looks to me like it simply means "over the age of 72".

http://info.dhhs.state.nc.us/olm/manuals/dma/abd/man/MA2250-07.htm reads, in part:

"R. Prouty (Special Age 72) Benefits
Definition - Special benefits paid by SSA to persons age 72 or over who have not worked under the Social Security system. The payments are minimal. Persons now receiving SSI are ineligible for these benefits. Some long term care recipients elect to have Prouty instead of SSI as they can receive a larger benefit."

hope this helps a bit