Background: Beside cognitive loss from a previously achieved level, persons with mild cognitive impairment (MCI) experience impairments in physical functions, and limitations in instrumental activities of daily living (IADL) are frequently reported. IADLs are complex tasks that are needed to live independently in society. Currently, there is no pharmacological treatment recommended to improve cognition or reduce the impact of cognitive loss on functioning in people with MCI. In contrary, evidence supports beneficial effects of multi-component interventions, e.g. a combination of physical exercise and cognitive training on specific aspects of cognitive and physical functioning. However, the pertinent components of such interventions are unknown, and whether these effects translate into improved IADL functioning. Aims: The objective of this doctoral thesis was to develop a study protocol of a randomised feasibility study for a multi-component intervention targeting IADL functioning in persons with MCI. The specific aims were to: 1) review the evidence for multi-component interventions in improving IADL performance, cognitive function and physical capacity in older adults, with or without MCI; 2) identify the most suitable measurement tool with good psychometric properties to assess IADL performance; and, 3) develop a multi-component intervention to improve IADL functioning in persons with MCI. Methods: The aims were addressed in four studies. Based on a systematic review, including Bayesian network meta-analyses, the evidence from randomised controlled trials on the effects of multi-component interventions on IADL performance, cognitive function, and physical capacity in elderly individuals with normal cognition (NC) and MCI were summarised. In an observational study, including a German-speaking sample of 96 elderly individuals with NC, MCI and mild dementia (MD) the Amsterdam IADL questionnaire short (A-IADL-Q-SV), was adapted, validated and relevant psychometric properties were evaluated. The first step to develop a multi-component intervention was to form the theoretical base by developing a model of IADL functioning using a four-round online Delphi study in 69 international IADL experts. The second step of the development of the intervention included the description of a draft of the planned intervention, that was elaborated using a patient and public involvement approach (PPI). Based on the findings of the preceding studies, the fourth study outlined the protocol of a randomised feasibility study to evaluate the feasibility, acceptability, and preliminary efficacy of the newly-developed multi-component intervention in persons with MCI. Results: The findings of the first study demonstrated the effectiveness and superiority of multi-component interventions on cognitive functions and physical capacity, while their effectiveness on IADL performance remained inconclusive. The results of the second study affirmed the successful adaptation and validation of the German version of the A-IADL-Q-SV and the determination of psychometric properties. The findings from the Delphi study depicted a comprehensive IADL functioning model encompassing relevant influencing factors and covering various aspects of human functioning, these factors were used to determine the components of the multi-component intervention. International guidelines and current literature were used to specify how the determined intervention components should be trained. The PPI resulted in design adaptations of the intervention. The developed multi-component intervention – the F.I.T.AL. (Function - Information - Training - therapy for everyday life) consists of three main components: cognitive training, physical training, and information and support. Discussion/Conclusion: This thesis outlines a research protocol of a randomised feasibility study to evaluate the feasibility, acceptability, and adherence of a multi-component intervention that has been designed to improve IADL in persons with MCI. The development process aligns with the British Medical Research Council framework and includes the current evidence on multi-component interventions in persons with MCI, and the newly developed IADL functioning model in persons with MCI. The selected outcome measure for the planned study to assess IADL performance, the A-IADL-Q-SV, was successfully adapted and validated. This thesis may have implications for clinical practice through the provision of a potential non-pharmacological treatment strategy for persons with MCI and a valuable measure for the assessment of IADL performance. This thesis may also stimulate future research in the field of IADL functioning in persons with MCI and multi-component interventions as treatment options for persons with MCI.

Cumulative doctoral/PhD Thesis, University of Lucerne