The study found that people experiencing occasional memory loss had a lower brain volume, despite not showing any such deficits on regular tests of memory or dementia.
In the study, 500 Netherlands residents between the age group of 50 to 85 without dementia were asked about occasional memory problems.
The questions dealt with problems like having trouble thinking of the right word or forgetting things that happened in the last day or two, or thinking problems such as having trouble concentrating or thinking more slowly than they used to.
Later, their brains were scanned to measure the size of the hippocampus, an area of the brain important for memory and one of the first areas damaged by Alzheimer's disease.
Out of the 500 people, 453 were found to have occasional memory or thinking problems, also called subjective memory problems, as they can't be seen on regular tests of memory and thinking abilities.
It was found that people with occasional subjective memory problems had smaller hippocampus than their normal counterparts.
On average, the hippocampus had a volume of 6.7 milliliters in those with occasional subjective memory problems, compared to 7.1 milliliters in people with no memory problems.
"These occasional, subjective memory complaints could be the earliest sign of problems with memory and thinking abilities and we were able to discover that these subjective memory complaints were linked to smaller brain volumes. Because occasional memory lapses were so common, though, much more work needs to be done to use such complaints diagnostically," said study author Frank-Erik de Leeuw, MD, neurologist and clinical epidemiologist, of Radboud University Nijmegen Medical Centre, Netherlands.
After measuring the amount of white matter lesions in all the participants, the researchers found that the amount of lesions was not tied to occasional memory problems.
All the participants had visited a neurology outpatient clinic not because of memory complaints but for reasons such as falls, vertigo, chronic head pain, or mild traumatic brain injury.
The study has been published in the latest issue of Neurology, the medical journal of the American Academy of Neurology.