Trunk recruitment during spoon use in tetraparetic cerebral palsy

In the present study we investigated the extent to which individuals suffering from spastic tetraparesis as a consequence of cerebral palsy tune their trunk involvement to accuracy demands in a spoon-handling task. Twenty-two participants (ten adolescents with spastic tetraparesis and 12 control participants) had to transport a spoon filled with water or sugar to a small or a large bowl that was placed within reach. Even though trunk displacement was larger in the tetraparetic participants than it was in the control participants, the effects of the imposed accuracy constraints were remarkably similar. Participants in both groups increased trunk displacement with increasing precision requirements. Furthermore, in both groups the largest trunk involvement was found in the initial and final part of the substance-transporting phase, when wrist velocity was lowest. We propose several explanations for these findings and conclude that the large trunk involvement in individuals with tetraparetic cerebral palsy should, in any case, not be regarded as a primary symptom of the disorder, but rather as an adaptive reaction to increased task demands.