Friday, May 28, 2021

Defining brain health

The term "brain health" is used with increasing frequency. Looking at the scholarly literature, there were only a handful of references to this term through the nineties and noughties, until it increased exponentially in the 2010's (even allowing for exponential increases in academic publishing more generally). Given the amount of money that can be ploughed into products and approaches claiming to enhance brain health, one might think "the experts" had a clear idea of exactly what brain health is. However, there is a lack of consensus on what the term "brain health" means. 

The authors used a hybrid concept analysis method which combined review of the existing literature (from 1990-2020) with original fieldwork. The latter involved an international online survey of the community of the Global Brain Health Institute. In a final analysis, they developed a working definition based on the two bodies of work. From the outset, the authors were keen not to define brain health as simply the absence of brain disease, citing the World Health Organisation's statement that ‘health is a state of complete physical, mental, and social well‐being and not merely the absence of disease or infirmity'. They also wished to avoid equating health with the idea of "average" or "normal".

The review of the existing literature found twelve difference models of "brain health": a biological function model, (absence of) disease model, cognitive model, prevention model, well-being and holistic model, multidomain model, fitness model, dynamic process life course model, optimal function model, autonomy-resilience model, subjective experience model and empirical referents model. Some of the cited papers drew on multiple models, suggesting a multifaceted concept of brain health. Interestingly, a lot of articles did not define the term "brain health", with some only using the term in their title. 

Key attributes of brain health identified by the authors include that it exists along a continuum from poor to optimal, it includes both objective and subjective components, is a dynamic process throughout life, and (as mentioned above) is a multidimensional construct. The authors also mention antecedents to brain health (e.g. lifestyle choices) and consequences (e.g. the ability to live independently), although I think these may not really be defining for what brain health is as a state/process.    

The survey had 73 respondents, most of whom were working in health or basic sciences. Besides respondents from North America and Western/Northern Europe, who are typically over-represented in this kind of work, 15 of these respondents were from South America, 7 from Southern/Eastern Europe, 4 from Africa and 2 from Western Asia. Most respondents in general reported that the term "brain health" was not commonly used in their country of origin. 

The proposed working definition the authors came up with was the following:

Brain health can be defined as a life‐long dynamic state of cognitive, emotional and motor domains underpinned by physiological processes. It is multidimensional and can be objectively measured and subjectively experienced. Brain health is influenced by eco‐ biopsychosocial determinants, resulting in a continuum of quality of life and wellness  

At a first reading, I personally think the final clause is perhaps a bit too focused on consequences, although this is probably necessary when the initial sentence doesn't seems to capture the idea of "positive" or "healthy" (apart from the term "brain health" itself). It is perhaps difficult to separate the following: (i). the consequences of brain processes that allow a brain-owner to function adaptively in their environment and (ii). an appraisal of these processes as healthy or unhealthy.   

In closing out the paper, the authors say their paper will help to operatonalise the concept of brain health for research, policy and practice. It will be interesting to see whether the definition above is taken up by those working in the area of brain health more generally. I hope it will help, given the inconsistencies that are highlighted here between overly reductive biomedical models and approaches that over-emphasise individuals' subjective appraisal of their own brain health. 

Disclosure: I am currently working on a (separate) project on staff mental health with the first author (Dr. Yaohua Chen).

Chen, Y., Demnitz, N., Yamamoto, S., Yaffe, K., Lawlor, B., & Leroi, I. (2021).  Defining brain health: A concept analysis. International Journal of Geriatric Psychiatry. DOI: 10.1002/gps.5564.

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