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Background: Greater gait variability increases the risk of falls. However, little is known about changes in gait variability in older age. The aims of this study were to examine: (1) change in gait variability across time and (2) factors that predict overall mean gait variability and its change over time.Methods: Participants (n = 410; mean age 72 years) were assessed at baseline and during follow up visits at an average of 30 and 54 months. Step time, step length, step width and double support time (DST) were measured using a GAITRite walkway. Variability was calculated as the standard deviation of all steps for each individual. Covariates included demographic, medical, sensorimotor and cognitive factors. Mixed models were used to determine (1) change in gait variability over time (2) factors that predicted or modified any change.Results: Over 4.6 years the presence of cardiovascular disease at baseline increased the rate of change for step length variability (p = 0.04 for interaction), lower education increased the rate of change for DST variability (p = 0.04) and weaker quadriceps strength increased the rate of change for step width variability (p = 0.01). Greater postural sway predicted greater variability on average across the three phases (p < 0.05). Arthritis, a higher body mass index (BMI), slower processing speed and lower quadriceps strength predicted greater mean step time variability (p < 0.05). Arthritis and a higher BMI predicted greater mean step length variability, while slower processing speed and BMI predicted greater mean DST variability (p < 0.05).Conclusion: Over a nearly 5-year period, variability in different gait measures do not show uniform changes over time. Furthermore, each variability measure appears to be modified and predicted by different factors. These results provide information on potential targets for future trials to maintain mobility and independence in older age.

Background Gait variability is a marker of cognitive decline. However, there is limited understanding of the cortical regions associated with gait variability. We examined associations between regional cortical thickness and gait variability in a population-based sample of older people without dementia. Method Participants (n = 350, mean age 71.9 ± 7.1) were randomly selected from the electoral roll. Variability in step time, step length, step width, and double support time (DST) were calculated as the standard deviation of each measure, obtained from the GAITRite walkway. Magnetic resonance imaging (MRI) scans were processed through FreeSurfer to obtain cortical thickness of 68 regions. Bayesian regression was used to determine regional associations of mean cortical thickness and thickness ratio (regional thickness/overall mean thickness) with gait variability. Results Smaller global cortical thickness was only associated with greater step width and step time variability. Smaller mean thickness in widespread regions important for sensory, cognitive, and motor functions were associated with greater step width and step time variability. In contrast, smaller thickness in a few frontal and temporal regions were associated with DST variability and the right cuneus was associated with step length variability. Smaller thickness ratio in frontal and temporal regions important for motor planning, execution, and sensory function and greater thickness ratio in the anterior cingulate was associated with greater variability in all measures. Conclusions Examining individual cortical regions is important in understanding the relationship between gray matter and gait variability. Cortical thickness ratio highlights that smaller regional thickness relative to global thickness may be important for the consistency of gait.

Background: The interrelationships between gait, cerebral small vessel disease (CSVD), and cognitive impairments in aging are not well-understood – despite their common co-occurrence. Objective: To systematically review studies of gait impairment in CSVD, pre-dementia, and dementia and to identify key gaps for future research and novel pathways toward intervention. Methods: A PRISMA-guided search strategy was implemented in PubMed to identify relevant studies. Potential articles (n=263) published prior to December 1st, 2021 were screened by two reviewers. Studies with sample sizes >20 and including some adult over >65 years (n=202) were included. Results: The key findings were that 1) adverse gait and cognitive outcomes were associated with several (rather than select) CSVD pathologies distributed across the brain, and 2) poor gait and CSVD pathologies were more strongly associated with dementia with a vascular, rather than an Alzheimer’s disease-related, cause. Discussion : A better understanding of the interrelationships between gait performance in CSVD, pre-dementia and dementia requires studies examining a) comprehensive patterns in the clinical manifestations of CSVD, b) racially/ethnically diverse samples, c) samples followed for extended periods of time or across the adult lifespan, d) non-traditional CSVD neuroimaging markers (e.g., resting-state fMRI), and e) continuous (e.g., wearable sensors) and complex (e.g., dual-task) walking performance.

Background falls share risk factors with cognitive decline but whether falls predict cognitive decline, pre-dementia syndromes and dementia is poorly understood. Objectives this study aimed to examine if falls are associated with cognitive decline in specific domains and the risk of Motoric Cognitive Risk (MCR) syndrome and dementia. Design cross-sectional study. Methods in older people (age 80.6 ± 5.3 years) free of dementia at baseline, the number of falls (none, one or multiple) during the year before enrolment and the first year of follow-up (exposure) were recorded. Decline in specific cognitive functions (global cognition, episodic verbal memory, verbal fluency, working memory, response inhibition and processing speed-attention), incident MCR and incident dementia were outcome measures. Linear mixed effects models were used to examine the associations between falls and cognitive decline, adjusting for confounders. Cox proportional hazards models were used to determine if falls predicted risk of incident MCR or dementia. Results of 522 eligible participants, 140 had a single fall and 70 had multiple falls. Multiple falls were associated with a greater decline in global cognition, episodic memory, verbal fluency and processing speed-attention compared to those with no falls (P &lt; 0.05). Over a median follow-up of 1.0 years 36 participants developed MCR and 43 participants developed dementia. Those with multiple falls had a two-fold increased risk of MCR compared to those with no falls, but no increased risk of developing dementia. Conclusions multiple falls may be an important marker to identify older people at greater risk of future cognitive decline and incident MCR.

Background Gait and cognition decline with advancing age, and presage the onset of dementia. Yet, the relative trajectories of gait and cognitive decline in aging are poorly understood – particularly among those with the Motoric Cognitive Risk (MCR) syndrome. This study compared changes in simple and complex gait performance and cognition, as a function of age and MCR. Methods We examined gait and cognitive functions of 1,095 LonGenity study participants (mean age = 75.4±6.7 years) with up to 12 years of annual follow-up. Participants were of Ashkenazi Jewish descent, free of dementia, ambulatory, and had a 12.2 % MCR prevalence at baseline. Gait speed was measured at usual pace walking (single-task walking, STW-speed) and walking while talking (WWT-speed). Eleven neuropsychological test scores were examined separately, and as a global cognition composite. Linear mixed-effects models adjusted for baseline sex, education, parental longevity, cognitive impairment and global health were used to estimate changes in gait and cognition, as a function of age and MCR. Results STW-speed, WWT-speed, and cognitive tests performance declined in a non-linear (accelerating) fashion with age. STW-speed declined faster than WWT-speed and cognitive test scores. People with MCR showed faster rates of decline on figure copy and phonemic fluency. Conclusions Gait declines at a faster rate than cognition in aging. People with MCR are susceptible to faster decline in visuospatial, executive, and language functions. This study adds important knowledge of trajectories of gait and cognitive decline in aging, and identifies MCR as a risk factor for accelerated cognitive decline.