Tuesday's Supreme Court ruling siding with a family over a rail operator in a case where a dementia suffer was struck and killed by a train highlights the burdens faced by family caregivers and the need for society to offer them assistance, an expert on the mental illness has said.

The high court ruled that the family was not obligated to compensate a railway operator for damages sustained after the man wandered onto the tracks and was killed.

The case marks the first time the top court has ruled on a family's responsibility in supervising dementia patients.