Assessment of frailty: a survey of quantitative and clinical methods

Panhwar et al. BMC Biomedical Engineering https://doi.org/10.1186/s42490-019-0007-y (2019) 1:7 BMC Biomedical Engineering RESEARCH ARTICLE Open Access Assessment of frailty: a survey of quantitative and clinical methods Yasmeen Naz Panhwar1* , Fazel Naghdy1 , Golshah Naghdy1 , David Stirling1 and Janette Potter1,2 Abstract Background: Frailty assessment is a critical approach in assessing the health status of older people. The clinical tools deployed by geriatricians to assess frailty can be grouped into two categories; using a questionnaire-based method or analyzing the physical performance of the subject. In performance analysis, the time taken by a subject to complete a physical task such as walking over a specific distance, typically three meters, is measured. The questionnaire-based method is subjective, and the time-based performance analysis does not necessarily identify the kinematic characteristics of motion and their root causes. However, kinematic characteristics are crucial in measuring the degree of frailty. Results: The studies reviewed in this paper indicate that the quantitative analysis of activity of daily living, balance and gait are significant methods for assessing frailty in older people. Kinematic parameters (such as gait speed) and sensor-derived parameters are also strong markers of frailty. Seventeen gait parameters are found to be sensitive for discriminating various frailty levels. Gait velocity is the most significant parameter. Short term monitoring of daily activities is a more significant method for frailty assessment than is long term monitoring and can be implemented easily using clinical tests such as sit to stand or stand to sit. The risk of fall can be considered an outcome of frailty. Conclusion: Frailty is a multi-dimensional phenomenon that is defined by various domains; physical, social, psychological and environmental. The physical domain has proven to be essential in the objective determination of the degree of frailty in older people. The deployment of inertial sensor in clinical tests is an effective method for the objective assessment of frailty. Keywords: Frailty assessment, Sensor technology, Gait analysis, Balance assessment, ADL Background Frailty is a physical phenomenon that is pervasive in older people. In spite of a significant number of studies in this area, there is a plethora of definitions for frailty but no prevailing consensus. Some definitions are derived from studies of certain populations and some are formulated based on clinical assessment methods. The most common approach is to associate frailty with aging [1], comorbidity, disabilities and chronic diseases even though frailty is a physical condition and different from aging, comorbidity and disability [2–4]. There are certain other characteristics associated with frailty. Loss of muscle mass (sarcopenia), dilapidation of the human body’s physiological system, and cognitive *Correspondence: 1 University of Wollongong, Wollongong, Australia Full list of author information is available at the end of the article impairments are also considered as markers of frailty [3, 5, 6]. Such conditions in older people are often associated with an increase in the risk of fall, hospitalization, mortality and morbidity.They also make the activities of daily living (ADL) less independent. This paper is a survey of the major quantitative and clinical methods proposed in the literature to assess and measure frailty. Each method is briefly reviewed and its strengths and deficiencies are identified. The state of the art in frailty assessment is determined and, research gaps and future directions in this discipline are discussed. Assessment tools of frailty using qualitative methods / clinical frailty instruments The topic of frailty is well examined in the medical literature; in particular in the field of Geriatric Medicine. Several clinical frailty instruments are routinely used by © The Author(s). 2019 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Panhwar et al. BMC Biomedical Engineering (2019) 1:7 geriatricians as clinical assessment tools. The first and foremost development began when Fried and colleague [3] demonstrated that frailty was a clinical state different from aging and comorbidity. However, they identified some relationship between disability, comorbidity and frailty [3]. Consequently, Fried et al. [3] provided a new view of the concept of frailty, from which Rockwood and team [5] identified a new approach, based on the accumulation of deficits, with which to address the frail condition of aged people. Rockwood extended his basic model defining frail status in the range of one to seven to a new scale of one to nine. Despite an abundance of such clinical instruments proposed in the literature, there is no standardized tool for frailty assessment. Because of its multi-directional nature, one assessment method cannot always guarantee accurate results in every domain [7, 8]. Moreover, these domains range from physical to psychological, and social to environmental. In the following subsections, the most widely used methods for addressing frailty in older adults in clinical practice are reviewed. Some of the methods are derived from population-based studies and then expanded to geriatric assessment tools. The selected clinical frailty models and their methods studied in this review paper are shown in Table 1. Page 2 of 20 Fried phenotype Fried et al. [3] propose a model for defining frailty. This model consists of five phenotypes of weakness or exhaustion , grip strength, ADL, weight loss and gait velocity. Exhaustion and ADL are measured by an interview and the other three parameters are quantitatively calculated over time. Of these five components, weight loss is proved to be the least significant in estimating the frail condition [9]. Chkeir et al. [10] use the balance assessment method along with the Fried phenotype to perform binary classification of frailty (Non-Frail or Frail). Hewson et al. [11] devised a monitoring system for frailty diagnosis by deploying the Fried phenotype model. They utilized an accelerometer for ADL and gait velocity, bathroom scale for weight loss, a grip ball for exhaustion and a dynamometer for grip strength. Since these five phenotypes are quantifiable, the frailty assessments methods developed in biomedical engineering research prefer the Fried model. Rockwood’s frailty accumulation (...truncated)