Dementia as a Predictor of Functional Disability: A Four-Year Follow-Up Study

Abstract

Background: Prospective studies have shown that cognitive impairment is a strong and consistent risk factor of physical disability. However, cognitive impairment has been based on the result of a single screening tool. Objective: To investigate the role of cognition in the subsequent incidence and decline of functional disability in basic activities of daily living (ADL) and instrumental activities of daily living (IADL) after a full assessment of dementia. Methods: A group of 1,358 Japanese atomic bomb survivors aged 61 years or older who lived in the community or in institutions in Hiroshima City were followed for 4 years. During the baseline survey (1993–1995), subjects were administered a screening test for cognitive impairment. Those suspected of dementia underwent a series of cognitive tests (Hasegawa’s dementia scale, Clinical Dementia Rating) and a neurological examination. The diagnosis of dementia was made according to DSM-III-R criteria. Study subjects were questioned about their reported ADL and their IADL. During the follow-up period, deaths were recorded and a follow-up survey (1997–1999) used to assess ADL and IADL performance. Results: Dementia, even after adjustment for age, sex and history of stroke, was a strong predictor of functional disability, as indicated by ADL (odds ratio, OR = 14.0; confidence interval, CI = 5.4–36.3), IADL (OR = 10.1, CI = 2.2–46.4), and also by assessment of decline in ADL (OR = 9.8, CI = 4.2–22.8) or IADL status (OR = 3.9, CI = 1.8–8.3). Conclusion: Dementia is an important determinant of functional status. Deterioration in ADL is more significant than deterioration in IADL, suggesting that factors other than cognition, such as motivation or perceptual, sensory and motor abilities, may be important in IADL performance. This study confirms previous findings on risk factors that affect functional ability and extends our knowledge by examining several criteria of function that are important in the daily lives of elderly people.

Avaliação das atividades de vida diária de idosos com diferentes níveis de demência

“…A study conducted by Teunisse et al 20 demonstrated a strong association between cognitive deficits and disability in ADL, with greater deficits resulting in greater functional dependence. Additionally, Sauvaget et al 12 demonstrated that dementia is the strongest predictor of physical incapacity and decreased ability in basic and instrumental activities of daily living. It is important to remark that dementia has been identified as a determining factor for …”

“…Since functional status is a basic domain of gerontological assessment 8,9 , several specific questionnaires for the assessment of ADL were developed and are commonly utilized 5,6,9,10,11,12 , specially the Kats Index (BADL) 9,10,13 , the Lawton-Brody Index 9,14 and the Pfeffer Index (IADL) 9,14,15 . However, in Brazil, these questionnaires have not yet been systematically utilized.…”

“…Considering the strong associations between functional performance and severity of dementia 5,12 and the utilization of several instruments to assess functionality in the absence of a consensus regarding which instrument to use for elderly people with specific conditions, the objective of the present study was to compare the performance of BADL and IADL among elderly people with different levels of severity of dementia. An additional objective of the study was to verify whether there was any association between two questionnaires commonly used in clinical settings and research studies to assess IADL.…”

Utility of the Clinical Dementia Rating in Asian Populations

“…35,36 Similar to data from the US and Europe, a recent Korean study reported that in subjects with mild cognitive impairment (MCI), the CDR sum of boxes score (especially when combined with word list recall) is a good predictor of progression to Alzheimer's disease. 37 Further evidence of the validity of CDR staging can be indirectly accrued from other Asian neuropathological, 38 genetic 39,40 and neuroimaging studies.…”

Tradução, adaptação cultural e análise das propriedades psicométricas do Activities of Daily Living Questionnaire (ADLQ) para avaliação funcional de pacientes com a doença de Alzheimer

“…These results show a significant negative correlation between the two instruments, which reinforces the strong association between cognitive levels and functional ability 24,25 . It also suggests that dementia works as a strong predictor of physical incapacity and of decline in basic and instrumental ADLs 26 .…”