Hi Amy

Given that it is labelled 'cognitive' decline, I would consider it to encompass not only memory, but also executive function or attention problems ..

Hi Clarissa,

Thank you very much for your comment. I totally agree, the problem I have had is that there is very little consensus regarding the defining characteristics of SCD. I have read so many papers that solely focus on memory, and do not really take into account other cognitive processes. It can be quite confusing. I am glad I am thinking along the same lines.

Very best wishes

Amy

I am not in a position to give you a very helpful response, but I assume you have had a look at the definitions for MCI? The criteria should be similar, but adding the component of subjectivity, which by the way is a bit confusing...

There should be evidence of lower performance in one or

more cognitive domains that is greater than would be expected

for the patient’s age and educational background. If

repeated assessments are available, then a decline in performance

should be evident over time. This change can occur in

a variety of cognitive domains, including memory, executive

function, attention, language, and visuospatial skills. An impairment

in episodic memory (i.e., the ability to learn and retain

new information) is seen most commonly in MCI

patients who subsequently progress to a diagnosis of AD dementia.

As far as I know, in MCI there are different subtypes according to the domains affected.

I think you will struggle for consensus on a definition for SCD. The definitions of MCI are still unclear after decades of research. I would imagine that the focus on memory in SCD is more related to the likelihood that this is the most noticed change in an individiual. People are increasingly vigilant for memory slips, particularly as they age, and these are what will be reported. Also the general population can define memory better than they can other cognitive domains, like executive dysfunction, which are unlikely to be "subjectively" reported

Xabier and Matthew, thank you both very much for your responses, they are very helpful and I really appreciate your input.

Very frequent by depressive patients. So called depressive pseudodementia.

Nikola, thank you for your comment. I am looking very closely at depression and SCD for this very reason, thank you for highlighting this on the thread.

You also might want to take a look at thought organization in terms of processing speed, categorization (divergent and convergent), sequencing, but it depends on your goal. There are a number of cognitive screenings and evaluations that are published that address these issues. Among them, you can consider the RBANS, Cognistat, and the Cognitive Linguistic Quick Test (CLQT). Email me privately if you'd like more information.

Just a thought --- When people go through a driving assessment , their processing speed and attention scope/capabilities (e.g., how many things can they attend to and for how long on each) are examined. May be able to find more in occupational therapy literature as well as well as the psychology literature?

Martin and Gabriela, thank you both very much for your helpful responses, I really appreciate it. I will be in touch for sure, best wishes

You might be interested in an article (epub ahead of print) by Rami et al. in the Journal of Alzheimer's Disease: "The Subjective Cognitive Decline Questionnaire (SCD-Q): A Validation study.

Hi Nikki, thank you for pointing me in the direction of this paper. It looks exactly like what I am studying. Very best wishes!

Dear Emiliano

You have made some very pertinent points here. As you mention it is subjective, so any measure of it is going to be difficult to standardize. Our main aim is to identify early markers which are generally present when someone initially complains of experiencing some form of cognitive decline. Such information we hope can be used to develop a more sensitive measure. It is predominantly only the person themselves who can notice and say they have identified a change in their cognitive functioning. We hope to help qualify such changes for them, provide specific intervention strategies relating to their areas of cognitive decline, and therefore help slow down any further decline. You are so very right though, it is difficult to use in rigorous research. Thank you again Emiliano for your helpful answer.

Very best wishes

Amy

you might also want to have a look at this very recent paper that mentions all these questions and gives some orientation for future research

http://www.alzheimersanddementia.com/article/S1552-5260%2814%2900002-8/abstract

Dear Renaud,

Thank you for your answer, I am very grateful. I am lucky to have been on the mailing list for when this paper came out so I do have it in my possession, but thank you again for pointing it out.

Very best wishes

Amy

"Subjective Cognitive Decline", also termed "Age-Related Cognitive Impairment", is difficult to define as its manifestation is progressive and primarily affects cerebral processing speed before affecting other cognitive performance. Its manifestation also depends of cognitive reserve and each individual's ability to compensate brain alterations at a neural network and behavioral level. Cerebral decline starts at 20 years of age (reduced processing speed) but its subjective manifestations might only appear at a much more advanced age with important between individuals differences [1-2].

Therefore, visual processing speed is one of the easiest mean to measure cerebral decline [3] but does not necessarily reflect negative consequences at a behavior level [4]. Another mean to measure cerebral decline is testing the learning function. This has the advantage of also providing an insight in neural plasticity [5] and each individual's ability to adapt brain functions to its changing state.

For older drivers, relying on normative values from neuropsychological tests can lead to force most people to cesse driving when it is not necessary [6,7]. This can have important consequences on their social isolation and mental health [8]. With normal aging, transposing results from neuropsychological tests to behavior, such as driving a motor vehicle, also requires investigating metacognition and each individual's ability to adapt their behavior to their condition [9].

References

1. Hayden KM, Reed BR, Manly JJ, Tommet D, Pietrzak RH, Chelune GJ, et al. Cognitive decline in the elderly: an analysis of population heterogeneity. Age Ageing. 2011;40(6):684-9.

2. Salthouse TA. When does age-related cognitive decline begin? Neurobiol Aging. 2009;30(4):507-14.

3. Salthouse TA. The processing-speed theory of adult age differences in cognition. Psychol Rev. 1996;103(3):403-28.

4. Voss MW, Wong CN, Baniqued PL, Burdette JH, Erickson KI, Prakash RS, et al. Aging Brain from a Network Science Perspective: Something to Be Positive About? PLoS ONE. 2013;8(11):e78345.

5. Persson J, Nyberg L. Altered brain activity in healthy seniors: what does it mean? Prog Brain Res. 2006;157:45-56.

6. Dobbs BM, Shergill SS. How effective is the Trail Making Test (Parts A and B) in identifying cognitively impaired drivers? Age Ageing. 2013;42(5):577-81.

7. Roy M, Molnar F. Systematic review of the evidence for Trails B cut-off scores in assessing fitness-to-drive. Canadian geriatrics journal : CGJ. 2013;16(3):120-42.

8. Windsor TD, Anstey KJ, Butterworth P, Luszcz MA, Andrews GR. The role

of perceived control in explaining depressive symptoms associated with driving cessation in a longitudinal study. Gerontologist. 2007;47(2):215- 23.

9. Blanchard RA, Myers AM. Examination of driving comfort and self- regulatory practices in older adults using in-vehicle devices to assess natural driving patterns. Accid Anal Prev. 2010;42(4):1213-9.

Hi Paul, the information you have provided me is thought provoking, thank you very much. I am new to the area but what I have noticed recently is that there has been a shift towards differentiating SCD and age-related cognitive decline/impairment…what are your thoughts on that? I look forward to hearing from you. Best wishes, Amy.

I think there is an important debate on whether cerebral decline is normal or not. Given age-related brain alteration becomes present in all human brains from a given age, should we consider these alteration as a disease, a disorder, or an impairment? On the other hand, these alterations can have important consequences on peoples quality of life and affects health [1,2]. So the definition of the process depends if we consider it from its clinical manifestations or from its underlying biological causes.

The problem is that underlying biological age-related brain alterations do not have the same effects at a behavior level depending of individuals cognitive reserve and their capacity to compensate. Therefore individuals can have important brain alterations without having any clear behavioral manifestation.

The term "impairment" suggests we are defining a condition from its manifestation at a behavior level. In other words, we are also considering the context (e.i. cortical reserve, brain plasticity) and not solely the underlying biological alterations. The impact of such impairment will also depend of needs, metacognition, and adaptive behavior. Time and training could reverse the manifestation and cognitive impairment can be reversible.

Cerebral decline is the generic term that corresponds to underlying biological alteration and also includes alterations that can be compensated for and therefore are not necessarily noticeable at a behavior level. I do not use the term cortical decline, as this term remains ambiguous. Biologically, aging does not affect solely the cortex but also the deeper brain, and functionally, it is impossible to distinguish cortical neural network age-related alterations from associated changes in the deeper brain, notably the thalamus and the striatum.

In normal aging, what distinguishes "impairment" from "decline" is neural plasticity. Once alternative neural networks cannot be created, consequences of aging become visible at a behavior level.

1. Whitehouse PJ, Gaines AD, Lindstrom H, Graham JE. Anthropological contributions to the understanding of age-related cognitive impairment. Lancet neurology. 2005;4(5):320-6.

2. Graham J, Stephenson P. Ethnography and the study of aging: A critical evaluation of ethnographic description, theory, data and metaphors in social gerontology. Santé, Culture, Health. 1992;8(1):55-76.

Thank you Paul for your response, there are some very interesting and thought provoking ideas mentioned. I appreciate your input! Best wishes, Amy

Just found an interesting new paper on SCI in the Journal of Geriatric Psychiatry and Neurology:

http://jgp.sagepub.com/content/early/2014/07/28/0891988714541873.abstract

Thank you very much Clarissa! Apologies for the delay, I did not realise this post was here :-)

A quite recent article by Hammar & Årdal actually found that the first trial of Rey-AVLT showed impaired performance among patients diagnosed as SCI. In an upcoming paper we also found similar supraspan deficits among SCI using a more factor analytic approach. Repeatededly SCI is found among people with relatively advanced occupations, although this may  only be anecdotal.

However, when a math teacher for instance, presents symptoms of cognitive decline, his/her test results may be found within the normal or even above normal range. Not only in numerical or logical tests. Still he/she may in fact be aware of a real cognitive deterioration. The word "Subjective" in a way obscures or diminishes actual symptoms of a dementing progress that neuropsychologists are not yet ready to accept as objective cognitive decline. 

Such findings or experiences from memory clinics should lead to the development of more sensitive tests. 

Thank you so much for your reply. I will most certainly be looking up the Rey-AVLT. I am currently looking more into cognitive reserve in relation to your point. Thank you again, very best wishes!

Amy