Purpose: To parents of children with profound multiple disabilities who do not use symbols in interaction a successful outcome of dyadic interaction with their children consists of shared experiences, mutual joy and understanding. In the last two decades interaction intervention for these parents and their children has become an issue for research with the aim to identify factors that facilitate mutually rewarding parent-child interaction. Interaction patterns between the child and his/her caregivers must be studied, assessed and intervened within relation to the family system and how it changes over time. The aim of this article is to discuss the methodological challenges in studying parent-child interaction in the context of the family system.
Method: Research methods designed to handle complexity, multidimensionality, heterogeneity among research subjects and small number of participants in the analysis are described.
Conclusions: It is concluded that the theories and methods used must guide the researcher in how to delimit a manageable number of factors to include in the analysis, in how to analyse the interrelationships between the factors, and in how to study changes in patterns of factors over time. Prerequisites to meet the methodological challenges are that the constructs investigated have a sound theoretical base and that longitudinal data are collected.