Figure 3. Mean (± SEM) metabolite ratios in the basal ganglia and pons of veterans with Gulf War syndromes 1-3 (Syn 1-Syn 3) and a replication sample of veterans with syndrome 2 from an independent veteran population (Syn 2 R), compared with an age-sex-education-matched group of well veterans (Controls). The NAA/Cr ratios in the basal ganglia (upper left) are significantly lower than that in the control group for the Gulf War veteran sample with syndrome 2 and for the veterans of the replication sample with syndrome 2, and there is a similar, though nonsignificant, trend for those with syndrome 1. The NAA/Cr ratios in the pons (upper right) are significantly lower than that in the control group for the veterans with syndromes 2 and 3 and in the replication sample with syndrome 2, but not in those with syndrome 1. The Cho/Cr ratios in basal ganglia (lower left) are lower than that in the control group for syndrome 1 and the replication sample but not for syndromes 2 and 3. The Cho/Cr ratios in the pons (lower right) tended to be lower than that in the control group for all syndrome groups, but none was statistically significant. For the basal ganglia, the P value is for a difference from the control group in both left and right basal ganglia (group effect), controlling for hemisphere effect and the group-by-hemisphere interaction by repeated-measures ANOVA. For the pons, the P value came from a t test of the difference from the control group.