538-P: Inter-Rater Agreement of Vibration and Pressure Sensation in the Assessment of Sensorimotor Dysfunction in Diabetes

Assessment of large fibre dysfunction is based on tuning fork (TF) for vibration perception and on monofilament (MF) for pressure sensation. Herein we examined the inter-rater variability of the MF and TF alongside with the VibraTip™ (VT), a new measure of vibration perception. We recruited 100 subjects with diabetes. Patients with active ulcers or peripheral vascular disease were excluded. A consultant diabetologist (CD) initially performed a general physical and foot examination at each foot which included MF, TF and VT. The tests were then performed by a podiatrist (P) and a diabetes specialist nurse (DSN) and the results were compared among the healthcare professionals (HCP); each examiner was blinded to the results of the other examiners. Inter-rater agreement was determined by weighted kappa (k) statistics. k values 0.41-0.60 represent moderate agreement, 0.61-0.8 good and >0.81 very good agreement. Diagnosis of insensation (%) by the CD, P and DSN were as follows: MF insensation 37.5%, 34.5% and 34.0%, respectively; TF insensation, 48.0%, 31.5% and 45.0%, respectively; VT insensation 39.0%, 35.0% and 35.5%, respectively. The inter-rater agreement (k, 95% confidence intervals) between the CD and the P, the P and the DSN as well as the CD and the DSN were as follows: TF 0.62 (0.52-0.73), 0.62 (0.51-0.72), 0.68 (0.57-0.78), respectively; MF 0.67 (0.57-0.78), 0.70 (0.59-0.80), 0.73 (0.63-0.83), respectively; VT 0.72 (0.62-0.82), 0.70 (0.60-0.81), 0.67 (0.56-0.78), respectively. The k statistics suggested good level (>0.6) of agreement of the three neurological modalities between the HCP. Despite the differences observed in the ability of various tests to diagnose reduced sensation, there is good overall agreement in the results of neurological examination by MF, TF and VT between HCP. Further research is required to examine the performance of these tests in the diagnosis of neuropathy.