Thursday August 27 2015
Having no memory of losing your memory is a concern
"Senior moments? Only worry if you don't notice them," the Daily Mail reports.
"Senior moments" is a term used to describe a sudden memory lapse, such as forgetting your PIN or a relative’s name. While these types of lapses can affect people of all ages, older people are often more concerned when they happen, in case they could be the initial symptoms of dementia.
A new study suggests this may be an unnecessary worry – the real warning sign could be when people "forget that they have forgotten". Being unaware of failing memory could be a warning sign of impending dementia.
The study included more than 2,000 older adults from the US and followed them over a period of 10 years. Participants had memory tests every year and were asked to rate their own memory and whether they experienced any problems. During the study period, around 10% of participants were diagnosed with dementia. They experienced a drop in memory awareness around 2.6 years before the development of dementia.
This study highlights the importance of being memory aware – knowing when your memory has let you down on occasion. The researchers state that loss of memory awareness appeared earlier in younger participants; this may be because older people were more likely to expect their memories to fade as a normal part of ageing. Friends and family members should look out for the warnings signs and ensure medical advice is sought if they are concerned.
Where did the story come from?
The study was carried out by researchers from Rush Alzheimer’s Disease Center and Department of Neurological Sciences, and was funded by the National Institute on Aging and the Illinois Department of Public Health.
The study was published in the peer-reviewed medical journal Neurology.
This story has been reported both widely and accurately by the UK media.
The Independent offers a particularly useful report, with additional advice about ways of reducing risk of dementia and highlighting the role of friends and family in aiding medical professionals in diagnosing the condition.
What kind of research was this?
This study combined people from three prospective cohort studies in the US to investigate the development of memory loss in dementia. The participants were free from dementia at study start; this is the best way to gather information on how a condition develops over time.
What did the research involve?
This study included participants from three longitudinal cohort studies to test whether being unaware of memory impairment is an indicator of dementia.
The participants came from:
- The Religious Orders Study – older Catholic nuns, priests and brothers.
- The Rush Memory and Aging Project – older individuals from the Chicago area.
- The Minority Aging Research Study – older black persons from the Chicago area recruited from the community and the clinical core of the Rush Alzheimer’s Disease Core Centre.
All participants were at least 50 years old and had not been diagnosed with dementia. A number of evaluations were carried out each year. These are as follows:
- Clinical evaluation – including a medical history, neurologic examination, and tests of memory and cognition. Dementia diagnosis was made by a doctor according to standard criteria.
- Self-assessment of memory – Participants were asked two questions about their memory; these were "How often do you have trouble remembering things?" and "Compared to 10 years ago, would you say your memory is better or worse?"
- Performance testing of memory – 19 cognitive tests were carried out to support clinical classification of dementia and measure change in cognitive function. These included tests of episodic memory (e.g. immediate and delayed recall of word lists) and working memory (e.g. numerical tests).
After death, those who had given consent during the study period had an autopsy of their brain.
The temporal course of memory awareness in dementia was investigated for those people who developed dementia before the end of the study and who had completed at least four annual evaluations.
What were the basic results?
The study included a total of 2,092 older people who had no memory or cognitive impairment at study start. Around 10% of participants (239 people) developed dementia during follow-up and had four annual assessments available from which to assess the course of their memory awareness.
These people had an average age of 79.2 years at study start and were followed up for 10.8 years. This included 7.5 years before dementia onset and 3.3 years after dementia onset. Memory awareness was stable until 2.6 years before the onset of dementia; after this point there was a rapid decline in memory awareness. Participants who were older at study start tended to have later onset of memory unawareness.
Brain autopsy was carried out in 385 of those who died during the study period. Decline in memory awareness could be linked to brain changes that are associated with dementia – such as protein tangles (characteristic of Alzheimer’s disease) and areas where the brain has been starved of oxygen (characteristic of vascular dementia). Where these changes were not found, decline in memory awareness had not been observed.
How did the researchers interpret the results?
The researchers conclude that awareness of memory impairment typically begins to decline about two to three years before dementia onset and is associated with post-mortem evidence of dementia.
This study investigated unawareness of memory loss as an indicator of dementia. The 10% of participants diagnosed with dementia during follow-up who had full assessments available experienced a drop in memory awareness around 2.6 years before the development of dementia. It was also noticed that a drop in memory awareness was associated with the characteristic features of dementia at brain autopsy.
Strengths of this study are the large sample size and long follow-up period. However, there are limitations related to the specific US population samples used. For example, one of the cohorts included only nuns, priests and brothers; another included only people of black ethnicity. These people may have distinct health and lifestyle characteristics, meaning they are not representative of everyone.
In practical terms, it may also be difficult to identify a clear cut-off point between the vague concepts of memory "awareness" and "unawareness". The study also has no direct implications in terms of preventing or slowing the development of dementia.
Nevertheless, the findings highlight the role that friends and family members can have in looking out for signs of unawareness of memory loss, and to ensure medical advice is sought if they are concerned.
Early symptoms of dementia can progress very slowly, so they may not be noticed or taken seriously, just thought to be a normal part of ageing. However, symptoms become more severe as the condition progresses. The speed at which symptoms get worse and the way they develop can depend on the cause and overall health of the person. This means that the symptoms and experience of dementia can vary greatly from person to person.
Memory loss is one of the key symptoms of dementia, but others include:
- increasing difficulty with tasks and activities that require concentration and planning
- changes in personality and mood
- periods of confusion
- difficulty finding the right words
There are no certain ways to prevent dementia. However, you may be able to reduce your risk of developing dementia by following normal healthy lifestyle advice – eating a balanced diet, taking regular exercise, not smoking and drinking alcohol in moderation.