THE VALUE OF THE NEUROMETER IN ASSESSING DIABETIC NEUROPATHY BY MEASUREMENT OF THE CURRENT PERCEPTION THRESHOLD

The Neurometer is a relatively new device for assessing neuropathy by measuring current perception threshold (CPT). The study aim was to ass ess the ability of the Neurometer to distinguish between different typ es of nerve fibre damage by using different frequencies (2000 Hz, 250 Hz, and 5 Hz) of electric stimulus (high frequencies for large fibres and low frequencies for small fibres) and comparing the results with s tandard sensory tests of vibration perception threshold (VPT) and ther mal perception threshold (TPT). CPT was determined on index finger and great toe of 51 patients with diabetic neuropathy and 28 non-diabetic control subjects, age and sex matched. CPT in neuropathic patients co uld be distinguished from controls at all three frequencies in both fe et and hands (p < 0.05). The best correlation was found between CPT at 2000 Hz and VPT (r = 0.48, p < 0.001) in the feet suggesting a degree of neuroselectivity. Internal correlations between CPT at the three f requencies showed the weakest correlation between CPT at 2000 Hz and 5 Hz (r = 0.27, p < 0.005), suggesting also that possibly different typ es of fibres were examined. CPT reproducibility was better in control (CV = 6.4-27.7%), than in neuropathic subjects (CV = 28.4-52.3%), alth ough the coefficient of variation was comparable to that of standard t ests of sensory function, VPT and TPT. The Neurometer is a simple inst rument to use in clinical practice. It has a degree of neuroselectivit y but like all subjective sensory tests has a large variability.