Clinical Experience with Pedunculopontine Nucleus Stimulation in Conditions with Nigrostriatal Disconnection

The pedunculopontine nucleus (PPN) is a part of the mesencephalic locomotor region and, in recent years, it has been considered a new surgical target for deep brain stimulation (DBS) for movement disorders including atypical parkinsonian syndromes such as progressive supranuclear palsy (PSP) and multiple system atrophy. Involvement of the PPN may play an important role in gait impairment in these disorders and the development of PPN DBS could potentially provide treatment for this disabling problem. However, the role of the PPN and the specific pathways involved in gait control and other motor functions are poorly understood.

We present a chronological account of our group's experience in the use of PPN DBS. This entails the treatment of four patients with disabling movement disorders who all exhibited either marked damage or disconnection of the nigro-striatal pathway.

Within our series, the results were variable in that 2 of the 4 patients benefited greatly from DBS but the other 2 did not.

Our findings suggest that in carefully selected patients, PPN DBS can potentially alleviate symptoms due to dopaminergic striatal inactivity; symptoms that are typically resistant to stimulation of other subcortical targets used for parkinsonian syndromes and movement disorders.