Low functioning autism is an antiquated term. But, for years those on the lower end of the autism spectrum were more often diagnosed than those on the higher end of functionality because their manifestation of ASD was more apparent. Within the last 20 years those on the higher functioning end of the spectrum have started outnumbering those on the lower end. Also, due to better rehabilitation resources for people with ASD some initially on the lower end of functioning were able to be reassessed as on the higher functioning end.