Basal ganglia motor function in relation to Hallervorden-Spatz syndrome

Hallervorden-Spatz syndrome (HSS) is a degenerative neurologic disorder ass ociated with progressive rigidity, dystonia, impaired voluntary movement, d ysarthria, and mental deterioration. Pathologically, there is iron depositi on in the basal ganglia, with destruction of basal ganglia output neurons. Recent advances in the understanding of basal ganglia functional anatomy an d physiology make it possible to hypothesize how specific neural mechanisms relate to specific clinical manifestations of HSS. Experimental lesions of the basal ganglia output nucleic cause involuntary muscle contractions, si milar to contractions observed in dystonia. A model of selection and suppre ssion of competing motor patterns by the basal ganglia is presented in rela tion to the manifestations of damage to basal ganglia output neurons. It is hypothesized that the dystonia and other motor abnormalities seen in HSS c an be attributed to degeneration of basal ganglia output neurons. (C) 2001 by Elsevier Science Inc. All rights reserved.