Exactly why this blunting of emotions may occur isn't known, Heilman said. He speculates there may be a degradation of part of the brain or loss of control of part of the brain important for experiencing emotion. Or a neurotransmitter important for experiencing emotion may undergo degradation.
What the finding suggests is that as the memory goes, so does some emotion, said Dr. Gary Kennedy, a geriatric psychiatrist at Montefiore Medical Center in New York City, who reviewed the findings.
"Emotion and memory go together," he said. "The more emotion you can attach to an event, the more likely you are to remember. I think what this paper is telling us is that the disease is causing the emotional response to become more and more shallow over time."
Apathy seen in Alzheimer's patients is often reported by family members, Kennedy said. "Apathy is a heartbreaker for the family," he said.
Even so, both Kennedy and Heilman had a positive message for family members. For family, it's not to take it personally if a loved one with Alzheimer's is apathetic. "Don't interpret it as being done willfully," Kennedy said.
Heilman said families can try to make information more explicit when talking to those with Alzheimer's, in an effort to help emotions kick in. If you show a loved one a picture, for instance, give verbal details about the person or object in it, he suggested. You may see less apathy in response.
The research was supported in part by Lundbeck Pharmaceutical Co., whose products include Alzheimer's medicine.
To learn more about the stage of Alzheimer's disease, visit the Alzheimer's Association.
All rights reserved