Tactile defensiveness in children with developmental disabilities: responsiveness and habituation.

Tactile defensiveness (TD) is characterized by behaviors such as rubbing, scratching, negative expressions, withdrawal, or avoidance in response to tactile stimulation. An inhibition deficit has been implied in the literature and is the focus of this study. School-aged children with developmental disabilities were first assessed for level of TD using three measures. Later, the children were presented with a repeated tactile stimulus while engaged in a computer game. Intensity, duration, and latency of the responses were recorded on each trial. It was hypothesized that higher levels of TD would be associated with (a) greater responsiveness and (b) slower habituation rates to the tactile stimulus. Correlations of three separate TD measures and a series of 3 x 10 (Level of TD by Responsiveness across trials) repeated measures ANOVAs were used to test the two hypotheses. Children who demonstrated higher levels of TD on some of the preliminary measures also showed higher responsiveness in the experimental situation. There was no general habituation effect, and the limited group by trials interactions were not interpretable. We conclude that there is evidence for a differential sensitivity in TD, but not an inhibition deficit. Another significant finding included a negative correlation between TD and developmental age.