Two pensioners have been charged with unlawful imprisonment after a 19-year-old with autism was found locked in a cage on a wooden bed.

A 65-year-old woman and 66-year-old man were arrested at the home and authorities removed three adults from the property on 20 October.

Two children, who were also found at the house, were taken away by protection services after a court ruling five days later.

Police found the man with a thin blanket on a wooden "bed" platform and the barred door chained shut after responding to an incident at the property in Paris Township, about 90 miles north of Detroit, Michigan.

The arrested pair are being charged with unlawful imprisonment and misdemeanour abuse of a vulnerable adult, and are held in the Huron County Jail.

Michigan's Department of Human Services says its adult protective services office is investigating the incident.

The department's spokesman Bob Wheaton said the home is a private residence and not a licensed care facility.

A spate of abuse against people with autism, a developmental disability characterised by impaired communication and social skills, has been reported over the past few months in the US.

Earlier this month, 46-year-old Kelli Stapleton, a former autism campaigner from Battle Creek, Michigan, was sentenced to at least 10 years in prison for first-degree child abuse after attempting to kill herself and her 15-year-old autistic daughter.