A traditional slave narrative, like Frederick Douglass' autobiography, was written during the time period from personal experience. These kinds of slave narratives would be considered primary sources.
A neo-slave narrative is written by contemporary authors who use their imaginations and historical information to create a fictional slave narrative. Dessa Rose would be considered a neo-slave narrative because it was published in 1999. Dessa Rose has historical context, real slave women rebelling against their masters in desperate circumstances and a white woman hiding runaway slaves (from book jacket).