LETHE-AT: a Personalized Multidomain Lifestyle Intervention for Individuals at Increased Risk of Memory Impairment. (LETHE-AT)

January 21, 2026 updated by: Elisabeth Stögmann, Medical University of Vienna

Digitally Supported Lifestyle Programme to Promote Brain Health Among Older Adults - the LETHE-AT Randomised-controlled, Multicentre Pilot Trial

The goal of this clinical trial is to learn whether a hybrid multidomain lifestyle program can prevent cognitive decline and reduce dementia risk in community-dwelling adults in mid- to late life who are at increased risk of Alzheimer´s disease or related dementias but do not yet have significant cognitive impairment.

The main question the study aims to answer are:

  • Whether the structured hybrid multidomain lifestyle intervention is feasible (e.g., adherence and retention rate), and how well the digital components are accepted and implemented in the intervention group.
  • Does the intervention reduces the overall burden of modifiable dementia risk factors and improves global cognitive performance compared with usual care.

Researchers will compare participants assigned to the tailored hybrid multidomain lifestyle intervention group with those in a self-guided multimodal lifestyle advice group.

Participants assigned to the intervention group will receive a plan adjusted to their individual dementia risk profile. A physician trained in motivational interviewing will review their progress continuously.

The self-guided multimodal lifestyle advice group will receive rigid but comprehensible lifestyle health advice with reduced access to digital support tools.

Participants will:

  • Complete an initial risk assessment that uses machine-learning triage to identify and prioritize their most important modifiable dementia risk factors.
  • Receive personalized recommendations for gradual lifestyle change, including physical activity, nutrition, cognitive training, other dementia risk-factor management (e.g. hearing impairment), stress & sleep management, and social activities.
  • Use a smartphone and smartwatch to passively collect digital biomarkers and to complete questionnaires at regular intervals, so that physicians trained in motivational interviewing can adapt goals through shared decision making.
  • Use a study app as the central access point for the program, including educational content, progress tracking, and gamified challenges with social comparison and incentives.

Study Overview

Detailed Description

LETHE AT is an 18 month multicentre randomized controlled trial in Austria that evaluates a tailored hybrid multidomain lifestyle intervention programme in older adults with multiple dementia risk factors and is conducted at the Medical Universities of Vienna, Innsbruck, and Graz.

Previous multidomain lifestyle trials have shown that structured interventions targeting modifiable risk factors can attenuate cognitive decline and reduce dementia risk. These programme have used different delivery formats, including intensive face to face interventions (FINGER), fully digital approaches (Maintain Your Brain), and hybrid models (SMART and LETHE EU). LETHE-AT builds on this foundation by combining refined risk profiling and motivational interviewing (MI) with a centrally organized online and telephone prescreening process. This approach identifies cognitively unimpaired adults with a high burden of dementia risk factors and reduces avoidable on-site screening failures and participant disappointment.

Following the prescreening, comprehensive on-site screening is conducted at three Austrian memory clinics to enroll 300 participants. Eligibility is determined using predefined inclusion and exclusion criteria, including age 55-75 years, preserved cognition, subjective cognitive decline or a first-degree family history of dementia, the presence of at least three of 14 established modifiable dementia risk factors (e.g. hearing impairment, elevated LDL cholesterol), and sufficient motivation for lifestyle change as evaluated by physicians trained in MI.

Eligible participants are invited for a baseline visit, where dementia risk is quantified using LIBRA2 and ANU-ADRI, and a harmonized neuropsychological and functional assessment battery is administered by trained neuropsychologists.

The study population is then stratified by sex, age and study site and randomly assigned in a 1:1 ratio to the tailored hybrid multidomain lifestyle intervention group or to the self-guided multimodal lifestyle advice group.

At a subsequent in-person visit, all participants attend a structured onboarding session. In both groups, the smartphone, smartwatch and LETHE-App are introduced, standardized usage instructions are provided, and access to ongoing technical support is ensured.

In the MI-guided hybrid multidomain lifestyle intervention group, onboarding additionally includes an individual consultation with a trained MI-coach.

The 14 modifiable risk factors are mapped onto six lifestyle domains (diet, physical activity, cognitive engagement, sleep and stress, social interactions, and other risk-factor management) to guide content and provide a replicable coaching framework. Additionally, the modifiable risk profile is processed by a dedicated AI-based decision-support tool that generates tailored goal recommendations, and a complemental questionnaire captures personal preferences and constraints. Based on this information, participants and the MI coach select personal goals from a predefined list, with each goal allocated to one of the six lifestyle domains.

The intervention programme begins with a small set of high-priority goals and is gradually expanded, with the number and intensity of goals adapted over time to each participant's risk profile, capacity and circumstances. The intervention programme is harmonized across study sites and supported by manuals to ensure consistent delivery.

The LETHE-App is provided to both study arms and serves several purposes. First, it enables continuous assessment of digital markers (e.g., log-in patterns), complemented by digital biomarkers from the smartwatch (e.g., sleeping-time). Second, it delivers frequent questionnaires on system satisfaction and risk-factor status. In addition, the app offers reminders and review functions for personal goals and provides evidence-based lifestyle information for each domain, including content supplied by the Austrian Agency for Health and Food Safety (AGES). Further functions, such as gamification elements to support adherence and motivation to change, are planned for iterative development.

Participants attend in-person study visits at baseline, month 9 and month 18, where they undergo an extended neuropsychological test battery, standardized dementia risk assessment and blood sampling. Brain MRI is performed as part of an imaging sub-study, and blood samples are stored for analysis of conventional risk markers and exploratory dementia-related biomarkers.

Outcome assessors for cognition, imaging and laboratory measures are blinded to group allocation, and group assignment is not revealed in study documentation used for these assessments.

Intervention study visits consist of individual MI-based tele-health sessions of approximately 20 to 30 minutes, scheduled at roughly three-month intervals to review progress, troubleshoot barriers and adjust goals. A harmonized protocol is used across sites, and sessions focus on strengthening intrinsic motivation for lifestyle change by exploring ambivalence, linking behaviour change to personally meaningful values and reinforcing self-efficacy in initiating and maintaining lifestyle modifications.

Safety is monitored through brief adverse event questionnaires at scheduled time points and through spontaneous reports during visits or phone contacts. All study related events are documented and managed according to protocol, and the intervention is nonpharmacologic and consistent with current dementia prevention guidelines. Data are pseudonymized and stored on secure servers with restricted access and audit trails, and trial conduct follows Good Clinical Practice and standardized operating procedures with trained staff and a central data management plan.

The planned sample of 300 participants reflects the focus on feasibility outcomes such as counseling acceptability, adherence and retention. Analyses follow the intention to treat principle and use linear mixed effects models with group, time and their interaction adjusted for baseline values and prespecified covariates. Effect estimates are reported with 95 percent confidence intervals, and missing data are examined in planned sensitivity analyses. No formal interim efficacy analysis is planned.

Study Type

Interventional

Enrollment (Estimated)

300

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

      • Vienna, Austria
        • Medical University of Vienna
        • Principal Investigator:
          • Elisabeth Stögmann, MD PhD
        • Contact:
        • Sub-Investigator:
          • Niklas Rast, MD
    • Styria
      • Graz, Styria, Austria, 8010
        • Medical University of Innsbruck
        • Contact:
        • Principal Investigator:
          • Stephan Seiler, Md PhD
        • Sub-Investigator:
          • Marko Stijic, M.Sc.
    • Tyrol
      • Innsbruck, Tyrol, Austria, 6020
        • Medical University of Innsbruck
        • Contact:
        • Principal Investigator:
          • Atbin Djamshidian-Tehrani, MD PhD
        • Sub-Investigator:
          • Livia Scanferla, M.Sc.

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Age between 55 and 75 years at the time of screening.
  • Fluency in German.
  • All participants must be able and willing to provide written informed consent form (ICF) prior to any study-related procedures.
  • Ownership of a compatible Android smartphone, or willingness and capability to use a study-provided Android smartphone for the duration of the study.
  • Subjective cognitive decline and/or a positive first-degree family history of dementia.
  • Willingness to make meaningful changes in at least three of six lifestyle domains: dietary counselling, physical activity, cognitive training, vascular risk management, social interaction, and sleep and relaxation.
  • Cognitive performance at or slightly below age expectations, defined as an m-TICS (modified Telephone Interview for Cognitive Status) score ≥ 37/50, and a Montreal Cognitive Assessment (MoCA) ≥ 26/30.

Exclusion Criteria:

  • Diagnosed or suspected dementia or substantial cognitive impairment, defined as an m-TICS score ≤ 36 or MoCA < 26, or current or previous use of Alzheimer´s disease or other dementia medication.
  • Significant neurological disease, including but not limited to Parkinson´s disease, Huntington´s disease, normal pressure hydrocephalus, brain tumour, progressive supranuclear palsy, seizure disorder, subdural haematoma, multiple sclerosis, or a history of significant head trauma with persistent neurological sequelae or known structural brain abnormalities.
  • Diminished decision-making capacity, inability to provide informed consent, inability to complete study assessments, or any condition preventing effective cooperation, as determined by clinical judgement.
  • Severe impairment of vision, hearing, or communication abilities that would preclude participation in study procedure.
  • Any medical or psychiatric condition affecting safe engagement, including but not limited to active malignancy, major depressive disorder, symptomatic cardiovascular disease, or revascularisation procedures within the past year.
  • Current participation in another interventional trial, unless the study team determines this does not interfere with participation in the LETHE-AT.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Sham Comparator: A self-guided multimodal lifestyle advice group
Participants in the control arm receive a self-guided lifestyle advice programme via the LETHE-AT app and smartwatch, with standardized information across all lifestyle domains but without motivational interviewing, structured coaching or algorithm-based personalization.
Participants receive a reduced version of the LETHE-AT app with general health information only. No structured in-person or remote counselling is provided and no individualized digital content is unlocked. They are encouraged to implement lifestyle changes independently. Throughout the trial, participants complete the same in-app questionnaires, wear a Garmin Vivosmart 5, and receive routine laboratory result with advice to seek certain medical care if needed. A pure no-treatment arm is not included for ethical reasons.
Active Comparator: A tailored hybrid multidomain lifestyle intervention group
Participants in the intervention arm receive an MI-guided hybrid multidomain lifestyle intervention that integrates AI-based risk profiling, personalized goal setting and structured telehealth coaching with app- and smartwatch-supported self-management across six lifestyle domains.
The structured counselling intervention combines interactive face-to-face workshops with ongoing remote coaching through the LETHE-AT mobile app and regular (video)-telephone sessions to support sustained lifestyle changes. Each participant is individually guided throughout the intervention by a dedicated coach (physician or psychologist), trained in motivational interviewing techniques aimed at facilitating behavioural changes across targeted lifestyle domains.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Operational feasibility: retention rate
Time Frame: Baseline to 18 months
Proportion of all randomized participants who complete the Month 18 assessment in each trial arm (percentage of all randomized participants; higher percentage = better retention).
Baseline to 18 months
Operational feasibility: adherence to the structured hybrid lifestyle intervention
Time Frame: Continuously assessed over 18 months
Composite adherence score combining attendance at workshops and telehealth sessions, engagement with the LETHE-AT app (logins and completed modules), and proportion of days with successful smartwatch data uploads (higher values = better adherence).
Continuously assessed over 18 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in health-related quality of life (SF-36)
Time Frame: Baseline to 18 months
Change in health-related quality of life assessed with the 36-Item Short Form Health Survey (SF-36; 0-100 points per domain; higher scores = better self-reported health status).
Baseline to 18 months
Change in health literacy (HLS-EU-Q16)
Time Frame: Baseline to 18 months
Change in health literacy assessed with the European Health Literacy Survey Questionnaire, 16-item version (HLS-EU-Q16; 0-16 points; higher scores = better general health literacy).
Baseline to 18 months
User acceptance of the digital solution (SUS)
Time Frame: 2 months past enrollment to 18 months
Change in perceived usability of the app and digital devices assessed with the System Usability Scale (SUS; 0-100 points; higher scores = better perceived usability and acceptance).
2 months past enrollment to 18 months
Change in perceived stress (PSS-14)
Time Frame: Baseline, Month 9, 18 months.
Change in perceived stress assessed with the Perceived Stress Scale-14 (PSS-14; 0-56 points; higher scores = more perceived stress during the past month).
Baseline, Month 9, 18 months.
Change in insomnia symptoms (ISI)
Time Frame: Baseline, Month 9, 18 months
Change in insomnia symptoms assessed with the Insomnia Severity Index (ISI; 0-28 points; higher scores = more severe insomnia complaints).
Baseline, Month 9, 18 months

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in global cognition assessed with the modified Neuropsychological Test Battery (mNTB)
Time Frame: Baseline (Month 0) to Month 18.

All test raw scores are converted to z-scores (baseline mean = 0, SD = 1, with sign reversal where lower times indicate better performance):

Wechsler Memory Scale - Fourth Edition (WMS-IV) Logical Memory (immediate and delayed recall, recognition)

Rey Auditory Verbal Learning Test (RAVLT / VLMT; list learning, immediate and delayed recall, recognition)

Rey-Osterrieth Complex Figure Test (copy, 3-minute and 30-minute delayed recall)

Wechsler Adult Intelligence Scale - Fourth Edition (WAIS-IV) Digit Span (forward, backward, sequencing)

Test of Attentional Performance (TAP) - Alertness

Test of Attentional Performance (TAP) - Divided Attention

WAIS-IV Digit Symbol Substitution Test (DSST)

Trail Making Test (TMT) Part A

Trail Making Test (TMT) Part B (shitime B-A)

Regensburg Word Fluency Test (semantic: animals; phonemic: letter P)

Colour-Word Interference Test (German Stroop; colour naming, word reading, interference condition)

Baseline (Month 0) to Month 18.
Change in dementia risk: LIBRA2
Time Frame: Baseline and Month 18.
Change in dementia risk estimated with the Lifestyle for Brain Health index (LIBRA2; theoretical range -5.9 to +12.7; higher scores = less healthy lifestyle and higher estimated dementia risk).
Baseline and Month 18.
Change in dementia risk: ANU-ADRI
Time Frame: Baseline and Month 18.
Change in dementia risk estimated with the Australian National University Alzheimer's Disease Risk Index (ANU-ADRI; theoretical range approximately -13 to +64; higher scores = higher estimated Alzheimer's disease risk).
Baseline and Month 18.
Change in physical activity (German-PAQ)
Time Frame: Baseline, Month 9, Month 18.
Change in self-reported physical activity assessed with the Short German Physical Activity Questionnaire (German-PAQ; minutes per week of moderate-to-vigorous activity; higher values = more physical activity).
Baseline, Month 9, Month 18.
Change in depressive symptoms (SDS)
Time Frame: Baseline, Month 9, Month 18
Change in depressive symptoms assessed with the Zung Self-Rating Depression Scale (SDS; 20-80 points; higher scores = more depressive symptom burden).
Baseline, Month 9, Month 18
Change in Mediterranean diet adherence (MEDAS)
Time Frame: Baseline, Month 9, Month 18
Change in diet quality assessed with the 14-Item Mediterranean Diet Adherence Screener (MEDAS; 0-14 points; higher scores = better adherence to a Mediterranean-style diet).
Baseline, Month 9, Month 18
Change in functional abilities (FAQ)
Time Frame: Baseline, Month 9, Month 18
Change in instrumental activities of daily living assessed with the Functional Activities Questionnaire (FAQ; 0-30 points; higher scores = greater functional impairment in IADL).
Baseline, Month 9, Month 18
Change in social engagement (LSNS-6)
Time Frame: Baseline, Month 9, Month 18
Change in social networks assessed with the Lubben Social Network Scale-6 (LSNS-6; 0-30 points; higher scores = larger and more supportive social network).
Baseline, Month 9, Month 18
Change in cognitive reserve (CRQi)
Time Frame: Baseline, Month 9, Month 18
Change in cognitive reserve assessed with the Cognitive Reserve questionnaire index. (higher scores = greater lifetime cognitive reserve from education and stimulating activities)
Baseline, Month 9, Month 18
Change in physical functioning (SPPB and grip strength)
Time Frame: Baseline, Month 9, Month 18
Change in lower-extremity function assessed with the Short Physical Performance Battery (SPPB; 0-12 points; higher scores = better balance, gait and chair-rise performance) and change in hand grip strength measured in kilograms with a dynamometer.
Baseline, Month 9, Month 18
Change in smoking dependence (FTND)
Time Frame: Baseline, Month 9, Month 18
Change in nicotine dependence among current smokers assessed with the Fagerström Test for Nicotine Dependence (FTND; 0-10 points; higher scores = stronger nicotine dependence).
Baseline, Month 9, Month 18
Change in alcohol consumption (AUDIT-C)
Time Frame: Baseline, Month 9, Month 18
Change in alcohol use assessed with the Alcohol Use Disorders Identification Test - Consumption subscale (AUDIT-C; 0-12 points; higher scores = higher risk of hazardous drinking).
Baseline, Month 9, Month 18
Change in AD-related blood biomarkers
Time Frame: Baseline and Month 18 (subsample).
Change in plasma Aβ42/40 ratio, phosphorylated tau (e.g. p-tau217) and neurofilament light chain (NfL) as markers of Alzheimer-related and neuroaxonal pathology (higher levels = greater pathology).
Baseline and Month 18 (subsample).
Ten-year cardiovascular disease risk (Framingham Risk Score)
Time Frame: Baseline and Month 18.
Change in 10-year cardiovascular risk estimated using the Framingham Risk Score (percentage probability based on age, blood pressure, lipids, smoking and diabetes status; higher values = higher predicted CVD risk).
Baseline and Month 18.
Change in attitudes towards dementia risk reduction (selected MCLHB-DRR items)
Time Frame: Baseline, 9 Months, 18 Months
Change in participants' motivation, perceived benefits, and perceived personal relevance of dementia risk reduction, assessed with selected items from the MCLHB-DRR scale (higher scores indicating more positive attitudes towards adopting risk-reducing behaviours).
Baseline, 9 Months, 18 Months
Change in hippocampal volume (MRI)
Time Frame: Near Baseline and near Month 18 (±2 months; optional MRI sub study)
Change in hippocampal volume measured on high resolution structural MRI.
Near Baseline and near Month 18 (±2 months; optional MRI sub study)
Change in cortical thickness (MRI)
Time Frame: Near Baseline and near Month 18 (±2 months; optional MRI sub study)
Change in cortical thickness measured on high resolution structural MRI.
Near Baseline and near Month 18 (±2 months; optional MRI sub study)
Change in white matter integrity (MRI)
Time Frame: Near Baseline and near Month 18 (±2 months; optional MRI sub study)
Change in white matter integrity measured on diffusion weighted MRI.
Near Baseline and near Month 18 (±2 months; optional MRI sub study)
Change in resting state connectivity indices (MRI)
Time Frame: Near Baseline and near Month 18 (±2 months; optional MRI sub study)
Change in resting state connectivity indices measured on resting state functional MRI.
Near Baseline and near Month 18 (±2 months; optional MRI sub study)
Change in resting heart rate (Continuously)
Time Frame: Continuously for 18 months.
Change in resting heart rate derived from continuous wrist photoplethysmography recorded day and night by the Garmin Vivosmart 5 smartwatch.
Continuously for 18 months.
Change in Sleep Score (Continuously)
Time Frame: Continuously for 18 months.
Change in Sleep Score derived from wearable identified sleep stages combined into a single Sleep Score (Garmin Vivosmart 5).
Continuously for 18 months.
Change in minutes of moderate to vigorous activity (Continuously)
Time Frame: Continuously for 18 months.
Change in minutes of moderate to vigorous activity captured by the Garmin Vivosmart 5 smartwatch.
Continuously for 18 months.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

January 8, 2026

Primary Completion (Estimated)

October 1, 2027

Study Completion (Estimated)

November 1, 2027

Study Registration Dates

First Submitted

December 14, 2025

First Submitted That Met QC Criteria

January 21, 2026

First Posted (Actual)

January 29, 2026

Study Record Updates

Last Update Posted (Actual)

January 29, 2026

Last Update Submitted That Met QC Criteria

January 21, 2026

Last Verified

November 1, 2025

More Information

Terms related to this study

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

De-identified individual participant data (including baseline characteristics, primary and key secondary outcomes) underlying the main published results will be made available to qualified researchers upon reasonable request, after approval by the sponsor and the relevant ethics committees.

IPD Sharing Time Frame

IPD and supporting information will be made available after publication of the primary results for a limited period to be specified in the final data sharing policy.

IPD Sharing Access Criteria

Access will be granted to qualified researchers upon reasonable request and subject to sponsor and ethics committee approval, according to the final data sharing policy.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP
  • ICF
  • ANALYTIC_CODE

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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