Neurologist gets dementia diagnosis after taking simple DNA test...and his first symptom was NOT memory loss

Daniel Gibbs, 73, reckons his first symptom was loss of smell

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Adam Chapman

By Adam Chapman


Published: 18/07/2024

- 15:37

Updated: 29/07/2024

- 09:12

Daniel Gibbs, 73, reckons his first symptom showed up in 2006

A neurologist who was diagnosed with dementia after doing a simple DNA test has revealed his first warning sign - and it appeared almost two decades ago.

Daniel Gibbs, 73, has been living with Alzheimer's disease for the past eight years.


In 2012, he took a DNA test to inform his wife’s genealogy research. The results would be life-changing.

Besides learning where his ancestors had lived and whether his face is likely to flush after drinking alcohol, Gibbs discovered he had two copies of the apolipoprotein E (APOE) ε4 allele.

As a practicing neurologist, he knew that inheriting two copies of this gene meant he had a greatly increased risk of developing Alzheimer disease.

His worst nightmare became a reality in 2016 - just four years after taking a DNA test - when he was diagnosed with Alzheimer's.

Head in hands

Gibbs was diagnosed with Alzheimer's in 2016 - just four years after taking a DNA test

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His first symptom

Gibbs believes that his first symptom occurred back in 2006, when he began to lose his sense of smell.

At the time, he chalked it up to normal ageing.

Research supports his hunch.

Having a good sense of smell is associated with slower loss of brain volume and cognitive decline in older adults, and the link between sense of smell and brain and cognitive changes may be especially pronounced among those who develop cognitive impairment or dementia, according to findings published in the journal Neurology.

For the study, scientists analysed sense of smell, brain imaging, and cognitive performance data from participants in the National Institute on Aging's Baltimore Longitudinal Study of Aging.

The researchers examined whether sense of smell, as reflected by odour identification scores, was associated with longitudinal changes in regional brain volumes and changes to cognitive function.

To examine the association between sense of smell and brain volume, they compared odour identification scores and brain MRI scans from a subset of 567 participants.

The association between sense of smell and cognitive function was analysed by comparing odour identification scores and cognitive evaluations from a subset of 754 participants.

The subsets were analysed separately but included 565 overlapping participants with both brain MRI scans and cognitive assessment data.

Participants who developed cognitive impairment or dementia had worse odour identification scores than those who did not.

Better odour identification scores were associated with slower loss of brain volume, particularly in the frontal and temporal regions — areas important for thinking and memory. Better scores were also associated with slower decline in memory, attention, processing speed, and sensorimotor integration skills over time.

However, when data points after a diagnosis of cognitive impairment or dementia were excluded from analysis, the associations between sense of smell with brain volume and cognitive functioning were not as strong.

How is the neurologist's health currently?

His short-term memory is "getting a little worse, but not alarmingly so", he told JAMA Network.

"I misplace things a little more often, but in general, I’m getting by," he said, adding that he attributes his stable condition to eating well, keeping mentally stimulated and engaging in social activities.

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