Trends and synergies in intellectual disability research.

03Original abstract

Selecting papers for this annual, open access edition of JIDR affords an opportunity to take stock of both the focus and content of all papers accepted for publication. One result of this review is the identification of trends in the emerging literature and synergies between areas that were previously unconnected. In this edition, papers have been selected to represent research that typifies these trends and shows how bringing together differing perspectives results in more complete explanatory models to account for the outcome of interest. In the 1960s research in the field of intellectual disability focussed on cognitive performance, and difference versus delay explanations of intellectual development, broadly defined. The last decade or so has seen a resurrection of interest in cognitive processes with exploration of their relationship with behaviours of clinical significance. This literature has developed primarily in the behavioural phenotype research that seeks to characterise differences or deficits in cognitive endophenotypes as candidate processes underpinning behaviours such as insistence on sameness and adherence to routine, as well as ADHD type phenomenology, such as compromised behavioural inhibition. In this edition, the paper by Bexkens et al. (2014) provides an overview of the importance of constructs such as compromised cognitive inhibition and their assessment, with meta-analysis applied to evaluate the strength of effects. The importance of this research is that it offers a level of explanation over and above that of degree of intellectual disability alone in understanding the prevalence and presentation of behavioural outcomes. Compromised inhibition is likely to become an increasingly important cognitive variable in explanatory models of behavioural difference. Two other papers in this edition focus on family context and the difficulties parents of children with intellectual disability experience resolving problems with their child (Wieland et al. 2014) and phenotype × environment interactions in a genetic syndrome (22q11.2 Deletion Syndrome) with a well characterised behavioural phenotype (Allen et al. 2014). The implications of these three papers are potentially related and show how a cognitive construct, such as impaired inhibition, merits greater attention when explaining behaviour and how in a genetic syndrome associated with impaired response inhibition (see Inan et al. 2013) outcome for children is related to family variables. It is not inconceivable that compromised response inhibition in children is associated with a greater challenge to parents when resolving problems with children and so a path (albeit a speculative one) starts to form from aetiology of intellectual disability to cognitive process to behaviour to environment. This hypothesis arises because the research has highlighted the importance of separating cognitive processes from intellectual disability and has formed links between child characteristics and the family context. This is the value of synergies and also the challenge for researchers. Two papers in this edition adopt longitudinal designs, arguably the most powerful design available for examining the influence of any variable on long term outcome. Hulbert-Williams et al. (2014) demonstrate that life events have the capacity to predict later psychological difficulties, a finding potentially relevant to the recent Winterbourne scandal. McCallion et al. (2014) provide robust data on the course of dementia in adults with Down syndrome in a large sample. In both instances there is obvious merit in the design given the evaluation of the prediction of later outcome from risk markers\factors identified at an earlier stage. Longitudinal studies of this kind are becoming more common in the literature on intellectual disability and are enabling causal pathways to be identified. These studies clearly indicate the value of maintaining cohorts over long periods of time and this is another challenge for researchers given the short term nature of most research funding. Papers on interventions are notably limited in the literature on intellectual disability despite having increasing importance in determining future delivery of healthcare. In this edition, Chadwick et al. (2014) evaluate the efficacy of training staff in administering fluids to people with dysphagia to illustrate the importance of the content and focus of training. This type of evidence can directly inform practice in an area of clinical importance on a day to day basis. The second study by de Kuijper et al. (2014) responds to the growing evidence that antipsychotic medication for the treatment of challenging behaviour is, at best, ineffective. The authors conclude: ‘Discontinuation of antipsychotics prescribed for challenging behaviour in patients with intellectual disability is associated with improved behavioural functioning.’ There is now a robust case for this research to be extended more widely and with urgency. Once again, this evidence has a day to day relevance to the well being of far too many people with intellectual disability. These three themes of synergy between fields, longitudinal studies and evaluations of ‘intervention’ represent ways in which research in the field of intellectual disability is growing stronger. However, they are associated with the obvious challenges of cross disciplinary collaboration, long term funding and the logistics associated with intervention trials. These are barriers that must be overcome if the quality, impact and value of research are to continue to improve. JIDR serves the research and clinical intellectual disability community by providing a vehicle for disseminating the best research in the field, such as that published in this edition. The efficiency of the journal is determined by reviewers and the editorial board but mainly by the editorial office. For many years Sue Hampton-Matthews has acted as the editorial manager and she has now stood down to be replaced by Jane Waite. We will miss Sue at JIDR. She had remarkable breadth to her knowledge of research in intellectual disability and who was currently active in any given area. She was accomplished in helping reviewers reappraise their priorities for the coming week without them ever knowing this had happened. Every editorial office needs someone like Sue to keep it running efficiently and JIDR is better as a result of her being part of the team and very grateful to her for her diligence and hard work. Thank you, Sue.

Journal of intellectual disability research : JIDR, 2014 · doi:10.1111/jir.12105