Open Access Research article

Determinants of response to a parent questionnaire about development and behaviour in 3 year olds: European multicentre study of congenital toxoplasmosis

A Salt1, K Freeman2, A Prusa3, N Ferret4, W Buffolano5, G Malm6, D Schmidt7, HK Tan8, RE Gilbert8* and The European Multicentre Study on Congenital Toxoplasmosis (EMSCOT)

Author Affiliations

1 The Neurodisability Service, Great Ormond Street Hospital for Children and Institute of Child Health, London, UK

2 Albert Einstein College of Medicine, Department of Epidemiology and Population Health, New York, U.S.A

3 Department of Pediatrics, Division of Neonatology and Intensive Care, Medical University of Vienna, Austria

4 CHU de NICE, Service Parasitologie – Mycologie, Hopital L'Archet II, BP 3079, 06202 NICE Cedex 3

5 Perinatal Infection Unit, Dept of Pediatrics, University of Naples Federico II, Naples, Italy

6 Karolinska University Hospital, Huddinge, Stockholm, Sweden

7 Department of Parasitology, Staten Seruminstitut, Copenhagen, Denmark

8 Centre for Paediatric Epidemiology and Biostatistics, Institute of Child Health, London, UK

For all author emails, please log on.

BMC Pediatrics 2005, 5:21  doi:10.1186/1471-2431-5-21

Published: 5 July 2005



We aimed to determine how response to a parent-completed postal questionnaire measuring development, behaviour, impairment, and parental concerns and anxiety, varies in different European centres.


Prospective cohort study of 3 year old children, with and without congenital toxoplasmosis, who were identified by prenatal or neonatal screening for toxoplasmosis in 11 centres in 7 countries. Parents were mailed a questionnaire that comprised all or part of existing validated tools. We determined the effect of characteristics of the centre and child on response, age at questionnaire completion, and response to child drawing tasks.


The questionnaire took 21 minutes to complete on average. 67% (714/1058) of parents responded. Few parents (60/1058) refused to participate. The strongest determinants of response were the score for organisational attributes of the study centre (such as direct involvement in follow up and access to an address register), and infection with congenital toxoplasmosis. Age at completion was associated with study centre, presence of neurological abnormalities in early infancy, and duration of prenatal treatment. Completion rates for individual questions exceeded 92% except for child completed drawings of a man (70%), which were completed more by girls, older children, and in certain centres.


Differences in response across European centres were predominantly related to the organisation of follow up and access to correct addresses. The questionnaire was acceptable in all six countries and offers a low cost tool for assessing development, behaviour, and parental concerns and anxiety, in multinational studies.