Atypical Types of Dementia: Hippocampal Sparing Alzheimer's Disease

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Earlier this year I began reading about a variant type of dementia called hippocampal sparing Alzheimer’s disease, which results in symptoms far different than Alzheimer’s disease. Those affected are mainly men and they often begin to show symptoms at a younger age.

Hippocampal sparing AD usually advances quickly and it presents initially as bizarre behaviors. Those with the disease frequently exhibit anger and sometimes have profane outbursts. They report feeling as though their limbs are uncontrollable and disconnected from their bodies. As the disease progresses, those afflicted report feeling as though an alien-type force is controlling them.

While those with this disease experience challenges with speech, language comprehension and eyesight, hearing and general vocalization (other than speech) are largely unaffected.
Earlier this year, a study by the Mayo Clinic in Florida concluded as much as 11 percent of those given an Alzheimer’s diagnosis actually have hippocampal sparing. This percentage translates into more than 600,000 individuals.

Now recognized as a subtype of traditional Alzheimer’s disease, hippocampal sparing AD doesn’t attack the brain’s hippocampus; therefore, memories remain mainly intact.
Neuroscientists believe this is related to how the tau, a type of protein, forms its classic tangles in the brain. Those identified with hippocampal sparing AD did have have fewer tangles, but more tangles were in the portions of the brain that control speech, vision, motor skills and general behavior.

Often misdiagnosed, hippocampal sparing is commonly confused with frontotemporal dementia.

Spotting the disease and securing a correct diagnosis is imperative since hippocampal sparing AD responds very well to the handful of existing memory-loss drugs currently on the market. Early diagnosis is imperative for the medications to work effectively.

Nancy Wurtzel, a frequent blogger for Third Age, is the editor of www.datingdementia.com.