Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Winder, K.
Measurement of distal motor latencies versus measurement of nerve conduction velocities in classification of hereditary peripheral neuropathies
[ Diplomarbeit ] Medical University of Graz; 2008. pp.80
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- Autor*innen der Med Uni Graz:
- Betreuer*innen:
- Quasthoff Stefan
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- Abstract:
- We performed an electrophysiological study in 67 patients with genetically proven hereditary neuropathies. The 28 patients with Charcot-Marie-Tooth type 1A (CMT1A) showed uniform and marked reduction of motor nerve conduction velocities (MNCVs) below 33 m/s in the four motor nerves and severe prolongation of median distal motor latencies (DMLs) > 8 ms in 93%. To compare DMLs in relation to MNCVs we calculated the terminal latency index (TLI). Mean median and ulnar TLIs in CMT1A-patients did not differ significantly to those of CMT2-patients, suggesting homogeneous conduction slowing along the entire length of the nerves. However, the range of TLIs in CMT1A-patients was wider in comparison to CMT2-patients. Therefore we differentiated three main types, namely the distal conduction slowing type, the proximal conduction slowing type and the homogeneous conduction slowing type. In the six CMT2-patients mean median TLI was 0.33 and mean ulnar TLI 0.4 with a low range. We took the CMT2-patients as control group. The MNCVs and DMLs of X-linked Charcot-Marie-Tooth disease (CMTX)-females and males did not differ significantly. Median TLI of the one female patient was 0.25, indicating distal accentuation of nerve conduction slowing, whereas ulnar TLI was in the normal range. In the six male CMTX-patients mean median TLI was 0.36 and mean ulnar TLI 0.43, suggesting rather homogeneous conduction slowing along the entire length of the motor nerves in the upper limbs in comparison to the female patients. The 14 patients with hereditary neuropathy with liability to pressure palsies (HNPP) were characterized by a sensorimotor background neuropathy with superimposed conduction slowing at proximal and distal entrapment sites. Median DMLs were significantly greater than those of the ulnar nerve. This was supported by a low mean median TLI with 0.25. The eight patients with mutations in the myelin protein zero (MPZ) gene showed a wide range of MNCVs but DMLs were slightly-to-moderately prolonged in all cases. Mean median TLI was increased with 0.41, with a wide range. In one female patient with Dejerine-Sottas syndrome (DSS) due to a MPZ-mutation we observed a median TLI of 1.53 indicating maximal proximal conduction slowing. In the two patients with mutations in the neurofilament light chain (NEFL) gene we observed a similar picture to that of patients with MPZ-mutations. The Silver syndrome (SS) patient showed a combination of axonal and demyelinating components only in the motor nerves with the most severe affection of the median nerve.