May 20, 2022
UCalgary research suggests new risk factors for early identification of dementia
Dr. Zahinoor Ismail, MD, a professor at the Cumming School of Medicine, has published a series of studies indicating the need for inclusion of additional indicators to help health professionals diagnose dementia sooner. Dr. Ismail and his colleagues hope to improve the accuracy of diagnosis for people living with dementia so that treatment and supports can be started earlier. He spoke to Shea Coburn, at the Hotchkiss Brain Institute, about the findings.
How do health professionals diagnose dementia, currently?
Traditionally, clinicians have looked to changes in memory and global cognition as signals of dementia risk. These are potential indicators of the underlying diseases that cause dementia. However, in many cases these symptoms become apparent when the disease has already progressed to the extent that opportunities for mitigative treatment may be limited.
Our research has shown by looking at non-cognitive markers of dementia, we can identify dementia risk in a substantial number of people when cognitive symptoms are mild or even absent. Earlier identification of those at risk can allow for an appropriate workup and potentially for implementation of preventative interventions.
Your research has shown that psychosis can sometimes be an early indicator of dementia. Tell us more about that.
About 40 per cent of people with Alzheimer's disease develop delusions and hallucinations, but these symptoms can also emerge in older adults in advance of dementia. Similar brain changes that result in cognitive decline can result in behavioural changes, such as psychosis. Our work published in Nature Reviews Neurology shows that exploring new-onset psychotic symptoms in older adults may be a promising approach to identifying dementia earlier on, which then offers opportunities for earlier intervention.
Why is including psychosis as an additional indicator important?
Early identification of dementia risk ensures that a dementia-sensitive history is obtained from the patient and a reliable informant, that appropriate laboratory investigations and brain scans are ordered, and that cognition, function and behaviour are measured at the time of symptom emergence and monitored over time. Further, treatments can be tailored correctly, e.g., considering anti-dementia medications rather than immediately choosing antipsychotics, choosing a treatment setting suitable for someone with a neurodegenerative disease, and creating a future plan for potential decline and care.
When late-life onset of symptoms of psychosis are diagnosed as schizophrenia or delusional disorder, the individual can be placed into a system of care that might ignore the risk of dementia, or consider this risk too late, thus impeding timely investigations.
Your work is also looking to draw attention to other non-cognitive markers of dementia. What are some examples of non-cognitive markers?
Non-cognitive markers of dementia include changes in five domains:
- motor function (e.g., gait, grip strength)
- sensory function (e.g., hearing, vision, olfaction)
- neuro-behavioural symptoms (e.g., drive and motivation, mood/anxiety symptoms, impulse dyscontrol, social cognition, psychotic symptoms)
- medical frailty
In 2020, my colleagues and I published updated Canadian dementia diagnostic and treatment guidelines in the journal Alzheimer’s & Dementia, in which we highlighted the importance of assessing these five domains as part of dementia risk assessments.
Additionally, in a series of recently published papers, my team has described the associations between late-life onset behavioural changes and 1) hearing disturbance; 2) a gait multi-tasking test; and Frailty Index scores, with these combinations potentially contributing to even greater dementia risk.
Some of these studies utilized data from the Comprehensive Assessment of Neurodegeneration and Dementia (COMPASS – ND). Much like in the psychosis study, paying attention to these additional markers would allow for a potentially earlier diagnosis of dementia, which could lead to better outcomes for those living with the disease.
You mentioned COMPASS-ND. Could you outline what COMPASS-ND is all about?
It is a Canada-wide observational cohort study of older adults with and without dementia. Including individuals both with and without the disease allows us to compare the progression of all of the above outlined factors across a spectrum.
COMPASS-ND also includes neuroimaging (MRI), detailed neuropsychological testing and assessment of non-cognitive symptoms such as increased agitation, apathy, anxiety, depression, frustration intolerance, impaired social functioning, as well as hearing loss, gait, and frailty.
COMPASS-ND is still recruiting, and those who are interested can contact our research team at firstname.lastname@example.org.
The COMPASS-ND study is supported by the Canadian Consortium on Neurodegeneration in Aging, which is funded by the Canadian Institutes of Health Research (CIHR).
Zahinoor Ismail is a professor in the departments of Psychiatry, Clinical Neurosciences, Community Health Sciences and Pathology, at the Cumming School of Medicine (CSM). He is also a member of the Hotchkiss Brain Institute, and the O’Brien Institute for Public Health at the CSM.