Intra-rater and Inter-rater Reliability of the Commander Pressure Algometer in Greek Patients With Chronic Neck Pain

Introduction Non-specific chronic neck pain (NSCNP) is a musculoskeletal disorder that affects 45%-54% of the general population. There is a strong correlation between patient-reported pain and mechanical pain pressure threshold (PPT) measured with an algometer. Purpose This study aims to investigate the intra- and inter-rater reliability of the Commander algometer in Greek NSCNP patients, in an urban primary care setting. Methods Thirty-three patients (22 women and 11 men) suffering from NSCNP (>3 months), the majority (42.4%) between the ages of 50 years and 59 years and overweight, were measured bilaterally both at the neck (mastoid, trapezius head-insertion and mid-portion, C5-C6 facet, insertion of levator scapula) and at the control areas (mid-deltoid and tibialis anterior) using the Commander algometer. Measurements were taken twice over a span of six days, by two raters, in a primary care setting. Intraclass correlation coefficient (ICC) statistics were used as measures of reliability (p = 0.05). Results Intra-rater reliability was "moderate to good" for both raters. ICC values for PPT at the seven bilaterally measured sites varied between 0.67 and 0.86 for the first rater (p ≤ 0.001) and 0.64 and 0.82 for the second rater (p ≤ 0.003). The inter-rater reliability was "moderate to excellent" (ICC = 0.68-0.92) in the first measurement (T1) and "moderate to good" (ICC = 0.68 to 0.89) in the second measurement (T2). Conclusion This study supports the intra- and inter-rater reliability of the Commander algometer in detecting reliably the mechanical PPT, in Greek NSCNP patients, as measured according to the procedures and methodology followed throughout this study.