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Pallidal stimulation as treatment for camptocormia in Parkinson’s disease


Abstract and Figures

Camptocormia is a common and often debilitating postural deformity in Parkinson’s disease (PD). Few treatments are currently effective. Deep brain stimulation (DBS) of the globus pallidus internus (GPi) shows potential in treating camptocormia, but evidence remains limited to case reports. We herein investigate the effect of GPi-DBS for treating camptocormia in a retrospective PD cohort. Thirty-six consecutive PD patients who underwent GPi-DBS were reviewed. The total and upper camptocormia angles (TCC and UCC angles) derived from video recordings of patients who received GPi-DBS were used to compare camptocormia alterations. Correlation analysis was performed to identify factors associated with the postoperative improvements. DBS lead placement and the impact of stimulation were analyzed using Lead-DBS software. Eleven patients manifested pre-surgical camptocormia: seven had lower camptocormia (TCC angles ≥ 30°; TCC-camptocormia), three had upper camptocormia (UCC angles ≥ 45°; UCC-camptocormia), and one had both. Mean follow-up time was 7.3 ± 3.3 months. GPi-DBS improved TCC-camptocormia by 40.4% (angles from 39.1° ± 10.1° to 23.3° ± 8.1°, p = 0.017) and UCC-camptocormia by 22.8% (angles from 50.5° ± 2.6° to 39.0° ± 6.7°, p = 0.012). Improvement in TCC angle was positively associated with pre-surgical TCC angles, levodopa responsiveness of the TCC angle, and structural connectivity from volume of tissue activated to somatosensory cortex. Greater improvement in UCC angles was seen in patients with larger pre-surgical UCC angles. Our study demonstrates potential effectiveness of GPi-DBS for treating camptocormia in PD patients. Future controlled studies with larger numbers of patients with PD-related camptocormia should extend our findings.
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Pallidal stimulation as treatment for camptocormia in
Parkinsons disease
Yijie Lai
, Yunhai Song
, Daoqing Su
, Linbin Wang
, Chencheng Zhang
, Bomin Sun
, Jorik Nonnekes
, Bastiaan R. Bloem
Dianyou Li
Camptocormia is a common and often debilitating postural deformity in Parkinsons disease (PD). Few treatments are currently
effective. Deep brain stimulation (DBS) of the globus pallidus internus (GPi) shows potential in treating camptocormia, but evidence
remains limited to case reports. We herein investigate the effect of GPi-DBS for treating camptocormia in a retrospective PD cohort.
Thirty-six consecutive PD patients who underwent GPi-DBS were reviewed. The total and upper camptocormia angles (TCC and
UCC angles) derived from video recordings of patients who received GPi-DBS were used to compare camptocormia alterations.
Correlation analysis was performed to identify factors associated with the postoperative improvements. DBS lead placement and
the impact of stimulation were analyzed using Lead-DBS software. Eleven patients manifested pre-surgical camptocormia: seven
had lower camptocormia (TCC angles 30°; TCC-camptocormia), three had upper camptocormia (UCC angles 45°; UCC-
camptocormia), and one had both. Mean follow-up time was 7.3 ± 3.3 months. GPi-DBS improved TCC-camptocormia by 40.4%
(angles from 39.1° ± 10.1° to 23.3° ± 8.1°, p=0.017) and UCC-camptocormia by 22.8% (angles from 50.5° ± 2.6° to 39.0° ± 6.7°,
p=0.012). Improvement in TCC angle was positively associated with pre-surgical TCC angles, levodopa responsiveness of the TCC
angle, and structural connectivity from volume of tissue activated to somatosensory cortex. Greater improvement in UCC angles
was seen in patients with larger pre-surgical UCC angles. Our study demonstrates potential effectiveness of GPi-DBS for treating
camptocormia in PD patients. Future controlled studies with larger numbers of patients with PD-related camptocormia should
extend our ndings.
npj Parkinson’s Disease (2021) 7:8 ;
Camptocormia, an abnormal uncontrollable forward exion of the
spine while standing or walking, is a common type of postural
deformity with an overall incidence of 519% in patients with
Parkinsons disease (PD)
. This deformity is often debilitating and
can hinder patients during walking or performing activities of daily
. Currently, few treatments are available for camptocormia in
PD. Levodopa or botulinum toxin injection may be partially
effective but the efcacy varies, and the majority of the patients
are not helped satisfactorily by these approaches
. Dopamine
agonists can even aggravate or induce camptocormia
In recent years, deep brain stimulation (DBS) has attracted
increasing attention as a potential treatment of postural
deformities in PD patients. Subthalamic nucleus (STN) and globus
pallidus internus (GPi) are the two main targets of DBS for PD
Various studies have reported the clinical effectiveness of STN-DBS
in treating PD postural deformities. Recently, results from studies
with large sample sizes showed that STN-DBS had a relatively
small but signicant therapeutic effect on abnormal posture
could especially bring about large improvement to those who
were complicated with camptocormia
. Based on its efcacy in the
treatment of primary dystonia, GPi-DBS has also been proposed to
be effective for dystonic posture in PD
. However, compared to
STN-DBS, the evidence for any efcacy of GPi-DBS for treating
PD-related camptocormia has been limited to case reports with
incongruent results
. Besides, the methods for measuring
postural deformities varied between studies and the international
consensus for determining patientsexion angle was not reached
until recently
. Larger studies with consensus-based methods
are therefore required to determine the effectiveness of GPi-DBS
on camptocormia in PD patients.
Here we report the effectiveness of GPi-DBS on camptocormia
in patients with PD based on a retrospective cohort of thirty-six
consecutive subjects who underwent GPi-DBS. The effect of pre-
surgical medication on total camptocormia or upper camptocor-
mia (TCC/UCC) angles, as dened in the recent consensus for the
measurement of the camptocormia angle
, was investigated by
comparing the angles during the medication-OFF state (med-OFF)
with angles during the medication-ON state (med-ON) before
surgery. The benet of DBS surgery was determined by comparing
these angles during the pre-surgical med-OFF state with the
angles during post-surgical med-OFF and stimulation-ON (med-
OFF/DBS-ON) state. We also looked for factors that were
potentially associated with post-surgical camptocormia angle
Characteristics of included patients
Thirty-six consecutive patients were included in this retrospective
study. The demographical data are presented in Table 1and the
results of motor assessment are presented in Table 2. Eleven
Center for Functional Neurosurgery, Department of Neurosurgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
Department, Shanghai Childrens Medical Center Afliated to the Medical School of Shanghai Jiao Tong University, Shanghai, China.
Department of Neurosurgery, Liaocheng
Peoples Hospital and Liaocheng Clinical School of Shandong First Medical University, Liaocheng, China.
Department of Rehabilitation, Radboud University Medical Center,
Donders Institute for Brain Cognition and Behavior, Nijmegen, The Netherlands.
Department of Neurology, Radboud University Medical Center, Donders Institute for Brain
Cognition and Behavior, Nijmegen, The Netherlands. email:
Published in partnership with the Parkinson’s Foundation
(30.6%) of these 36 patients had camptocormia, in whom 7
(19.4%) patients were diagnosed with TCC-camptocormia (or
lower camptocormia) as presenting with a TCC angle of 30° and
3 (8.3%) patients were diagnosed with UCC-camptocormia (or
UCC) as presenting with a UCC angle of 45°. One (2.8%) patient
presented with both TCC-camptocormia and UCC-camptocormia.
Effect of levodopa treatment on posture angles in the overall
population and in patients with/without camptocormia
Pre-surgically, small but signicant improvement was observed in
the TCC angles (from 21.7° ± 11.6° to 18.4° ± 8.3°, p=0.0185) and
the UCC angles (from 36.4° ± 7.1° to 33.4° ± 5.6°, p=0.0012) in
response to levodopa treatment (Fig. 1). In patients with TCC-
camptocormia, both the TCC angles (from 39.1° ± 10.1° to 27.8° ±
8.3°, p=0.0566) and the UCC angles (from 38.2° ± 9.2° to 34.0° ±
7.1°, p=0.0905) showed a nonsignicant reduction after admin-
istration of levodopa. In patients with UCC-camptocormia, a
signicant improvement was seen in the UCC angles (from 50.5° ±
2.6° to 36.3° ± 8.5°, p=0.0317) but not with the TCC angles (from
25.4° ± 5.7° to 22.7° ± 9.1°, p=0.4114). In patients without
camptocormia, improvement in the TCC angles (from 15.9° ± 5.4°
to 14.9° ± 5.1°, p=0.0689) was not signicant, whereas a small but
signicant reduction was seen in the UCC angles (from 34.2° ± 4.5°
to 32.8° ± 4.5°, p=0.0032).
Effect of GPi-DBS on posture angles in the overall population and
in patients with/without camptocormia
At a mean follow-up of 7.3 ± 3.3 months, both the TCC angles
(from 21.7° ± 11.6° to 18.8° ± 7.1°; p=0.0976; Fig. 1a) and the UCC
angles (from 36.4° ± 7.1° to 35.4° ± 7.1° (p=0.4198; Fig. 1b)
showed a nonsignicant decrease in all patients treated with
bilateral GPi-DBS. In patients with TCC-camptocormia, the TCC
angles signicantly decreased from 39.1° ± 10.1° to 23.3° ± 8.2°
(p=0.0168; Fig. 2a), whereas no signicant improvement was
seen in the UCC angles (from 38.2° ± 9.2° to 40.4° ± 8.5° p=0.3715;
Fig. 2b); in the UCC-camptocormia group, signicant improvement
was seen in the UCC angles (50.5° ± 2.6° to 39.0° ± 6.7°, p=0.0124;
Fig. 2b) but not in the TCC angles (from 25.4° ± 5.7° to 17.6° ± 2.2°,
p=0.1073; Fig. 2a); in patients without camptocormia, a slight but
signicant deterioration was seen in the TCC angles (from 15.9° ±
5.4° to 17.3° ± 6.6°, p=0.0308; Fig. 2a), whereas a nonsignicant
improvement was found in the UCC angles (from 34.2° ± 4.5° to
33.5° ± 5.9°, p=0.6261; Fig. 2b). In addition, the levodopa
equivalent daily dosage (LEDD) signicantly decreased from
675.1 ± 275.3 mg to 534.0 ± 221.7 mg (p< 0.001) after surgery in
the whole population.
Factors associated with DBS effectiveness
In the univariate analysis of the whole population, greater
improvement in the TCC angles was found in patients with larger
pre-surgical TCC angles during the med-OFF state (p=0.0001;
Fig. 3a) and better levodopa responsiveness of the TCC angle (p=
0.0043; Fig. 3b); improvement of the UCC angles were positively
Table 1. Characteristics of included patients.
Characteristics Value
Age at surgery (years) 63.7 ± 8.6
Gender 15 F/21 M
Age at PD onset 52.9 ± 9.2
Duration of PD (years) 10.8 ± 4.4
Follow-up time (months) 7.3 ± 3.3
LEDD (mg) 675.1 ± 275.3
Stimulation parameters
Amplitudes (V) L 3.1 ± 0.5/R 3.0 ± 0.6
Frequency (Hz) L 134.1 ± 30.5/R 134.9 ± 30.6
Pulse width (μsec) L 71.3 ± 13.0/R 72.3 ± 12.7
Table 2. Pre-surgical examinations at med-OFF state.
Items Overall Without CC TCC-CC UCC-CC
n36 25 8 4
Total 54.0 ± 18.3 49.5 ± 16.0 69.9 ± 19.2 48.8 ± 11.7
Tremor 7.1 ± 5.9 6.6 ± 5.8 9.5 ± 5.5 5.8 ± 6.8
Rigidity 11.7 ± 5.3 11.1 ± 5.0 14.8 ± 5.8 8.0 ± 3.9
Bradykinesia 24.6 ± 8.6 22.5 ± 8.3 31.3 ± 7.1 24.0 ± 6.5
Axial 10.6 ± 4.7 9.2 ± 4.2 14.4 ± 5.4 11.0 ± 3.2
Posture 2.1 ± 1.3 1.6 ± 1.3 3.3 ± 0.7 2.8 ± 0.5
Camptocormia angles
TCC angle 21.7 ± 11.6 15.9 ± 5.4 39.1 ± 10.1 25.4 ± 5.7
UCC angle 36.4 ± 7.1 34.2 ± 4.5 38.2 ± 9.2 50.5 ± 2.6
TCC-camptocormia 7 0 7
30 3
Both camptocormia
10 11
TCC total camptocormia angle, TCC-camptocormia group of patients with a
clinically diagnosed camptocormia as dened by a TCC angle 30°, UCC
upper camptocormia angle, UCC-camptocormia group of patients with a
clinically diagnosed camptocormia as dened by a UCC angle 45°.
Both camptocormia means presenting with both TCC- and UCC-
Fig. 1 Effect of levodopa and surgery on camptocormia angles in
the whole population. Pre- and post-surgical total- (a) and upper (b)
camptocormia angles (TCC/UCC angles) were shown for individual
PD patient. *p< 0.05; **p< 0.01; n.s.: not signicant.
Y. Lai et al.
npj Parkinson’s Disease (2021) 8 Published in partnership with the Parkinsons Foundation
correlated with pre-surgical UCC angles (p=0.0065; Fig. 3c). No
signicant correlation was found between percent improvement
of TCC/UCC angles after surgery and the rest of the variables,
including age at surgery, duration of PD, length of follow-up,
baseline Movement Disorder Society-Sponsored Revision of the
Unied Parkinsons Disease Motion Assessment Scale Part III (MDS-
UPDRS-III) total scores, percent improvement in MDS-UPDRS-III
total scores in response to levodopa and levodopa responsiveness
of the UCC angle (all ps > 0.05). In addition, in patients presented
with TCC-camptocormia, values of pre-surgical TCC/UCC angles or
levodopa responsiveness of TCC/UCC angles were not signicantly
correlated with the post-surgical improvements in TCC/UCC
angles (all ps > 0.05). In the multivariate analysis incorporating
aforementioned variables, pre-surgical TCC angles (β=0.61,
p=0.0020) were identied as the independent predictor of
post-surgical improvement in the TCC angles, whereas none of the
rest of the variables remained predictive of the TCC/UCC angle
improvements (all ps > 0.05).
To investigate the impact of different stimulation parameters on
the outcome of GPi-DBS, a total of 28 patients (10 in 11
camptocormia patients) with available imaging and stimulation
data were analyzed to reconstruct the location of DBS electrodes
and model the stimulation impact. No signicant outliers among
the electrodes were identied through the manual examination
(Fig. 4). In volume of tissue activated (VTA) analysis, although
signicant correlation was found between VTA overlap with GPi
and percent improvements in axial subscores (R=0.38, p=
0.0300; Fig. 5a), improvements in the TCC/UCC angles were not
correlated with the volume of VTA intersection with GPi (all p>
0.05; Fig. 5b, c). By analyzing the possible bers traversing through
the VTA and projected to the volumetric space of the vast brain
areas, we found the structural connectivity from VTA to right
somatosensory cortex (S1) was signicantly correlated with
improvements in TCC angles (R=0.39, p=0.0380; Fig. 6).
This cohort study focused on the effectiveness of GPi-DBS for
treating postural deformities in PD patients and its possible
predictors. Pre-surgically, levodopa provided a small but signicant
Fig. 2 Improvements in camptocormia angles after surgery.
Colored dots represent pre- and post-surgical total (a) and upper
(b) camptocormia angles (TCC/UCC angles) in patients with lower
camptocormia (blue symbols and lines), upper camptocormia (red
symbols and lines) and without camptocormia (green symbols and
lines). *p< 0.05; n.s.: not signicant.
Fig. 3 Relation between improvement in camptocormia angles and clinical variables. The improvement in TCC angles was signicantly
correlated with pre-surgical values of TCC angles (a) and its responsiveness to levodopa (b); improvement in UCC angles was found correlated
with pre-surgical UCC angles. Gray areas represent the 95% CI. PD: Parkinsons disease; TCC: total camptocormia; UCC: upper camptocormia;
pre-surg: pre-surgical.
Fig. 4 Reconstruction of the DBS electrodes. The electrodes of 10
patients with camptocormia (marked in orange) and 18 patients
without camptorcormia (maked in blue) were shown on the T1-
weighted Montreal Neurological Institute (MNI) template. Active
contacts were marked in red. Masses with yellow described the
location of the STN, red for the red nucleus, and green for the GPi.
Y. Lai et al.
Published in partnership with the Parkinsons Foundation npj Parkinson’s Disease (2021) 8
improvement of bending angles in the whole population of PD
patients, with an approximately equal effect on the measurement
of TCC and UCC angles. The follow-up results showed that GPi-DBS
can signicantly improve postural alignments in PD patients with
camptocormia, and the correlation analysis suggests that patients
with larger pre-surgical TCC/UCC angles, better levodopa respon-
siveness of the TCC angle and higher connectivity from VTA to
right S1 cortex could possibly gain greater benets following
surgery. These ndings add to and extends previously published
data in the aspect of clinical effectiveness and candidate selection
of GPi-DBS for the treatment of camptocormia in PD
The effect of GPi-DBS on camptocormia could be described as a
mean of 40.4% improvement seen for TCC-camptocormia and 22.8%
for UCC-camptocormia; this marked improvement (around 16° in TCC
and 11° in UCC on average) in patients with severe postural
deformities showed important clinical utility (an example of patient
with TCC-camptocormia before and after surgery can be seen in
Fig. 7). This benecial effect were comparable with previous reports
on the treatment effect of GPi-DBS for PD-related camptocormia: in
2005, Micheli et al.
reported a sustained improvement in
camptocormia 6 months after GPi-DBS in a 62-year-old man with
early PD symptoms; a 33% reduction in the BurkeFahnMarsden
motor trunk subscore was observed 36 months after surgery in a
patient with PD-related camptocormia
; Thani et al.
utilized high-
frequency neuromodulation of the GPi to successfully achieve relief
of camptocormia in a 57-year-old womanwithPD.However,despite
a number of successful cases, treatment failure was also reported: in
a patient whose camptocormia only minimally responded to
dopaminergic medications, the immediate post-surgical alleviation
after bilateral GPi-DBS did not sustained at the longer follow-up
(15 months)
. In our study, improvements in the TCC/UCC angles
ranged from 0.3% to 69.6% (mean 33.4%) in the subgroup of 11
patients with camptocormia, and similarly, a wide range of post-
surgical improvements was also seen in the whole population. These
ndings suggest that the therapeutic effect of DBS on postural
abnormalities could be promisingingeneral,buttheoutcomemay
differ from person to person.
To date, much of the knowledge about the factors inuencing
the effectiveness of DBS on camptocormia were from studies on
. In 2018, a meta-analysis pooled the efcacy measures
of ve bilateral STN-DBS studies with an overall decrease in the
mean sagittal plane bending angles from 56.6° ± 5.1° to 38.4° ± 6.6°
after surgery and proposed duration of camptocormia of 2 years or
less as predictive of better outcomes
retrospective nature of our study, we were not able to include
duration of camptocormia as a covariate because the accurate time
of camptocormia onset could not be retrieved
. Instead, we
investigated the impact of PD disease duration on surgery outcome
and found it was not correlated with the treatment effect of GPi-
DBS. Preoperative levodopa responsiveness was another important
factor suggested to be predictive of DBS effect on camptocor-
, although, as discussed in previous literature, the correlation
between preoperative levodopa responsiveness and benetfrom
STN-DBS may be the result of methods used in statistical analysis
and was not always congruent between studies
univariate analysis of factors associated with improvements in
camptocormia angles, the results showed that levodopa respon-
siveness of the TCC angle was positively correlated to DBS benet.
This suggests that the occurrence of camptocormia could be a type
of off-period dystonia, in which favorable outcomes after DBS can
be expected
. However, the above association found in our study
still needs further validation as it did not reach signicance in the
following multivariate analysis. In both the univariate and multi-
variate analysis, larger pre-surgical TCC angles were suggested to
predict higher post-surgical improvements. Similar ndings were
also reported in STN-DBS, which showed that patients with
camptocormia were more likely to have a substantial improvement
Fig. 5 Correlation between percentage of VTA overlap with GPi and outcomes. The overlap volume signicantly correlated with
improvements in subscores for axial symptoms (a), but not with improvements in TCC angles (b) and UCC angles (c). Gray areas represent the
95% CI. PD: Parkinsons disease; VTA: volume of tissue activated; TCC: total camptocormia; UCC: upper camptocormia.
Fig. 6 Signicant correlation was found between structural
connectivity from VTA to right S1 and percent improvement in
TCC angles. Gray areas represent the 95% CI. PD: Parkinsons
disease; S1: somatosensory cortex; PD: Parkinsons disease; TCC: total
camptocormia; UCC: upper camptocormia.
Y. Lai et al.
npj Parkinson’s Disease (2021) 8 Published in partnership with the Parkinsons Foundation
after STN-DBS compared to those with normal camptocormia
.Thesendings suggest that patients with better respon-
siveness to levodopa can be expected to gain larger improvements
after DBS and camptocormia should not be a contraindication for
DBS, but it might even benet from the surgery.
It is important to note that, unlike tremor and rigidity, which are
supposed to improve within minutes to hours, axial symptoms,
such as postural abnormalities, usually require days and even
months to improve after electrodes were turned on
consequence, repeat programming is expected in order to achieve
optimal relief and the stimulation parameters could therefore be
highly inuential in improvements in postural alignments
However, despite brief documentation of stimulation parameters
in some of the studies, few researchers investigated the effect of
different sets of stimulation parameters on camptocormia
Through the stimulation analysis, we modeled the effect of various
stimulation settings on local regions. When correlating stimulation
volume on GPi to clinical outcomes, in contrast to the axial
subscore improvements, the overlap volume of VTA with GPi was
not found signicantly associated with improvement in campto-
cormia angles, which resembles recent ndings that suggest the
volume of VTA-GPi overlap may not positively related to outcomes
of pallidal stimulation in dystonic symptoms
. Aside from its local
effects on stimulated brain targets, DBS is also proposed to exert
its therapeutic effect by modulating remote structures and the
distributed brain networks
. In connectivity analysis, we found
that the structural connectivity from VTA to right somatosensory
cortex was signicantly correlated with improvements in TCC
angles, suggesting the role of somatosensory cortex and
proprioceptive integration in mediating the effect of DBS
treatment for camptocormia. In previous studies, proprioceptive
disintegration was found highly related to postural deformities in
PD and in patients with camptocormia
. Although the
pathophysiology of camptocormia remains unclear, our ndings
indirectly lend support to the theory that postural control could
require a complex system involving the integration of vestibular,
visual, and proprioceptive sensory information
At the time of the study, there was no strong evidence for the
superiority of STN-DBS over the GPi-DBS, or vice versa
. In our
study, camptocormia was not the primary indication for surgery.
The main motivation of choosing GPi as the preferred target was
based on the concern of a possible cognitive impact of STN-DBS
and also, due to the relatively low doses of levodopa administra-
tion in our current cohort (mean LEDD of 675.1 mg, 31 patients
<1000 mg), the benet of reducing medications, which is a key
advantage for STN-DBS, was not a top priority
. Additional
considerations were the need for less intensive monitoring of
medication and stimulation adjustments, as previously suggested
for most patients received GPi-DBS
. Therefore, the selection of
the GPi as target was largely a pragmatic one. According to
previous systematic reviews, there was also not enough evidence
to adequately compare STN and GPi as the target for parkinsonian
camptocormia or any of the postural deformities, e.g., Pisa
syndrome and anterocollis, particularly because of the relatively
small sample sizes
. Although compared to STN-DBS, impressive
outcome (improvement of 50100%) was seen in patients with
dystonic camptocormia after GPi-DBS, this nding may not be
easily replicated in PD, as dystonic camptocormia patients were
younger, had shorter disease duration, and longer camptocormia
. Studies utilizing randomized designs are now required
to provide stronger evidence for optimal target selection
There are several limitations of our study. First, the length of
follow-up in the overall population was restricted to within
12 months after surgery. Though this narrowed follow-up period
was adopted to prevent substantial disease progression during
the study, it may not allow full improvement in dystonic
symptoms, which can sometimes take months after optimal
settings are found
. Also, as there are studies indicating that
DBS might lost its initial benecial effect at long term
longitudinal studies with repeated assessments at longer follow-
ups, e.g., 5 years post surgery, were needed to assess the effect of
DBS on camptocormia taking the fact of disease progression into
. Second, due to the potential for overtting of the
data, the relatively small number of participants limited our power
in making inference based on the multivariate analysis
. Also, the
mere four patients presented with UCC-camptocormia makes it
difcult to draw rm conclusion on the effect of GPi-DBS in
patients with UCC-camptocormia. To deal with this issue, multi-
center studies could be expected for not only enlarging the
sample size but also contributing in validating the reproducibility
of results across datasets. Third, our study was retrospective in
nature. Prospective and controlled studies therefore remain useful
in investigating other predictive factors, including the duration of
and features in the electromyogram recordings
of exor and extensor muscles of the trunk
Our study demonstrates effectiveness of GPi-DBS in improving
camptocormia in PD patients. Specically, patients present with
larger pre-surgical TCC/UCC angles, better pre-surgical respon-
siveness of TCC angles to levodopa, and higher VTA to
S1 structural connectivity may experience larger improvement in
Fig. 7 Measurement of the camptocormia angles angle in a
patient with TCC-camptocormia pre- and post surgery. a Pre-
surgical UCC angle; bUCC angle at 12 month post-surgery; cpost-
surgical TCC angle; dTCC angle at 12 months post-surgery. Written
consent was obtained for publication of the photographs. C7:
spinous process of vertebra C7; L5: suspected location of the
spinous process of vertebra L5; LM: lateral malleolus; FC: vertebral
fulcrum, the point with the greatest distance from the spine.
Y. Lai et al.
Published in partnership with the Parkinsons Foundation npj Parkinson’s Disease (2021) 8
posture. These ndings suggest that camptocormia should not be
a contraindication for DBS, but it might even improve following
GPi-DBS. Further randomized controlled studies with repeat
measurement and multicenter data could help determine the
long-term effects of DBS, identify predictors of outcome, and
validate the reproducibility of results across datasets.
This study has been carried out in accordance with The Code of Ethics of
the World Medical Association (Declaration of Helsinki). The ethics
committee of the Ruijin Hospital Shanghai Jiao Tong University School
of Medicine approved this retrospective clinical research. Written informed
consent was obtained from all patients. The authors afrm that human
research participants provided informed consent, for publication of the
images in Fig. 7.
Study population
PD patients who were treated with bilateral GPi-DBS at Ruijin Hospital from
January 2017 to January 2019 with video-taped pre- and post-surgical
assessments were retrospectively analyzed. A lateral view was obtained
from the video for each assessed condition.
Inclusion and exclusion criteria
The inclusion criteria were as follows: (a) PD in Hoehn and Yahr stages 24,
(b) 4075 years old, (c) available video-taped motor examinations for pre-
surgical (med-ON and med-OFF) and post-surgical (med-OFF/DBS-ON)
conditions within 1-year follow-up after surgery, and (d) bilateral GPi- DBS
The exclusion criteria were as follows: (a) other neurological disease or
injuries which could affect gait and posture, (b) history of lesions or DBS of
other brain targets or spinal surgery, (c) severe orthopedic spine injuries or
diseases (such as vertebral fracture, severe osteoporosis, Potts disease,
etc.), and (d) postural abnormalities caused by trauma or disease after DBS.
Surgical procedure
Preoperatively, the location of the GPi was determined using a stereotactic
computed tomography (CT) scan [with the Leksell (Elekta, Inc.) head frame]
coregistered to high-resolution 3.0 T T1- and T2-weighted magnetic
resonance imaging (MRI) images with Leksell SurgiPlan (Elekta, Stockholm,
Sweden). In general, the target was dened directly under the guidance of
coregistered image and the location was about 24mm anterior to the
midpoint of the anterior commissureposterior commissure line (ACPC),
1822 mm lateral to the ACPC line, and 24 mm below the ACPC line. The
procedure was performed under general anesthesia. After conrmation of
location of the electrodes (Model 3387, Medtronic, Inc., Minneapolis, MN,
USA; or Model L302, PINS, Inc., Beijing, China) with intraoperative CT, the
impulse generator was implanted. A CT or MRI scan was performed 1 week
after the surgery to conrm the location of the electrodes.
Symptom assessment and computational methods
Pre-surgical evaluation was conducted 12 days before surgery and post-
surgical evaluation was conducted during the corresponding follow-ups.
The length of follow-up was restricted to within 12 months after surgery
(median: 6 months; range: 112 months), during which a marked disease
progression was unlikely to happen.
Posture analysis. Based on the method recommended in the consensus
statement by Margraf et al.
, postural angles were determined by two
blinded physicians with an analysis of lateral view pictures of each patient
standing still with the camera lens at approximately waist level;
discrepancies were solved during a consensus meeting. The photographs
were marked as follows
: C7 (spinous process of vertebra C7), L5
(suspected location of the spinous process of vertebra L5), LM (lateral
malleolus), and FC (vertebral fulcrum, the point with the greatest distance
from the spine).
According to the above points, the camptocormia angles were
calculated as follows: (a) TCC angle =the angle between the line from
the LM to L5 and the line between L5 and C7, (b) UCC angle =the angle
between the line from L5 to FC and the line from FC to C7. An online tool
was used to calculate the angles (
. Using the cut-off for severity of
postural angles in previous studies (TCC angle 30° for lower campto-
cormia, or TCC-camptocormia and UCC angle 45° for UCC or UCC-
, whether TCC-camptocormia or UCC-camptocormia was
present was determined. In addition, a clinical posture score using the item
posturein the MDS-UPDRS-III was obtained.
Motor examination: MDS-UPDRS-III was used to assess the patients
motor symptoms. Preoperatively, the evaluation was carried out in med-
OFF state (12 hoursdiscontinuation of levodopa and 72 h of other anti-
Parkinson medication) and med-ON state (1.5 times routine drug use and
45 min after administration); after surgery, the evaluation was carried out
at med-OFF/DBS-ON state.
Collection of clinical information: Age at surgery, gender, duration of
PD, medication, stimulation parameters, and other medical histories were
Based on the postoperative CT or MRI images: Position of the electrodes
in the nucleus was reconstructed using the lead-DBS toolbox (version 2.2.3)
on Matlab according to the methods described by Horn et al.
estimated with Lead-DBS based on nite element models. Conductivity
values for white matter were set to 0.14S/mm and for gray matter to 0.33 S/
mm. Thresholding of the potential gradient at 0.2 V/mm then determined
activated tissue
. GPi were located on the DISTAL atlas, as this atlas was
designed for surgical targets in basal ganglia and was proved to be of high
accuracy of localization
. Overlaps between VTAs and the GPi were
calculated for both hemispheres and summed up and normalized with the
total volume of GPi. For structural connectivity, the normative group
connectome from 32 subjects of the Human Connectome Project at
Massachusetts General Hospital ( was used.
These data were acquired on a specially designed MRI scanner with more
powerful gradients than available on conventional MRI scanners. The
processing steps were described previously
. In each subject, 200,000 bers
were sampled and transformed into MNI space. Structural connectivity was
calculated as bers traversing through the VTA and projected to the
volumetric space of the brain in 2 mm isotropic resolution, denoting the
portion of bers (connected to the VTA) that traversed through each
. Parcellation of motor cortices was based on the Human Motor
Area Template atlas, in which primary motor cortex (M1), somatosensory
cortex (S1), supplementary motor area (SMA), pre-SMA, lateral premotor
cortex along the dorsal and ventral plane (PMd and PMv) were dened
Statistical analysis
Data were described using means and SDs for continuous variables and
frequencies for categorical variables. A two-tailed paired t-test was used to
analyze the changes in TCC and UCC angles before and after operation.
Univariate and multivariate analysis were used to evaluate the association
between clinical/demographic characteristics and the extent of the effect
of GPi-DBS on camptocormia angles, which was measured using the
percentage changes (pre-surgical med-OFF vs. post-surgical med-OFF/DBS-
ON evaluation) of the TCC and UCC angles. Age at surgery, gender,
duration of PD, follow-up time, pre-surgical motor score (MDS-UPDRS-III) at
med-OFF, relative response to levodopa in motor score, and TCC/UCC
angles (pre-surgical med-OFF vs. pre-surgical med-ON evaluation) were
explored as covariates of interest. Two-sided p-values < 0.05 were
considered signicant. STATA 14.0 was used to analyze the data.
Reporting summary
Further information on research design is available in the Nature Research
Reporting Summary linked to this article.
The data that support the ndings of this study are available from the corresponding
author upon reasonable request.
Received: 26 June 2020; Accepted: 8 December 2020;
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B.S. received research support from DBS industry SceneRay and PINS (donated
devices); D.L. and C.Z. received honoraria and travel expenses from Medtronic,
SceneRay, and PINS. B.R.B. currently serves as co-Editor in Chief for the Journal of
Parkinsons Disease; serves on the editorial board of Practical Neurology; has received
honoraria for serving on the scientic advisory board for Abbvie, Biogen, and UCB;
has received fees for speaking at conferences from AbbVie, Zambon, and Bial; and
has received research support from the Netherlands Organization for Scientic
Research, the Michael J Fox Foundation, UCB, Abbvie, the Stichting Parkinson Fonds,
the Hersenstichting Nederland, the Parkinsons Foundation, Verily Life Sciences,
Horizon 2020, the Topsector Life Sciences and Health, and the Parkinson Vereniging.
Other authors report no disclosures. This study was supported by the grant from the
National Natural Science Foundation of China (81971294).
D.L., Y.L., and Y.S. conceived the study, collected and interpreted the data, and wrote
the manuscript. B.R.B. and J.S. conceived the study, interpreted the data, and
contributed to writing of the manuscript. Y.L. and Y.S. did statistical analysis and
visualization. D.L., D.S., and B.S. did the surgery. All authors contribut ed to data
collection and critical revision of the manuscript. Y.L. and Y.S. contributed equally as
rst authors.
The authors declare no competing interests.
Supplementary information is available for this paper at
Correspondence and requests for materials should be addressed to D.L.
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© The Author(s) 2021
Y. Lai et al.
Published in partnership with the Parkinsons Foundation npj Parkinson’s Disease (2021) 8
... [23][24][25][26]28,30,[32][33][34][35][36][37][38][39]42,[44][45][46][47][48][50][51][52][53][54][55][56][57][58][59] The Movement Disorder Society-Sponsored Revision of the UPDRS (MDS-UPDRS III) 84 was used in eight studies. 27,29,31,40,41,43,60,61 The Gait and Falls Questionnaire (GFQ), Freezing of Gait Questionnaire (FoGQ) and a Stepping in place task (SIP), were used to assess axial symptoms in patients with Parkinson's disease. 49,57 For generalised, focal, segmental dystonia and X-linked Dystonia-Parkinsonism, the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) 85 was administered in eight studies. ...
... Most studies undertook an outcome connectivity mapping approach, with 12 studies exploring contact profiles from seeds at the STN, 23 for assessing camptocormia symptoms, 40 and also from patient-specific implantation regions associated with stimulation-induced or non-stimulation-induced dyskinesia symptoms. 53 ...
... ,169 DBS has been indicated to normalise oscillatory coherence with, and decrease overactivity of the primary motor cortex.170,171 Furthermore, identified optimal outcomes arising from ventral GPi implantations with association to increased connectivity with primary somatosensory cortex provide additional support for sensorimotor networks as a Finally, although indicated as a symptom of Parkinson's disease, efficacious contacts determined by GPi-primary somatosensory cortex and STN-pre/supplementary motor cortex connectivity in patients with camptocormia highlights the salience of sensorimotor network involvement for abnormal posturing symptoms across disorders.40,41 Further exploration of these circuits may help to elucidate a therapeutic target aimed at altering sensorimotor networks to control dystonic and postural symptoms. ...
Full-text available
Patients with movement disorders treated by deep brain stimulation do not always achieve successful therapeutic alleviation of motor symptoms, even in cases where surgery is without complications. Magnetic resonance imaging (MRI) offers methods to investigate structural brain-related factors that may be predictive for clinical motor outcomes. This review aimed to identify features which have been associated with variability in clinical post-operative motor outcomes in patients with Parkinson’s disease, dystonia, and essential tremor from structural MRI modalities. We performed a literature search for articles published between January 01, 2000, and April 01, 2022, and identified 5197 articles. Following screening through our inclusion criteria, we identified 60 total studies (39 = Parkinson’s disease, 11 = dystonia syndromes and 10 = essential tremor). The review captured a range of structural MRI methods and analysis techniques used to identify factors related to clinical post-operative motor outcomes from deep brain stimulation. Morphometric markers, including volume and cortical thickness were commonly identified in studies focused on patients with Parkinson’s disease and dystonia syndromes. Reduced metrics in basal ganglia, sensorimotor and frontal regions showed frequent associations with reduced motor outcomes. Increased structural connectivity to subcortical nuclei, sensorimotor and frontal regions were also associated with greater motor outcomes. In patients with tremor, increased structural connectivity to the cerebellum and cortical motor regions showed high prevalence across studies for greater clinical motor outcomes. In addition, we highlight conceptual issues for studies assessing clinical response with structural MRI and discuss future approaches towards optimising individualised therapeutic benefits. Although quantitative MRI markers are in their infancy for clinical purposes in movement disorder treatments, structural features obtained from MRI offer powerful potential to identify candidates who are more likely to benefit from deep brain stimulation and provide insight into the complexity of disorder pathophysiology.
... However, the results of spinal surgery for degenerative spinal conditions in patients with PD are disappointing with failure rates of 25.8-100% [8][9][10][11][12]. As an alternative treatment strategy for the underlying pathomechanism, some authors have described the influence of deep brain stimulation on PD-related postural abnormalities [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30]. We aim to present a systematical review of the current literature. ...
... The included studies have been conducted between 2003 and 2021. Regarding study designs, nine case reports [5, 13, 17-20, 23, 25, 28] (i.e., 50%), four case series [14,16,22,26] (i.e., 22.2%), three retrospective observational cohort studies [21,24,30] (i.e., 16.6%), one review article including two reported cases [27] (i.e., 5.6%), and one prospective trial [29] (i.e., 5.6%) were assessed. Fifteen studies [13, 14, 16-21, 25, 27-30, 32] reported follow-up data with a mean follow-up time of 21.5 months (range 5-67 months). ...
... Parkinson Rating Scale [UPDRS]-III item 28 score [26]), four studies anecdotally reported the clinical outcome without standardizes scores [13,18,19,27], and nine studies did not take the clinical course into account. (2) Changes of the sagittal thoraco-lumbar angle (TLA) (or shoulder-hip knee and head-shoulder-hip angle) assessed by photographs were assessed in 13 (i.e., 72,2%) studies [5,14,17,[19][20][21][22][23][24][25][28][29][30], with outcome parameter either defined as improvement in case of > 50% relative reduction of the TLA or as absolute value < 30° of the TLA at last follow-up (Table 1). Two studies further distinguished improvement as effective and partially effective: in Sakai et al., partially effective was defined when the TLA became < 30° after DBS but did not last for > 6 months [21]. ...
Full-text available
Deep brain stimulation (DBS) has become a well-established treatment modality for Parkinson’s disease (PD), especially regarding motor fluctuations, dyskinesias, and tremor. Although postural abnormalities (i.e., Camptocormia [CC] and Pisa syndrome [Pisa]) are known to be a major symptom of PD as well, the influence of DBS on postural abnormalities is unclear. The objective of this study is to analyze the existing literature regarding DBS for PD-associated postural abnormalities in a systematic review and meta-analysis. In compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we conducted a systematic review and meta-analysis of 18 studies that reported the effect of DBS regarding postural abnormalities. After screening of 53 studies, a total of 98 patients (44 female, 53 males, 1 not reported; mean age: 62.3, range 30–83 years) with postural abnormalities (CC n = 98; Pisa n = 11) were analyzed from 18 included studies. Of those patients, 94.9% underwent STN-DBS and 5.1% had GPi as DBS target area. A positive outcome was reported for 67.8% with CC and 72.2% with Pisa. In the meta-analysis, younger age and lower pre-operative UPDRS-III (ON/OFF) were found as positive predictive factors for a positive effect of DBS. DBS might be a potentially effective treatment option for PD-associated postural abnormalities. However, the level of evidence is rather low, and definition of postoperative outcome is heterogenous between studies. Therefore larger, prospective trials are necessary to give a clear recommendation.
... These included 4 electrophysiology studies and 4 imaging studies. [11][12][13][27][28][29][30][31] Among the included imaging studies, normative connectomes were applied in 2 studies, 30,31 patient-specific presurgical diffusion tensor imaging data were used in 1 study, 13 and patient-specific postsurgical fMRI data were used in another study. 29 No investigation was made based on patient-specific presurgical fMRI data. ...
... Changes in thalamocortical connectivity correlated w/ GPi DBS-induced motor improvement Sobesky et al., 2021 30 28 fMRI (normative) Connectivity profiles were able to cross-predict outcomes Lai et al., 2021 31 28 DTI (normative) Connectivity btwn VTA & rt S1 correlated w/ improvements in total camptocormia angle Primate studies ...
... Using diffusionweighted MRI for structural connectivity, Middlebrooks et al. demonstrated that improvement in UPDRS III motor score was most strongly correlated with the VTA in the GPi subregion connected to M1, and then nonsignificantly followed by SMA and PMC. 13 Recently, Sobesky et al. and our group have reported the value of normative connectomes in GPi DBS surgery, in which the data sets reveal beneficial connections in an average human brain but do not account for individual variations of connectivity. 30,31 In the current study, we did a hypothesis-based re- search, in which the results demonstrated the importance of connectivity between motor cortices and stimulation sites within the GPi in GPi DBS response. The relevant motor cortical areas were largely similar to those in STN DBS studies, and the predictive value was also comparable (13.1% ± 11.3% compared to 15.7% ± 14.2%). ...
Objective: Functional connectivity shows the ability to predict the outcome of subthalamic nucleus deep brain stimulation (DBS) in Parkinson disease (PD). However, evidence supporting its value in predicting the outcome of globus pallidus internus (GPi) DBS remains scarce. In this study the authors investigated patient-specific functional connectivity related to GPi DBS outcome in PD and established connectivity models for outcome prediction. Methods: The authors reviewed the outcomes of 21 patients with PD who received bilateral GPi DBS and presurgical functional MRI at the Ruijin Hospital. The connectivity profiles within cortical areas identified as relevant to DBS outcome in the literature were calculated using the intersection of the volume of tissue activated (VTA) and the local structures as the seeds. Combined with the leave-one-out cross-validation strategy, models of the optimal connectivity profile were constructed to predict outcome. Results: Connectivity between the pallidal areas and primary motor area, supplementary motor area (SMA), and premotor cortex was identified through the literature as related to GPi DBS outcome. The similarity between the connectivity profile within the primary motor area, SMA, pre-SMA, and premotor cortex seeding from the VTA-GPi intersection from an out-of-sample patient and the constructed in-sample optimal connectivity profile predicts GPi DBS outcome (R = 0.58, p = 0.006). The predictions on average deviated by 13.1% ± 11.3% from actual improvements. On the contrary, connectivity profiles seeding from the GPi (R = -0.12, p = 0.603), the VTA (R = 0.23, p = 0.308), the VTA outside the GPi (R = 0.12, p = 0.617), or other local structures were found not to be predictive. Conclusions: The results showed that patient-specific functional connectivity seeding from the VTA-GPi intersection could help in GPi DBS outcome prediction. Reproducibility remains to be determined across centers in larger cohorts stratified by PD motor subtype.
... The exclusion criteria were: (1) Review article; (2) Articles with missing or non-extractable data; (3) Duplicate articles or those with repeat clinical data. Twenty studies containing a total of 152 patients [3,[8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] met all of the criteria and were included in the analysis. Three studies used globus pallidus internus deep brain stimulation (GPi-DBS), 16 used subthalamic nucleus deep brain stimulation (STN-DBS), and one study used both (Fig. 1). ...
... Information extracted from the selected papers included authors, year of publication, type of research, number of participants, age, gender, PD duration, camptocormia duration, bending angles (in both On and Off periods), the Unified Parkinson's Disease Rating Scale III (UPDRS-III) score (in both On and Off periods), mean follow-up time, and the L-dopa equivalent daily dose (LEDD) assessed both pre-and post-DBS (Tables 1,2, Ref. [3,[8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26]). ...
Full-text available
Background: Camptocormia is one of the most common postural disorders of Parkinson's disease (PD) which has limited treatment options. In this review, we summarize the efficacy of deep brain stimulation (DBS) for camptocormia in PD. Methods: The PubMed ( and EMBASE databases ( were searched for the terms "Parkinson Disease" and "camptocormia" in combination with "deep brain stimulation". We then explored the efficacy of DBS for camptocormia by statistical analysis of the bending angle, the Unified Parkinson's Disease Rating Scale III (UPDRS-III) and L-dopa equivalent daily dose (LEDD), and by evaluating the prognosis after DBS. Results: Twenty articles that reported results for 152 patients were included in this review. These comprised 136 patients from 16 studies who underwent subthalamic nucleus deep brain stimulation (STN-DBS), and 13 patients from 3 studies who underwent globus pallidus internus deep brain stimulation (GPi-DBS). One study used both STN-DBS (2 patients) and GPi-DBS (one patient). After 3-21 months of follow-up, the mean bending angle during the Off-period was significantly reduced compared to pre-DBS (31.5 ± 21.4 vs. 53.6 ± 22.7, respectively; p < 0.0001). For the STN-DBS trials, the mean post-operative bending angles during both Off- and On-periods were significantly reduced compared to pre-operative (32.1 ± 22.7 vs. 55.4 ± 24.1, p = 0.0003; and 33.1 ± 21.5 vs. 43.7 ± 20.6, p = 0.0003, respectively). For GPi-DBS, the mean bending angle post-DBS during the Off-period was considerably lower than pre-DBS (28.5 ± 10.7 vs. 42.9 ± 9.9, p < 0.001). The decrease in bending angle after DBS was negatively correlated with the duration of camptocormia (R = - 0.433, p = 0.013), whereas positively associated with the pre-bending angle (R = 0.352, p = 0.03). Conclusions: DBS is an effective treatment for camptocormia in PD. Patients in the early stage of camptocormia with more significant bending angle may benefit more from DBS.
... Innovatively, deep brain stimulation and botulinum neurotoxin might have beneficial effects on Pisa syndrome and camptocormia in people with PD [8][9][10]. ...
Full-text available
This paper describes the second part of the PASSO (Parkinson smart sensory cues for older users) project, which designs and tests an innovative haptic biofeedback system based on a wireless body sensor network using a smartphone and different smartwatches specifically designed to rehabilitate postural disturbances in persons with Parkinson’s disease. According to the scientific literature on the use of smart devices to transmit sensory cues, vibrotactile feedback (particularly on the trunk) seems promising for improving people’s gait and posture performance; they have been used in different environments and are well accepted by users. In the PASSO project, we designed and developed a wearable device and a related system to transmit vibrations to a person’s body to improve posture and combat impairments like Pisa syndrome and camptocormia. Specifically, this paper describes the methodologies and strategies used to design, develop, and test wearable prototypes and the mHealth system. The results allowed a multidisciplinary comparison among the solutions, which led to prototypes with a high degree of usability, wearability, accessibility, and effectiveness. This mHealth system is now being used in pilot trials with subjects with Parkinson’s disease to verify its feasibility among patients.
... Antidromic modulations from targets of DBS of the pathway were evidenced by both human and animal studies 37 . Connectivity analysis showed that structural and functional connectivity to this region was associated with the clinical improvement of DBS [38][39][40][41][42] . The reduced cortical thickness and diminished volume of this region were also reported to correlate with motor outcomes in our review 10,11 . ...
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While the efficacy of deep brain stimulation (DBS) is well-established in Parkinson's Disease (PD), the benefit of DBS varies across patients. Using imaging features for outcome prediction offers potential in improving effectiveness, whereas the value of presurgical brain morphometry, derived from the routinely used imaging modality in surgical planning, remains under-explored. This review provides a comprehensive investigation of links between DBS outcomes and brain morphometry features in PD. We systematically searched PubMed and Embase databases and retrieved 793 articles, of which 25 met inclusion criteria and were reviewed in detail. A majority of studies (24/25), including 1253 of 1316 patients, focused on the outcome of DBS targeting the subthalamic nucleus (STN), while five studies included 57 patients receiving globus pallidus internus (GPi) DBS. Accumulated evidence showed that the atrophy of motor cortex and thalamus were associated with poor motor improvement, other structures such as the lateral-occipital cortex and anterior cingulate were also reported to correlated with motor outcome. Regarding non-motor outcomes, decreased volume of the hippocampus was reported to correlate with poor cognitive outcomes. Structures such as the thalamus, nucleus accumbens, and nucleus of basalis of Meynert were also reported to correlate with cognitive functions. Caudal middle frontal cortex was reported to have an impact on postsurgical psychiatric changes. Collectively, the findings of this review emphasize the utility of brain morphometry in outcome prediction of DBS for PD. Future efforts are needed to validate the findings and demonstrate the feasibility of brain morphometry in larger cohorts.
... There is also an argument over the effectiveness of DBS in the STN vs. Globus Pallidus internus (GPi). In a case study of two patients with near crippling camptocormia (a trunk flexion exceeding 30˚ [39]), GPi DBS completely reversed the camptocormia and restored posture to normal [40]. Furthermore, in a small study of three patients with PD, two with bilateral DBS in the STN and one with bilateral GPi DBS, no or mild improvement of trunk flexion was seen in the two patients with DBS in the STN but a moderate improvement was seen in the patient with GPi DBS [41]. ...
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Parkinson’s disease (PD) can produce postural abnormalities of the standing body position such as kyphosis. We investigated the effects of PD, deep brain stimulation (DBS) in the subthalamic nucleus (STN), vision and adaptation on body position in a well-defined group of patients with PD in quiet standing and during balance perturbations. Ten patients with PD and 25 young and 17 old control participants were recruited. Body position was measured with 3D motion tracking of the ankle, knee, hip, shoulder and head. By taking the ankle as reference, we mapped the position of the joints during quiet standing and balance perturbations through repeated calf muscle vibration. We did this to explore the effect of PD, DBS in the STN, and vision on the motor learning process of adaptation in response to the repeated stimulus. We found that patients with PD adopt a different body position with DBS ON vs. DBS OFF, to young and old controls, and with eyes open vs. eyes closed. There was an altered body position in PD with greater flexion of the head, shoulder and knee (p≤0.042) and a posterior position of the hip with DBS OFF (p≤0.014). With DBS ON, body position was brought more in line with the position taken by control participants but there was still evidence of greater flexion at the head, shoulder and knee. The amplitude of movement during the vibration period decreased in controls at all measured sites with eyes open and closed (except at the head in old controls with eyes open) showing adaptation which contrasted the weaker adaptive responses in patients with PD. Our findings suggest that alterations of posture and greater forward leaning with repeated calf vibration, are independent from reduced movement amplitude changes. DBS in the STN can significantly improve body position in PD although the effects are not completely reversed. Patients with PD maintain adaptive capabilities by leaning further forward and reducing movement amplitude despite their kyphotic posture.
Botulinum neurotoxins (BoNTs) can relieve painful muscle spasms through inhibition of acetylcholine release and alleviate neuropathic pain by blocking the release of pain mediators such as calcitonin gene-related peptide (CGRP), glutamate, and substance P (SP). In addition to the common pain disorders discussed in the preceding chapters, data is now available on the possible efficacy of BoNTs in alleviating pain in some uncommon and rare disorders. In this chapter, four uncommon and rare conditions—stiff-person syndrome, painful legs-moving toes, painful camptocormia, and nontraumatic central pain—are discussed. The limited data available in the literature about the use of BoNT in these conditions is presented. Case reports are included from the author’s experience to illustrate the clinical features and the technique of BoNT injection employed to relieve pain in these disorders.
Objectives This interventional pilot study aimed to 1) examine whether a novel wearable vibro-tactile feedback device (‘UpRight Go’) effective and feasible to improve postural alignment in Parkinson’s disease (PD); 2) explore relationships between postural alignment and attention in PD; 3) explore effect of vibro-tactile device on balance and gait; and 4) gain initial feedback on the use of the vibro-tactile device in the laboratory and at home. Methods 25 people with PD sat, stood and walked for two-minutes without and with the UpRight device attached to their upper backs to provide feedback on postural alignment in the laboratory. A sub-group (n=12) wore the UpRight device at home for 60mins per day for 7-days of postural feedback. Subjective feedback on use of the device was obtained in the laboratory and at the end of the 7-day period. The primary outcome for this study was posture measured by verticality of inertial measurement units (IMUs) at the neck, trunk and low back, which was done with and without the UpRight device. Secondary outcomes included clinical measures of posture, subjective feedback on the device, computerized attention measures, gait and balance. Results Neck postural alignment in PD was significantly improved (reduced neck flexion) with the UpRight during sitting and standing in both clinical measures (p=0.005) and IMU outcomes (p=0.046), but trunk and low back posture did not change. There was no change in postural alignment during walking with the UpRight. Postural alignment response was related to attentional capabilities. Many subjects (68%) reported that they felt a benefit from the UpRight and most participants reported that the device was acceptable (Lab use; 72%, Home use; 75%). Conclusion The UpRight Go feedback device may improve neck/upper-back posture in PD during sitting and standing, but not during walking. Postural alignment response to the device may depend on attentional mechanisms.
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The process of altering neural activity – neuromodulation – has long been used to treat patients with brain disorders and answer scientific questions. Deep brain stimulation in particular has provided clinical benefit to over 150,000 patients. However, our understanding of how neuromodulation impacts the brain is evolving. Instead of focusing on the local impact at the stimulation site itself, we are considering the remote impact on brain regions connected to the stimulation site. Brain connectivity information derived from advanced magnetic resonance imaging data can be used to identify these connections and better understand clinical and behavioral effects of neuromodulation. In this article, we review studies combining neuromodulation and brain connectomics, highlighting opportunities where this approach may prove particularly valuable. We focus on deep brain stimulation, but show that the same principles can be applied to other forms of neuromodulation, such as transcranial magnetic stimulation and MRI-guided focused ultrasound. We outline future perspectives and provide testable hypotheses for future work.
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DBS is an effective neuromodulatory therapy that has been applied in various conditions, including PD, essential tremor, dystonia, Tourette syndrome, and other movement disorders. There have also been recent examples of applications in epilepsy, chronic pain, and neuropsychiatric conditions. Innovations in neuroimaging technology have been driving connectomics, an emerging whole‐brain network approach to neuroscience. Two rising techniques are functional connectivity profiling and structural connectivity profiling. Functional connectivity profiling explores the operational relationships between multiple regions of the brain with respect to time and stimuli. Structural connectivity profiling approximates physical connections between different brain regions through reconstruction of axonal fibers. Through these techniques, complex relationships can be described in various disease states, such as PD, as well as in response to therapy, such as DBS. These advances have expanded our understanding of human brain function and have provided a partial in vivo glimpse into the underlying brain circuits underpinning movement and other disorders. This comprehensive review will highlight the contemporary concepts in brain connectivity as applied to DBS, as well as introduce emerging considerations in movement disorders. © 2020 International Parkinson and Movement Disorder Society
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Background Deep brain stimulation (DBS) within the pallidum represents an effective and well-established treatment for isolated dystonia. However, clinical outcome after surgery may be variable with limited response in 10–25% of patients. The effect of lead location on clinical improvement is still under debate.Objective To identify stimulated brain regions associated with the most beneficial clinical outcome in dystonia patients.Methods18 patients with cervical and generalized dystonia with chronic DBS of the internal pallidum were investigated. Patients were grouped according to their clinical improvement into responders, intermediate responders and non-responders. Magnetic resonance and computed tomography images were co-registered, and the volume of tissue activated (VTA) with respect to the pallidum of individual patients was analysed.ResultsVTAs in responders (n = 11), intermediate responders (n = 3) and non-responders (n = 4) intersected with the posterior internal (GPi) and external (GPe) pallidum and the subpallidal area. VTA heat maps showed an almost complete overlap of VTAs of responders, intermediate and non-responders. VTA coverage of the GPi was not higher in responders. In contrast, VTAs of intermediate and non-responders covered the GPi to a significantly larger extent in the left hemisphere (p < 0.01).ConclusionsDBS of ventral parts of the posterior GPi, GPe and the adjacent subpallidal area containing pallidothalamic output projections resulted in favourable clinical effects. Of note, non-responders were also stimulated within the same area. This suggests that factors other than mere lead location (e.g., clinical phenotype, genetic background) have determined clinical outcome in the present cohort.
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Introduction: Postural abnormalities are common in Parkinson's disease (PD) and increasing with disease progression. While many studies focus on balance and gait, postural alignment is only infrequently studied. Purpose: The aim of the present study was to examine the immediate and long-term effects of medication and deep brain stimulation (DBS) in the subthalamic nucleus on postural alignment in PD. Materials and Methods: PD patients (n = 192) in an advanced stage of disease were videotaped during a standardized l-dopa trial before and after DBS. The patients were tested with and without medication pre-surgical and retested post-surgical (6–24 months) in all treatment combinations of medication and DBS regarding the on and off conditions. The forward bending as total camptocormia (TCC) and upper camptocormia (UCC) angles and lateral bending as Pisa angle were assessed with the free downloadable NeuroPostureApp ( Three subgroups were defined according to normative values of healthy controls and according to clinical criteria: patients with normal posture, with stooped posture, and with postural disorders. Results: A stooped posture was found in 82% of the patients with regard to the TCC angle and in 54% for the UCC angle. Sixty-two percent had an abnormal Pisa angle. Camptocormia was diagnosed in ~7% and a Pisa syndrome in 1% of the patients. Medication and DBS both significantly improved postural alignment in the entire cohort. Female and male patients benefit similarly by medication and stimulation. Subgroup analyses revealed that the effects were also significant for patients with stooped posture, and the effects were strongest for patients with camptocormia: they led to angles below the diagnostical criterion for camptocormia for 13 of 14 patients with TCC and 11 of 26 patients with UCC. DBS had an additional effect to medication over time for the Pisa angle. Conclusion: Medication and DBS both improved postural alignment in PD patients, but effects were small for the entire cohort. Patients with camptocormia according to the TCC angle benefit strongest. The large differences of the treatment effects may indicate distinct pathological mechanisms for stooped posture and postural disorders. The TCC angle was shown to be sensitive to change. The UCC angle was less sensitive but may be a useful assessment tool for a subgroup.
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Deep brain stimulation (DBS) is a highly efficacious treatment option for movement disorders and a growing number of other indications are investigated in clinical trials. To ensure optimal treatment outcome, exact electrode placement is required. Moreover, to analyze the relationship between electrode location and clinical results, a precise reconstruction of electrode placement is required, posing specific challenges to the field of neuroimaging. Since 2014 the open source toolbox Lead-DBS is available, which aims at facilitating this process. The tool has since become a popular platform for DBS imaging. With support of a broad community of researchers worldwide, methods have been continuously updated and complemented by new tools for tasks such as multispectral nonlinear registration, structural / functional connectivity analyses, brain shift correction, reconstruction of microelectrode recordings and orientation detection of segmented DBS leads. The rapid development and emergence of these methods in DBS data analysis require us to revisit and revise the pipelines introduced in the original methods publication. Here we demonstrate the updated DBS and connectome pipelines of Lead-DBS using a single patient example with state-of-the-art high-field imaging as well as a retrospective cohort of patients scanned in a typical clinical setting at 1.5T. Imaging data of the 3T example patient is co-registered using five algorithms and nonlinearly warped into template space using ten approaches for comparative purposes. After reconstruction of DBS electrodes (which is possible using three methods and a specific refinement tool), the volume of tissue activated is calculated for two DBS settings using four distinct models and various parameters. Finally, four whole-brain tractography algorithms are applied to the patient‘s preoperative diffusion MRI data and structural as well as functional connectivity between the stimulation volume and other brain areas are estimated using a total of eight approaches and datasets. In addition, we demonstrate impact of selected preprocessing strategies on the retrospective sample of 51 PD patients. We compare the amount of variance in clinical improvement that can be explained by the computer model depending on the method of choice. This work represents a multi-institutional collaborative effort to develop a comprehensive, open source pipeline for DBS imaging and connectomics, which has already empowered several studies, and may facilitate a variety of future studies in the field.
Background: Deep brain stimulation (DBS) effects on postural deformities are still poorly explored. Methods: Systematic review in accord with the Preferred Reporting Items for Systematic review and Meta-Analysis guidelines (PRISMA). Results: All 38 studies that met predefined eligibility criteria had high risk of bias attributed to retrospective analysis of heterogeneous populations with variable and incompletely reported demographic and clinical characteristics, definitions, outcomes, DBS indications, targets, and settings. Five patient groups were identified in the 35 studies with individual data available: (1) parkinsonian camptocormia (n = 96): 89 patients underwent subthalamic (STN) and 7 globus pallidus pars interna (GPi) DBS. Camptocormia was the indication in 3 patients. After DBS, camptocormia improved in 57 of 96 patients (4.3-100% improvement) and remained stable or worsened in 39 of 96 patients (2-100% worsening). (2) dystonic camptocormia (n = 16): All underwent GPi-DBS. They were younger and with shorter disease duration, but longer deformity duration, compared with parkinsonian camptocormia. After GPi-DBS, camptocormia improved in all patients (50-100% improvement). (3) Parkinsonian Pisa syndrome (n = 14): 11 patients underwent STN-DBS for motor fluctuations whereas Pisa syndrome was the indication for pedunculopontine and GPi-DBS in 2 patients. After DBS, Pisa improved in 10 of 14 patients (33.3-66.7% improvement). (4) Dystonic opisthotonus: 2 young patients remarkably responded to GPi-DBS. (5) Parkinsonian anterocollis: There were variable responses in 3 patients after STN-DBS for motor fluctuations. Conclusions: Low-quality level of evidence suggests that dystonic camptocormia and opisthotonus improve after GPi-DBS. Parkinsonian camptocormia, Pisa syndrome, and anterocollis have variable responses, and their dystonic features should be further explored.
The efficacy of deep brain stimulation (DBS) for Parkinson disease (PD) is well established for up to 1 or 2 years, but long-term outcome data are still limited. In this Review, we critically discuss the evidence on the long-term outcomes of DBS and consider the clinical implications. Although many patients are lost to follow-up, the evidence indicates that subthalamic nucleus DBS improves motor function for up to 10 years, although the magnitude of improvement tends to decline over time. Functional scores recorded during on-medication periods worsen more quickly than those recorded in off periods, consistent with the degeneration of non-dopaminergic pathways. Dyskinesia, motor fluctuations and activities of daily living in off periods remain improved at 5 years, but quality-of-life scores have usually fallen below preoperative levels. The incidence and severity of dementia among patients receiving DBS are comparable to those among patients who receive medical treatment. Severe adverse events are rare, but adverse events such as dysarthria are common and probably under-reported. Long-term data on the outcomes of globus pallidus interna DBS are limited and mostly confirm the efficacy for dyskinesia. A trend towards offering DBS in the earlier stages of PD creates a need to identify factors that predict long-term outcomes and to discuss realistic expectations with patients preoperatively.
Introduction: We sought to assess the effect of subthalamic deep brain stimulation (STN DBS) on Parkinson's disease (PD)-associated postural abnormalities. Methods: A computerized analysis of posture was used to quantify the thoracolumbar, thoracic, and cervical-occipital ventral angles, as well as the thoracolumbar and cervical-occipital lateral angles from the video-repository of three specialized movement disorder centers (n = 158 patients). Data was extracted from frames from video-recordings in the pre-surgical medication-ON (dopaminergic therapy) and post-surgical stimulation-ON/medication-ON states (STN DBS plus dopaminergic therapy). The sum of the five postural angles (global postural angle) was used to compare pre-vs. post-surgical trunk posture alterations. A multivariate analysis was used to examine the association between changes in the postural angles and demographic or clinical variables. Results: There was a 6.7% amelioration in the global postural angle between the pre- and post-surgical assessments (p = 0.031). Motor response to and pre-surgical dosage of levodopa, male gender, and shorter PD duration were identified as predictors for posture improvement after STN DBS. Cases meeting criteria for lower (n = 2) or upper (n = 1) camptocormia respectively improved by 48.1% in the ventral thoracolumbar angle (from 36.4 ± 0.0° to 18.9 ± 4.2°) and 13.8% in the ventral thoracic angle (from 49.1° to 42.3°). Cases meeting criteria for Pisa syndrome (n = 2) improved by 67.5% in the lateral thoracolumbar angle (from 16.9 ± 2.0° to 5.5 ± 4.7°). Conclusions: STN DBS has a relatively small but significant effect on PD-associated postural abnormalities, potentially enhancing the effect of dopaminergic medications alone.
In the medical literature, hundreds of prediction models are being developed to predict health outcomes in individuals. For continuous outcomes, typically a linear regression model is developed to predict an individual's outcome value conditional on values of multiple predictors (covariates). To improve model development and reduce the potential for overfitting, a suitable sample size is required in terms of the number of subjects (n) relative to the number of predictor parameters (p) for potential inclusion. We propose that the minimum value of n should meet the following four key criteria: (i) small optimism in predictor effect estimates as defined by a global shrinkage factor of ≥0.9; (ii) small absolute difference of ≤ 0.05 in the apparent and adjusted R²; (iii) precise estimation (a margin of error ≤ 10% of the true value) of the model's residual standard deviation; and similarly, (iv) precise estimation of the mean predicted outcome value (model intercept). The criteria require prespecification of the user's chosen p and the model's anticipated R² as informed by previous studies. The value of n that meets all four criteria provides the minimum sample size required for model development. In an applied example, a new model to predict lung function in African‐American women using 25 predictor parameters requires at least 918 subjects to meet all criteria, corresponding to at least 36.7 subjects per predictor parameter. Even larger sample sizes may be needed to additionally ensure precise estimates of key predictor effects, especially when important categorical predictors have low prevalence in certain categories.
OBJECTIVE Camptocormia is a potentially debilitating condition in the progression of Parkinson’s disease (PD). It is described as an abnormal forward flexion while standing that resolves when lying supine. Although the condition is relatively common, the underlying pathophysiology and optimal treatment strategy are unclear. In this study, the authors systematically reviewed the current surgical management strategies for camptocormia. METHODS PubMed was queried for primary studies involving surgical intervention for camptocormia in PD patients. Studies were excluded if they described nonsurgical interventions, provided only descriptive data, or were case reports. Secondarily, data from studies describing deep brain stimulation (DBS) to the subthalamic nuclei were extracted for potential meta-analysis. Variables showing correlation to improvement in sagittal plane bending angle (i.e., the vertical angle caused by excessive kyphosis) were subjected to formal meta-analysis. RESULTS The query resulted in 9 studies detailing treatment of camptocormia: 1 study described repetitive trans-spinal magnetic stimulation (rTSMS), 7 studies described DBS, and 1 study described deformity surgery. Five studies were included for meta-analysis. The total number of patients was 66. The percentage of patients with over 50% decrease in sagittal plane imbalance with DBS was 36.4%. A duration of camptocormia of 2 years or less was predictive of better outcomes (OR 4.15). CONCLUSIONS Surgical options include transient, external spinal stimulation; DBS targeting the subthalamic nuclei; and spinal deformity surgery. Benefit from DBS stimulation was inconsistent. Spine surgery corrected spinal imbalance but was associated with a high complication rate.