Medical texts from Ancient Greece and Rome suggest that severe memory loss was extremely rare 2500 years ago, unlike today. The corresponding review was published in the Journal of Alzheimer's Disease.
Records show that the ancient Greeks and Romans were mainly concerned with physical frailty in old age, and made little mention of advanced cognitive decline. Such an absence of data on cognitive decline suggests that conditions like Alzheimer's disease and related dementia may arise from modern environments and lifestyles.
To understand more about the prevalence of dementia and cognitive decline during the Greco-Roman period, the researchers behind the current review examined texts by Greek and Roman authors from the 8th century BCE to the 3rd century CE that mentioned memory loss and dementia.
While they found reports of deafness, dizziness, and digestive disorders, they found no ancient account of cognitive loss equivalent to what is described in modern clinical data. They further noted that while the word 'dementia' was occasionally used during this period, it was not necessarily tied to old age, and that the ancient Greeks and Romans expected intellectual competence beyond 60 years old.
"The ancient Greeks had very, very few- but we found them- mentions of something that would be like mild cognitive impairment," said first author Caleb Finch, Professor at the University of Southern California Leonard Davis School of Gerontology, in a press release.
"When we got to the Romans, and we uncovered at least four statements that suggest rare cases of advanced dementia- we can't tell if it's Alzheimer's. So, there was a progression going from the ancient Greeks to the Romans," he noted.
Prof. Finch noted that the Romans may have experienced more cognitive decline as their cities grew denser and pollution increased. The researchers also noted that increased exposure to neurotoxin lead during Roman times- in cooking vessels, water pipes, and to sweeten wine, for example- may have contributed to the emergence of advanced Alzheimer's disease and related dementias.
As the researchers lacked demographic data for ancient Greece and Rome, they turned to the Tsimane Amerindians, an indigenous people of the Bolivian Amazon, to model pre-industrial living. Seemingly akin to the ancient Greeks and Romans, the Tsimane have a very physically active lifestyle and low rates of dementia. Whereas 10.7% of people in the US aged 65 years and older have dementia, the same is true for around 1% of older Tsimane people.
"The Tsimane data, which is quite deep, is very valuable. This is the best-documented large population of older people that have minimal dementia, all of which indicates that the environment is a huge determinant on dementia risk. They give us a template for asking these questions," concluded Prof. Finch.