Measurement Properties of the Brazilian-Portuguese Version of the Lumbar Spine Instability Questionnaire.

STUDY DESIGN: Cross-cultural adaptation and analysis of measurement properties. OBJECTIVE: To translate and cross-culturally adapt the Lumbar Spine Instability Questionnaire (LSIQ) into Brazilian-Portuguese and to test its measurement properties in Brazilian patients with low back pain. SUMMARY OF BACKGROUND DATA: The selection of subgroup of patients that respond better to specific interventions is the top research priority in the field of back pain. The LSIQ is a tool able to stratify patients with low back pain who responds better to motor control exercises. There is no Brazilian-Portuguese version of the LSIQ available. METHODS: The original version of the LSIQ was translated and cross-culturally adapted. We collected data from 100 patients with low back pain. In addition to LSIQ, we also collected information about physical activity levels (measured by the International Physical Activity Questionnaire short version), disability (measured by the Roland Morris Disability Questionnaire), pain intensity (measured by the Pain numerical Rating Scale), kinesiophobia (measured by the Tampa Scale of Kinesiophobia), and depression (measured by the Beck Depression Inventory). The measurement properties tested were internal consistency, reproducibility (reliability and agreement), construct validity, and ceiling and floor effects. RESULTS: The Brazilian-Portuguese version of the LSIQ showed good measurement properties with a Cronbach alpha of 0.79, an intraclass correlation coefficient of 0.75, a standard error of measurement of 1.65 points, and a minimal detectable change of 3.54 points. We did not detect ceiling and floor effects. The construct validity analysis was observed a moderate correlation between the LSIQ and Pain Numerical Rating Scale r = 0.46, Roland Morris Disability Questionnaire r = 0.66, Tampa Scale of Kinesiophobia r = 0.49, and Beck Depression Inventory r = 0.44. CONCLUSION: The Brazilian-Portuguese version of LIQ has adequate measurement properties and can be used in clinical practice and research. LEVEL OF EVIDENCE: NA.

Comparison of different analysis techniques for the determination of muscle onset in individuals with patellofemoral pain syndrome.

To understand patellofemoral pain syndrome (PFPS), recent studies have focused on assessing the onset in the vastus medialis and vastus lateralis to determine whether there is a delay between these muscles' activation. However, the results of these studies are not in agreement, as some research shows that there is a delay in the VMO, while others do not show delay. It has been suggested that this discrepancies may be due to differences in the signal processing and analysis. For this reason, this study aimed to compare the three techniques used for onset determination - automatic detection, visual inspection and cross-correlation - and to verify whether these methods are able to detect PFPS. The surface electromyography evaluation procedure was conducted in 22 pain-free control individuals and 11 with PFPS diagnoses, during a stair climbing. The standard error of measurement (SEM) showed that cross-correlation presents the lower variation (2.56/3.27, control/PFPS) in relation to visual (3.77/10.19, control/PFPS) and automatic detection (43.23/51.98, control/PFPS, respectively). But when using the cross-correlation technique, we were not able to distinguish the groups (-6.56/-9.74ms, control/PFPS, p=0.15). Therefore, use of muscle onset may not be the best way to distinguish individuals with PFPS.