COGNITIVE DECLINE IN OLDER ADULTS

Cognitive Decline in Older Adults

Abstract

This study investigates the implications of different levels of cognitive decline on functional status in frail older adults. Four cognitive trajectories, including two with catastrophic cognitive decline, were defined in a 3-year study. Participants with complete cognitive and functional status data at baseline, 12 and 36 months of follow-up were included in the study (n = 456). Data were analysed with repeated measures statistics. Substantial functional deterioration over time was observed for the participants with catastrophic cognitive decline. Catastrophic cognitive decline influenced performance in instrumental activities of daily living (IADL) and activities of daily living (ADL) at 12 months, whereas basic physical and mental actions were affected at 36 months. IADL were found to deteriorate more than ADL. The results have implications on planning appropriate geriatric rehabilitation and long-term care program.

Table of Contents

Abstract2

Cognitive Decline in Older Adults3

1. Introduction3

2. Materials and methods3

2.1. Study population3

2.2. Measurements3

2.2.1. Cognition3

2.2.2. Functional limitations3

2.2.3. IADLs3

2.2.4. ADLs3

2.2.5. Depressive symptomatology3

2.2.6. Hearing and visual problems3

2.2.7. Comorbidity questionnaire3

2.3. Analyses3

3. Results3

3.1. Groups according to trajectories of cognitive decline3

3.2. Functional limitations over time3

3.3. Disability in IADL over time3

3.4. Disability in ADL over time3

4. Discussion3

5. Conclusion3

References3

Cognitive Decline in Older Adults

1. Introduction

Cognitive decline qualifies as a complex phenomenon showing substantial variation among older individuals in the population (Christensen, 2001). Although average performance on most cognitive tasks declines with age ([McDonald-Miszczk et al., 1996] and [Lyketsos et al., 1999]), other studies show older adults remaining intact ([Shimamura et al., 1995] and [Christensen, 2001]). Cognitive decline is known to be associated with a variety of socio-demographic factors including lifestyles (Scarmeas and Stern, 2003), occupation (Alvarado et al., 2001), social relations ([Bassuk et al., 1999] and [Béland et al., 2005]), race and ethnicity ([Léveillé et al., 1998] and [Black et al., 1999]) and education ([Inouye et al., 1993] and [Schmand et al., 1997]). Comorbid conditions such as stroke and depression ([Lichtenberg et al., 1995] and [Rummans et al., 1997]), diabetes ([Strachan et al., 1997] and [Kumari et al., 2000]), auditory and vision problems ([Salthouse et al., 1996] and [Baltes and Lindenberger, 1997]) are associated with cognitive decline.

Cognitive decline plays a pivotal role in the maintenance of functional status in late life. Functional status may be defined by the concepts of disability and functional limitations (Verbrugge and Jette, 1994). Functional limitations are restrictions in performing fundamental physical and mental actions such as climbing stairs and producing intelligible speech. They are strong determinants of subsequent disability (Verbrugge and Jette, 1994). Disability is experienced difficulty doing activities in any domain of life due to a health or physical problem, and is further divided into two sets of activities including basic ADL and IADL (Lawton and Brody, 1969).

Numerous studies provide evidence of the role of cognitive decline as a risk factor for ADL and IADL decline in older adults ([Agüero-Torres et al., 2002], [Raji et al., 2004] and [McGuire and Ajani, 2006]). McGuire and Ajani (2006) investigated the contribution of cognitive status to functional disability in ADL and IADL over 2 years in a sample of 4077 ...