Print This PostEvery January the wonderful ISTAART and professional interest groups (PIAs) come together to create individual year in review webinars. These webinars discuss some of the most impactful and important research that has been published in that field over the previous 12 months, decided by PIA members. I had the pleasure of attending the subjective cognitive decline (SCD) PIA year in review webinar a few weeks ago. So, stick around to hear about some of the key findings in this important research area.
Subjective cognitive decline (also referred to as SCD) is defined as a feeling of confusion and/or experience of memory loss, without an impaired performance on memory tests. As SCD occurs without any objective changes in memory tests, it’s important for the field to understand whether SCD may or may not be an early biomarker for the later development of Alzheimer’s disease. The ISTAART subjective cognitive decline PIA is a community of researchers, clinicians, and professionals who are all interested in some aspect of subjective cognitive decline.
Before I highlight some of the take home messages from the year in review webinar, I’d love to take the time to highlight the organisers, presenters and panellists. The session was moderated by Elizabeth Kuhn, the speaker and presenter was Elke Butterbrod and the panellists were Silvia Chapman, Katherine Gifford, Davide Moretti and Rachel Nosheny. Elke gave a really interesting presentation which gave an in-depth overview of some of the major studies in the field published in the last year – I definitely learnt a lot! The presentation was also followed by an insightful discussion with the panellists about some of the key take home messages from the year, along with some overall issues the SCD field needs to address.
There were a number of key messages in the year in review webinar – sadly there won’t be time for me to discuss them all. However, there were a number of common themes of research that focused upon SCD that came up throughout the year. These included: measurement of SCD, diversity and access to care, biomarkers both structural and functional and plasma, CSF and PET biomarkers, dyadic research and caregivers, trajectories and prognostic value, methodological advances (including machine learning), cognitive testing, quality of life and psychosocial factors, and intervention studies. It was really hard to choose just a few, as all of the points that were made were important but I’ll delve into a few highlights below.
The year in review webinar highlighted the importance of harmonising a measurement of self-perceived cognitive function. Currently, there is no standardised measurement criteria for SCD. Different research groups may use different methods within their studies to measure SCD which can obviously make comparisons across studies difficult. Therefore, many research groups are aiming to try and harmonise how SCD is measured. One study conducted by Rabin and colleagues used a number of international aging studies. The studies included used different measures of SCD. The research group aimed to see if they could link specific items on self-report questionnaires across these studies. In total, 40 different questionnaires to assess SCD were included in the study. The researchers found that they were able to link all the questionnaires. Furthermore, they found that a single factor structure was possible. Interestingly, they found that questionnaire items that had the largest influence on the measurement accuracy assessed ‘general and specific memory problems’, some features of executive function, ‘attention, language, calculation and visuospatial skills’. An important take home from this study is that harmonisation of different measurement methods is possible – which is definitely a good thing! The authors suggested that their future work could use the study’s results to develop new questionnaires and establish associations with relevant outcomes of aging.
Another important take home message from the webinar was the importance of including informant reports (also referred to as study-partner reports). An individual can self-report changes in their cognition, but these changes can also be reported by someone close to them (such as a relative), so called ‘informant report’ or ‘study partner’ report. There is a lack of literature which has looked at the association of informant reported subjective cognitive decline and the relationship this may have with biomarkers of Alzheimer’s disease (such as amyloid PET levels). Kuhn and colleagues reported that informant reported subjective cognitive decline strongly correlated to a higher amyloid level in individuals with mild cognitive impairment (MCI). Additionally, they found a slight correlation with poorer cognition. Their findings suggest the importance of informant reports of subjective cognitive decline, especially in patients with MCI.
Finally, another very important take home from the year in review was the importance of diversity in research studies. Subjective cognitive decline may be a very early sign of Alzheimer’s disease. However, there are few studies that have investigated SCD across ethnoracial groups. Robinson and colleagues wanted to explore the relationship between SCD, amyloid and cognition in a diverse population. Using data from the anti-amyloid in asymptomatic Alzheimer’s disease (a4) study they reported that: ‘the association between SCD and objective cognition was moderated by ethnoracial group’, ‘the association between SCD and amyloid was moderated by ethnoracial group’ and that ‘depression and anxiety were strong predictors of SCD in black and Hispanic groups’. They also reported that study partner and self-reported SCD were similar across groups. The study highlights the need for all studies to include diverse samples as the results show that the relationship between SCD, a measure of objective cognition and amyloid varies across ethnoracial groups.
As well as the webinar focusing on the above, the panellist discussion at the end again highlighted other important points, such as the nomenclature used within the field. Just as there is no current one way of assessing SCD the nomenclature researchers also use to describe SCD can be different. This again highlights the need for harmonisation across studies, especially with regards to how SCD is measured across studies and the terms used to describe SCD.
There were so many interesting studies talked about in the year in review webinar, and sadly I’ve not been able to mention them all. But, it seems like 2024 will be another exciting year for subjective cognitive decline research. Don’t forget, you can get involved in the SCD PIA by joining ISTAART and get access to previous webinars!
Beth Eyre
Author
Beth Eyre is a Postdoctoral Researcher (Dr pending minor corrections) at The University of Sheffield, researching Neurovascular and cognitive function in preclinical models of Alzheimer’s disease. Beth has a background in psychology, where she gained her degree from the University of Leeds. Inside and outside the lab, Beth loves sharing her science and we are delighted to have her contributing as a regular blogger with Dementia Researcher, sharing her work and discussing her career.
Adam Smith
Dementia Researcher
