The Cervical Radiculopathy Impact Scale: development and evaluation of a new functional outcome measure for cervical radicular syndrome

Abstract

Objective: To develop and validate an outcome scale for the cervical radicular syndrome and to build a mapping, predicting EQ-5D utility from the new scale.Study design and setting: An item pool was developed based on literature and patient and clinician interviews. Item selection was based on symptomatology, factor analysis, and internal consistency. We assessed: (a) test–retest reliability by standard error of measurement and intraclass correlation coefficients; (b) construct validity by testing 22 hypotheses on relationships with existing measures and known-group differences. For the mapping, performance was assessed by mean absolute error and root mean squared error.Results: A total of 254 patients with cervical radicular syndrome completed the first questionnaire, 61 stable patients a retest. Item selection led to a 21-item questionnaire consisting of three subscales: Symptoms, Energy and postures, and Actions and activities. Standard error of measurement values ranged from 6.7 to 11.2 on a 0 to 100 scale. All subscales showed good reliability (intraclass correlation coefficients: 0.84, 0.87, and 0.94). All hypotheses for construct validity were confirmed. A linear utility mapping was preferred, with reasonable statistical performance.Conclusion: We developed a reliable and valid cervical radicular syndrome specific outcome scale, called the Cervical Radiculopathy Impact Scale (CRIS). This new questionnaire may facilitate (cost-)effectiveness studies in this field.Implications for RehabilitationThe cervical radicular syndrome is a frequently occurring and invalidating health problem, which causes severe radiating pain in the arm and/or hand, which can be accompanied by motor and/or sensory deficits.The Cervical Radiculopathy Impact Scale (CRIS) is a newly developed self-report questionnaire which covers measurement of symptoms and limitations in patients with cervical radiculopathy due to irradiating pain, tingling sensations and sensory loss in the arm in combination with neck disability.The CRIS consists of 21 items divided over three subscales: (i) symptoms, (ii) energy and postures, and (iii) actions and activities.The CRIS shows good content validity, test-retest reliability, construct validity and is able to discriminate between groups.The CRIS predicts EQ-5D utility and is therefore useful for (cost)effectiveness studies in this field.