A clinical study of sensory and pain threshold values of upper limb nerves in diabetes mellitus patients

Abstract

WHO has predicted 31.5 million Indians to be affected by type 2 diabetes by the year 2030. Peripheral neuropathy is most common complication of diabetes affecting up to 50–60 % of patients with poor glycaemic control. Hence, evaluation of sensory and pain threshold values in diabetic patients would be useful to investigate underlying diabetic neuropathic process. Convenient sample of 150 diabetics and control group of age and sex-matched 150 healthy individuals were recruited for this descriptive study. Sensory threshold was tested for three peripheral nerves (median, ulnar and radial) of upper limb using Semmes Weinstein monofilament, two point discriminator and electrical stimulator, and pain threshold was recorded using an electrical stimulator. Sensory threshold values of diabetics on monofilament for median, ulnar and radial nerve (3.61, 3.61 and 4.31, respectively) were significantly higher (p < 0.0001) as compared to non-diabetics (2.83, 2.83, 3.61, respectively). Two point discrimination for median (7 mm) and ulnar nerve (7 mm) were significantly higher as compared to non-diabetics (4 mm) (p < 0.0001). Sensory threshold values using an electrical for median, ulnar and radial nerves (22.68 ± 6.61, 20.86 ± 6.37, 24.50 ± 7.53 volts, respectively) were higher as compared to non-diabetics (12.12 ± 2.94, 11.98 ± 3.00, 14.24 ± 3.45 volts) (p < 0.0001). Pain threshold values using an electrical stimulator for median, ulnar and radial nerves (31.6 ± 7.6, 30.3 ± 8, 32.7 ± 8.2 volts, respectively) were also significantly higher (p < 0.0001) as compared to non-diabetics (20 ± 4.9, 19.36 ± 4.7, 22.50 ± 5.3 volts, respectively). Sensory and pain threshold values in diabetics are higher than age- and gender-matched non-diabetics, although they did not present with symptoms, thus indicating possible underlying neuropathy changes. Also, an electrical stimulator can be used as clinical tool to diagnose early neuropathic changes in diabetics.