A multimodal investigation of altered cortical metabolism in patients with disorders of consciousness

Disorders of consciousness are characterized by marked reductions in cerebral glucose metabolism, but the specific cellular and neurochemical processes causing this impairment have not been clearly understood. The study included 15 patients with disorders of consciousness and 14 healthy controls examined using positron emission tomography and magnetic resonance spectroscopy. Patients showed decreased levels of glutamate, creatine, and N-acetylaspartate in the posterior medial cortex, as well as a reduced glutamate to GABA ratio. Glucose metabolism was substantially reduced in patients and positively correlated with N-acetylaspartate and creatine levels. Baseline choline concentrations positively predicted long-term clinical recovery, measured by changes in Coma Recovery Scale-Revised scores at follow-up after an average of 127 days. The findings suggest that reduced glucose metabolism may be linked to disrupted mitochondrial energy production pathways and a shift towards relative synaptic inhibition.