PHILADELPHIA - Aides at an assisted living facility assaulted and mocked a half-naked dementia patient as the elderly woman struggled to flee her room and escape the torment, according to video evidence captured by a hidden camera in the room.

The woman's family had left a clock containing the hidden camera in the woman's room after officials at the Quadrangle Assisted Living Facility in suburban Philadelphia dismissed their complaints, instead pointing to the victim's dementia, authorities said Thursday.

"Why do they keep picking on me?" the distressed 78-year-old woman had asked her family, according to police documents.

Three aides _ Samirah Traynham, 22, Tyrina Griffin, 21, and Ayesha Muhammad, 19 _ were charged with aggravated assault, neglect of a care-dependent person and related charges for the alleged verbal and physical assault on the patient.

Traynham struck the woman in the face and head as the woman struggled to put her shirt on, and shoved her in her bed, the police affidavit states. Griffin "shadow boxed" with the patient and danced to a bed post in a manner that the woman's relative likened to a stripper's pole dance, the affidavit said.

Muhammad admitted to police that she and her co-defendants blocked the patient from leaving her room several times but denied having any physical contact with her, the affidavit states.

"Seniors are some of the most vulnerable members of our community, especially seniors suffering from mental diseases, such as Alzheimer's and dementia," said Assistant District Attorney Michael Mattson. "It's a very big concern."

Traynham is free on bail, and a message for her was not immediately returned. Muhammad also did not return messages.

Griffin told reporters that any mistreatment "wasn't intentional."

The woman's daughter and son-in-law, Mary and Paul French, installed the hidden camera and went to police with their evidence after the victim complained to them of mistreatment, and their concerns were rebuffed by administrators at the Haverford facility, authorities said. The couple also photographed unexplained bruises they found on the woman's mother, police said.

Sunrise Senior Living Inc of McLean, Virginia, operates the facility and more than 300 others in the U.S., Canada and Great Britain. The company issued a statement saying it took the allegations seriously and was cooperating with police.

"Our No 1 concern, above all else, is the safety of our residents. We have a number of policies and procedures in place that address their welfare and are intended to prevent any inappropriate activity in our community," the company said.