[Motor-sensory hereditary neuropathy. III. Histological changes].

The authors describe the results of histological examinations of the sural nerve in 40 cases of sensorimotor hereditary neuropathy. A comparison of the morphological findings with the values of conduction velocity showed that all cases with "primary demyelination" belonged to the I type of this neuropathy (with conduction velocity under 38 m/sec) while those with axonal changes (and conduction velocity over 38 m/sec) belonged to type II. In 2 cases the degree of demyelination and axonal changes was similar, but the electrophysiological criteria failed to correspond to those of the "intermediate" type. These observations confirmed the validity of the classification of Harding and Thomas, but give no basis for isolation of an "intermediate" group as suggested in the classification of Bradley et al. A progression of demyelination changes was observed with increasing intensity of the pathological process, and frequent coexistence of axonal changes in type I, and possibility of greater damage to the thin myelinated fibres in relation to thick fibres in type II.