Peripheral Nerve Axon Involvement in Myotonic Dystrophy Type 1, Measured Using the Automated Nerve Excitability Test

BACKGROUND AND PURPOSE: Primary involvement of the peripheral nerves in myotonic dystrophy type I (MyD1) is controversial. We investigated whether the involvement of peripheral nerves is a primary event of MyD1 or secondary to another complication such as diabetes mellitus (DM). METHODS: The subjects comprised 12 patients with MyD1, 12 with DM and no peripheral nerve involvement, and 25 healthy volunteers. We measured multiple excitability indices in the median motor axons. The strength-duration time constant was calculated from the duration-charge curve, the threshold electrotonus and current-threshold relationships were calculated from the sequential subthreshold current, and the recovery cycle was derived from double suprathreshold stimulation. RESULTS: The depolarizing and hyperpolarizing threshold electrotonus were significantly reduced and exhibited increased refractoriness in the MyD1 group compared with the DM and control groups. The SDTC, superexcitability, and subexcitability were not significantly altered in the MyD1 group. CONCLUSIONS: The MyD1 group exhibited a depolarized axonal membrane potential. The significant differences in peripheral nerve excitability between the MyD1 group and the DM and normal control groups suggest that peripheral neuropathy is a primary event in MyD1 rather than a secondary complication of DM.

Correlation study on syndrome type and effect of TCM and facial nerve excited threshold in facial paralysis patients / 中华中医药杂志

0.05).Conclusions:Facial nerve excited threshold detection was a simple and effective method of conjecturing TCM syndrome and severity and prognosis of facial paralysis patients.

Analysis of Nerve Excitability Test and Stapedial Reflex on the Prognosis of Facial Nerve Paralysis / 听力学及言语疾病杂志

Objective To evaluate the clinical application of nerve excitability test and stapedial reflex on the prognosis of facial nerve paralysis. Methods The threshold of excitability of the branches of facial nerves in both sides and stapedial reflex were tested in 50 patients.Results 34 patients out of 42 with differences of nerve excited threshold less than 3.5 mA showed complete recovery (81%),while only 2 patients out of 8 with the differences of nerve excited threshokd more than 3.5 mA showed recovery (25%), 32 patients out of 36 with positive response of stapedial reflex showed recovery (88.9%), but only 3 patients out of 14 recovered (21.4%) in non-response group.Conclusion The difference of nerve excited threshold of both sides less than 3.5 mA and positive response of stapedial refles showed a better prognosis, suggesting no severe injury to facial nerve and both nerve excitability test and stapedial reflex were useful chinical parameters to predict the prognosis of facial paralysis.