Reflex erector spinal responses in disorders of the central nervous system.

In 64 patients with various central and peripheral nervous system disorders, the lumbar erector spinal muscle responses evoked by electrical stimulation of the brachial plexus at Erb's point or of the posterior tibial nerve in the popliteal fossa while standing were recorded. These responses were either absent or delayed in patients with involvement of the posterior columns. The latency of the responses was the same in patients with cerebellar syndromes, Parkinsonism, spastic hemiparesis or vestibular ataxia as in normal subjects. The size of the responses was diminished in patients with cerebellar syndromes and increased in those with Parkinsonism and spastic hemiparesis as compared with normal subjects.