A controversial study has linked a lack of interest in the world to the onset of dementia.
Dementia is an umbrella term for a range of conditions that cause a decline in brain function, with Alzheimer’s being the most common.
Many forms of dementia are associated with an abnormal build-up of proteins in the brain, which cause nerve cells to die and different areas of the vital organ to shrink.
Exactly why this occurs is often unclear, however, it has been linked to strokes, as well as a family history of the disease.
After looking at more than 2,000 people, scientists from the University of California in San Francisco found dementia was more common among apathetic individuals.
One expert stressed it is unclear whether apathy contributes to cognitive decline, or vice versa.
She added, however, dementia is often misdiagnosed as depression. Better understanding the less-recognised symptoms of the memory-robbing disease could aid diagnosis and treatment, she said.
Dementia affects 850,000 people in the UK, which is expected to rise to 1.6 million by 2040. Alzheimer’s is the most common type of the disease, affecting up to 75% of patients.
To better understand why dementia occurs, the San Fransisco scientists looked at 2,018 “community-dwelling older adults” who took part in the Health, Aging, and Body Composition study.
The volunteers completed a questionnaire that was designed to evaluate apathy – defined as a “lack of interest, enthusiasm or concern”.
The volunteers were divided into groups according to low, moderate or severe apathy.
Over the next nine years, 381 of the participants developed “probable dementia”.
This was diagnosed via an algorithm that worked off an individual’s medication use, hospital records, and memory and thinking skills.
Results, published in the journal Neurology, revealed 25% of the participants who showed signs of severe apathy at the start of the study went on to endure notable cognitive decline.
This is compared to 14% of those in the lowest apathy group – a statistically significant difference.
“This study provides novel evidence for apathy as a prodrome [early symptom] of dementia,” concluded the scientists.
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Dementia is often associated with memory loss, confusion and personality changes. Early symptoms can be vague, however, with patients sometimes just misplacing items, forgetting the names of objects or struggling to find the right word.
Finding it tricky to make decisions or experiencing difficulties in day-to-day life can also occur with depression.
One expert therefore hopes raising awareness of the less recognised signs of dementia may enable quicker diagnoses.
“Symptoms of apathy are common in dementia and are not necessarily symptoms of depression,” said Dr Sara Imarisio from Alzheimer's Research UK.
“Many people with dementia are mistakenly diagnosed as having depression, particularly in the early stages.
“Building a better understanding of some of the less well recognised symptoms of dementia, like apathy, could inform our efforts to develop better treatments for the condition.”
She added, however, the San Fransisco study had some shortcomings.
“The scientists used algorithms to identify likely dementia and a dementia diagnosis wasn’t necessarily confirmed by a doctor,” said Dr Imarisio.
“It’s still not clear whether apathy contributes to memory problems or vice versa.
“To continue to unpick this link and make real breakthroughs for people who need them, we need to see sustained investment in dementia research.”
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