[Effects of the cervical spinal cord stimulation on persistent vegetative syndrome: experimental and clinical study]

Influence of spinal cord stimulation (SCS) on electroencephalograms (EEGs) and intracerebral neurotransmitters were studied in cats, and clinical usefulness of the stimulation was reviewed in patients with vegetative syndrome. Cat spinal cords were transdurally stimulated at the second cervical spine for two hours with a pulse width of 1.0 milliseconds, a frequency of 200 Hz and an amplitude ranging from 10 to 15 volts. EEGs were recorded at the frontal epidural space and neurotransmitters in the frontal cortex, such as acetylcholine (ACh), 5-hydroxyindoleacetic acid (5-HIAA), aspartate, glutamate and gamma-aminobutyric acid (GABA), were measured by an in vivo microdialysis method. The background activities of the EEGs were increased by 2 Hz after the SCS. The ACh content increased to 320% three hours after initiation of the SCS, although the other four neurotransmitters did not show any change. Epidural SCS at the upper cervical level was applied to 15 vegetative patients for the amelioration of their vegetative state. Eleven of the 15 patients were treated later than three months after the onset of vegetative state and the other four within three months. Three of the 11 patients treated late and one of the four treated early escaped from the vegetative state (good group). Some clinical improvements were observed in four cases (fair group), two of whom were treated late and the other treated early. The other seven patients showed no improvement (no change group).(ABSTRACT TRUNCATED AT 250 WORDS)