An analysis of the research literature suggests that a variety of sign systems have been used with retarded individuals of varying ages. The application or success or failure of that therapy does not seem to be determined by a particular treatment model and/or set of guidelines. (Author)

Effects of high and low levels of manual sign translucency and referential concreteness on the manual sign learning of 40 moderately/severely mentally retarded adolescents were investigated. High levels of translucency were a significant facilitator while low levels inhibited learning. Concreteness did not significantly affect sign learning.…

Symmetrical signs were acquired significantly faster than were asymmetrical signs, and touch signs were acquired significantly faster than were nontouch signs. Results of the acquisition of iconic v abstract signs were inconclusive. (Author)

A study involving six institutionalized retarded males was designed to determine if sign-object and sign-word training would lead to acquisition of word-object associations. (Author)

To better understand the mechanisms underlying encoding, manual signs and spoken words were presented in a short term memory task to six severely retarded children (11 to 14 years old). It was found that manual signs were encoded differently from spoken words for short term memory storage. (Author/PHR)