REDUCED BRAIN N-ACETYL-ASPARTATE IN FRONTAL LOBES SUGGESTS NEURONAL LOSS IN PATIENTS WITH AMYOTROPHIC-LATERAL-SCLEROSIS

We performed proton magnetic resonance spectroscopy (IH-MRS) in three patients with amyotrophic lateral sclerosis (ALS) to evaluate the dist ribution and extent of cortical neuronal damage as demonstrated by dec reased N-acetyl-aspartate (NAA) levels. We examined primary motor (pre central gyrus) and parietal neocortical (superior parietal gyrus) regi ons. ALS was defined with lower and upper motor neuron signs. Compared with matched healthy controls, ALS patients had a significant decreas e in NAA levels in the primary motor cortex (p<0.001) compared with pa rietal regions and homologous regions in healthy controls. Two clinica l applications can be extracted: first, the upper motor neuron signs p resent in the ALS, come from a neuronal loss within the primary motor cortex and may explain the frontal syndrome associated with ALS. Secon d clinical applications of 1H-MRS could include identification of exte nt of upper motor neuron involvement, aiding diagnosis of syndromes pr esenting with an ALS-like syndrome.