While this subtype of the disease spares the memory, it can alter behavior in bizarre ways
The claim: Roughly 1 out of 10 Alzheimer's patients—particularly men—may suffer from a subtype of the disease called hippocampal sparing Alzheimer's (HSP). As the name suggests, this form of the disease spares the patient's hippocampus, or memory center. But it can cause angry outbursts, vision problems, and other bizarre behavior that often leads to wrong diagnoses and incorrect treatment, according to Mayo Clinic researchers.
The research: The study team examined the brains of more than 1,800 confirmed Alzheimer's patients. They found the types of protein blockages and tangles associated with the hippocampal sparing form of Alzheimer's in 11% of those brain specimens. In this subtype, one type of protein called tau forms "tangles" in the parts of brain that control behavior, motor awareness, speech, and vision, explains Melissa Murray, PhD, who led the Mayo Clinic research team.
What it means: Most people—doctors included—associate Alzheimer's with memory problems. And because this subtype of the disease spares sufferers' memories, it's misdiagnosed as some other type of brain disorder nearly 50% of the time. That's a big problem, because patients may not receive proper treatment, Murray says. More bad news: Hippocampal-sparing Alzheimer's tends to set in earlier—late 50s or early 60s—than traditional Alzheimer's, which usually doesn't show up until after age 65. Subtype sufferers also tend to decline at faster rates than other Alzheimer's patients. On the other hand, Murray says there's some (very preliminary) evidence that current Alzheimer's treatments may work even better for patients with this hippocampal sparing subtype—which means spotting the disease early is absolutely critical.
The bottom line: Angry or profane outbursts, vision problems, trouble with language, or a feeling that your limbs are somehow beyond your control are some of the strange symptoms of hippocampal sparing Alzheimer's. While doctors need to do a better job differentiating this disease from other cognitive issues, Murray says people should practice the same preventive measures proven to help ward off traditional forms of the disease: walking 30 minutes a day, controlling blood pressure, and keeping your mind active (especially after retirement) could help postpone the onset of symptoms, she says.
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Published May 2014, Prevention