Vibration sensibility of the median nerve in a population with chronic whiplash associated disorder: intra- and inter-rater reliability study

Whiplash Associated Disorders (WAD) grade II are the most prevalent group of whiplash patients seen on a regular basis by musculoskeletal physiotherapists. Impairment of vibration sensibility may be an early indicator of nerve pathology and it has previously been demonstrated in individuals with chronic WAD symptoms utilising vibrameters. A less expensive option, such the tuning fork (TF) may assist with these measures, but research regarding its measurement properties is lacking. Objectives: To investigate the intra- and inter-rater reliability of vibration sensibility of the median nerve in chronic WAD II (CWAD II). Methods A double blinded, within day intra- and inter-rater reliability study was undertaken. A convenience sample of 26 individuals (8 males, 18 females, age mean 29.9 ± 10.0 years) with CWADII was recruited. Exclusion criteria: WAD I, III & indications of neuropathic pain. Vibration attenuation times were recorded from skin innervated by the median nerve (thenar eminence). Results: Descriptive statistics (mean scores) and reliability statistics [intraclass correlation coefficient (ICC2,1) and Bland and Altman limits of agreement] were undertaken with p = 0.05. Almost perfect intra-rater reliability (Intraclass Correlation Coefficiency (ICC): 0.972–0.955) and inter-rater reliability (ICC: 0.983) were identified. Confidence Intervals (CI) for inter-rater reliability were 95% CI: −1.461 to −0.056. Conclusions: Almost perfect reliability scores across intra- and inter-rater reliability were found. This provides evidence that, with a standardised testing protocol the TF can be a highly reliable means of vibration sensibility testing. Future studies assessing the validity of the TF in different WAD populations may provide further information about the usefulness of this protocol.