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When dementia isn't Alzheimer's disease

December 22, 2016 | UCI Health
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Dementia comes in many forms, and it can strike as early as one's 50s.

Mention dementia and most people will think of Alzheimer’s disease and memory loss. Yet the disorder comes in many forms, can strike as early as someone’s 50s, and present symptoms that resemble mental illness.

Take, for instance, the case of a 60-year-old man whose wife contemplated divorce because he had grown indifferent toward her. He also became obsessive, stopped showering and neglected his physical appearance.

Then, one day, the wife fell from a ladder and he ignored her injury, walking right past her as she lay on the hard floor.

That episode was so far out of character, she brought her husband to see UCI Health neurologist Dr. Seyed Ahmad Sajjadi, who diagnosed the man with frontotemporal dementia (FTD).

“His diagnosis had an immediate effect on his wife. For her, knowing that her husband was becoming impossible to live with was due to a brain disease helped to restore marital harmony says Sajjadi, who is part of the UCI Health Memory Disorders Program.

“She decided to stay with him and help him through it.”

A family of dementia disorders

FTD includes a family of disorders that, unlike Alzheimer’s and vascular dementia, tends to affect those under age 65 and causes symptoms that can be overlooked or misdiagnosed.

FTD and other atypical dementias can manifest in surprising ways:

  • Depression or obsessive-compulsive behavior, for example, might stem from a psychiatric disorder. However, either can also be a symptom of FTD and other types of dementia.
  • Visual hallucinations might not be related to schizophrenia, but rather arise from dementia with Lewy bodies, which is the third most common dementia after Alzheimer’s and vascular dementia.

Further complicating diagnosis is that other health issues can mimic dementia:

  • Someone could have seizures that affect brain function and behavior without experiencing convulsions or tremors.
  • Certain cancers can affect memory long before a tumor is detected, Sajjadi says.
  • Even thyroid function and vitamin deficiencies can cause cognitive and behavioral symptoms similar to those found in dementia.

Diagnosing dementia

“When making a diagnosis, we consider the history of the patient’s symptoms,” says Sajjadi.

“With most of non-dementia causes, the course of the disease is much faster, weeks to months rather than months to years. So that would be our clue, along with lab tests and neuroimaging.”

Tools such as MRI scans and positron emission tomography (PET scans) reveal whether a patient has atrophy or a reduction in glucose uptake in a part of the brain associated with a particular dementia.

Other clues include family history and the age of symptom onset:

  • If you have a first-degree relative who was diagnosed with dementia or an unexplained mental illness in his or her older years, your symptoms may suggest dementia.
  • If you or a family member have new onset of unusual psychiatric problems at age 50 or older — without having experienced these symptoms in your 20s, 30s or 40s — you may possibly be in the early stages of dementia.

Developing a standard 

Even though several forms of dementia exist, most patients never get a specific diagnosis. This is due in part to a lack of criteria to differentiate the multiple subtypes and to identify them in their earliest stages.

“When patients first see a doctor while their symptoms are very mild, it can be almost impossible to tell if it is just normal aging or an actual dementia that will get worse over time,” Sajjadi says. “So my main research involves devising ways to diagnose these conditions in the early stage.”

He and his team have applied sophisticated imaging techniques to examine brain atrophy and have developed neuropsychological tests, including speech analysis, to identify impairments. They combine these with lab tests, patient histories and, in the case of genetically associated dementias such as FTD, genetic testing. Treating memory loss ›

Do I have dementia?

It is possible for you to have dementia and be unaware of it. Because the disorder affects the brain, usually a friend or family member is the first to notice a change in someone’s cognitive function or behavior. The key is to identify symptoms that are out of character or seem unrelated to normal aging.

“If someone developed memory problems in their 70s or 80s, there’s a good chance it could be Alzheimer’s. But if they develop some abnormal problem such as being obsessive, uninhibited or physically aggressive in their 60s or 70s, that would be a different concern,” Sajjadi says.

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