Gait as Predictor of Dementia and Falls. The Gait and Brain Cohort Study

Study Overview
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Brief Summary
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Motor slowing and cognitive slowing are more prevalent as we age. Importantly, the presence of both in an older person increases their risk of having dementia by ten times. Currently, there are no clinically meaningful predictors of progression to dementia in people with mild cognitive impairment (MCI). The main hypothesis is that subtle variations in gait while performing a simple cognitive task is a reliable, easy to perform, and feasible methodology to detect those older adults at higher risk of progression to dementia and also, at higher risk of further mobility decline and falls. Rationale. The Canadian population is aging. According to recent estimates, the proportion of the population aged 65 and older will increase rapidly from 13% in 2005 to 25% by 2031. This increase in proportion is accompanied by a considerable amount of disability and subsequent dependency which has major effects on both the quality of life of older adults and their caregivers, and on the Canadian health care system. An important goal of geriatric medicine is to reduce the gap between life expectancy and disability-free life expectancy by reducing disability and dependency in the later years of life. A substantial portion of this disability stems from two major geriatric syndromes: cognitive impairment and mobility limitation. The ultimate manifestations of these syndromes are dementia and falls. Interestingly, these manifestations often coexist in elderly people: falling is a common geriatric syndrome affecting about a third of older adults each year, and dementia affects about a third of Canadians aged 80 and over. Together, dementia and falls are responsible for much of the discomfort, disability, and health care utilization in older adults and each will become more prevalent as older Canadians are expected to number approximately $9 million by 2031. The combined direct cost of dementia and falls for the Canadian Health System is over $4.9 billion per year. Establishing reliable and easy to obtain predictors to accurately identify MCI patients at highest risk of progressing to dementia is essential first, to determine who will benefit from additional and/or invasive testing and second, to implement preventative strategies, including cognitive training, physical exercises, and aggressive vascular risk factors correction to delay progression. Even a modest one-year delay in dementia incidence could save Canada $109 billion over 30 years.

Detailed Description
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This longitudinal cohort study started in 2007 and is aiming to assess 600 older persons (60 y/o to 85 y/o) at risk of development cognitive impairment and dementia, during a 25 year of follow-up, since we expanded the study to recruit more participants, which was approved by our Institutional Research Board. The follow-up period was selected in order to cover the potential progression to dementia of at least two-third of the participants. From 2007 to 2023, for the first five years of follow up, assessments were conducted at baseline and every 6 months; since 2023, this was changed by which assessments are being conducted every 12-months along with performing a virtual assessment of outcomes only, every 6-months. After the visit at 60 months, participants will then be followed once a year for 20 years. The six months period between assessments during the first 5 years was selected since it is the minimum time required for detecting significant changes between assessments in cognitive measurements and for avoiding testing learning effects. If changes are not noted within the first five years, then the annual follow-up period will provide sufficient time periods to detect significant changes in cognition, gait, and balance measures. Blood test for genotyping (ApoE4 carrier) is being performed only at baseline assessments. Cognitive, gait and balance assessments are being performed in all 12-month follow-up visits. From 2010 to 2021, 3Tesla Magnetic Resonance Imaging (structural and functional -resting state-) and MRI spectroscopy are being performed at four different time points: at baseline, month 18 and month 36, and month 60, following the Canadian Dementia Imaging protocol (http://www.cdip-pcid.ca.). Since 2021, the 18-month MRI timepoint changed to be performed at 12-month visit to align MRI timepoints with blood draw, which allows analysis of MRI and biomarker comparisons over time. For the 20-month Follow-Up period, MRI was performed at Year-2, Year-5 and Year-7 until 2018. Since 2018, the 20-Year Follow-Up MRI timepoints changed to Year-3, Year-5, Year-7 and Year-10. Blood and brain imaging were added after the second wave of the study, in 2010.

Official Title
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Gait as Predictor of Cognitive Decline, Dementia, and Risk of Falls in MCI. A Cohort Study

Conditions
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Gait Apraxia, Mild Cognitive Impairment, Subjective Cognitive Impairment, Cerebral Atrophy, Alzheimer Disease, Dementia

Participation Criteria
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Eligibility Criteria
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General Inclusion Criteria: Absence of Dementia (DSM IV-TR or DSM V criteria) Aged 60-85 years Able to walk independently 10 meters without any gait aid (for example: walker, cane); Exclusion Criteria: Unable to understand English; Parkinsonism or any neurological disorder with residual motor deficit (e.g.: stroke, epilepsy); Musculoskeletal disorder detected by clinical examination which affects gait performance; Active osteoarthritis affecting the lower limbs at clinical evaluation Use of psychotropics which can affect motor performance (e.g. neuroleptics and benzodiazepines) Severe Depression (score > 12/15 on the Geriatric Depression Scale).

Ages Eligible for Study
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Minimum Age: 60 Years
Maximum Age: 85 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Cognitively Normal (Control Group)<br>Participants aged 60 and older, with absence of Dementia (by DSM IV and DSM V) criteria. Normal age-, sex-, and education-adjusted performance on standardized cognitive tests, which are used to classify mild cognitive impairment (MCI) or prodromal AD. | |
| Subjective Cognitive Impairment (SCI)<br>Participants aged 60 and older, with absence of Dementia (by DSM IV and DSM V) criteria. Normal age-, sex-, and education-adjusted performance on standardized cognitive tests, which are used to classify mild cognitive impairment (MCI) or prodromal AD. Self-experienced persistent decline in cognitive capacity in comparison with a previously normal status and unrelated to an acute event. Answering yes to both of the following questions: Do you feel like your memory or thinking is becoming worse? and Does this concern you? | |
| Mild Cognitive Impairment (MCI)<br>Participants aged 60 and older that have self-experienced persistent decline in cognitive capacity and unrelated to an acute event. MCI is operationalized following Peterson's criteria as: i) presence of subjective memory complaints from the patient and family; ii) objective memory impairment in cognitive tests (below 1.5 SD on standardized cognitive tests adjusted by age, sex, and education-); iii) preserved activities of daily living (assessed using the Lawton-Brody scale); iv) absence of clinical dementia established using DSM-IV-TR (from 2007 to 2013) and DSM V (from 2014 and onwards) | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Progression to Dementia | The primary outcome is progression to dementia ascertained by clinician investigator using DSM-IV-TR (from 2007 to 2013) and DSM V (from 2014 and onwards). At the time of diagnosis, clinicians are blinded to baseline gait or baseline neuro-psychological test scores. Participants are being re-assessed after six months of the time point of ascertainment of dementia to confirm dementia status. | 25 years of follow-up | 
| Type of Dementia | Type of dementia is being established using standardized criteria for Alzheimer's disease (AD) dementia, frontotemporal dementia, Lewy body dementia, and vascular dementia (VaD). | 25 years of follow-up | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Development of Mobility Decline | It is expected that MCI individuals with higher gait variability at baseline will develop mobility decline, defined as incident slowing in gait velocity (cm/s) by 10 cm/s | 25 years of follow-up | 
| Incidence of Falls | Falls is defined as 'an unintentionally coming to rest on the ground, floor, or other lower level and not due to a seizure or an acute stroke. Recurrent falls are defined as two or more events in a 12 months period. This outcome will be analyzed as the rate of falls over 36 months (defined as number of falls person-time at risk), the proportion of participants who fall (0, 1) and the proportion of recurrent fallers (2+ falls). | 25 years of follow-up | 
| Brain anatomical changes (grey matter) | Changes in grey matter volume are being as absolute change (in cm3) across assessments | 25 years of follow-up | 
| Brain anatomical changes (white matter) | Changes in white matter volume is being evaluated as absolute change (in cm3) across assessments. | 25 years of follow-up | 
| Brain anatomical changes (ventricular volume) | Changes in ventricular volume is being evaluated as absolute change (in cm3) across assessments | 25 years of follow-up | 
| Mortality | When a participant pass away informed/documented by caregiver or medical record | 25 years of follow up |