E-Move recently sent out an abstract on a study that found "Loss of cholinergic function predicts falling in Parkinson’s disease, according to a new study, independent of dopaminergic denervation."
They reported that
"Thalamic acetylcholinesterase activity derives mainly from terminals of brainstem pedunculopontine nucleus neurons that play a role in the generation of movement,” the authors state, “and loss of AChE is likely to reflect PPN neuron dysfunction or degeneration. Our results are consistent with a key role for the PPN in the maintenance of balance in humans and with PPN dysfunction/degeneration as a cause of impaired postural control and gait in PD.” They suggest that cholinergic therapy may have a role to play in treatment of gait disorder in PD, but “it is uncertain whether the current generation of cholinesterase inhibitors have sufficient brain penetrance to produce meaningful clinical benefits.” (www.mdvu.org)
The journal article : History of falls in Parkinson disease is associated with reduced cholinergic activity

NI Bohnen, MLTM Muller, RA Koeppe, SA studenski, MA Kilbourn, KA Frey, RL Albin

Neurology 2009;73:1670-1676

This seems to fit with the warning that DBS which targets the dopamine pathways should not be expected to improve gait or falling problems.
Anticholinergic drugs (like artane) are not often prescribed currently becuase of their side effects. But maybe this should be a new area of research and drug development? Or is it already?
Note the last sentence in the excerpt above....