The abuse took place from May 2010 to September 2011 at Hillcroft nursing home in Slyne-with-Hest, near Lancaster.
All four workers were charged with ill-treatment and wilful neglect of a person with lack of capacity under the Mental Capacity Act 2005.
A court heard how residents, many of whom had dementia, were mocked, bullied and tormented because they would have no memory of the abuse.
The offences related to eight victims, seven men and one woman, all aged in their 70s or 80s, with the eldest aged 85.
The vulnerable victims were also pelted with bean bags and had balls thrown at their heads.
Darren Smith, 35, from Lancaster, pleaded guilty and was jailed for eight months at Preston Crown Court.
Katie Cairns, 27, was sentenced to five months in prison, Carol Moore, 54, was jailed for four months and 28-year-old Gemma Pearson was given a 12-month community order.
Sentencing them at Preston Crown Court yesterday, Judge Michael Byrne said: “Much evidence in the trial revealed that there was, at the relevant times, a lax regime with weak and inadequate management on the unit which allowed the kind of conduct to carry on undetected and without proper and adequate control.”
He said the offences committed were “an indictment” on Hillcroft management.
Judge Byrne continued: “Some of the offences were gratuitous sport at the expense of vulnerable victims. Each of these defendants broke the trust placed in them.”
The court was told one man had his foot stamped on and another was nearly tipped out of his wheelchair.
One victim’s son, who chose to stand in the witness box to give his witness impact statement in person, said he was “angry”.
Michael Rowlinson, whose father, Norman, has Alzheimer’s disease, said: “We had feelings of guilt for not being able to look after him.
“Our feelings of guilt only worsened when we found out that dad had been subjected to humiliation and ill-treatment by those who were trusted to care for him.”
The son of one resident whose foot was stamped on by Cairns thanked whistleblowers who were “brave enough” to come forward and report the four care workers.
The court had heard the staff had previously been suspended from the home following abuse allegations made by a receptionist and a cleaner in September 2011.
But they returned to work after being handed warnings as a result of an internal investigation and the matter was not referred to the police or social services.
It was several months later that arrests were made after a whistleblower wrote to health inspectors.
Detective Chief Inspector Andy Hulme, of Lancashire Police, said a review was taking place to “ensure better protection for vulnerable adults in residential care” and “all recommendations will be addressed accordingly”.
Det Chief Insp Hulme described the abusers as “cowardly” and said their conduct was “utterly contemptible”.
He added: “I don’t believe that the behaviour shown by Smith, Cairns, Pearson and Moore is a true reflection of the majority of staff at Hillcroft.”