Measurement of current perception threshold (CPT) using the Neurometer at 2000, 250 and 5 Hz assesses function in three different nerve fibre types. This method was used to investigate peripheral neuropathy in 116 patients with type 2 diabetes mellitus and 38 healthy controls. The CPT at 2000 Hz was significantly higher in diabetic patients than in controls, and showed a significant negative correlation with motor and sensory nerve conduction velocities. ⋯ At 5 Hz, the change in systolic blood pressure in the Schellong test in patients with hypoaesthesia tended to be less than in those with normal sensation or hyperaesthesia. Significantly higher CPT values were obtained in patients with proliferative diabetic retinopathy and macroalbuminuria. These data suggest that CPT is useful in detecting abnormalities of myelinated as opposed to unmyelinated nerve fibres in patients with type 2 diabetes.
Department of Internal Medicine, Koshigaya Hospital, Dokkyo University School of Medicine, Koshigaya, Japan. rika@de.mbn.or.jp
J. Int. Med. Res. 2005 Jul 1; 33 (4): 442-53.
AbstractMeasurement of current perception threshold (CPT) using the Neurometer at 2000, 250 and 5 Hz assesses function in three different nerve fibre types. This method was used to investigate peripheral neuropathy in 116 patients with type 2 diabetes mellitus and 38 healthy controls. The CPT at 2000 Hz was significantly higher in diabetic patients than in controls, and showed a significant negative correlation with motor and sensory nerve conduction velocities. At 250 Hz, CPT showed a significant positive correlation with the vibration perception threshold. At 5 Hz, the change in systolic blood pressure in the Schellong test in patients with hypoaesthesia tended to be less than in those with normal sensation or hyperaesthesia. Significantly higher CPT values were obtained in patients with proliferative diabetic retinopathy and macroalbuminuria. These data suggest that CPT is useful in detecting abnormalities of myelinated as opposed to unmyelinated nerve fibres in patients with type 2 diabetes.