"When someone's character suddenly changes, for example, they become aggressive, scream or begin making defensive motions with their hands, this often is an indication of pain," said professor Rolf Dieter Hirsch, chairman of the German Academy for Gerontological Psychiatry and Gerontological Psychotherapy in Bonn.
In many cases people suffering dementia have toothache, said Hirsch. One indication of a painful dental condition is when a patient refuses food by clamping the jaws together.
A patient who has been mobile and suddenly avoids movement also might be experiencing pain, and his or her relatives should be informed. The patient could have a fracture. Other things to watch out for are problems when urinating, which could be a sign of a malfunctioning internal organ, and constant scratching, which could indicate a fungus or a metabolic illness, Hirsch said.
Loved-ones should not rely on the patient to express his or her pain through facial expressions. Some dementia patients show no emotion, Hirsch said. In addition not every affliction is expressed through pain, he said, adding that their perception of pain is "completely distorted".
Hirsch and Hans Juergen Freter, spokesman for a German Alzheimer's assistance centre in Berlin, both recommend that relatives contact a doctor or dentist, if a patient behaves oddly. Even when a doctor visits a patient regularly, Freter said signs of pain might not be detectable. The doctor's visit lasts perhaps one-quarter of an hour, Freter said. Relatives and caregivers typically spend far more time with the patients.