Teaching topography-based and selection-based verbal behavior to developmentally disabled individuals: Some considerations.

The author looked at twenty years of studies on two kinds of AAC. One kind needs finger moves only. The other needs mouth or hand shapes.

He asked which kind is easier for kids and adults who have developmental delays. He also showed how stimulus-equivalence tests can guide the pick.

Topography-based systems, like signs or writing, were learned faster in most cases. Selection-based boards took more trials to master.

The paper gives a simple rule: if the learner can form signs or letters, start there. Then use equivalence drills to link the new form to spoken words.

Delamater et al. (1986) proved the point with an autistic adult. They replaced his echolalia with correct answers by teaching him to write the words first.

Griffith et al. (2012) showed the same idea with coins. After kids felt the coins, they could name them without extra teaching. This is stimulus equivalence in action.

Wilkins et al. (2009) chained long echoic stories with kids with autism. Their mouths shaped the sounds, another win for topography-based work.

If your client has even small hand or mouth control, try signs, writing, or typing first. Run match-to-sample lessons so the new form links to pictures and spoken words. You may see faster gains and less prompt dependence than with picture boards alone.