Outcomes tested in non-pharmacological interventions in mild cognitive impairment and mild dementia: a scoping review

Objectives Non-pharmacological treatments are an important aspect of dementia care. A wide range of interventions have been trialled for mild dementia and mild cognitive impairment (MCI). However, the variety of outcome measures used in these trials makes it difficult to make meaningful comparisons. The objective of this study is to map trends in which outcome measures are used in trials of non-pharmacological treatments in MCI and mild dementia. Design Scoping review. Data sources EMBASE, PsychINFO, Medline and the Cochrane Register of Controlled Trials were searched from inception until February 2018. An additional search was conducted in April 2019 Eligibility We included randomised controlled trials (RCTs) testing non-pharmacological interventions for people diagnosed with MCI or mild dementia. Studies were restricted to full RCTs; observational, feasibility and pilot studies were not included. Charting methods All outcome measures used by included studies were extracted and grouped thematically. Trends in the types of outcome measures used were explored by type of intervention, country and year of publication. Results 91 studies were included in this review. We extracted 358 individual outcome measures, of which 78 (22%) were used more than once. Cognitive measures were the most frequently used, with the Mini-Mental State Examination being the most popular. Conclusions Our findings highlight an inconsistency in the use of outcome measures. Cognition has been prioritised over other domains, despite previous research highlighting the importance of quality of life and caregiver measures. To ensure a robust evidence base, more research is needed to highlight which outcome measures should be used over others. PROSPERO registration number CRD42018102649.

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Other than as permitted in any relevant BMJ Author's Self Archiving Policies, I confirm this Work has not been accepted for publication elsewhere, is not being considered for publication elsewhere   Delivery of treatment in the early stages of dementia has been identified as a global priority 1 2 . Current pharmacological treatments for the cognitive symptoms of dementia have been found to have greater effect when delivered as early as possible 3 however, the benefits of delivering nonpharmacological treatments early are less well understood. Non-pharmacological treatments are an important clinical tool for managing dementia as they are more acceptable to some and less prone to side effects, making them a safe alternative to drug treatments 4 Those diagnosed earlier in the disease have more cognitive abilities available to engage with non-pharmacological treatments and bolster their own methods for coping with the disease 5 . Previous systematic reviews have found non-pharmacological treatments can improve outcomes; however, these reviews were restricted to a small number of outcome measures 6 7 .
Mild cognitive impairment (MCI) has been identified as a potential prodrome for dementia, with approximately 10% of people with MCI converting to a diagnosis of dementia 8 . There is an interest in MCI, as a diagnosis of MCI can facilitate an early diagnosis of dementia and therefore earlier access to dementia services and treatment 9 . MCI is a potentially reversible condition, with many people with MCI reverting back to normal levels of cognition 9 therefore, it is important treatments are available. However, it is not clear which treatments can reverse MCI or prevent conversion to dementia 3 . No drug treatments for MCI have been found to be effective 10 11 and acetylcholinesterase inhibitors are not recommended however, there is some limited evidence that non-pharmacological interventions may be beneficial 3 12 .
Randomised Controlled Trials (RCTs) testing non-pharmacological treatments in dementia and MCI are becoming more common. However, they are highly heterogeneous in terms of participants recruited, quality of the study and the types of interventions they are testing, making it difficult to establish the effectiveness of one treatment over another 6 12 . Compounding these issues is the inconsistent use of outcome measures in this area of work 9 13 . Systematic reviews have identified possible benefits of non-pharmacological treatment, yet metaanalyses are difficult to conduct due to the variation in outcome measures used by studies and typically yield small to moderate effect sizes 6 7 . It is possible that these small effect sizes are due to the selection of outcome measures which either lack sensitivity or the change following the intervention not being in the area covered by the outcome measure. It is important researchers are clear on which domains their interventions are targeting, and which measures are best able to capture this change 14 . As non-pharmacological treatments become more effective, there needs to be a more coherent use of outcome measure internationally to ensure a broad and robust evidence base 14 .
In 2008, the INTERDEM group, a consortium of dementia researchers across Europe, did work to draw a consensus on which outcome measures should be used when evaluating nonpharmacological treatments. They recommended 22 measures across nine domains including quality of life, mood, global functioning, behaviour, daily living skills, caregiver mood, caregiver burden and staff morale 14 . This guidance does not explore outcomes by the stage of the disease. Furthermore, the outcome measures were selected based on their applicability to European research, it is important to have consistency in outcome measures globally.
It is not understood which outcome measures are currently being used in non-pharmacological treatments for early dementia and MCI. Scoping reviews present the opportunity to map the evidence on a topic 15 , unlike a systematic review scoping reviews can be used to summarise the evidence in a heterogeneous body of literature. Therefore, the aim of this scoping review is to map which outcome measures are being used in RCTs for non-pharmacological treatments in MCI and early dementia.

Objectives
The specific objectives of this scoping review are to:

Protocol registration
The protocol for this review was developed following the guidelines set out by the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Extension (PRISMA) statement 16 and the PRISMA guidelines for Scoping Reviews (PRISMA-ScR) 15 . The protocol was registered prospectively on PROSPERO (ID: CRD42018102649).

Eligibility criteria
We included RCTs testing non-pharmacological interventions for people diagnosed with MCI or early-stage dementia. Studies were restricted to full RCTs; observational, feasibility and pilot studies were not included.
Studies were included if they met the following criteria:

Selection of sources of evidence
Study selection was managed in Rayyan, where citations were screened against the inclusion and exclusion criteria. Rayyan is an online app for systematic reviews which allows researchers to create their own coding system for decision making 17 . References were first screened by title and abstract, followed by a full-text screening. A second reviewer (MC) screened 10% of the articles at each stage of the review. Disagreements were resolved by discussions with a third reviewer (MP).
A critical appraisal or assessment of the risk of bias is not necessary for a scoping review 15 . This scoping review is not aiming to critically appraise the cumulative literature of outcome measures for early non-pharmacological treatment in dementia, therefore we did not conduct a critical appraisal or risk of bias assessment for this review.

Data charting process and data items
Data from eligible studies were charted using a standardised extraction tool designed for this study.
Items deemed most relevant to the review objectives were the diagnosis of the study participants, description of interventions being tested, the number of intervention groups, and outcome measures used with references.

Synthesis of results
The charted data were mapped to reflect the objectives of this review. Following data charting, outcome measures which used more than once across the included studies were grouped by domain, we grouped the interventions thematically by the type of intervention being tested.
We explored which types of outcome measures were used by intervention type, by tabulating the type of intervention against the domain of the outcome measure. We excluded interventions which were only used once from this summary. Results were presented in tables and summarised narratively.

Types of non-pharmacological interventions
We grouped the interventions thematically by type. The most frequently tested type of intervention was cognitive training (n=37) followed by physical activity (n=25), combined physical activity and cognitive training (n=4), multicomponent psychosocial interventions (n=4) and support groups (n=3).
Animal-assisted therapies, art-based therapies, case management, Chinese calligraphy, music-based interventions and reminiscence therapy were each tested in two studies.
A group weight loss programme, mindfulness, social activities, transcranial direct current stimulation (TDS), transcutaneous electrical nerve stimulation (TENs), and Transcranial magnetic stimulation (TMS) were each trialled once. These interventions were not included in the analysis of trends in outcome measures. Table 2 presents the PLWD specific outcome measures grouped by domain. The most frequently measured domain in PLWD was cognition/memory, which was measured 219 times across the 93 included studies. The most frequent measure of cognition was the MMSE, which was measured 37

PLWD outcome measures
times. In addition to measures of memory performance knowledge of memory strategies was measured 3 times in PLWD.
The next most frequently measured domain in PLWD was behavioural and psychological symptoms of dementia (BPSD), within this depression was the most commonly measured BPSD. The Geriatric Depression Scale was the most used measure in this domain, followed by the Neuropsychiatric Inventory which examines a greater number of symptoms. Other BSPDs measured were apathy and agitation resulting from memory problems.
Quality of life and wellbeing were measured 15 times across the included study. Quality of life was measured 15 times using four different instruments, the most popular of which was Logsdon's Quality of Life in Alzheimer's disease scale which was used seven times. Measures of everyday living, physical ability, biological outcomes and adherence to the intervention delivered in the study were measured less than 20 times across the included studies.

Caregiver measures
Eight interventions in this study were dyadic [18][19][20][21][22][23][24][25] , all included outcome measures specific to the caregiver in addition to the PLWD. One study of an intervention solely delivered to the PLWD also included a caregiver specific measure 26 . Table 2 also presents the outcome measures administered to caregivers grouped by domain. The Center for Epidemiological Studies Depression Scale and the Zarit Caregiver Burden interview were the only measures which were administered solely to caregivers. The other caregiver measures were also administered to PLWD. The most frequently measured domain in caregivers was depression, followed by caregiver burden. General wellbeing, knowledge of memory strategies, quality of life and stress were each measured once.    Table 3 presents diagnosis and type of intervention by the domains measured. Cognition/memory was the most measured domain across all diagnostic groups, followed by BPSD. The next most common domain measured for studies of people with dementia was caregiver specific measures, whereas in MCI it was physical performance.

Use of outcome measures by intervention
Cognition/memory was measured in all types of intervention. BPSD was measured in all types of interventions except for combined cognitive and physical training interventions but was particularly favoured by studies testing cognitive training and psychosocial interventions. Quality of life was measured by studies of case management, cognitive training, psychosocial interventions, physical activity and support groups.
Caregiver measures were used in five types of interventions. Case management, cognitive training and psychosocial interventions; followed by arts-based therapy and support groups.

Discussion
In this study, we used a scoping review to map which outcome measures had been used in trials for non-pharmacological treatments of early dementia and MCI. We extracted 361 individual outcome measures used in 92 trials, only 22% of which were used more than once. We grouped the outcome measures which had been used more than once and examined differences in their use over time, by diagnostic group and by the type of intervention they were being used to evaluate. Measures of cognition and BPSDs were the most frequently used across all studies and types of intervention.
Perhaps unsurprisingly, measures of cognition or memory are the most prevalent across all diagnostic groups and types of intervention with the MMSE being the most frequently used outcome measure, despite the ADAS-cog having been validated as the gold-standard measure of cognition 14 27 F o r p e e r r e v i e w o n l y 13 28 . Measuring cognition is central to measuring the progression of dementia and is clinically and empirically useful outcome to measure in dementia research 28 , however, in this review, we charted 40 different measures of cognition. This indicates that while cognition has been prioritised as an outcome in studies of non-pharmacological interventions, there is no consensus between researchers on which specific measures should be used. In addition to measures of cognitive performance, three studies have also measured participants knowledge or retention of memory strategies, indicating an interest in longer-term coping strategies for memory loss.
Measures of the BPSD have become more common over time, becoming in 2017 the most measured outcome after cognition. There is not much variety in the BPSDs which have been measured.
Generally, depression was measured over other BPSDs. Other BPSDs such as agitation were measured less, perhaps because they are more associated with the later stages of the disease and depression is associated with the earlier stages 29 .
Quality of life and wellbeing was not amongst the most measured domains. Four measures of quality of life were used 13 times across the included studies, all but one of these measures were dementia specific measures. It is surprising quality of life has not been measured more, as previous research has stated that in the absence of a cure, health care providers have a greater ability to improve quality of life than alter the progression of the disease 30 . Furthermore, in a priority setting exercise in people diagnosed with MCI and their caregivers, both people with MCI and caregivers rated quality of life of the patient as the most important outcome to measure, followed by caregiver quality of life/burden 31 . Indicating while quality of life has been identified as a priority by PLWD, MCI and their caregivers in previous research, the findings of this study shows this is not being translated into trials of non-pharmacological treatments for early dementia and MCI.
Likewise, caregiver measures had consistent low use across the studies included in this review. We charted eight caregiver measures which were used 11 times across the included studies. Caregiver measures were more commonly used in studies of PLWD, rather than MCI. Previous research has  32 . However, a third of caregivers of people with MCI also report extreme levels of burden 33 , yet the findings of this study show this is less investigated.
There was a lot of variability in the types of outcome measures being used to evaluate the different types of intervention. All studies measured cognition and all but one measured BPSD. Outcome measures should be selected depending on the domains the intervention is seeking to address 28 In 2008, the INTERDEM group recommended 22 outcome measures for use across nine domains 14 .
We found 11 of these 22 measures (50%) were used by the studies included in this review, one of the recommended domains (staff carer morale) was not applicable to the studies included in this review. All measures recommended for measuring patient mood, patient quality of life and patient quality of life were charted in this review. Only one of the recommended measures for the activities of daily living, caregiver mood, caregiver burden and caregiver quality of life domains were charted and no measures under the global measures domain were charted in this review. This indicates that there is some consistency between which measures are recommended and which measures are utilised, this is largely for patient measures and there is less consistency for caregiver measures.

Limitations
The findings of this review must be interpreted in the context of the study. To make this review feasible we only included full RCTs, other outcome measures may have been used in different types of studies. Furthermore, only outcome measures which were published could be included in this review. The studies included in this study were heterogeneous in terms of participants recruited, interventions tested, and outcome measures used, making it difficult to group them thematically. It is possible some nuance is lost in the exploration of broader themes. As with the nature of scoping reviews, we are only able to present which outcome measures have been used in previous research, we are unable to draw conclusions as to which outcome measures should be used over others.

Conclusions
In summary, this study has found RCTs for non-pharmacological treatments in early dementia and MCI use a broad range of outcome measures, with a small proportion being used more than once.
Excepting measures of cognition, there is very little commonality between studies. Where previous research has set priorities on outcome measures preferred by PLWD, people with MCI and caregivers, quality of life for example, this has not yet translated into studies measuring new treatments. Further research to understand which outcomes should be prioritised and how they should be measured.

Type of Intervention
Animal Assisted Therapy    Provide a structured summary that includes (as applicable): background, objectives, eligibility criteria, sources of evidence, charting methods, results, and conclusions that relate to the review questions and objectives.

Rationale 3
Describe the rationale for the review in the context of what is already known. Explain why the review questions/objectives lend themselves to a scoping review approach.

5
Objectives 4 Provide an explicit statement of the questions and objectives being addressed with reference to their key elements (e.g., population or participants, concepts, and context) or other relevant key elements used to conceptualize the review questions and/or objectives.

Protocol and registration 5
Indicate whether a review protocol exists; state if and where it can be accessed (e.g., a Web address); and if available, provide registration information, including the registration number.

6
Eligibility criteria 6 Specify characteristics of the sources of evidence used as eligibility criteria (e.g., years considered, language, and publication status), and provide a rationale.

6-7
Information sources* 7 Describe all information sources in the search (e.g., databases with dates of coverage and contact with authors to identify additional sources), as well as the date the most recent search was executed.

7
Search 8 Present the full electronic search strategy for at least 1 database, including any limits used, such that it could be repeated. Table 1 Selection of sources of evidence † 9 State the process for selecting sources of evidence (i.e., screening and eligibility) included in the scoping review. 8

Data charting process ‡ 10
Describe the methods of charting data from the included sources of evidence (e.g., calibrated forms or forms that have been tested by the team before their use, and whether data charting was done independently or in duplicate) and any processes for obtaining and confirming data from investigators. Give numbers of sources of evidence screened, assessed for eligibility, and included in the review, with reasons for exclusions at each stage, ideally using a flow diagram. 9 and Figure  1 Characteristics of sources of evidence 15 For each source of evidence, present characteristics for which data were charted and provide the citations. 9 and Table 2 Critical appraisal within sources of evidence 16 If done, present data on critical appraisal of included sources of evidence (see item 12).
For each included source of evidence, present the relevant data that were charted that relate to the review questions and objectives.
Not feasible

Synthesis of results 18
Summarize and/or present the charting results as they relate to the review questions and objectives. 10-12

Summary of evidence 19
Summarize the main results (including an overview of concepts, themes, and types of evidence available), link to the review questions and objectives, and consider the relevance to key groups.

12
Limitations 20 Discuss the limitations of the scoping review process. 14

Conclusions 21
Provide a general interpretation of the results with respect to the review questions and objectives, as well as potential implications and/or next steps.

Funding 22
Describe sources of funding for the included sources of evidence, as well as sources of funding for the scoping review. Describe the role of the funders of the scoping review.
15 JBI = Joanna Briggs Institute; PRISMA-ScR = Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews. * Where sources of evidence (see second footnote) are compiled from, such as bibliographic databases, social media platforms, and Web sites. † A more inclusive/heterogeneous term used to account for the different types of evidence or data sources (e.g., quantitative and/or qualitative research, expert opinion, and policy documents) that may be eligible in a scoping review as opposed to only studies. This is not to be confused with information sources (see first footnote). ‡ The frameworks by Arksey and O'Malley (6) and Levac and colleagues (7) and the JBI guidance (4,5) refer to the process of data extraction in a scoping review as data charting. § The process of systematically examining research evidence to assess its validity, results, and relevance before using it to inform a decision. This term is used for items 12 and 19 instead of "risk of bias" (which is more applicable to systematic reviews of interventions) to include and acknowledge the various sources of evidence that may be used in a scoping review (e.g., quantitative and/or qualitative research, expert opinion, and policy document). establish the effectiveness of one treatment over another 6 12 13 . Compounding these issues is the 25 inconsistent use of outcome measures in this area of work 9 14 . non-pharmacological treatment in MCI and mild dementia, therefore we did not conduct a critical 2 appraisal or risk of bias assessment for this review. 3 Data charting process and data items 4 Data from eligible studies were charted using a standardised extraction tool designed for this study.

5
Items deemed most relevant to the review objectives were the diagnosis of the study participants, 6 description of interventions being tested, the number of intervention groups, and outcome 7 measures used with references. 8

9
The charted data were mapped to reflect the objectives of this review. Following data charting, 10 outcome measures which were used more than once across the included studies were grouped by 11 domain. We grouped the interventions thematically by the type of intervention being tested. 12 We explored which types of outcome measures were used by intervention type, by tabulating the  The studies included in this review are described in Table 1 Netherlands, Turkey, and the United Kingdom; these countries had fewer than 5 included studies 10 each.

11
Most studies only recruited participants with MCI (n=72), followed by mild dementia only (n=15), 12 and six studies recruited both participants with MCI and mild dementia.

13
Results of individual sources of evidence 14 We

19
Types of non-pharmacological interventions 20 We grouped the interventions thematically by type. The most frequently tested type of intervention 21 was cognitive training (n=36) followed by physical activity (n=25), combined physical activity and 22 cognitive training (n=4), multicomponent psychosocial interventions (n=4) and support groups (n=3).

23
Animal-assisted therapies, art-based therapies, case management, Chinese calligraphy, music-based 24 interventions and reminiscence therapy were each tested in two studies. times. In addition to measures of memory performance knowledge of memory strategies was 10 measured 3 times in PLWD.

Rationale 3
Describe the rationale for the review in the context of what is already known. Explain why the review questions/objectives lend themselves to a scoping review approach.

5-6
Objectives 4 Provide an explicit statement of the questions and objectives being addressed with reference to their key elements (e.g., population or participants, concepts, and context) or other relevant key elements used to conceptualize the review questions and/or objectives.

Protocol and registration 5
Indicate whether a review protocol exists; state if and where it can be accessed (e.g., a Web address); and if available, provide registration information, including the registration number.

6
Eligibility criteria 6 Specify characteristics of the sources of evidence used as eligibility criteria (e.g., years considered, language, and publication status), and provide a rationale.

7-8
Information sources* 7 Describe all information sources in the search (e.g., databases with dates of coverage and contact with authors to identify additional sources), as well as the date the most recent search was executed.
8 Search 8 Present the full electronic search strategy for at least 1 database, including any limits used, such that it could be repeated. Table 1 Selection of sources of evidence † 9 State the process for selecting sources of evidence (i.e., screening and eligibility) included in the scoping review. 8-9 Data charting process ‡ 10 Describe the methods of charting data from the included sources of evidence (e.g., calibrated forms or forms that have been tested by the team before their use, and whether data charting was done independently or in duplicate) and any processes for obtaining and confirming data from investigators.

9
Data items 11 List and define all variables for which data were sought and any assumptions and simplifications made. 9 Critical appraisal of individual sources of evidence §

12
If done, provide a rationale for conducting a critical appraisal of included sources of evidence; describe the methods used and how this information was used in any data synthesis (if appropriate).
10 and Table  2 Critical appraisal within sources of evidence 16 If done, present data on critical appraisal of included sources of evidence (see item 12). N/A

Results of individual sources of evidence 17
For each included source of evidence, present the relevant data that were charted that relate to the review questions and objectives.
Not feasible

Synthesis of results 18
Summarize and/or present the charting results as they relate to the review questions and objectives. 10-13

Summary of evidence 19
Summarize the main results (including an overview of concepts, themes, and types of evidence available), link to the review questions and objectives, and consider the relevance to key groups.

Conclusions 21
Provide a general interpretation of the results with respect to the review questions and objectives, as well as potential implications and/or next steps.

Funding 22
Describe sources of funding for the included sources of evidence, as well as sources of funding for the scoping review. Describe the role of the funders of the scoping review.
18 JBI = Joanna Briggs Institute; PRISMA-ScR = Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews. * Where sources of evidence (see second footnote) are compiled from, such as bibliographic databases, social media platforms, and Web sites. † A more inclusive/heterogeneous term used to account for the different types of evidence or data sources (e.g., quantitative and/or qualitative research, expert opinion, and policy documents) that may be eligible in a scoping review as opposed to only studies. This is not to be confused with information sources (see first footnote). ‡ The frameworks by Arksey and O'Malley (6) and Levac and colleagues (7) and the JBI guidance (4,5) refer to the process of data extraction in a scoping review as data charting. § The process of systematically examining research evidence to assess its validity, results, and relevance before using it to inform a decision. This term is used for items 12 and 19 instead of "risk of bias" (which is more applicable to systematic reviews of interventions) to include and acknowledge the various sources of evidence that may be used in a scoping review (e.g., quantitative and/or qualitative research, expert opinion, and policy document).  1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16  17  18  19  20  21  22  23  24  25  26  27  28  29  30  31  32  33  34  35  36  37  38  39  40  41  42  43  44  45  46  47  48  49  50  51  52  53  54  55  56  57  58  59 1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16  17  18  19  20  21  22  23  24  25  26  27  28  29  30  31  32  33  34  35  36  37  38  39  40  41  42  43  44  45  46  47  48  49  50  51  52  53  54  55  56  57  58  59 5 . Previous systematic reviews have found non-pharmacological treatments can improve outcomes; however, these reviews were restricted to a small number of outcome measures 6 7 .
Mild cognitive impairment (MCI) has been identified as a potential prodrome for dementia, with approximately 10% of people with MCI converting to a diagnosis of dementia per annum 8 . There is an interest in MCI, as a diagnosis of MCI can facilitate an early diagnosis of dementia and therefore earlier access to dementia services and treatment 9 . MCI is a potentially reversible condition, with many people with MCI reverting back to normal levels of cognition 9 . Therefore, it is important treatments are available. However, it is not clear which treatments can reverse MCI or prevent conversion to dementia 3 . No drug treatments for MCI have been found to be effective 10 11 and acetylcholinesterase inhibitors are not recommended, however, there is some limited evidence that non-pharmacological interventions may be beneficial 3 12 .
Randomised Controlled Trials (RCTs) testing non-pharmacological treatments in dementia and MCI are becoming more common. However, they are highly heterogeneous in terms of participants recruited, quality of the study and the types of interventions they are testing, making it difficult to establish the effectiveness of one treatment over another 6 12 13 . Compounding these issues is the inconsistent use of outcome measures in this area of work 9 14 .

Objectives
The specific objectives of this scoping review are to: (1) Chart which outcomes measures have been used to assess the effectiveness of nonpharmacological treatments in mild dementia and MCI (2) Highlight which types of measures have been used most frequently (3) Explore whether the outcome measures used differ depending on the type of intervention, study population, and country the research was conducted in.

Protocol registration
The protocol for this review was developed following the guidelines set out by the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Extension (PRISMA) statement 19 and the PRISMA guidelines for Scoping Reviews (PRISMA-ScR) 18 . The protocol was registered prospectively on PROSPERO (ID: CRD42018102649).

Eligibility criteria
We included RCTs testing non-pharmacological interventions for people diagnosed with MCI or mild dementia. Studies were restricted to full RCTs; observational, feasibility and pilot studies were not included.   Additional papers were identified by searching the references of included papers and other systematic reviews. Conference abstracts and publications were not included.

Selection of sources of evidence
Study selection was managed in Rayyan, where citations were screened against the inclusion and exclusion criteria. Rayyan is an online app for systematic reviews which allows researchers to create their own coding system for decision making 20 . References were first screened by title and abstract, followed by a full-text screening. A second reviewer (MC) screened 10% of the articles at each stage of the review. Disagreements were resolved by discussions with a third reviewer (MP).
A critical appraisal or assessment of the risk of bias is not necessary for a scoping review 18 . This scoping review is not aiming to critically appraise the cumulative literature of outcome measures for non-pharmacological treatment in MCI and mild dementia, therefore we did not conduct a critical appraisal or risk of bias assessment for this review.

Data charting process and data items
Data from eligible studies were charted using a standardised extraction tool designed for this study.
Items deemed most relevant to the review objectives were the diagnosis of the study participants, description of interventions being tested, the number of intervention groups, and outcome measures used with references.

Synthesis of results
The charted data were mapped to reflect the objectives of this review. Following data charting, outcome measures which were used more than once across the included studies were grouped by domain. We grouped the interventions thematically by the type of intervention being tested.
We explored which types of outcome measures were used by intervention type, by tabulating the type of intervention against the domain of the outcome measure. We excluded interventions which were only used once from this summary. Results were presented in tables and summarised narratively.

Patient and Participant Involvement
The South London and Maudsley MALADY group, of current and former carers of people living with dementia, were consulted in the planning of this study.

Included studies
After duplicates were removed, a total of 7,056 citations were screened for inclusion, 653 were  The studies included in this review are described in Table 1 Most studies only recruited participants with MCI (n=72), followed by mild dementia only (n=15), and six studies recruited both participants with MCI and mild dementia.

Results of individual sources of evidence
We extracted 358 individual outcome measures from the included studies, of these 78 (22%) were used more than once. Out of the 78 measures used more than once, 70 (88%) were measures of participants living with dementia (PLWD), 6 measures were used in both the PLWD and their caregiver, 2 measures were only of the caregiver. The number of outcome measures used by each study ranged between one and 21 with an average of 6.85.

Types of non-pharmacological interventions
We grouped the interventions thematically by type. The most frequently tested type of intervention was cognitive training (n=36) followed by physical activity (n=25), combined physical activity and cognitive training (n=4), multicomponent psychosocial interventions (n=4) and support groups (n=3).
Animal-assisted therapies, art-based therapies, case management, Chinese calligraphy, music-based interventions and reminiscence therapy were each tested in two studies.  times. In addition to measures of memory performance knowledge of memory strategies was measured 3 times in PLWD.

PLWD outcome measures
The next most frequently measured domain in PLWD was behavioural and psychological symptoms of dementia (BPSD), within this depression was the most commonly measured BPSD. The Geriatric Depression Scale was the most used measure in this domain, followed by the Neuropsychiatric Inventory which examines a greater number of symptoms. Other BSPDs measured were apathy and agitation resulting from memory problems.
Quality of life and wellbeing were measured 15 times across the included study. Quality of life was measured 15 times using four different instruments, the most popular of which was Logsdon's Quality of Life in Alzheimer's disease scale which was used seven times.
Measures of everyday living, physical ability, biological outcomes and adherence to the intervention delivered in the study were measured less than 20 times across the included studies.

Conclusions
In summary, this study has found RCTs for non-pharmacological treatments in mild dementia and MCI use a broad range of outcome measures, with a small proportion being used more than once.  1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16  17  18  19  20  21  22  23  24  25  26  27  28  29  30  31  32  33  34  35  36  37  38  39  40  41  42  43  44  45  46  47  48  49  50  51  52  53  54  55  56  57  58  59  60   F  o  r  p  e  e  r  r  e  v  i  e  w  o  n  l  y   18   EC designed the study, carried out the literature review, the data charting and synthesis, data interpretation, article preparation, article review and correspondence. AMP and VL contributed to the study design, data interpretation, and article review. MC contributed to the data charting.

Funding
EC is supported by a studentship from the ESRC LISS-DTP.

Competing interests
None declared

Rationale 3
Describe the rationale for the review in the context of what is already known. Explain why the review questions/objectives lend themselves to a scoping review approach.

5-6
Objectives 4 Provide an explicit statement of the questions and objectives being addressed with reference to their key elements (e.g., population or participants, concepts, and context) or other relevant key elements used to conceptualize the review questions and/or objectives.

Protocol and registration 5
Indicate whether a review protocol exists; state if and where it can be accessed (e.g., a Web address); and if available, provide registration information, including the registration number.

6
Eligibility criteria 6 Specify characteristics of the sources of evidence used as eligibility criteria (e.g., years considered, language, and publication status), and provide a rationale.

7-8
Information sources* 7 Describe all information sources in the search (e.g., databases with dates of coverage and contact with authors to identify additional sources), as well as the date the most recent search was executed.
8 Search 8 Present the full electronic search strategy for at least 1 database, including any limits used, such that it could be repeated. Table 1 Selection of sources of evidence † 9 State the process for selecting sources of evidence (i.e., screening and eligibility) included in the scoping review. 8-9 Data charting process ‡ 10 Describe the methods of charting data from the included sources of evidence (e.g., calibrated forms or forms that have been tested by the team before their use, and whether data charting was done independently or in duplicate) and any processes for obtaining and confirming data from investigators.

9
Data items 11 List and define all variables for which data were sought and any assumptions and simplifications made. 9 Critical appraisal of individual sources of evidence §

12
If done, provide a rationale for conducting a critical appraisal of included sources of evidence; describe the methods used and how this information was used in any data synthesis (if appropriate).

Synthesis of results 13
Describe the methods of handling and summarizing the data that were charted. 9 Give numbers of sources of evidence screened, assessed for eligibility, and included in the review, with reasons for exclusions at each stage, ideally using a flow diagram. 9-10 and Figure 1 Characteristics of sources of evidence 15 For each source of evidence, present characteristics for which data were charted and provide the citations. 10 and Table  2 Critical appraisal within sources of evidence 16 If done, present data on critical appraisal of included sources of evidence (see item 12

Summary of evidence 19
Summarize the main results (including an overview of concepts, themes, and types of evidence available), link to the review questions and objectives, and consider the relevance to key groups.

Conclusions 21
Provide a general interpretation of the results with respect to the review questions and objectives, as well as potential implications and/or next steps.

Funding 22
Describe sources of funding for the included sources of evidence, as well as sources of funding for the scoping review. Describe the role of the funders of the scoping review.
18 JBI = Joanna Briggs Institute; PRISMA-ScR = Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews. * Where sources of evidence (see second footnote) are compiled from, such as bibliographic databases, social media platforms, and Web sites. † A more inclusive/heterogeneous term used to account for the different types of evidence or data sources (e.g., quantitative and/or qualitative research, expert opinion, and policy documents) that may be eligible in a scoping review as opposed to only studies. This is not to be confused with information sources (see first footnote). ‡ The frameworks by Arksey and O'Malley (6) and Levac and colleagues (7) and the JBI guidance (4,5) refer to the process of data extraction in a scoping review as data charting. § The process of systematically examining research evidence to assess its validity, results, and relevance before using it to inform a decision. This term is used for items 12 and 19 instead of "risk of bias" (which is more applicable to systematic reviews of interventions) to include and acknowledge the various sources of evidence that may be used in a scoping review (e.g., quantitative and/or qualitative research, expert opinion, and policy document).  1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16  17  18  19  20  21  22  23  24  25  26  27  28  29  30  31  32  33  34  35  36  37  38  39  40  41  42  43  44  45  46  47  48  49  50  51  52  53  54  55  56  57  58  59  60