Clinically cases incur which present a combination of paraplegic weakness with spasm and ataxy, and in which the pathological findings are a combined sclerosis of the lateral and posterior columns of the cord. The extent of the degeneration is, however, subject to a good deal of variation, and the clinical characters are also subject to considerable variety, so that a given case may exhibit signs closely allied to either spastic paraplegia or locomotor ataxy; still in the great majority of cases the condition is sufficiently distinctive clinically to be easily recognized.

The sclerosis in the posterior columns differs, however, from that in tabes, in so far that it is usually less marked in the lumbar region than in the dorsal, and it has not its location specially in the root-zones of the postero-external columns. The degeneration in the lateral columns may also extend at times beyond the pyramidal tract and occasionally the direct cerebellar tract may even be invaded.