Cognitive Decline, Memory Impairment, Mild Cognitive Impairment
Conditions
Keywords
exercise
Brief summary
This study evaluates the effects of physical exercise on cognition, functional status, brain atrophy and blood flow, and cerebrospinal fluid biomarkers of Alzheimer's disease in adults with a mild memory impairment. Half of participants will participate in a stretching-balance-range of motion exercise program, while the other half will participate in a moderate/high aerobic training program.
Detailed description
Overall Study Design: The EXERT trial was a multicenter phase 3 randomized, single-blind study that examined the effects of aerobic exercise on cognition, functional status, whole and regional cerebral blood flow, and cerebrospinal fluid biomarkers of Alzheimer's disease in approximately 300 adults with amnestic MCI. EXERT included an 18-month behavioral intervention trial, with a 12-month supervised exercise intervention phase with its primary endpoints, followed by a 6-month unsupervised exercised phase. Subject Populations and Group Assignments: The study population included male and female subjects aged 65 to 89 diagnosed with test scores and clinical ratings consistent with amnestic Mild Cognitive Impairment (MCI). Assignment to study groups: involved randomization to either treatment or active control, and study staff performing assessments were blinded to intervention assignment to maintain the single-blind structure of the trial. Participants were to complete EXERT interventions at participating YMCAs located near the selected clinic sites across the U.S. The YMCA provided 18-month memberships at no cost to participants. In the first 12 months, a study-certified YMCA Trainer supervised all participants for the first 8 exercise sessions completed (weeks 1 and 2), and for 2 of 4 weekly sessions thereafter through Month 12. At Month 12, participants transitioned to independent exercise and were instructed to continue their assigned exercise programs for the final 6 months of the study without supervision. To encourage adherence and optimize cost efficiency, Trainers provided supervision to small groups of participants (2-4 individuals) randomized to the same intervention whenever possible. Compliance was evaluated using multiple mechanisms including heart rate monitoring, participant ratings of perceived exertion, entries in participants' Physical Activity Logs, Trainer assessment of effort, and weekly data review by the YMCA-Project Manager (Y-PM) and the Intervention Oversight Team (includes the Project Directors, Wake Forest team of exercise trial specialists, and Y-USA). These mechanisms provided multiple and regular opportunities to discuss participant progress, identify and resolve barriers, and encourage high levels of adherence to study protocols. The Intervention Oversight Team had the necessary expertise to successfully accomplish this objective in EXERT.
Interventions
BEHAVIORALAerobic exercise
Moderate/high intensity aerobic exercise will involve training at 70-80% heart rate reserve for 30 min, with an additional 10 minutes for warm-up and 5 minutes for cool-down, 4 times per week, for 12 months while supervised twice per week by a study-certified trainer at a participating YMCA .
BEHAVIORALStretching/balance/range of motion exercise
The stretching/balance/range of motion program will involve exercise at or below 35% heart rate reserve for 30 min, with an additional 10 minutes for warm up and 5 minutes for cool-down, 4 times per week, for 12 months while supervised twice per week by a study-certified trainer at a participating YMCA.
Sponsors
National Institute on Aging (NIA)
Wake Forest University Health Sciences
Alzheimer's Disease Cooperative Study (ADCS)
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
65 Years to 89 Years
Healthy volunteers
No
Inclusion criteria
1. Age between 65 and 89 years old, inclusive 2. MMSE: ≥24 for participants with 13 or more years of education; ≥22 for participants with 12 or fewer years of education 3. Global CDR score of 0.5 with a memory score of at least 0.5 4. Profile of test scores and clinical ratings is consistent with amnestic mild cognitive impairment 5. Speaks English fluently 6. Visual and auditory acuity adequate for cognitive testing 7. Completed at least 6 years of formal education or work history sufficient to exclude mental retardation 8. Has an informant who knows the participant well, has regular contact, and is available to accompany the participant to clinic visits or complete study partner assessments remotely. 9. Sedentary or underactive, determined by responses to the staff-administered EXERT Telephone Assessment of Physical Activity (TAPA) survey 10. Willing to be randomized to either intervention group and to complete the assigned activities as specified for 18 months 11. Willing and able to reliably travel to the identified YMCA, 4 times per week for 18 months 12. Ability to safely participate in either intervention and complete the 400 m Walk Test within 15 min without sitting or use of any assistance 13. Plans to reside in the area for at least 18 months 14. For planned travel, total time away must be no more than 2 months over the course of the study, and no more than 1 month at any one time; participants must be willing to continue the assigned exercise program if travelling out of the area for more than 1 week 15. In overall good general health with no disease or planned surgery that could interfere with study participation 16. Modified Hachinski ≤4 17. Stable use of cholinesterase inhibitors, memantine, vitamin E, estrogens, aspirin (81 300 mg daily), beta-blockers, or cholesterol-lowering agents for 12 weeks prior to screening (important for biomarker analyses) 18. Stable use of antidepressants lacking significant anticholinergic side effects for 4 weeks prior to screening as long as the participant does not meet DSM V criteria for major depression currently or in the last 12 months; GDS scores are to be used to inform clinical decisions but there is no specified cut-off score for inclusion 19. When applicable, willing to complete 4-week washout of psychoactive medications, including disallowed antidepressants, neuroleptics, chronic anxiolytics or sedative hypnotics, and willing to avoid these medications for the duration of the trial 20. Able to complete all baseline assessments
Exclusion criteria
1. Any significant neurologic disease, other than MCI, including any form of dementia, Parkinsons disease, Huntington's disease, normal pressure hydrocephalus, brain tumor, progressive supranuclear palsy, seizure disorder, subdural hematoma, multiple sclerosis, or history of significant head trauma with persistent neurologic sequelae or known structural brain abnormalities 2. Sensory or musculoskeletal impairment sufficient to preclude successful and safe completion of the intervention or assessment protocols; must be able to walk safely and unassisted on a treadmill 3. Contraindications for MRI studies, including claustrophobia, metal (ferromagnetic) implants, or cardiac pacemaker 4. Brain MRI at screening shows evidence of infection, infarction, or other clinically significant focal lesions, including multiple lacunes in prefrontal or critical memory regions; inconclusive findings may be subject to review by the ADCS Imaging Core 5. History of major depression or bipolar disorder (DSM V criteria), psychotic features, agitation or behavioral problems within the last 12 months 6. History of schizophrenia, as per DSM V criteria 7. History of alcohol or substance abuse or dependence within the past 2 years, as per DSM V criteria 8. Currently consumes more than 3 alcoholic drinks per day 9. Clinically significant or unstable medical condition, including uncontrolled hypertension or significant cardiac, pulmonary, hematologic, renal, hepatic, gastrointestinal, endocrine, metabolic or other systemic disease in the opinion of clinic medical personnel that may put the participant at increased risk, influence the results or compromise the participants ability to participate in the study (treated atrial fibrillation for more than 1 year or occasional premature ventricular contractions on ECG are not exclusions) 10. History in the last 6 months of myocardial infarction, coronary artery angioplasty, bypass grafting, or STENT placement 11. History in the last 3 months of transient ischemic attack or small vessel stroke (if more than 3 months, small vessel stroke with no residual effects are permitted) 12. Expected joint replacement surgery within the next 18 months 13. History within the last 5 years of a primary or recurrent malignant disease with the exception of non-melanoma skin cancers, resected cutaneous squamous cell carcinoma in situ, basal cell carcinoma, cervical carcinoma in situ, or in situ prostate cancer with normal prostate-specific antigen posttreatment 14. Hemoglobin A1c \>7.0 15. Clinically significant abnormalities in screening laboratory blood tests: low B12 is exclusionary, unless follow-up labs (homocysteine \[HCY\] and methylmalonic acid \[MMA\]) indicate that it is not physiologically significant 16. Current or past use of insulin to treat type 2 diabetes (other diabetes medications are acceptable if hemoglobin A1c ≤7) 17. Current use (within 60 days of screening) of psychoactive medications including tricyclic antidepressants, antipsychotics, mood-stabilizing psychotropic agents (e.g. lithium salts), psychostimulants, opiate analgesics, antiparkinsonian medications, anticonvulsant medications (except gabapentin and pregabalin for non-seizure indications), systemic corticosteroids, or medications with significant central anticholinergic activity. Limited use of antipsychotics (quetiapine ≤ 50mg/day or risperidone ≤ 0.5mg/day), and non-chronic use of opiate analgesics on an as needed basis is permitted; such medications must be avoided for 8 hours before clinic assessments 18. Chronic use of anxiolytics or sedative hypnotics except as follows: use of benzodiazepines for treatment on an as-needed basis for insomnia or daily dosing of anxiolytics is permitted; medications must be avoided for 8 hours before clinic assessments 19. Previous or current treatment involving active immunization against amyloid 20. Previous treatment with approved or investigational agents with anti-amyloid properties or passive immunization against amyloid are prohibited 12 months prior to screening and for the duration of the trial; treatment with other investigational agents are prohibited 3 months prior to screening and for the duration of the trial 21. For LP, current use of anticoagulants such as Coumadin, Plavix, or high dose Vitamin E 22. For LP, current blood clotting or bleeding disorder, or significantly abnormal prothrombin time (PT) or partial thromboplastin time (PTT) at screening 23. For LP, presence of physical distortions due to spinal surgery, severe degenerative joint disease or deformity, or obesity that could interfere with CSF collection (as per investigator judgment) 24. Participants whom the PI deems otherwise ineligible
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| ADAS-Cog-Exec Global Composite | Baseline to mean (Mo 6, Mo 12) | The ADAS-Cog-Exec Composite is a weighted sum of standardized (Z-score) change on subtests from the Alzheimer's Disease Assessment Scale - Cognitive (ADAS-Cog13; Immediate and Delayed Word Recall, Orientation, and Number Cancellation); box scores for the cognitive components of the Clinical Dementia Rating Scale (Memory, Orientation, Judgement & Problem Solving); and additional tests requiring executive function (Trail Making Test A & B, Digit Symbol Substitution, Category Fluency). See https://doi.org/10.1002/trc2.12059 for a detailed description regarding the development and validation of the ADAS-Cog-Exec. Change for the analysis of this primary outcome was calculated comparing the average of scores from month 6 and month 12 to baseline. The theoretical range for the ADAS-Cog-Exec is -3.00 to +3.00 in EXERT, with higher scores indicating improvement in cognitive function from baseline. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Volumetric Magnetic Resonance Imaging (MRI) of Prefrontal Composite Region | 12 Months | Assessment of volumetric change in prefrontal composite regions of the brain, measured by structural Magnetic Resonance Imaging (MRI), comparing MRI scans taken at baseline and month 12. The prefrontal composite includes: superior frontal, caudal-middle frontal, rostral-middle frontal, pars opercularis, and pars triangularis regions. Scans are compared and analyzed to give a percent deformation between timepoints. |
| Arterial Spin Labeling (ASL) Magnetic Resonance Imaging (MRI) of Prefrontal Composite Region | Baseline to 12 Months | Assessment of change in blood flow activity in the prefrontal composite regions of the brain, measured using Arterial Spin Labeling (ASL) magnetic resonance imaging (MRI) scans. The prefrontal composite includes: superior frontal, caudal-middle frontal, rostral-middle frontal, pars opercularis, and pars triangularis regions. Scans taken at baseline and month 12 are compared and analyzed to assess change in blood flow. The unit of cerebral blood flow from ASL is ml/100g/min, which means the amount of blood flow into 100g of tissue during one minute. |
| Arterial Spin Labeling (ASL) Magnetic Resonance Imaging (MRI) of AD Signature Composite Region | Baseline to 12 Months | Assessment of change in blood flow activity in the Alzheimer's Disease (AD) signature regions of the brain, measured using Arterial Spin Labeling (ASL) magnetic resonance imaging (MRI) scans. The AD signature composite includes: parahippocampus, fusiform, inferior temporal, middle temporal, and inferior-parietal regions. Scans taken at baseline and month 12 are compared and analyzed to assess change in blood flow. The unit of cerebral blood flow from ASL is ml/100g/min, which means the amount of blood flow into 100g of tissue during one minute. |
| Ratio of AD Biomarkers in Blood | 12 Months | Change in ratio of plasma amyloid beta peptides in blood plasma from baseline to12 months. A lower ab42/ab40 ratio in plasma is associated with a higher risk of dementia. |
| AD Biomarkers in CSF (ab42/ab40) | 12 Months | Change in ratio of amyloid beta peptides in cerebrospinal fluid (CSF) from baseline to 12 months. A lower ab42/ab40 ratio is associated with a higher risk of dementia. |
| AD Biomarkers in CSF (ab42/Tau) | 12 Months | Change in ratio of key peptides in cerebrospinal fluid (CSF) from baseline to 12 months. A lower ab42/tau ratio is associated with a higher risk of dementia. |
| AD Biomarkers in CSF (ab42/P-tau) | 12 Months | Change in ratio of key peptides in cerebrospinal fluid (CSF) from baseline to 12 months. A lower ab42/p-tau ratio is associated with a higher risk of dementia. |
| ADAS-Cog-Exec Global Composite in Subset Population | Baseline to mean (Mo 6, Mo 12) | The ADAS-Cog-Exec Composite is a weighted sum of standardized (Z-score) change on subtests from the Alzheimer's Disease Assessment Scale - Cognitive (ADAS-Cog13; Immediate and Delayed Word Recall, Orientation, and Number Cancellation); box scores for the cognitive components of the Clinical Dementia Rating Scale (Memory, Orientation, Judgement & Problem Solving); and additional tests requiring executive function (Trail Making Test A & B, Digit Symbol Substitution, Category Fluency). See https://doi.org/10.1002/trc2.12059 for a detailed description regarding the development and validation of the ADAS-Cog-Exec. Change for the analysis of this primary outcome was calculated comparing the average of scores from month 6 and month 12 to baseline. The theoretical range for the ADAS-Cog-Exec is -3.00 to +3.00 in EXERT, with higher scores indicating improvement in cognitive function from baseline. |
| Executive Function Composite Score | Baseline to mean (Mo 6, Mo 12) | The Executive Function Composite is the average standardized (Z-score) change on eight measures requiring attention and executive control: Trail Making, Part B; Digit Symbol Substitution; Category Fluency; Letter Fluency; Alzheimer's Disease Assessment Scale - Cognitive (ADAS-Cog13) Number Cancellation; NIH Toolbox Flanker; NIH Toolbox Dimension Change Card Sort, and Cogstate One Back. Change for analysis of this secondary outcome was calculated comparing the average of scores from month 6 and month 12 to baseline. The theoretical range for the Executive Function Composite is -3.00 to +3.00, with higher scores indicating improvement in executive function from baseline. |
| Episodic Memory Composite Score | Baseline to mean (Mo 6, Mo 12) | The Episodic Memory Composite is the average standardized (Z-score) change on five measures of memory: Immediate and Delayed Word Recall from the Alzheimer's Disease Assessment Scale - Cognitive (ADAS-Cog13); Cogstate Face-Name Associative Memory; Cogstate Behavioral Pattern Separation of Objects; and Cogstate One Card Learning. Change for analysis of this secondary outcome was calculated comparing the average of scores from month 6 and month 12 to baseline. The theoretical range for the Episodic Memory Composite is -3.00 to +3.00, with higher scores indicating improvement in episodic memory from baseline. |
| Volumetric Magnetic Resonance Imaging (MRI) of Hippocampus | 12 Months | Assessment of volumetric change in the hippocampus region of the brain, measured by structural Magnetic Resonance Imaging (MRI), comparing MRI scans taken at baseline and month 12. Scans are compared and analyzed to give a percent deformation between timepoints. |
| Volumetric Magnetic Resonance Imaging (MRI) of AD Signature Composite Region | 12 Months | Assessment of volumetric change in Alzheimer's Disease (AD) signature regions of the brain, measured by structural Magnetic Resonance Imaging (MRI), comparing MRI scans taken at baseline and month 12. The AD signature composite includes: parahippocampus, fusiform, inferior temporal, middle temporal, and inferior-parietal regions. Scans are compared and analyzed to give a percent deformation between timepoints. |
| Arterial Spin Labeling (ASL) Magnetic Resonance Imaging (MRI) of Hippocampus | Baseline to 12 Months | Assessment of change in blood flow activity in the hippocampus region of the brain, measured using Arterial Spin Labeling (ASL) magnetic resonance imaging (MRI) scans. Scans taken at baseline and month 12 are compared and analyzed to assess change in blood flow between the timepoints. The unit of cerebral blood flow from ASL is ml/100g/min, which means the amount of blood flow into 100g of tissue during one minute. |
Other
| Measure | Time frame | Description |
|---|---|---|
| Clinical Dementia Rating Scale-Sum of Boxes (CDR) and Alzheimers Disease Assessment Scale-Cognitive 13-item (ADAS-Cog13) | 12 Months | To test whether 12 months of aerobic exercise, relative to the control, reduces clinical ratings of cognitive impairment as measured by the CDR Sum of Boxes, and total score on the ADAS Cog13. |
| Measures of Cognitive Function and Well-being Including (1) ADCS-ADL-MCI); (2) BRIEF-A; (3) GDS; (4) NPI; SF-36; EuroQol: 5-Item Health Questionnaire; (5) CCI: Cognitive Change Index); and (6) Study Partner Self-Assessment | 12 Months | To test whether 12 months of aerobic exercise, relative to the control, improves self-report measures of cognitive function and well-being, including (1) daily living skills (ADCS-Activities of Daily Living-MCI); (2) BRIEF-A: Behavior Rating Inventory of Executive Function-Adult Version); (3) mood (GDS); (4) health-related quality of life (NPI: Neuropsychiatric Inventory; SF-36: 36-Item Short Form Health Survey; EuroQol: 5-Item Health Questionnaire); (5) subjective memory concerns (CCI: Cognitive Change Index); and (6) Study Partner Self-Assessment Questionnaire |
| ADAS-Cog-Exec, Executive Function, and Episodic Memory Composites | 18 Months | To examine enduring cognitive effects (measured by ADAS-Cog-Exec, Executive Function and Episodic Memory Composites) of the intervention following a 6-month extension (through Month 18) when the prescribed exercise is continued without supervision. |
| Subgroup Treatment Responder Analyses | 12 Months | To explore whether sex, age, baseline AD biomarker profile in CSF (ab42/ab40, ab42/tau, ab42/p-tau) and blood (ab42/ab40), and ApoE4 genotype (e4+, e4-) predict treatment response. |
| Intervention Effects on Secondary Outcomes in a Subset of Participants Who Completed 12 Months of the Study Prior to the COVID-19 Pandemic. | 12 months | To examine intervention effects on secondary outcomes listed above in participants who had the opportunity to complete a full 12 months of the study before the pandemic affected trial conduct. |
| Exploratory Magnetic Resonance Imaging (MRI) Volumes and Perfusion and Individual AD Biomarkers in CSF and Blood Measures | 12 Months | To test whether 12 months of aerobic exercise, relative to the control, favorably affects MRI whole brain, ventricular and entorhinal volumes; perfusion in whole brain, gray matter and white matter; and individual AD biomarkers in CSF (ab42, ab40, total tau, p-tau, BDNF) and blood (ab42, ab40). |
Countries
United States
Participant flow
Recruitment details
This study was conducted at Academic Institutions and participating Y-USA Centers across the nation. Recruitment for the overall study began June 2016 and ended in October 2021. This study consisted of a four week screening period, followed by 12 months of supervised exercise (the ITT period), and an additional 6 month unsupervised exercise period.
Pre-assignment details
Screening duration: From signed consent up to 4 weeks. At baseline visit, participants are randomized to trial arms. A total of 532 participants consented to participate in the trial. Of these consented, 236 participants were screening failures. 296 participants were assigned/randomized to the trial.
Participants by arm
| Arm | Count |
|---|---|
| Aerobic Moderate/high intensity aerobic exercise will involve training at 70-80% heart rate reserve for 30 min, with an additional 10 minutes for warm-up and 5 minutes for cool-down, 4 times per week, for 12 months while supervised twice per week by a study-certified trainer at a participating YMCA .
Aerobic exercise: Moderate/high intensity aerobic exercise will involve training at 70-80% heart rate reserve for 30 min, with an additional 10 minutes for warm-up and 5 minutes for cool-down, 4 times per week, for 12 months while supervised twice per week by a study-certified trainer at a participating YMCA . | 148 |
| Stretching/Balance/Range of Motion The stretching/balance/range of motion program will involve exercise at or below 35% heart rate reserve for 30 min, with an additional 10 minutes for warm up and 5 minutes for cool-down, 4 times per week, for 12 months while supervised twice per week by a study-certified trainer at a participating YMCA.
Stretching/balance/range of motion exercise: The stretching/balance/range of motion program will involve exercise at or below 35% heart rate reserve for 30 min, with an additional 10 minutes for warm up and 5 minutes for cool-down, 4 times per week, for 12 months while supervised twice per week by a study-certified trainer at a participating YMCA. | 148 |
| Total | 296 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 |
|---|---|---|---|
| Overall Study | Adverse Event | 4 | 3 |
| Overall Study | Death | 1 | 1 |
| Overall Study | early termination-study terminated | 1 | 2 |
| Overall Study | Lost to Follow-up | 3 | 4 |
| Overall Study | non site physician decision | 1 | 0 |
| Overall Study | Other | 0 | 4 |
| Overall Study | participant noncompliance | 1 | 1 |
| Overall Study | safety risk | 2 | 1 |
| Overall Study | Withdrawal by Subject | 20 | 14 |
Baseline characteristics
| Characteristic | Total | Aerobic | Stretching/Balance/Range of Motion |
|---|---|---|---|
| Age, Continuous | 74.46 years STANDARD_DEVIATION 5.96 | 74.26 years STANDARD_DEVIATION 5.71 | 74.65 years STANDARD_DEVIATION 6.23 |
| Alzheimer's Disease Assessment Scale - Cognitive Subscale 13 (ADAS-Cog 13) | 14.02 units on a scale STANDARD_DEVIATION 6.71 | 13.82 units on a scale STANDARD_DEVIATION 6.62 | 14.23 units on a scale STANDARD_DEVIATION 6.81 |
| Clinical Dementia Rating - Sum of Boxes (CDR-SB) | 1.5 units on a scale STANDARD_DEVIATION 0.86 | 1.43 units on a scale STANDARD_DEVIATION 0.84 | 1.57 units on a scale STANDARD_DEVIATION 0.87 |
| Ethnicity (NIH/OMB) Hispanic or Latino | 3 Participants | 3 Participants | 0 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 287 Participants | 142 Participants | 145 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 6 Participants | 3 Participants | 3 Participants |
| Mini-Mental State Examination (MMSE) | 27.97 units on a scale STANDARD_DEVIATION 1.87 | 27.92 units on a scale STANDARD_DEVIATION 1.91 | 28.03 units on a scale STANDARD_DEVIATION 1.83 |
| Race (NIH/OMB) American Indian or Alaska Native | 3 Participants | 2 Participants | 1 Participants |
| Race (NIH/OMB) Asian | 7 Participants | 3 Participants | 4 Participants |
| Race (NIH/OMB) Black or African American | 29 Participants | 15 Participants | 14 Participants |
| Race (NIH/OMB) More than one race | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 1 Participants | 1 Participants | 0 Participants |
| Race (NIH/OMB) White | 256 Participants | 127 Participants | 129 Participants |
| Region of Enrollment United States | 296 participants | 148 participants | 148 participants |
| Sex: Female, Male Female | 169 Participants | 85 Participants | 84 Participants |
| Sex: Female, Male Male | 127 Participants | 63 Participants | 64 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 1 / 148 | 2 / 148 |
| other Total, other adverse events | 148 / 148 | 148 / 148 |
| serious Total, serious adverse events | 23 / 148 | 23 / 148 |
Outcome results
Primary
ADAS-Cog-Exec Global Composite
The ADAS-Cog-Exec Composite is a weighted sum of standardized (Z-score) change on subtests from the Alzheimer's Disease Assessment Scale - Cognitive (ADAS-Cog13; Immediate and Delayed Word Recall, Orientation, and Number Cancellation); box scores for the cognitive components of the Clinical Dementia Rating Scale (Memory, Orientation, Judgement & Problem Solving); and additional tests requiring executive function (Trail Making Test A & B, Digit Symbol Substitution, Category Fluency). See https://doi.org/10.1002/trc2.12059 for a detailed description regarding the development and validation of the ADAS-Cog-Exec. Change for the analysis of this primary outcome was calculated comparing the average of scores from month 6 and month 12 to baseline. The theoretical range for the ADAS-Cog-Exec is -3.00 to +3.00 in EXERT, with higher scores indicating improvement in cognitive function from baseline.
Time frame: Baseline to mean (Mo 6, Mo 12)
Population: Modified Intent-to-Treat (mITT) Population: Includes all eligible participants who (1) began the exercise intervention (Intervention Session 1) and (2) completed at least one post-baseline assessment for the primary analysis at Month 6 or Month 12.~All consented randomized participants are grouped according to the treatment assigned at randomization, regardless of any protocol violations.
| Arm | Measure | Value (LEAST_SQUARES_MEAN) | Dispersion |
|---|---|---|---|
| Aerobic | ADAS-Cog-Exec Global Composite | -0.146 Change score | Standard Error 0.063 |
| Stretching/Balance/Range of Motion | ADAS-Cog-Exec Global Composite | -0.068 Change score | Standard Error 0.063 |
p-value: 0.29Regression, Linear
Secondary
ADAS-Cog-Exec Global Composite in Subset Population
The ADAS-Cog-Exec Composite is a weighted sum of standardized (Z-score) change on subtests from the Alzheimer's Disease Assessment Scale - Cognitive (ADAS-Cog13; Immediate and Delayed Word Recall, Orientation, and Number Cancellation); box scores for the cognitive components of the Clinical Dementia Rating Scale (Memory, Orientation, Judgement & Problem Solving); and additional tests requiring executive function (Trail Making Test A & B, Digit Symbol Substitution, Category Fluency). See https://doi.org/10.1002/trc2.12059 for a detailed description regarding the development and validation of the ADAS-Cog-Exec. Change for the analysis of this primary outcome was calculated comparing the average of scores from month 6 and month 12 to baseline. The theoretical range for the ADAS-Cog-Exec is -3.00 to +3.00 in EXERT, with higher scores indicating improvement in cognitive function from baseline.
Time frame: Baseline to mean (Mo 6, Mo 12)
Population: Subset of participants who had the opportunity to complete a full 12 months of the study (i.e., 12 months of exercise and the 12 Month outcome assessments) before the COVID-19 pandemic affected trial conduct.
| Arm | Measure | Value (LEAST_SQUARES_MEAN) | Dispersion |
|---|---|---|---|
| Aerobic | ADAS-Cog-Exec Global Composite in Subset Population | -0.18 Change score | Standard Error 0.08 |
| Stretching/Balance/Range of Motion | ADAS-Cog-Exec Global Composite in Subset Population | -0.15 Change score | Standard Error 0.076 |
p-value: 0.74Regression, Linear
Secondary
AD Biomarkers in CSF (ab42/ab40)
Change in ratio of amyloid beta peptides in cerebrospinal fluid (CSF) from baseline to 12 months. A lower ab42/ab40 ratio is associated with a higher risk of dementia.
Time frame: 12 Months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Aerobic | AD Biomarkers in CSF (ab42/ab40) | -0.00348 Change in ratio | Standard Deviation 0.00784 |
| Stretching/Balance/Range of Motion | AD Biomarkers in CSF (ab42/ab40) | -0.00413 Change in ratio | Standard Deviation 0.00611 |
p-value: 0.64Regression, Linear
Secondary
AD Biomarkers in CSF (ab42/P-tau)
Change in ratio of key peptides in cerebrospinal fluid (CSF) from baseline to 12 months. A lower ab42/p-tau ratio is associated with a higher risk of dementia.
Time frame: 12 Months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Aerobic | AD Biomarkers in CSF (ab42/P-tau) | -2.48 Change in ratio | Standard Deviation 2.7 |
| Stretching/Balance/Range of Motion | AD Biomarkers in CSF (ab42/P-tau) | -3.39 Change in ratio | Standard Deviation 5.47 |
p-value: 0.94Regression, Linear
Secondary
AD Biomarkers in CSF (ab42/Tau)
Change in ratio of key peptides in cerebrospinal fluid (CSF) from baseline to 12 months. A lower ab42/tau ratio is associated with a higher risk of dementia.
Time frame: 12 Months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Aerobic | AD Biomarkers in CSF (ab42/Tau) | -0.22 Change in ratio | Standard Deviation 0.445 |
| Stretching/Balance/Range of Motion | AD Biomarkers in CSF (ab42/Tau) | -0.299 Change in ratio | Standard Deviation 0.729 |
p-value: 0.97Regression, Linear
Secondary
Arterial Spin Labeling (ASL) Magnetic Resonance Imaging (MRI) of AD Signature Composite Region
Assessment of change in blood flow activity in the Alzheimer's Disease (AD) signature regions of the brain, measured using Arterial Spin Labeling (ASL) magnetic resonance imaging (MRI) scans. The AD signature composite includes: parahippocampus, fusiform, inferior temporal, middle temporal, and inferior-parietal regions. Scans taken at baseline and month 12 are compared and analyzed to assess change in blood flow. The unit of cerebral blood flow from ASL is ml/100g/min, which means the amount of blood flow into 100g of tissue during one minute.
Time frame: Baseline to 12 Months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Aerobic | Arterial Spin Labeling (ASL) Magnetic Resonance Imaging (MRI) of AD Signature Composite Region | 0.05 ml/100g/min | Standard Deviation 0.23 |
| Stretching/Balance/Range of Motion | Arterial Spin Labeling (ASL) Magnetic Resonance Imaging (MRI) of AD Signature Composite Region | 0 ml/100g/min | Standard Deviation 0.25 |
p-value: 0.31Regression, Linear
Secondary
Arterial Spin Labeling (ASL) Magnetic Resonance Imaging (MRI) of Hippocampus
Assessment of change in blood flow activity in the hippocampus region of the brain, measured using Arterial Spin Labeling (ASL) magnetic resonance imaging (MRI) scans. Scans taken at baseline and month 12 are compared and analyzed to assess change in blood flow between the timepoints. The unit of cerebral blood flow from ASL is ml/100g/min, which means the amount of blood flow into 100g of tissue during one minute.
Time frame: Baseline to 12 Months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Aerobic | Arterial Spin Labeling (ASL) Magnetic Resonance Imaging (MRI) of Hippocampus | 0.07 ml/100g/min | Standard Deviation 0.42 |
| Stretching/Balance/Range of Motion | Arterial Spin Labeling (ASL) Magnetic Resonance Imaging (MRI) of Hippocampus | 0.01 ml/100g/min | Standard Deviation 0.224 |
p-value: 0.61Regression, Linear
Secondary
Arterial Spin Labeling (ASL) Magnetic Resonance Imaging (MRI) of Prefrontal Composite Region
Assessment of change in blood flow activity in the prefrontal composite regions of the brain, measured using Arterial Spin Labeling (ASL) magnetic resonance imaging (MRI) scans. The prefrontal composite includes: superior frontal, caudal-middle frontal, rostral-middle frontal, pars opercularis, and pars triangularis regions. Scans taken at baseline and month 12 are compared and analyzed to assess change in blood flow. The unit of cerebral blood flow from ASL is ml/100g/min, which means the amount of blood flow into 100g of tissue during one minute.
Time frame: Baseline to 12 Months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Aerobic | Arterial Spin Labeling (ASL) Magnetic Resonance Imaging (MRI) of Prefrontal Composite Region | 0.04 ml/100g/min | Standard Deviation 0.31 |
| Stretching/Balance/Range of Motion | Arterial Spin Labeling (ASL) Magnetic Resonance Imaging (MRI) of Prefrontal Composite Region | 0.03 ml/100g/min | Standard Deviation 0.29 |
p-value: 0.78Regression, Linear
Secondary
Episodic Memory Composite Score
The Episodic Memory Composite is the average standardized (Z-score) change on five measures of memory: Immediate and Delayed Word Recall from the Alzheimer's Disease Assessment Scale - Cognitive (ADAS-Cog13); Cogstate Face-Name Associative Memory; Cogstate Behavioral Pattern Separation of Objects; and Cogstate One Card Learning. Change for analysis of this secondary outcome was calculated comparing the average of scores from month 6 and month 12 to baseline. The theoretical range for the Episodic Memory Composite is -3.00 to +3.00, with higher scores indicating improvement in episodic memory from baseline.
Time frame: Baseline to mean (Mo 6, Mo 12)
| Arm | Measure | Value (LEAST_SQUARES_MEAN) | Dispersion |
|---|---|---|---|
| Aerobic | Episodic Memory Composite Score | 0.005859 Change in score | Standard Error 0.04137 |
| Stretching/Balance/Range of Motion | Episodic Memory Composite Score | -0.014384 Change in score | Standard Error 0.03997 |
p-value: 0.7086Regression, Linear
Secondary
Executive Function Composite Score
The Executive Function Composite is the average standardized (Z-score) change on eight measures requiring attention and executive control: Trail Making, Part B; Digit Symbol Substitution; Category Fluency; Letter Fluency; Alzheimer's Disease Assessment Scale - Cognitive (ADAS-Cog13) Number Cancellation; NIH Toolbox Flanker; NIH Toolbox Dimension Change Card Sort, and Cogstate One Back. Change for analysis of this secondary outcome was calculated comparing the average of scores from month 6 and month 12 to baseline. The theoretical range for the Executive Function Composite is -3.00 to +3.00, with higher scores indicating improvement in executive function from baseline.
Time frame: Baseline to mean (Mo 6, Mo 12)
| Arm | Measure | Value (LEAST_SQUARES_MEAN) | Dispersion |
|---|---|---|---|
| Aerobic | Executive Function Composite Score | -0.02903 Change in score | Standard Error 0.03303 |
| Stretching/Balance/Range of Motion | Executive Function Composite Score | -0.03847 Change in score | Standard Error 0.03246 |
p-value: 0.8284Regression, Linear
Secondary
Ratio of AD Biomarkers in Blood
Change in ratio of plasma amyloid beta peptides in blood plasma from baseline to12 months. A lower ab42/ab40 ratio in plasma is associated with a higher risk of dementia.
Time frame: 12 Months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Aerobic | Ratio of AD Biomarkers in Blood | 0.00001 Change in ratio | Standard Deviation 0.0185 |
| Stretching/Balance/Range of Motion | Ratio of AD Biomarkers in Blood | -0.00062 Change in ratio | Standard Deviation 0.01119 |
p-value: 0.817Regression, Linear
Secondary
Volumetric Magnetic Resonance Imaging (MRI) of AD Signature Composite Region
Assessment of volumetric change in Alzheimer's Disease (AD) signature regions of the brain, measured by structural Magnetic Resonance Imaging (MRI), comparing MRI scans taken at baseline and month 12. The AD signature composite includes: parahippocampus, fusiform, inferior temporal, middle temporal, and inferior-parietal regions. Scans are compared and analyzed to give a percent deformation between timepoints.
Time frame: 12 Months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Aerobic | Volumetric Magnetic Resonance Imaging (MRI) of AD Signature Composite Region | -0.612 percent deformation | Standard Deviation 1.02 |
| Stretching/Balance/Range of Motion | Volumetric Magnetic Resonance Imaging (MRI) of AD Signature Composite Region | -0.643 percent deformation | Standard Deviation 0.951 |
p-value: 0.49Regression, Linear
Secondary
Volumetric Magnetic Resonance Imaging (MRI) of Hippocampus
Assessment of volumetric change in the hippocampus region of the brain, measured by structural Magnetic Resonance Imaging (MRI), comparing MRI scans taken at baseline and month 12. Scans are compared and analyzed to give a percent deformation between timepoints.
Time frame: 12 Months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Aerobic | Volumetric Magnetic Resonance Imaging (MRI) of Hippocampus | -0.66 percent deformation | Standard Deviation 1.12 |
| Stretching/Balance/Range of Motion | Volumetric Magnetic Resonance Imaging (MRI) of Hippocampus | -0.343 percent deformation | Standard Deviation 0.98 |
p-value: 0.06Regression, Linear
Secondary
Volumetric Magnetic Resonance Imaging (MRI) of Prefrontal Composite Region
Assessment of volumetric change in prefrontal composite regions of the brain, measured by structural Magnetic Resonance Imaging (MRI), comparing MRI scans taken at baseline and month 12. The prefrontal composite includes: superior frontal, caudal-middle frontal, rostral-middle frontal, pars opercularis, and pars triangularis regions. Scans are compared and analyzed to give a percent deformation between timepoints.
Time frame: 12 Months
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Aerobic | Volumetric Magnetic Resonance Imaging (MRI) of Prefrontal Composite Region | -0.34 percent deformation | Standard Deviation 1.36 |
| Stretching/Balance/Range of Motion | Volumetric Magnetic Resonance Imaging (MRI) of Prefrontal Composite Region | -0.51 percent deformation | Standard Deviation 1.11 |
p-value: 0.33Regression, Linear
Other Pre-specified
ADAS-Cog-Exec, Executive Function, and Episodic Memory Composites
To examine enduring cognitive effects (measured by ADAS-Cog-Exec, Executive Function and Episodic Memory Composites) of the intervention following a 6-month extension (through Month 18) when the prescribed exercise is continued without supervision.
Time frame: 18 Months
Other Pre-specified
Clinical Dementia Rating Scale-Sum of Boxes (CDR) and Alzheimers Disease Assessment Scale-Cognitive 13-item (ADAS-Cog13)
To test whether 12 months of aerobic exercise, relative to the control, reduces clinical ratings of cognitive impairment as measured by the CDR Sum of Boxes, and total score on the ADAS Cog13.
Time frame: 12 Months
Other Pre-specified
Exploratory Magnetic Resonance Imaging (MRI) Volumes and Perfusion and Individual AD Biomarkers in CSF and Blood Measures
To test whether 12 months of aerobic exercise, relative to the control, favorably affects MRI whole brain, ventricular and entorhinal volumes; perfusion in whole brain, gray matter and white matter; and individual AD biomarkers in CSF (ab42, ab40, total tau, p-tau, BDNF) and blood (ab42, ab40).
Time frame: 12 Months
Other Pre-specified
Intervention Effects on Secondary Outcomes in a Subset of Participants Who Completed 12 Months of the Study Prior to the COVID-19 Pandemic.
To examine intervention effects on secondary outcomes listed above in participants who had the opportunity to complete a full 12 months of the study before the pandemic affected trial conduct.
Time frame: 12 months
Other Pre-specified
Measures of Cognitive Function and Well-being Including (1) ADCS-ADL-MCI); (2) BRIEF-A; (3) GDS; (4) NPI; SF-36; EuroQol: 5-Item Health Questionnaire; (5) CCI: Cognitive Change Index); and (6) Study Partner Self-Assessment
To test whether 12 months of aerobic exercise, relative to the control, improves self-report measures of cognitive function and well-being, including (1) daily living skills (ADCS-Activities of Daily Living-MCI); (2) BRIEF-A: Behavior Rating Inventory of Executive Function-Adult Version); (3) mood (GDS); (4) health-related quality of life (NPI: Neuropsychiatric Inventory; SF-36: 36-Item Short Form Health Survey; EuroQol: 5-Item Health Questionnaire); (5) subjective memory concerns (CCI: Cognitive Change Index); and (6) Study Partner Self-Assessment Questionnaire
Time frame: 12 Months
Other Pre-specified
Subgroup Treatment Responder Analyses
To explore whether sex, age, baseline AD biomarker profile in CSF (ab42/ab40, ab42/tau, ab42/p-tau) and blood (ab42/ab40), and ApoE4 genotype (e4+, e4-) predict treatment response.
Time frame: 12 Months