SHORT-TERM-MEMORY IN PERSONS WITH INTELLECTUAL DISABILITIES AND DOWNS-SYNDROME

The present study was designed to investigate verbal and spatial short -term memory abilities in persons with Down's syndrome (DS) and intell ectual disability (ID) of different aetiology. For this purpose, we co mpared performances of DS (n = 15; mean mental age = 5.2 years; SD = 1 .2 years; mean chronological age = 16.6 years; SD = 2.9 years) and ID subjects (n = 14; mean mental age = 5.8 years; SD = 2.1 years; mean ch ronological age = 16.4 years; SD = 2.5 years) with those of normally d eveloped subjects matched for mental age (n = 24) on tasks of forward and backward immediate recall of verbal and spatial sequences. Our res ults are discussed in the light of the Working Memory model developed by Baddeley (1986, 1990). Altogether, our data documents a deficit of verbal and spatial backward spans in persons with DS. The deficit seem s to be specific for this particular aetiology group, confirming the h ypothesis that ID is not a uniform condition, characterized by an undi fferentiated delay of the cognitive development, but rather that it is characterized by a deficit in a complex cognitive system in which som e cognitive abilities can be disrupted more than others (Detterman 198 7; Vicari et al. 1992).