THE DESCRIPTOR DIFFERENTIAL SCALE OF PAIN INTENSITY - AN EVALUATION OF ITEM AND SCALE PROPERTIES

Improved methods for pain measurement have both theoretical and clinic al importance. This study evaluated the Descriptor Differential Scale (DDS) of Pain Intensity, a recent methodology designed for assessing p ain reports in clinical samples. Experiment 1 evaluated the sensitivit y of the measure to small changes in electrocutaneous stimulation rela tive to a traditional visual analogue scale (VAS) of pain intensity. A dditionally, direct psychophysical scaling methods were employed to de termine ratio-scale values for the DDS sensory items in relation to th e electrocutaneous stimuli. This ratio scale was cross-validated by co mparison with previously published ratio-scaled data from cross-modali ty matching pain intensity judgement studies. Experiment 2 evaluated t he performance of the measure in both experimental and clinical pain s amples, as well as the similarity of item-response patterns in each of these samples. Results indicate that the DDS of Pain Intensity is sen sitive to small changes in electrocutaneous stimulation, has consisten t ratio-scale properties across two different psychophysical methods, and demonstrates similar item-response patterns across divergent exper imental and clinical samples. The results support the validity of the sensory DDS as a measure of pain intensity.