, die einer Reihe von verschiedenen physiologischen und psycho- logischen Tests unterzogen wurden, werden Einzelheiten angegeben. Ausgewiihlte Gruppen dieser Kinder werden in zwei dafiir eingerichteten Kindergarten in Mauritius betreut und man beabsichtigt, diese Kinder iiber die folgenden 2 Dekaden zu beobachten. Es werden die

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DEVELOPMENTAL MEDICINE AND CHILD NEUROLOGY. 1975, 17

Vorteile dieser Untersuchung fur die Entwicklung einer para-medizinischen und erzieher- ischen Praxis in einem Entwicklungsland dargelegt.

RESUMEN Estudio psicoJisioldgico longitudirial de niiios Mauricios de tres aiios de edad

Se describe el racionamiento para el us0 de grupos de alto riesgo para la investigacion de la etiologia de la esquizofrenia. Se han obtenido detalles de un estudio a largo plazo de niiios de tres afios de edad en la isla Mauricio que fueron sometidos a una variedad de tests fisiol6gicos y psicol6gicos. Seleccionados grupos de estos niiios estan siendo cuidados en dos jardines de infancia establecidos en Mauricio y se tiene la intenci6n de seguir estos niiios durante un period0 de dos dtcadas. Se ponen de relieve 10s beneficios de esta investiga- cion para el desarrollo de la prictica paramidica y educacional en un pais en vias de desarrollo.

REFERENCES Ax. A. F., Bamford, J. L. (1970) ‘The GSR recovery limb in chronic schizophrenia.’Psychophysiology, 7, 145. Bell, C. R., Weller, G. M., Woldrop, E. (1971) ‘Newborn and preschooler: organization of behavior and

Gruzelier, J. H., Venables, P. H. (1972) ‘Skin conductance orienting activity in a heterogeneous sample of

Mednik, S. A. (1973) ‘Studies of children at high risk for schizophrenia.’ In Dean, S. R. (Ed.) Schizophrenia:

- McNeil, T. F. (1968) ‘Current methodology in research on the etiology of schizophrenia: serious

- Schulsinger, F. (1968) ‘Some prernorbid characteristics related to breakdown in children with schizo-

relations between periods.’ Monographs of the Society for Research in Child Development, 142, 36.

schizophrenics.’ Journal of Nervous and Mentai Disease, 155,277.

The First Ten Dean AwardLecfures. New York: MSS Information.

difficulties which suggest the use of the high-risk-group method.’ Psychological Bulletin, 70, 681.

phrenic mothers.’ Journal ofPsychiarric Research, 6 , suppl. 1, 267.

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