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The "Onion Effect"

People with Alzheimer's Syndrome, a degenerative brain disease of old age, often suffer from anterograde amnesia similar to H.M.'s. They tend to forget recent events, such as conversations held a few minutes earlier. As the condition worsens, forgetfulness may extend back for years, and the old person may fail to recognize his or her grandchildren. In the final, most pathetic state, the old person may call visitors by the names of long-dead brothers and sisters. It is almost as though memory is organized like an onion, in layers. The most recent layers peel off first, followed by the older ones.

What is the "onion" effect in memory loss of old age?

A student describes the peeling away of memories.

In December, my great-grandmother will be 103 years old. She lived a remarkably healthy life up until about three years ago. Today she is bedridden or confined to a wheelchair most of the time. She lives very little of her conscious life in the present; her mind is now in the past. After studying the lesson on Memory, I realized she lost her memory and retreated to the past by going through the "onion peeling" or layer process we heard about. First of all, she began to forget the most recent things on her mind. She commonly misplaced things or forgot what she was doing. When she made homemade rolls, she would forget they were in the oven. Therefore, to prevent them from burning, she would pull up a chair and sit in front of the oven until they were done. The next major change was that she forgot her great-grandchildren. When we visited her, we would have to tell her who we were (partially due to bad eyesight) and then she would remember us. Her next loss of memory was for her grandchildren. She once asked my grandmother who the girl was my father married. My father is actually her grandson-in-law and my mother is her granddaughter. Just recently she has lost her memory for her own children. Today she lives in the past. Once when we visited her she had a very worried look on her face. When asked what was wrong, she replied "I'm worried about the baby." When asked what was wrong with the baby, she replied, "It's sick." We asked who the baby was and she replied "George." George is my grandfather and her son. [Author's files]

What did Reisberg find to be typical of memory loss in Alzheimer's patients?

Researcher Barry Reisberg at the New York University Medical Center documented this effect. He found that memory loss due to Alzheimer's Syndrome exactly reversed the cognitive gains of a young child. The first abilities to disappear were adult skills such as financial management. Next came clothing selection, dressing ability, bathing, and control of bathroom functions. In late stages of Alzheimer's disease, speech ability dwindled to a few words, then only one. Finally this one word was lost, followed by the ability to sit up. The last thing to go was the ability to smile, the first organized behavior of babyhood, which appears around the age of two months (Turkington, 1985).

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