It’s unclear whether staff at the Park Health and Rehab nursing home could have prevented 76-year-old Zheng Diao from becoming so agitated last month that he was tasered by police and died from complications after the shock caused a traumatic fall.

Experts declined to speculate on the incident — which became public this week when the Hennepin County Medical Examiner released details — but said it is an important reminder about the need to soothe residents with dementia and prevent agitation.

“People generally don’t go off in a matter of minutes or hours,” said Terri McCarthy, a University of Minnesota expert who managed a nursing home unit for residents with delirium. “There’s generally an indication that something is wrong for days before there is a crisis.”

Nursing homes need consistent staffing so workers learn subtle, nonverbal cues from residents with dementia, McCarthy said. Outbursts are often attempts to communicate.

“One time we found a guy whose toenail had been torn off,” she said. “He was in agony but he couldn’t articulate it and nobody knew that was the problem.”

Antipsychotic drugs and restraints, once overused as forms of behavior management, are being limited. Nursing home staff need training on residents’ cues and emotions, said Eilon Caspi, a Twin Cities resident studying the prevention of nursing home resident aggression as a postdoctoral fellow for the Providence VA Medical Center.

While other portions of the brain break down, the amygdala that is responsible for emotional regulation often remains intact. So dementia patients often have full emotional ranges and heightened sensitivity to others, he said. “If I’m anxious, the person will sort of mirror my emotions and respond accordingly.”

Nursing homes can keep residents calmer if they “look and feel and smell like home” and if they keep residents with dementia active in personally meaningful ways, he said.

“It’s the main weapon,” he said, “against behavioral expression and violent behavior in patients with dementia.”