Effects of current perception threshold in evaluating the peripheral nerves in diabetic patients / 中华神经科杂志

ABSTRACT

Objective To evaluate the impairment of large and small fibers of peripheral nerves in patients with diabetes mellitus according to the current perception threshold ( CPT ) comparing with nerve conduction studies ( NCS) and sympathetic skin response ( SSR).Methods Fourty-nine diabetic patients were enrolled from August to December 2014 in Tianjin Third Central Hospital.The CPT was examined by the Neurometer?CPT/C in diabetic patients and 23 healthy subjects.Electrical stimulations of 2 000, 250 and 5 Hz were delivered respectively to the first toe distal section , the bottom of the knee-patella middle line and the index finger distal section.NCS and SSR were performed in diabetic patients.The patients were divided into normal NCS ( NCSN) group and abnormal NCS ( NCSA) group according to the results of the nerve conduction.According to the results of SSR , the patients were divided into normal SSR ( SSRN) group and abnormal SSR ( SSRA ) group.Results In three testing areas , the CPT in NCSN group had no significant difference compared with control group , which was tested by different frequency;NCSA group had increased CPT (393.5 ±68.4, 213.1 ±39.7, 172.5 ±52.8, 221.6 ±48.0, 91.7 ±33.1, 76.2 ±27.8, 274.0 ±48.4, 120.1 ±26.6, 75.3 ±21.9) compared with control group (278.1 ±53.6, 128.9 ±46.7, 78.7 ±28.7, 149.3 ±54.6, 52.3 ±23.2, 41.9 ±18.7, 214.2 ±46.0, 96.0 ±29.3, 48.6 ±17.0; F=36.277, 40.827, 50.301, 10.240, 12.837, 13.832, 11.749, 5.559, 17.412,all P<0.01).At the first toe section, CPT decreased in SSRN group ( 91.0 ±29.0, 55.2 ±21.3 ) compared with control group (128.9 ±46.7, 78.7 ±28.7;F=23.071, 22.646, both P<0.05), which was tested by the currents of 250 Hz and 5 Hz frequency.In three testing areas , the SSRA group had increased CPT compared with control group , which was tested by different frequency.Conclusion Hyperesthesia as an early manifestation of small fiber damage can be detected by CPT in diabetic patients; CPT has no advantage in the evaluation of large fiber damage.