Violence is uncommon among people suffering from dementia, and acts of extreme violence are rarer still, say specialists who were stunned by allegations that a Shrewsbury man stricken with the condition had brutally slain his wife.
Authorities say that Jieming Liu, 79, killed his wife, Yuee Zhou, 73, and then appeared to have eaten some of her flesh.
“In my 25 years at the Alzheimer’s Association, I have seen only a scant handful of violent cases, and certainly nothing as violent as this one appears to be,’’ said Paul Raia, vice president of clinical services at the Alzheimer’s Association of Massachusetts and New Hampshire.
Authorities said the couple’s son told them his father suffers from Alzheimer’s and that when the father and mother moved here last fall from China, the older man did not recognize his son.
Confusion and agitation are common among Alzheimer’s patients, particularly as the disease progresses, and even minor changes in routine can provoke anxiety. So the move from China may have been especially traumatic for the elderly dementia patient, specialists said.
“A big part of the disease is an inability to learn new things,’’ said Robert Stern, director of the Alzheimer’s Disease Center Clinical Core at Boston University School of Medicine.
“Just moving from one home to another home in the same country or going on vacation to a new environment or visiting the kids if you are not familiar with their house, all of those things can be very disorienting and lead to agitation,’’ Stern said.
A dementia patient’s sense of reality is severely altered, which may lead the person to act aggressively if agitated, he said. “They are also unable to control impulses in a way that an individual with a healthy brain can do. So when you have someone who cannot make sense of the world and they can’t control their impulse, if they are strong, then it can very infrequently lead to this kind of violence.’’
Statistics on the frequency of violence by dementia patients are hard to find. One small 1992 study by University of Illinois researchers found that roughly 16 percent of Alzheimer’s patients had been violent toward a family member who cared for them in the year since their diagnosis. The violence was defined as hitting, kicking, biting, punching, or threats with a weapon.Kay Lazar can be reached at email@example.com. Follow her on Twitter @GlobeKayLazar.