Navigating and diagnosing cognitive frailty in research and clinical domains

Abstract

While physical frailty has been recognized as a clinical entity for some time, the concept of cognitive frailty (CF) is now gaining increasing attention in the geriatrics research community. CF refers to the co-occurrence of physical frailty and cognitive impairment in older adults, which has been suggested as a potential precursor to both dementia and adverse physical outcomes. However, this condition represents a challenge for researchers and clinicians, as there remains a lack of consensus regarding the definition and diagnostic criteria for CF, which has limited its utility. Here, using insights from both the physical frailty literature and cognitive science research, we describe emerging research on CF. We highlight areas of agreement as well as areas of confusion and remaining knowledge gaps, and provide our perspective on fine-tuning the current construct, aiming to stimulate further discussion in this developing field.

Fig. 1 ∣. Schematic of the interplay of biological mechanisms, biomarkers and risk factors in CF.

The outer circle highlights that both physical frailty and cognitive decline possess common biological mechanisms, biomarkers and risk factors. These shared elements can interact with each other throughout all stages, forming the foundation of the concept of CF. The middle circle showcases the symptoms that emerge from these biological mechanisms. When there is a sufficient convergence of physical and cognitive symptoms, it leads to the manifestation of physical frailty and/or cognitive decline phenotypes. The presence of both signifies the onset of CF. HPA, hypothalamic–pituitary–adrenal.

Fig. 2 ∣. Integrating CF concepts for clarity as a complex, multidimensional geriatric syndrome resulting from the complex interplay of biological, environmental, and psychosocial factors.

Psychosocial, environmental and age-related biological factors intertwine with observed declines in physical and cognitive abilities. Although these age-influenced biological changes may vary in their effect, they collectively play a part in the decline. The culmination of these factors leads to a condition known as CF, which underscores the interplay between cognitive and physical deterioration. Despite physical and cognitive decline potentially evolving separately, these shared influences can shape their progression concurrently.

Fig. 3 ∣. Schematic of CF categories.

Level 1 represents the combination of physical pre-frailty and subjective cognitive decline (SCD); level 2 represents physical frailty and SCD; level 3 represents physical pre-frailty and mild cognitive impairment (MCI); and level 4 represents physical frailty and MCI. NC, normal cognition.