Characterisation of Physical Frailty and Associated Physical and Functional Impairments in Mild Cognitive Impairment

Ma Shwe Zin Nyunt,Tze Pin Ng,Philip L K Yap,Xinyi Gwee,Tih Shih Lee,Chang Yuan Soh,Audrey S L Ling,Keng Bee Yap,Qi Gao,Wee Shiong Lim

doi:10.3389/fmed.2017.00230

Abstract

To characterize the physical frailty phenotype and its associated physical and functional impairments in mild cognitive impairment (MCI). Participants with MCI (N = 119), normal low cognition (NLC, N = 138), and normal high cognition (NHC, N = 1,681) in the Singapore Longitudinal Ageing Studies (SLAS-2) were compared on the prevalence of physical frailty, low lean body mass, weakness, slow gait, exhaustion and low physical activity, and POMA balance and gait impairment and fall risk. There were significantly higher prevalence of frailty in MCI (18.5%), than in NLC (8.0%) and NHC (3.9%), and pre-frailty in MCI (54.6%), NLC (52.9%) than in NHC (48.0%). Age, sex, and ethnicity-adjusted OR (95% CI) of association with MCI (versus NHC) for frailty were 4.65 (2.40-9.04) and for pre-frailty, 1.67 (1.07-2.61). Similar significantly elevated prevalence and adjusted ORs of association with MCI were observed for frailty-associated physical and functional impairments. Further adjustment for education, marital status, living status, comorbidities, and GDS significantly reduced the OR estimates. However, the OR estimates remained elevated for frailty: 3.86 (1.83-8.17), low body mass: 1.70 (1.08-2.67), slow gait: 1.84 (1.17-2.89), impaired gait: 4.17 (1.98-8.81), and elevated fall risk 3.42 (1.22-9.53). Two-thirds of MCI were physically frail or pre-frail, most uniquely due to low lean muscle mass, slow gait speed, or balance and gait impairment. The close associations of frailty and physical and functional impairment with MCI have important implications for improving diagnostic acuity of MCI and targetting interventions among cognitively frail individuals to prevent dementia and disability.

Highlights

Late life cognitive impairment and physical impairment are principal causes of disability, falls, hospitalisation, institutionalisation, and death among the elderly
Mild cognitive impairment (MCI) and the physical frailty phenotype are early cognitive and physical syndromes preceding the development of dementia and disability among older people
These motor functional deficiencies in MCI are present in physical frailty, a syndrome that may reverse to the robust state or progress to functional disability [13]

Summary

Introduction

Late life cognitive impairment and physical impairment are principal causes of disability, falls, hospitalisation, institutionalisation, and death among the elderly. Studies show that older individuals with MCI compared to their counterparts without cognitive impairment performed more poorly not just on tests of neurocognitive performance tasks, and on tests of complex motor and psychomotor domains tasks [5,6,7], and exhibited greater gait impairment especially on tests that include motor-cognitive dual tasks [8,9,10,11,12] These motor functional deficiencies in MCI are present in physical frailty, a syndrome that may reverse to the robust state or progress to functional disability [13]. The physical phenotype of frailty is represented by low levels of lean body mass, muscle strength, gait performance, physical activity (PA), and energy

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