Validade instrumental e confiabilidade intra e inter examinadores de um algômetro digital de baixo custo

Abstract

BACKGROUND: The quantification of pain in different musculoskeletal syndromes with dysfunctional conditions requires an objective assessment. Among the evaluation instruments, pressure algometers stand out. The economic context of several countries makes this equipment costly, which may limit its access in research and clinical practice. A valid and reliable adapted low-cost pressure algometer could be considered as a standard equipment, and it would increase access to objective pressure pain’s assessment for several health professionals. OBJECTIVES: Analyze the instrumental validity and intra and inter-rater reliability of a low-cost digital pressure algometer adapted from a suspended scale. METHODS: 60 random compressions were applied on a gold standard force platform, by a single evaluator. Pressure pain thresholds - LDP of 20 volunteers were collected 02 times (interval of 03 days) by 02 evaluators. The main outcome measures were the compressive peak strength – in kPa (adapted pressure algometer vs. force platform) and the LDP. Internal consistency was assessed using the Chronbach α test. The measurement’s standard error provided estimation of measurement errors, and the Bland-Altman method estimated the measurement bias, with lower and upper limits of agreement. RESULTS: There were no differences between the results of compressive strength of the equipment’s (adapted pressure algometer vs. force platform). Intra-examiner validity and reliability ranged from 0.84 to 0.99, and the standard measurement error was 0.005 to 0.04 kPa. Moderate to excellent internal consistency was observed, with low standard error of the measurement values and very strong correlations (r = 0.73– 0.74) to almost perfect (r = 0.99), with low risk of bias for all measures. The results demonstrated the validity and intra-rater reliability of the adapted pressure algometer. Inter-rater reliability results were moderate (r = 0.55-0.60; Cronbach's α = 0.71–0.75). CONCLUSION: The equipment had sufficiently acceptable validity and reliability, when accurately replicating values obtained with gold standard equipment. It offered information on compressive strength and pain assessment, and it can be considered as standard equipment. The ease of access, such as cost, friendly operating system and portability would favor the inclusion of systematic pressure pain assessment in research and clinical routine, resulting in possibilities for its quantification, in addition to obtaining parameters for therapeutic guidelines.