A paramedic said the toddler, Isaac Bartholomew, was dead when he arrived about 7:13 p.m., The (Lorain) Morning Journal reported.
In addition, six other children have been removed from the child's home and four of them have been admitted to a Cleveland hospital with complex medical issues, the newspaper said.
The children's parents, Adrienne Bartholomew, 34, and James Brothers, 33, told sheriff's deputies five of the seven children "suffer from various severe physical and mental handicaps that require around-the-clock care," the report said.
"Malnourishment is one of the overarching problems for all four [of the children hospitalized]," Chief Deputy Jared Oliver said. "There was a 6-year-old that weighs 23 pounds."
Oliver said an autopsy showed the child who died was "extremely malnourished and dehydrated."
The newspaper said Bartholomew told deputies the toddler had a severe acid reflux, gastrointestinal issues and heart murmurs, and that she and Brothers had fallen asleep in their living room. They were aroused by their 11-year-old telling them he found the baby unresponsive.
"We did some checking in the medical records and learned that the child hadn't been seen by a doctor in eight months," Oliver said, the newspaper reported. "We've kind of got some conflicting statements."
When an investigation is complete, "we'll definitely confer with the prosecutor's office," he said