Scientists have discovered an additional type of Alzheimer's disease (AD), which could be relatively common.
The study looked at 1,821 brains of people with the condition and it transpired 11 per cent of those had this variant, which is known as hippocampal sparing AD.
As almost half of those with this subtype could be misdiagnosed, it is thought as many as 600,000 Americans may in fact have this condition.
The researchers from the Mayo Clinic in Florida revealed the main symptoms of this variant are substantially different to those of the more well-known condition.
Male patients are generally more susceptible to it and often have frequent outbursts of rage and the sensation that their limbs do not belong to their body, as they are controlled by some form of paranormal being.
Not only do those with this subtype acquire the condition younger than those with Alzheimer's tend to, but they also experience decline at a heightened pace.
Lead author Dr Melissa Murray, assistant professor of neuroscience at Mayo Clinic, spoke of how she hoped this research would open the minds of those diagnosing the condition, especially as memory loss is not a feature of every single case of Alzheimer's disease.
"Many of these patients, however, have memories that are near normal, so clinicians often misdiagnose them with a variety of conditions that do not match the underlying neuropathology.
"What is tragic is that these patients are commonly misdiagnosed and we have new evidence that suggests drugs now on the market for AD could work best in these hippocampal sparing patients."
She added how such drugs had the potential to be even more effective than they are on the more well-known form of the condition.
The lead author also called for further research in amyloid and tau imaging biomarkers to facitiliate the correct diagnosis of AD. This is because these proteins are hallmarks of both AD and the new subtype.
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