Sleep stages and growth hormone in manganese poisoning. Effects of L dopa

: Sleep characteristics are studied in 7 patients with sequelae of manganese intoxication and in 8 controls. A reduction in the length of the REM stage was observed, which could be prolonged by L Dopa administration, but without achieving values comparable to the controls. No changes were noted in the non-REM stage of sleep. These results are similar to the ones obtained in Parkinson's disease, suggesting clinical and probably biochemical similarities between the 2 conditions. The blood concentrations of growth hormone during sleep in the manganic patients was lower than in the control group, and no significant variations were noted after L Dopa administration.