Assessing the Current State of Cognitive Frailty: Measurement Properties.

BACKGROUND

Currently, an estimated 25-30% of people ages 85 or older have dementia, with a projected 115 million people worldwide living with dementia by 2050. With this worldwide phenomenon fast approaching, early detection of at-risk older adults and development of interventions focused on preventing loss in quality of life are increasingly important. A new construct defined by the International Consensus Group (I.A.N.A/I.A.G.G) as «cognitive frailty» combines domains of physical frailty with cognitive impairment and provides a framework for research that may provide a means to identify individuals with cognitive impairment caused by nonneurodegenerative conditions. Using the integrative review method of Whittemore and Knafl., 2005 this study examines and appraises the optimal measures for detecting cognitive frailty in clinical populations of older adults.

METHODS

The integrative review was conducted using PubMed, CINAHL, Web of Science, PsycInfo, and ProQuest Dissertations and Theses. From the total 185 articles retrieved, review of titles and key words were conducted. Following the initial review, 168 articles did not meet the inclusion criteria for association of frailty and cognition. Of the 18 fulltext articles reviewed, 11 articles met the inclusion criteria; these articles were reviewed in-depth to determine validity and reliability of the cognitive frailty measures.

RESULTS

Predictive validity was established by the studies reviewed in four main areas: frailty and type of dementia MCI (OR 7.4, 95% CI 4.2-13.2), vascular dementia (OR 6.7, 95% CI 1.6-27.4) and Alzheimer's dementia (OR 3.2, 95% CI 1.7-6.2), frailty and vascular dementia (VaAD) is further supported by the rate of change in frailty x macroinfarcts (r = 0.032, p < 0.001); frailty and the individual domains of cognitive function established with the relationship of neurocognitive speed and change in cognition using regression coefficients; individual components of frailty and individual domains of cognitive function associations inculded slow gait and executive function (β -0.20, p < 0.008 ), attention (β -0.25 p < 0.008), processing speed (β -0.16, p < 0.008), word recall (β - 0.18, p = 0.02), and logical memory (β = 0.04, p =0.04). Weak grip was predictive for changes in executive function (β - 0.16, p =0.008). Physical activity was associated with changes in executive function (β = -0.18, p= 0.02) and word recall (β = 0.17, p= 0.02), individual components of frailty and global cognitive function were found in several studies which included grip strength (r = - 0.51, p < 0.001), gait speed (r = - 0.067, p < 0.001), and exhaustion (β - 0.18, p < 0.008).

CONCLUSIONS

This paper presents the first-known review of the measurement properties for the cognitive frailty construct since the published results from the International Consensus Group (I.A.N.A/I.A.G.G). Evidence presented in this review continues to support the link between physical frailty and cognition with developing validity to support distinct relationships between components of physical frailty and cognitive decline. Results call attention to inconsistencies in reporting of reliability, validity, and heterogeneity in the measurements and operational definition for cognitive frailty. Further research is needed to establish an operational definition and develop psychometrically appropriate clinical measures to construct an understanding of the relationship between physical frailty and cognitive decline.