A new classification of developmental language disorders (DLD)

Abstract

Eighty children with DLD were examined with 18 language tests, mainly derived from a neuropsychological investigation called NEPSY (NEuroPSYchological Investigation for Children). The children were 6-0 to 7-9 years old and attended kindergarten. The test profiles of the first 40 children, Group 1, were utilized for the elaboration of a classification of DLD. The test profiles were grouped into five subgroups with the aid of a Q-type factor analysis. Then the classification was modified to suit clinical application by collapsing two pairs of subgroups. The resulting categories were called: the Global Subtype, the Specific Dyspraxia Subtype, and the Specific Comprehension Subtype. The classification was validated, first, by a follow-up study. It was predicted that spelling problems would occur in the Global and the Specific Comprehension Subtypes, but not in the Specific Dyspraxia Subtype. At follow-up, 3 years later, the hit rate was found to be 80.5%. In a second validation procedure, the classification was tried out on the 40 children examined later, Group 2. The coverage of the classification was 85%. Five outliers (12.5%) seemed to form a fourth category, called the Specific Dysnomia Subtype. An expressive subtype was not observed.