Updated

A New York man who spent years caring for his ailing 88-year-old mother before strangling her with a necktie while she slept will spend 17 years to life in prison.

James Olsen was sentenced Monday for the 2011 killing of his mother, Ruth, who had dementia.

Olsen was convicted of murder in May. A jury rejected a claim of insanity.

Prosecutors said Olsen methodically planned the crime in their comfortable Garden City, Long Island, home -- even picking out the necktie the night before she was killed.

His attorney said Olsen snapped from the stress of caring for her.