Two assessments to evaluate imagery ability: translation, test-retest reliability and concurrent validity of the German KVIQ and Imaprax

Background: A combination of physical practice and motor imagery (MI) can improve motor function. It is essential to assess MI vividness in patients with sensorimotor impairments before implementing MI interventions. The study's aims were to translate the Canadian Kinaesthetic and Visual Imagery Questionnaire (KVIQ) and the French Imaprax, and to examine reliability and validity of the German versions. Methods: Questionnaires were translated according to guidelines. With examiner's help patients (diagnosis: stroke: subacute/chronic, brain tumour, Multiple Sclerosis, Parkinson's disease) were tested twice within seven days (T0, T1). KVIQ-G: Patients were shown a movement by the examiner, before executing and imagining the movement. They rated vividness of the image and intensity of the sensations on a five-point Likert-scale. Imaprax required a 3-step procedure: imagination of one of six gestures; evaluation of gesture understanding, vividness, and imagery perspective. Questionnaire data were analysed overall and for each group. Reliability parameters were calculated: intraclass correlation coefficient (ICC), Cronbach's alpha, standard error of measurement, minimal detectable change. Validity parameters included Spearman's rank correlation coefficient and factor analysis of the KVIQ-G-20. Results: Patients (N = 73, 28 females, age: 63 +/- 13) showed the following at T0: KVIQ-G-20(vis) 41.7 +/- 9, KVIQ-G-10(vis) 21.1 +/- 5. ICC for KVIQ-G-20(vis) and KVIQ-G-10(vis) was 0.77; KVIQ-G-20(kin) 36.4 +/- 12, KVIQ-G-10(kin) 18.3 +/- 6. ICCs for KVIQ-G-20(kin) and KVIQ-G-10(kin) were 0.83/0.85; Imaprax(vis) 32.7 +/- 4 and ICC 0.51. Internal consistency was estimated for KVIQ-G-20 alpha(vis)= 0.94/alpha(kin) = 0.92, KVIQ-G-10 alpha(vis) = 0.88/alpha(kin) = 0.96, Imaprax-G alpha(vis) = 0.70. Validity testing was performed with 19 of 73 patients, who chose an internal perspective: r(s) = 0.36 (p = 0.13). Factor analysis revealed two factors correlating with r = 0.36. Both explain 69.7% of total variance. Conclusions: KVIQ-G and Imaprax-G are reliable instruments to assess MI in patients with sensorimotor impairments confirmed by a KVIQ-G-factor analysis. KVIQ-G visual values were higher than kinaesthetic values. Patients with Multiple Sclerosis showed the lowest, subacute stroke patients the highest values. Hemiparetic patients scored lower in both KVIQ-G subscales on affected side compared to non-affected side. It is suggested to administer the Imaprax-G before the KVIQ-G to test patient's ability to distinguish between external and internal MI perspective. Duration of both questionnaires lead to an educational effect. Imaprax validity testing should be repeated.