Are specific reading disability and specific language impairment the same thing?

There is a growing trend to merge specific reading disability (SRD) and specific language impairment (SLI) into a single language-learning impaired (LLI) group. This study tested the validity of this trend by comparing the distal cognitive deficits of 64 children with impaired reading and intact spoken language (SRD), 26 children with impaired reading and impaired spoken language (language impaired-reading disabled; LIRD), and 37 children with intact reading and intact spoken language (controls). The children with SRD and LIRD had similar deficits in rapid auditory processing, frequency discrimination, phoneme discrimination, automatisation, and rapid lexical access. However, the LIRD group had more severe deficits in phonemic discrimination and phonemic short-term memory than the SRD group. These results suggest that SRD and SLI, while very similar, are not the same the same thing. This questions the validity of merging these two disorders into a single LLI group.