On Denny-Brown's 'spastic dystonia' - What is it and what causes it?

The purpose of the present review is to discuss some of the possible mechanisms that may be involved in the hope that this may guide future research. We discuss the existence of persistent inward currents in spinal motoneurones and present the evidence that the channels involved may be upregulated following central motor lesions. We also discuss a possible contribution from alterations in synaptic inputs from surviving or abnormally branched sensory and descending fibres leading to over-activity and lack of motor coordination. We finally discuss evidence of alterations in motor cortical representational maps and basal ganglia lesions.