The effects of tactile defensiveness and tactile discrimination on in-hand manipulation.

The purpose of this study was to compare in-hand manipulation efficiency in children with and without tactile defensiveness and low tactile discrimination. Fifty children, aged 4 to 6 years, were tested with the use of three subtests of the Southern California Sensory Integration Tests (SCSIT) (Ayres, 1980), which measured tactile function, and three in-hand manipulation tasks. Tactile defensiveness was rated during performance of the selected SCSIT subtests. Nine of the children had mild developmental delays and 41 were without delays. Low correlations between scores on tactile defensiveness and tactile discrimination suggested that these two aspects of tactile function are separate but related phenomena. Children with both defensiveness and discrimination problems demonstrated the least efficiency on all of the in-hand manipulation tasks and had significantly higher time scores on the turn and translation in-hand manipulation tasks. Poor discrimination or tactile defensiveness alone did not relate to poor in-hand manipulation. The results suggest that a child's tactile function should be considered in therapy to improve manipulation skill. Strategies to decrease tactile defensiveness and improve tactile discrimination may facilitate achievement of higher levels of in-hand manipulation.