Development of a model on factors affecting instrumental activities of daily living in people with mild cognitive impairment – a Delphi study

Abstract The level of functioning in instrumental activities of daily living (IADL) is crucial for a person’s autonomy. A clear understanding of the nature of IADL and its limitations in people with mild cognitive impairment (MCI) is lacking. Literature suggests numerous possible influencing factors, e.g. cognitive function, however, without considering other domains of human functioning, e.g. environmental factors. Therefore, we aimed to propose a comprehensive model for IADL functioning that pictures relevant influencing factors. Methods We conducted a four-round online Delphi study in a sample of international IADL experts (N=69). In the first round, panelists were asked to mention all possible relevant cognitive and physical function factors as well as environmental and personal factors influencing IADL functioning. In the subsequent rounds panelists rated the relevance of these factors. Consensus was defined as: 1) ≥70% agreement between panelists on a factor and 2) stability between two succeeding rounds. Results Response rates of the four rounds were high (83% to 100%). In the first round, 229 influencing factors were mentioned, whereof thirteen factors reached consensus in the subsequent rounds and were used to build a model for IADL functioning. The final model includes five cognitive function factors (i.e. memory, attention, executive function, executive function subdomains (problem solving / reasoning and organization / planning), five physical function factors (i.e. seeing functions, hearing functions, balance, gait / mobility functions and functional mobility functions), two environmental factors (i.e. social network / environment and support of social network / environment) and one personal factor (i.e. education). Conclusions This study proposes a comprehensive model on IADL functioning in people with MCI. The results from this Delphi suggest that IADL functioning is not merely affected by cognitive function factors, but also by physical function, environmental and personal factors. The numerousness of mentioned factors in the first round also underlines the individuality of IADL functioning in people with MCI. The model may serve as ground for future research in IADL functioning in people with MCI.