Researchers have revealed that dementia may begin sending warning signals through the five senses years—and perhaps decades—before the onset of more familiar symptoms such as memory loss and language impairment.
These discoveries, made by an international research team led by Professor Andrea Tellez of Swansea University, overturn the traditional criteria for diagnosing dementia, which for decades has focused solely on memory tests.
The study, conducted by experts from Swansea University, Charles University in Prague, and Public Health Wales, reveals that subtle sensory changes long before diagnosis are often overlooked. Researchers noted that many patients report vision problems, a gradual loss of smell, balance disturbances, and even changes in their senses of taste and touch, years before they are diagnosed with dementia.
What's even more interesting is that some of these signs may appear 20 years before the traditional symptoms, such as in cases of spatial awareness disorders that cause a person to stand inappropriately close to others.
"Combining sensory assessment with traditional cognitive testing could revolutionize early diagnosis, especially in the preclinical stages when therapeutic interventions and lifestyle modifications are most effective," says Professor Jan Kremláček of Charles University in Prague. Dr. Emma Richards emphasizes that "these sensory changes are often reported by patients themselves, but they remain outside the scope of standard assessments, missing valuable opportunities for early intervention."
The biological mechanisms behind this phenomenon are due to the neurodegenerative nature of dementia, where the gradual atrophy and loss of brain tissue disrupts sensory signal processing, even in the very early stages of the disease. Previous studies indicate that loss of the sense of smell may be an early warning sign, preceding diagnosis by 10 years, while vision and motor coordination problems appear as the first symptoms in one-third of patients with early-onset Alzheimer's.
