Three of the suspects were in custody, including the children's grandmother, Edwina Louis, 52, WSAZ-TV in Huntington, W. Va., reported. Investigators were seeking a fourth.
Scioto County deputies came to the home in Wheelersburg, a small town on the Ohio River southeast of Cincinnati, after a teacher at Ohio Virtual Academy received an e-mail from one of the children, WTTE-TV in Columbus, Ohio, said.
The two older children told investigators they were chained to their beds much of the time, freed only to do schoolwork on their computer. They said they were beaten and paddled and given little food.
All four children were taken to Nationwide Children's Hospital in Columbus, WTTE said.
Louis' daughter, Bobbi Sue Pack, 31, and Juan Sanchez, 44, were also arrested. Leah Dillon, 24, who was described as leaving the house quickly when child welfare workers arrived, is being sought.
Scioto County Sheriff Mark Donini told WSAZ injuries observed on the children's bodies backed up their story.
Louis denied abusing her grandchildren.
"They're accusing me of tying up my grandkids, not feeding them," she told WSAZ. "They accused me of biting my grandkids. I got no teeth. I hit with my hand and I ain't got much strength as it is."
She said she was trying to get the children out of the house after two of them reported Sanchez "did bad things." He is also charged with sexual assault.
Jill Bays, a neighbor, described the family as very quiet.
"I just can't believe that was going on in that house," Bays said. "I only saw two little kids. I never knew older kids were there. I thought it was just babies."