Developing behavioural indicators for intellectual functioning and adaptive behaviour for ICD-11 disorders of intellectual development.

BACKGROUND: We present the work conducted to arrive at deriving behavioural indicators that could be used to guide clinical judgement in determining the presence and severity of deficits in intellectual functioning and adaptive behaviour for the purpose of making a diagnosis of disorders of intellectual development. METHODS: An interdisciplinary expert panel provided guidance in developing behavioural indicators for intellectual functioning. A national dataset of adaptive behaviour on a sample of individuals with a diagnosis of intellectual disability was used to develop the behavioural indicators for the adaptive behaviour. The adaptive behaviour data were analysed using a cluster analysis procedure to define the different severity groupings by chronological age groups. RESULTS: We present a series of tables containing behavioural indicators across the lifespan for intellectual functioning and adaptive behaviour, including conceptual, social and practical skills. These tables of behavioural indicators have been proposed for use in the clinical version of the 11th revision of the International Classification of Diseases and Related Health Problems (ICD-11) to be published by the World Health Organization. CONCLUSIONS: The proposed behavioural indicators for disorders of ID described in the present article and to be included in the ICD-11 Clinical Descriptions and Diagnostic Guidelines are put forth to assist professionals in making an informed clinical decision regarding an individual's level of intellectual functioning and adaptive behaviour for the purpose of making a determination about the presence and severity of disorders of ID.

Difficulties in working memory updating in individuals with intellectual disability.

BACKGROUND: Despite the critical role attributed to working memory (WM) updating for executive functions and fluid intelligence, no research has yet been carried out on its specific role in the vital case of fluid intelligence weakness, represented by individuals with intellectual disability (ID). Furthermore, the relationship between updating and other WM functions has not been considered in depth. METHOD: The current study examines these areas by proposing a battery of WM tasks (varying in degree of active attentional control requested) and one updating task to groups of ID individuals and typically developing children, matched for fluid intelligence performance. RESULTS: Comparison between the group of ID individuals and a group of children showed that, despite being matched on the Raven test, the updating measure significantly differentiated the groups as well as the WM complex span. Furthermore, updating proved to be the task with the greatest power in discriminating between groups. CONCLUSIONS: Our results confirm the importance of the demand for active attentional control in explaining the role of WM in fluid intelligence performance, and in particular show that updating information in WM plays an important role in the distinction between typically developing children and ID individuals.