Effects of cervical spinal cord stimulation on glucose consumption in patients with posttraumatic prolonged...

The effects of cervical spinal cord stimulation (CSCS) on glucose consumption were examined in two patients with prolonged disturbance of consciousness due to head injuries. Several clinical parameters, including glucose consumption using positron emission tomography (PET) with [18F]2-fluoro-2-deoxy-D-glucose (FDG), were compared before and after CSCS. After a 4-month period of stimulation, one patient (Case 1) regained consciousness and began to speak, but the other patient (Case 2) showed no improvement in consciousness level. Computed tomography and magnetic resonance imaging showed Case 1 had no abnormalities in the thalamus and brainstem and no diffuse brain atrophy. Case 2 had a low density area in the left thalamus and enlargement of the aqueduct with diffuse atrophy of the left cerebral hemisphere. Cerebral blood flow studies and electrophysiological examinations revealed no remarkable change after CSCS. The PET study showed an increase in FDG uptake in the hypothalamus and the thalamus in both patients, but an increase in FDG uptake in the left cingulate gyrus and left frontal lobe was observed only in Case 1. These observations suggest that activation of the ascending reticular activating system, hypothalamus, thalamus, cingulate gyrus, and frontal cortex, and the preservation of the fiber connections between the limbic system and the thalamus and hypothalamus are important for CSCS treatment to improve the level of consciousness.