Editing Deep brain stimulation (section)

====Posture====
Parkinson's is often characterized by [[camptocormia]], a classic stooped [[kyphosis|kyphotic]] posture that develops as the disease progresses as well as [[Pleurothotonus|Pisa syndrome]], characterized by a persistent tilted posture. The impact of DBS to the STN or GPi on posture in Parkinson's have been heterogenous and inconsistent at best.<ref>{{cite journal |last1=Chan |first1=AK |last2=Chan |first2=AY |last3=Lau |first3=D |last4=Durcanova |first4=B |last5=Miller |first5=CA |last6=Larson |first6=PS |last7=Starr |first7=PA |last8=Mummaneni |first8=PV |title=Surgical management of camptocormia in Parkinson's disease: systematic review and meta-analysis. |journal=Journal of Neurosurgery |date=1 August 2019 |volume=131 |issue=2 |pages=368–375 |doi=10.3171/2018.4.JNS173032 |pmid=30215560}}</ref> Though some studies have shown positive effect, the quality of evidence is quite low.<ref>{{cite journal |last1=Spindler |first1=P |last2=Alzoobi |first2=Y |last3=Kühn |first3=AA |last4=Faust |first4=K |last5=Schneider |first5=GH |last6=Vajkoczy |first6=P |title=Deep brain stimulation for Parkinson's disease-related postural abnormalities: a systematic review and meta-analysis. |journal=Neurosurgical Review |date=October 2022 |volume=45 |issue=5 |pages=3083–3092 |doi=10.1007/s10143-022-01830-3 |pmid=35790655|pmc=9492622 }}</ref>

The pedunculopontine nucleus (PPN) is being studied as a target for postural instability and [[Parkinsonian gait|gait freezing]], but clinical research is still in its early stages.<ref name ="PPN Consensus 2018">{{cite journal |last1=Garcia-Rill |first1=E |last2=Saper |first2=CB |last3=Rye |first3=DB |last4=Kofler |first4=M |last5=Nonnekes |first5=J |last6=Lozano |first6=A |last7=Valls-Solé |first7=J |last8=Hallett |first8=M |title=Focus on the pedunculopontine nucleus. Consensus review from the May 2018 brainstem society meeting in Washington, DC, USA. |journal=Clinical Neurophysiology |date=June 2019 |volume=130 |issue=6 |pages=925–940 |doi=10.1016/j.clinph.2019.03.008 |pmid=30981899|pmc=7365492 }}</ref> It is located in the mesopontine tegmentum next to the crossing of the superior cerebellar peduncle and is theorized to play a role in reflex reactions, sleep-wake cycles, posture and gait.<ref name ="PPN Consensus 2018"/> It is inhibited by the GPi while the STN excites it.<ref name = "Persistent 2018"/> Freezing, as part of the pattern of akinesia, usually responds to levodopa. When freezing of gait persists, and is not improved by drugs, it is usually not improved by STN stimulation.<ref name ="Benabid 2009"/> The loss of verbal fluency after PPN or VIM stimulation is greater than even that seen with the STN.<ref>{{cite journal |last1=Rački |first1=V |last2=Hero |first2=M |last3=Rožmarić |first3=G |last4=Papić |first4=E |last5=Raguž |first5=M |last6=Chudy |first6=D |last7=Vuletić |first7=V |title=Cognitive Impact of Deep Brain Stimulation in Parkinson's Disease Patients: A Systematic Review. |journal=Frontiers in Human Neuroscience |date=2022 |volume=16 |page=867055 |doi=10.3389/fnhum.2022.867055 |doi-access=free |pmid=35634211|pmc=9135964 }}</ref>