Journal of Alzheimer's Disease - Volume 71, issue s1

Authors: Sathyan, Sanish | Ayers, Emmeline | Gao, Tina | Milman, Sofiya | Barzilai, Nir | Rockwood, Kenneth | Verghese, Joe

Article Type: Research Article

Abstract: Background: Frailty is highly prevalent among older adults, and associated with cognitive decline. Relationship between frailty and motoric cognitive risk syndrome (MCR), a pre-dementia syndrome characterized by the presence of subjective cognitive complaints and slow gait, is yet to be elucidated. Objective: To examine whether frailty increases the risk of developing incident MCR. Methods: We analyzed 641 adults, aged 65 and above, participating in the LonGenity study. Frailty was defined using a 41-point cumulative deficit frailty index (FI). MCR was diagnosed at baseline and annual follow-up visits using established criteria. Cox proportional hazard models were used …to study the association of baseline frailty with incident MCR, and reported as hazard ratio (HR) with 95% confidence intervals (CI) adjusted for age, sex, and education. Results: At baseline, 70 participants (10·9%) had prevalent MCR. Of the remaining 571 non-MCR participants (mean age 75.0, 57.3% women), 70 developed incident MCR (median follow-up 2.6 years). Higher frailty scores at baseline were associated with an increased risk of incident MCR (HR for each 0.01 increase in the FI: 1.07; 95% CI 1.03–1.11; p  = 0.0002). The result was unchanged even after excluding mobility related or chronic illnesses items from the FI as well as accounting for reverse causation, competing risk of death, baseline cognitive status, social vulnerability, and excluding participants with mild cognitive impairment syndrome. Conclusions: Higher levels of frailty increase risk for developing MCR and suggest shared mechanisms. This association merits further study to identify strategies to prevent cognitive decline. Show more

Keywords: Cognition, cumulative frailty score, dementia, slow gait

DOI: 10.3233/JAD-190517

Citation: Journal of Alzheimer's Disease, vol. 71, no. s1, pp. S85-S93, 2019

Authors: Ayers, Emmeline | Verghese, Joe

Article Type: Research Article

Abstract: Background: Motoric cognitive risk (MCR) syndrome is a cognitive-motor syndrome associated with increased risk of transition to dementia. The clinical phenotype of MCR is not yet established. Objective: To systematically assess clinical gait abnormalities in older adults with MCR. Methods: Of the 522 community-dwelling non-demented adults aged 65 and older enrolled in the Central Control of Mobility in Aging study, 43 were diagnosed with MCR (47% women) based on presence of cognitive complaints and slow gait velocity (MCRv). Four additional subtypes of MCR were defined by substituting slow gait with short stride length (MCRsl, n  = 41), …slow swing time (MCRsw, n  = 21), high stride length variability (MCRslv, n  = 24), and high swing time variability (MCRswv, n  = 25). The prevalence of clinical gait abnormalities (neurological or non-neurological) in MCR overall (n  = 81) and subtypes was studied. We also examined if gait abnormalities predicted further cognitive and functional decline in MCR cases. Results: Most clinical gait abnormalities were mild (walked without assistance) in the five MCR subtypes (44 to 61%). Neurological (range 24 to 46%) and non-neurological gait abnormalities (33 to 61%) were common in all MCR subtypes. Neurological gaits were most frequent in MCRsl (46%) and non-neurological gaits in MCRv (61%). Over a median 3.02 years of follow-up, presence of gait abnormality in MCR cases at baseline predicted worsening disability scores (estimate 0.17, p -value = 0.033) but not decline on cognitive scores (p -value = 0.056). Conclusion: Clinical gait abnormalities are common in MCR syndrome and its subtypes, and are associated with accelerated functional decline. Show more

Keywords: Cognition, gait, motoric cognitive risk syndrome

DOI: 10.3233/JAD-181227

Citation: Journal of Alzheimer's Disease, vol. 71, no. s1, pp. S95-S103, 2019

Authors: Hunter, Susan W. | Divine, Alison | Omana, Humberto | Wittich, Walter | Hill, Keith D. | Johnson, Andrew M. | Holmes, Jeffrey D.

Article Type: Research Article

Abstract: Background: People with Alzheimer’s disease (AD) exhibit balance and walking impairments that increase falls risk. Prescription of a mobility aid is done to improve stability, yet also requires increased cognitive resources. Single-point canes require unique motor sequencing for safe use. The effect of learning to use a single-point cane has not been evaluated in people with AD. Objectives: In people with AD and healthy adult controls: 1) examine changes in gait while using a cane under various walking conditions; and 2) determine the cognitive and gait costs associated with concurrent cane walking while multi-tasking. Methods: Seventeen …participants with AD (age 82.1±5.6 years) and 25 healthy controls (age 70.8±14.1 years) walked using a single-point cane in a straight (6 meter) and a complex (Figure of 8) path under three conditions: single-task (no aid), dual-task (walking with aid), and multi-task (walking with aid while counting backwards by ones). Velocity and stride time variability were recorded with accelerometers. Results: Gait velocity significantly slowed for both groups in all conditions and stride time variability was greater in the AD group. Overall, multi-tasking produced a decrease in gait and cognitive demands for both groups, with more people with AD self-prioritizing the cognitive task over the gait task. Conclusion: Learning to use a cane demands cognitive resources that lead to detrimental changes in velocity and stride time variability. This was most pronounced in people with mild to moderate AD. Future research needs to investigate the effects of mobility aid training on gait performance. Show more

Keywords: Aged, assistive devices, cane, dementia, gait

DOI: 10.3233/JAD-181169

Citation: Journal of Alzheimer's Disease, vol. 71, no. s1, pp. S105-S114, 2019

Authors: Hunter, Susan W. | Divine, Alison | Omana, Humberto | Wittich, Walter | Hill, Keith D. | Johnson, Andrew M. | Holmes, Jeffrey D.

Article Type: Research Article

Abstract: Background: Cognitive deficits and gait problems are common and progressive in Alzheimer’s disease (AD). Prescription of a 4-wheeled walker is a common intervention to improve stability and independence, yet can be associated with an increased falls risk. Objectives: 1) To examine changes in spatial-temporal gait parameters while using a 4-wheeled walker under different walking conditions, and 2) to determine the cognitive and gait task costs of walking with the aid in adults with AD and healthy older adults. Methods: Twenty participants with AD (age 79.1±7.1 years) and 22 controls (age 68.5±10.7 years) walked using a 4-wheeled …walker in a straight (6 m) and Figure of 8 path under three task conditions: single-task (no aid), dual-task (walking with aid), and multi-task (walking with aid while counting backwards by ones). Results: Gait velocity was statistically slower in adults with AD than the controls across all conditions (all p values <0.025). Stride time variability was significantly different between groups for straight path single task (p  = 0.045), straight path multi-task (p  = 0.031), and Figure of 8 multi-task (0.036). Gait and cognitive task costs increased while multi-tasking, with performance decrement greater for people with AD. None of the people with AD self-prioritized gait over the cognitive task while walking in a straight path, yet 75% were able to shift prioritization to gait in the complex walking path. Conclusion: Learning to use a 4-wheeled walker is cognitively demanding and any additional tasks increases the demands, further adversely affecting gait. The increased cognitive demands result in a decrease in gait velocity that is greatest in adults with AD. Future research needs to investigate the effects of mobility aid training on gait performance. Show more

Keywords: Aged, gait, assistive devices, cane, dementia

DOI: 10.3233/JAD-181170

Citation: Journal of Alzheimer's Disease, vol. 71, no. s1, pp. S115-S124, 2019

Authors: Taylor, Morag E. | Brodie, Matthew A. | van Schooten, Kimberley S. | Delbaere, Kim | Close, Jacqueline C.T. | Payne, Narelle | Webster, Lyndell | Chow, Jessica | McInerney, Garth | Kurrle, Susan E. | Lord, Stephen R.

Article Type: Research Article

Abstract: Understanding the characteristics of physical activity and daily-life gait in older people with dementia may help identify those at risk of negative health outcomes and inform targeted interventions. Questionnaires are often used to assess physical activity but may be more affected by recall bias in people with dementia and provide little information about daily-life gait characteristics. The aim of the study was to assess differences in daily-life activity levels and gait characteristics between community-dwelling older people with mild to moderate dementia (n  = 45; mean age 81±6 years, 42% female) and age-sex matched (1:2) cognitively-healthy controls (n  = 90). Participants wore a …tri-axial accelerometer (DynaPort MoveMonitor, McRoberts) on their lower back for 7 days and were assessed on neuropsychological and physical performance. Compared to age-sex matched controls, participants with dementia demonstrated reduced daily-life activity (fewer steps per day, fewer and shorter walking bouts, and lower daily walk time) and walking intensity (reduced speed, stride length and cadence). Participants with dementia also had significantly increased within-walk variability (stride time) and less regular gait (higher sample entropy). Within the group of participants with dementia, higher daily-life activity levels were associated with greater self-reported physical activity and better executive function. Fallers (1+ falls past year) with dementia had significantly reduced daily-life activity and walking speed when compared to non-fallers with dementia. In conclusion, people with dementia are less active in daily-life and present with significant impairments across multiple gait domains when compared to age-sex matched controls. These findings highlight opportunities for targeted interventions and support further research to examine interventions aimed at addressing these deficits. Show more

Keywords: Accidental falls, daily-life gait, dementia, executive function, neurocognitive disorders, physical activity, walking speed

DOI: 10.3233/JAD-181174

Citation: Journal of Alzheimer's Disease, vol. 71, no. s1, pp. S125-S135, 2019