Researchers have said using memory loss as the main diagnostic tool for dementia could mean other forms of the condition, which don’t always cause memory problems, could be missed
Researchers at Northwestern’s Cognitive Neurology and Alzheimer’s Disease Centre in the US have said relying only on clinical symptoms of memory loss could mean you miss other forms of dementia when diagnosing someone.
There are over 200 different types of dementia, and while memory loss is often the most common symptom, it is by no means the only one. Other types of dementia and Alzheimer’s can cause symptoms such as mood changes, depression, appetite changes, language problems, and issues with judgement or spatial awareness.
‘These individuals are often overlooked in clinical trial designs and are missing out on opportunities to participate in clinical trials to treat Alzheimer’s,’ said first study author Emily Rogalski.
So, for example, if the dementia affects personality, it may cause lack of inhibition. ‘Someone who was very shy may go up to grocery store clerk – who is a stranger – and try to give her a hug or kiss,’ Rogalski said.
Symptoms often depend on what part of the brain the dementia affects, and often this is impossible to see until an autopsy is performed after death. However, emerging evidence suggests an amyloid PET scan, an imaging test that tracks the presence of amyloid – the protein which is a hallmark of Alzheimer’s – may be used during life to determine the likelihood of the disease.
In the study, researchers looked at participants with primary progressive aphasia (PPA), a rare form of Alzheimer’s that causes progressive decline in language abilities, but often leaves memory and thinking intact in the early stages. Using an amyloid PET scan meant they were able to diagnose the Alzheimer’s before memory problems had become an issue.
The study demonstrates that knowing an individual’s clinical symptoms isn’t sufficient to determine whether someone has PPA due to Alzheimer’s disease or another type of neurodegenerative disease. Therefore, biomarkers, such as amyloid PET imaging, are necessary to identify the neuropathological cause, the authors said.
‘We wanted to describe these individuals to raise awareness about the early clinical and brain features of PPA to develop metrics which would advocate for their inclusion in clinical trials targeting Alzheimer’s disease,’ said Rogalski. ‘These individuals are often excluded because they don’t have memory deficits, but they share the same disease [Alzheimer’s] that’s causing their symptoms.’
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