Intraexaminer and Interexaminer Reproducibility of the Downing Test for Sacroiliac Joint Evaluation of Symptomatic and Asymptomatic Individuals.

OBJECTIVE: This study aimed to assess the intraexaminer and interexaminer reproducibility of the Downing test in sacroiliac joint evaluation in symptomatic and asymptomatic individuals. METHODS: A reliability study was conducted with a test-retest design in 54 college students of both sexes. To assess the intraexaminer reproducibility, each participant was evaluated twice by the same examiner with a 7-day interval, and to assess the interexaminer reproducibility, each participant was evaluated by 2 examiners. RESULTS: Of the 54 participants included in the study, 18 (33.3%) were asymptomatic and 36 (66.7%) were symptomatic; a total of 108 sacroiliac joints were evaluated. Sacroiliac joint diagnosis based on the Downing test presented low intraexaminer reproducibility in all participants (κ = 0.12, 95% confidence interval [CI] 0.03-0.22), in asymptomatic individuals (κ = 0.18, 95% CI 0.02-0.34), and in symptomatic individuals (κ = 0.28, 95% CI 0.17-0.39). The interexaminer reproducibility also was low in all participants (κ = 0.18, 95% CI 0.09-0.27), in asymptomatic individuals (κ = 0.22, 95% CI 0.15-0.37), and in symptomatic individuals (κ = 0.16, 95% CI 0.05-0.27). The standard error of the measurement values were not lower than smallest detectable change values considering a CI of 95% for all participants. CONCLUSION: For this group of asymptomatic and symptomatic participants, the reproducibility of the Downing test was poor. The clinical utility of this test used in isolation is not supported by the present study.

Concurrent validity of the pressure biofeedback unit and surface electromyography in measuring transversus abdominis muscle activity in patients with chronic nonspecific low back pain / Validade concorrente da unidade de biofeedback pressórico e eletromiografia de superfície na mensuração da atividade muscular do transverso abdominal em pacientes com dor lombar crônica inespecífica

BACKGROUND: The Pressure biofeedback unit (PBU) is an assessment tool used in clinical practice and research aimed to indirectly analyze the transversus abdominis (TrA) muscle activity. The concurrent validity of the PBU in a clinically relevant sample is still unclear. OBJECTIVE: The purpose of this study was to evaluate the concurrent validity and diagnostic accuracy of the PBU in measuring TrA muscle activity in patients with chronic nonspecific low back pain. METHOD: This study was performed using a validation, cross-sectional design. Fifty patients with chronic nonspecific low back pain were recruited for this study. To test the concurrent validity both PBU measures (index test) and superficial electromyographic measures (reference-standard test) were compared and collected by a physical therapist in a series of voluntary contraction maneuvers of TrA muscle. RESULTS: Participants were on average 22 years old, weighed 63.7 kilos, 1.70 meters height and mean low back pain duration was 1.9 years. It was observed a weak and non-significant Phi coefficient (r=0.2, p<0.20). With regards to diagnostic accuracy tests, our results suggest a low sensitivity (60%) and specificity (60%) of the PBU. The positive predictive value was high (0.8) and negative predictive value was low (0.2). Conclusions: Concurrent validity of the PBU in measuring TrA muscle activity in patients with chronic nonspecific low back pain is poor given the low correlation and diagnostic accuracy with superficial EMG.

CONTEXTUALIZAÇÃO: A Unidade de Biofeedback Pressórico (UBP) é uma ferramenta de avaliação usada na prática clínica e pesquisa científica para analisar indiretamente a atividade muscular do transverso abdominal (TrA). A validade concorrente da UBP em uma amostra clinicamente relevante ainda não está esclarecida. OBJETIVO: Avaliar a validade concorrente e acurácia diagnóstica da UBP em mensurar a atividade muscular do TrA em pacientes com dor lombar crônica inespecífica. MÉTODO: Este estudo foi realizado usando um delineamento de validação. Cinquenta pacientes com dor lombar crônica inespecífica foram recrutados. Para testar a validade concorrente, ambas as medidas pressóricas (teste índice) e eletromiográficas superficiais (teste padrão de referência) foram comparadas e coletadas por um fisioterapeuta a partir de uma manobra de contração voluntária do músculo TrA. RESULTADOS: Os participantes tinham em média 22 anos, 63,7 kg, 1,70 m de altura, e a duração média de dor lombar era de 1,9 ano. Observou-se um coeficiente Phi fraco e não significativo (r=0,2; p<0,20). Com relação aos testes de acurácia diagnóstica, os resultados sugerem uma baixa sensibilidade (60%) e especificidade (60%) da UBP. O valor preditivo positivo foi elevado (0,8), e o valor preditivo negativo foi baixo (0,2). Conclusões: A validade concorrente da UBP em mensurar a atividade muscular do TrA em pacientes com dor lombar crônica inespecífica é pobre, considerando a baixa correlação e acurácia diagnóstica com a EMG de superfície.

Concurrent validity of the pressure biofeedback unit and surface electromyography in measuring transversus abdominis muscle activity in patients with chronic nonspecific low back pain.

BACKGROUND: The Pressure biofeedback unit (PBU) is an assessment tool used in clinical practice and research aimed to indirectly analyze the transversus abdominis (TrA) muscle activity. The concurrent validity of the PBU in a clinically relevant sample is still unclear. OBJECTIVE: The purpose of this study was to evaluate the concurrent validity and diagnostic accuracy of the PBU in measuring TrA muscle activity in patients with chronic nonspecific low back pain. METHOD: This study was performed using a validation, cross-sectional design. Fifty patients with chronic nonspecific low back pain were recruited for this study. To test the concurrent validity both PBU measures (index test) and superficial electromyographic measures (reference-standard test) were compared and collected by a physical therapist in a series of voluntary contraction maneuvers of TrA muscle. RESULTS: Participants were on average 22 years old, weighed 63.7 kilos, 1.70 meters height and mean low back pain duration was 1.9 years. It was observed a weak and non-significant Phi coefficient (r=0.2, p<0.20). With regards to diagnostic accuracy tests, our results suggest a low sensitivity (60%) and specificity (60%) of the PBU. The positive predictive value was high (0.8) and negative predictive value was low (0.2). CONCLUSIONS: Concurrent validity of the PBU in measuring TrA muscle activity in patients with chronic nonspecific low back pain is poor given the low correlation and diagnostic accuracy with superficial EMG.