Effect of occupational manganese exposure on the central nervous system of welders: 1H magnetic resonance spectroscopy and MRI findings

Neuroimaging in Manganese-Induced Parkinsonism

“…However, although the cited authors used a PRESS sequence with a short echo time, mI levels was not analyzed, unlike in the study of Chang et al cited above. The results of the latter work agree with those of a previous study (Kim et al, 2007), but a direct comparison of mI levels is not possible. Guilarte et al (2006) reported a decrease in NAA level in the parietal cortex and frontal WM of the brains of Mn-exposed monkeys.…”

“…Further, in the frontal lobe of the brain, the mI/tCr ratio was significantly correlated with verbal memory scores as well as blood Mn concentrations. Kim et al (2007) found no statistically significant differences in the levels of brain metabolites (NAA and Cho only were measured) between welders and controls. However, although the cited authors used a PRESS sequence with a short echo time, mI levels was not analyzed, unlike in the study of Chang et al cited above.…”

“…However, little is known about the effects of chronic Mn exposure on brain metabolites in vivo. Two reports employed MRS to investigate the potential neurotoxic effects of chronic Mn exposure on the brain (Guilarte et al, 2006;Kim et al, 2007). Guilarte et al (2006) assessed the toxic effects of chronic Mn exposure on the levels of brain metabolites in non-human primates.…”

“…A reduction in NAA levels in the brain can be interpreted as indicating neuronal dysfunction or even neuronal loss (Vion-Dury et al, 1994). Kim et al (2007) investigated the potential neurotoxic effects of chronic Mn exposure in welders. Using point-resolved spectroscopy (PRESS) at 1.5 T, the cited authors measured the NAA/Cr, choline/creatine (Cho/Cr), and NAA/Cho ratios in the basal ganglia, and found no significant differences between welders and control subjects.…”

Neuromotor function in ship welders after cessation of manganese exposure

“…Several studies of workers with current Mn exposure have shown decreased performance in fine motor function (Bowler et al 2003;Chang et al 2009;Chia et al 1993;Sjögren et al 1996), some of them also using the grooved pegboard test (Bowler et al 2003;Chang et al 2009). Mn accumulation in the brain is reflected by high signal intensity in the basal ganglia, mainly the globus pallidus area, in T1-weighted images MRI (Dietz et al 2001;Kim 2006;Kim et al 2007), and high signal intensity on MRI is associated with decreased performance in neurobehavioral tests ). High pallidal index on MRI has been reported to be associated with decrement in fine motor function (Shin et al 2007) and poorer dominant hand performance in the grooved pegboard test (Chang et al 2009).…”