Reactivity in Pain-Free Subjects and a Clinical Pain Population: Evaluation of the Kohn Reactivity Scale-Dutch Version

Background: Patients with pain are more reactive to various types of sensations, not limited to pain alone. A potential useful instrument to assess reactivity is the Kohn Reactivity Scale (KRS). This study examines the psychometric characteristics of the KRS-Dutch version and its ability to differentiate between subjects with and without pain. Methods: Internal consistency, convergent validity, and test retest reliability of the Dutch translation of the KRS were assessed in 321 pain-free control subjects and different subgroups of this sample. Subsequently, reactivity scores were compared between the pain-free subjects and 291 pain patients who were referred to a pain clinic for treatment. Results: Reliability analyses indicated good internal consistency (alpha >= 0.77) and high test-retest reliability (intraclass correlation = 0.95) of the KRS in the control subjects. Validity analyses yielded positive correlations of the KRS with related constructs like pain vigilance and awareness (r = 0.37), symptom severity (r = 0.29), and the personality characteristic neuroticism (r = 0.20). Pain patients had overall significantly higher KRS scores than the pain-free subjects indicating increased reactivity, particularly for the patients with medically unexplained pain. Conclusions: These findings indicate that the KRS is a useful instrument to screen for reactivity in pain patients, which may be of particular relevance for those suffering from medically unexplained pain.