"In behavioral variant frontotemporal dementia, there are major changes in personality," Dr. Knopman said in an interview. "People become either very quiet and apathetic, or they become disinhibited, impulsive, and socially inappropriate."
In more severe cases the lack of inhibition can lead to public behaviors that are acutely embarrassing to family and friends, and the patient's behavioral changes cause severe disruption in relationships. In addition, patients may develop cognitive problems including difficulty reasoning, impaired mental agility, and difficulty solving problems.
A second classic presentation of the disorder is disturbance in expressive speech, with loss of fluency and ability to communicate well with others. In some patients the behavioral and speech presentations may be mixed, depending on the brain region involved, Dr. Morris said.
According to the National Institute on Aging, distinguishing frontotemporal dementias from Alzheimer's disease is crucial, because some agents used to treat the latter, such as cholinesterase inhibitors, may be harmful or ineffective in patients with frontotemporal dementias.
