title: Manual signing in adults with intellectual disability: influence of sign characteristics on functional sign vocabulary.
abstract: OBJECTIVE
  The purpose of this study was to investigate the influence of sign characteristics in a key word signing (KWS) system on the functional use of those signs by adults with intellectual disability (ID).
  
  
  METHODS
  All 507 signs from a Flemish KWS system were characterized in terms of phonological, iconic, and referential characteristics. Phonological and referential characteristics were assigned to the signs by speech-language pathologists. The iconicity (i.e., transparency, guessing the meaning of the sign; and translucency, rating on a 6-point scale) of the signs were tested in 467 students. Sign functionality was studied in 119 adults with ID (mean mental age of 50.54 months) by means of a questionnaire, filled out by a support worker.
  
  
  RESULTS
  A generalized linear model with a negative binomial distribution (with log-link) showed that semantic category was the factor with the strongest influence on sign functionality, with grammatical class, referential concreteness, and translucency also playing a part. No sign phonological characteristics were found to be of significant influence on sign use.
  
  
  CONCLUSIONS
  The meaning of a sign is the most important factor regarding its functionality (i.e., whether a sign is used in everyday communication). Phonological characteristics seem only of minor importance.
authors.forename: Kristien
authors.initials: K
authors.lastname: Meuris
authors.forename: Bea
authors.initials: B
authors.lastname: Maes
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: De Meyer
authors.forename: Inge
authors.initials: I
authors.lastname: Zink
mesh_terms: D000328:Adult; D003142:Communication; D003147:Communication Disorders / Q000534:rehabilitation*; D005149:Facial Expression; D005260:Female; D006801:Humans; D008607:Intellectual Disability / Q000534:rehabilitation*; D016014:Linear Models; D008037:Linguistics; D008297:Male; D009068:Movement; D010700:Phonetics; D012660:Semantics; D012813:Sign Language; D013066:Speech-Language Pathology; D014825:Vocabulary