肯尼迪病的电生理研究

Characteristics of Electrophysiological Findings in Kennedy Disease

目的探讨肯尼迪病针极肌电图和神经传导的神经电生理改变特征和诊断要点,并对其敏感性进行分析。方法对42例肯尼迪病患者的运动和感觉传导、F波和H反射等电生理指标分析,观察针极肌电图中神经源性损害的范围和特点。另选择77名年龄匹配的正常人为对照组。结果 42例肯尼迪病患者平均年龄(51.1±10.8)岁,起病年龄(44.5±10.8)岁,病程(79.6±61.0)个月。针极肌电图检查发现42例肯尼迪病患者的4个下运动神经元支配区均有慢性神经源性损害,且累及三叉神经运动核支配肌;神经传导检查发现各项指标与对照组比较,差异均有统计学意义(P<0.01),其中以感觉神经传导异常最为明显。结论肯尼迪病电生理以广泛的慢性神经源性损害为最主要改变,多伴感觉和运动神经传导异常,且感觉异常比运动异常更多见。对肯尼迪病电生理特点的认识有助于该病的早期诊断,并对缺乏基因诊断的地区提供了电生理诊断的思路。

Aim To determine the characteristics ofelectrophysiological findings in Kennedy disease（KD） patients. Methods Nerve conduction studies including F-wave and tibial H-reflexes as well as needle EMG were performed in 42 patients with genetically confirmed Kennedy disease and 77 normal control subjects. Motor conduction studies included median, ulnar, peroneal and tibial nerve while sensory conduction studies were done in median, ulnar, superficial and sural nerve. Needle EMG included muscles in all four lower motor neuron regions. Results In the 42 patients, the average age at evaluation was 51 years[（51.1 ± 10.8） years], age at onset 44 years [（44.5 ± 10.8） years], mean disease course （79.6 ±61.0） months. Motor conduction velocities （MCV）, compound muscle action potentials （CMAP）, sensory conduction velocities （SCV） and sensory nerve action potentiMs （SNAP） were significantly decreased in all nerves in KD patients compared with the findings in the normal controls. Latencies of F-wave and H-reflexes as well as distal motor latencies were significantly prolonged. Decreased SNAP and CMAP amplitudes were found in 92.9% and 64.3% KD patients respectively. The extent of amplitude changes was more profound in SNAPs than in CMAPs. The occurrence and extent of abnormal CMAPs were of no significant difference among the four nerves in upperand lower extremities while the decrease of SNAPs m superllclal ana sural nerve was more prominent man ulat in median nerve（P〈0.05）. Needle EMG revealed widespread chronic denervation and reinnervation in all the muscles in the four lower motor neuron regions including the masseter which was innervated by trigeminal motor nucleus. Conclusion The characteristics of electrophysiological findings in KD patients were widespread chronic neurogenic changes in the four lower motor neuron regions accompanied with/without sensory or motor conduction abnormalities. Sensory nerve conduction was more involved than motor nerve. Recognition of the hallmark of electrophysiological changes in KD will be very useful in the early diagnosis of KD and shorten the course between disease onset and gene analysis. It also proposes a new concept of electrodiagnosis of KD in areas where gene study is not available.