Análise da mobilidade, dupla tarefa funcional e quedas em idosos preservados cognitivamente, com comprometimento cognitivo leve e doença de Alzheimer

Abstract

Introduction: Recent studies reported mobility deficits and higher prevalence of falls in older people with cognitive impairment, even in mild stages of impairment. However, differences in mobility during simple and dual task situations between older people with preserved cognition (PC), mild cognitive impairment (MCI) and Alzheimer’s disease (AD) (mild stage) are still not clear. Sophisticated mobility tools and dual task activities with new, functional and challenging secondary tasks could be effective in identifying subtle motor changes. Moreover, a better understanding about the relationship between cognitive and motor changes and the fall risk factors in older people with MCI and AD could provide new knowledge about the physiopathology of MCI and AD and could help in better planning of screening, prevention and interventions of falls, MCI and AD. Objective: to analyze mobility, functional dual task and falls in older people with PC, MCI and mild AD. Method: The sample was composed by 40 community-dwelling older people with PC, 40 MCI and 38 mild AD. All volunteers performed an assessment, including anamneses, history of falls in the past year, cognition (Addenbrooke’s cognitive Examination-revised version and Frontal Assessment Battery), dual task (Timed up and go test-TUG associated with the motor-cognitive task of calling a phone number) and functional mobility (10-meter walk test and TUG). The TUG phases (sit-to-stand, walking forward, turn, walking back and turn-to-sit) were assessed using a system of movement analysis (Qualisys motion system). Still, the occurrence of falls was collected prospectively in a 6-month follow up using falls calendar and monthly calls in older people with MCI and AD. Sociodemographic and clinical, level of physical activity, functional status, functional mobility, cognitive and depressive variables were analyzed as potential fall risk factors. For statistical analysis, a significance level of α=0.05 was adopted and the SPSS software was used (20.0). Results: Older people with cognitive impairment (MCI and mild AD) presented more falls (retrospective data) compared to people with PC, and specific characteristics (place, consequences) about history of falls between groups were identified. Regarding dual task and 10-meter walk tests, only measures of dual task test distinguished older people with mild AD from PC and MCI and no measure could differ MCI and PC groups. In relation to functional mobility (kinematic data), all TUG phases could differentiate older people with AD from PC, except the sit-to-stand phase. The walking forward phase differed older people with PC from MCI, specifically on range of motion variables during stance phase. The walking back, turn and turn-to-sit phases distinguished older subjects with AD from MCI. Regarding the association between cognitive domains and mobility, different cognitive domains predicted the 10-meter walk test and the isolated cognitive-motor task measures among groups. The visuospatial domain was independently associated with TUG (total time) in MCI and AD groups and with the dual task test in all three groups. No significant associations were found between the walking TUG phases and cognitive domains in any group. However, executive function deficits was associated with impairments of transition TUG phases in the three groups. The visuospatial domain was identified as an independent predictor of turn-to-walk and turn-to-sit measures in the AD Group. During the 6-month follow-up, 52,6% of MCI people and 51,4% of AD people fell at least once. After multivariate analysis, the dual task test and the turn-to-sit phase were able to independently predict falls in older people with MCI and AD, respectively. Conclusion: The dual task test used was able to distinguish older people with AD from PC and MCI. The analysis of transition and also the walking TUGT phases separately is essential in the identification of mobility patterns among cognitive profiles of older people. Still, the findings demonstrate the importance of considering the influence of specific cognitive domains in daily mobility tasks in order to improve rehabilitation and prevention of cognitive and mobility disturbances. The prediction of visuospatial domain on postural transition tasks may provide insight into why people with AD have an elevated fall risk. The modifiable fall risk factors found can be used to detect risk of falls, as well as improving interventions for preventing falls in older adults with MCI and AD, with focus on exercises involving dual task and transition postural activities.