The future of deep brain stimulation (DBS) for Parkinson's disease (PD) lies in new
closed‐loop systems that continuously supply the implanted stimulator with new settings
obtained by analyzing a feedback signal related to the patient's current clinical
condition.1 The most suitable feedback for PD is subthalamic local field potential
(LFP) activity recorded from the stimulating electrode itself.2, 3, 4 This closed‐loop
technology known as adaptive DBS (aDBS) recently proved superior to conventional open‐loop
DBS (cDBS) in patients with PD.2
No studies have yet tested aDBS in freely moving humans for a prolonged time. This
information is an essential prerequisite for developing new implantable aDBS devices
for chronic PD treatment.
In this single‐case study, we tested whether a portable DBS device we developed is
suitable to compare the clinical benefit in a freely moving PD patient induced by
either aDBS or cDBS. To do so, after a first experimental session for extracting patient
settings to personalize the aDBS algorithm, we treated a blinded patient (51 y old,
male, 8 y PD history) with cDBS and aDBS in two separate experimental sessions each
lasting 120 min, 5 and 6 d, respectively, after DBS electrode implant. To ensure reliable
results, the patient underwent repeated clinical assessments every 20 min (T1‐T5)
by two independent blinded neurologists through Unified Parkinson's Disease Rating
Scale (UPDRS) III subsections and Rush Dyskinesia Rating Scale (see Supplemental Data
for details).
The aDBS portable device we used was equipped with an ad hoc algorithm that analyzed
patient's LFP beta band power (13‐17 Hz) and adapted voltage stimulation linearly
each second (Fig. 1A).
Figure 1
(A) Sample of aDBS functioning lasting 10 min. Upper panel, the local field potential
(LFP) beta band (13‐17 Hz) power and below the stimulation voltage. The dotted line
represents the time levodopa (l‐dopa) took to achieve its clinical effect. The voltage
delivered by aDBS followed the beta‐band changes: When l‐dopa reduced beta‐band LFP
activity, the voltage linearly diminished. (B) Clinical results for axial symptoms
and dyskinesias during gait. Mean Unified Parkinson's Disease Rating Scale (UPDRS)
III subsection (items 28, 29, 30) and mean Rush Dyskinesias Rating Scale (DRS) (during
gait) percentage score changes from baseline evaluated at T5 (120 min after the experiment
began) for cDBS and aDBS. Assessment at T5 showed that the patient's axial symptoms
improved to a similar extent after aDBS and cDBS, but dyskinesias during gait reduced
more during aDBS than during cDBS. (C) Clinical results for bradykinesia. Mean changes
from baseline in the UPDRS III subsection (items 23, 24, 31) percentage score changes
from baseline for the upper limb contralateral to the stimulation side for cDBS and
aDBS from T1 to T5. The UPDRS III subscore improved significantly more during aDBS
than during cDBS (Wilcoxon matched pairs test; *P < 0.05). (D) Clinical results for
dyskinesias at rest. Mean Rush DRS (at rest) percentage score changes from baseline
for cDBS and aDBS from T1 to T5. Except at T3, aDBS induced a lower mean Rush DRS
increase than cDBS (Wilcoxon matched pairs test; P > 0.05) (see Supplemental Data
for data analysis details).
The patient during aDBS experienced a more stable condition than during cDBS, with
better control of symptoms and dyskinesias over time (Fig. 1; video 1). In particular,
aDBS and cDBS improved patient's axial symptoms to a similar extent (Fig. 1B), but
compared with cDBS, aDBS significantly improved his main symptom, bradykinesia (Fig.
1C). aDBS did not elicit side effects and was well tolerated.
Because we evaluated the patient a few days after surgery when he probably manifested
a stunning effect,5 the aDBS‐ and cDBS‐induced improvements were lower than those
reported by others in follow‐up DBS studies.6 A major clinical achievement was that
compared with cDBS, aDBS greatly reduced the patient's dyskinesias during gait and
at rest (Fig. 1B; Fig. 1D). Presumably it did so because we designed the adaptive
algorithm to avoid dyskinesias related to hyperstimulation: when l‐dopa reduced beta‐band
LFP activity, the voltage linearly diminished, avoiding hyperstimulation.
Our results, besides corroborating findings reported by Little and colleagues2 showing
that aDBS promises to be more efficient and effective than cDBS, expand them for two
important reasons. First, we tested aDBS for a longer observation time than Little
et al., and in a more ecological condition (freely moving patient). Second, the personalized
algorithm continuously adapts stimulation settings according to LFP beta changes,
instead of providing an on–off strategy.
The aDBS device we used here can assess large patient series in real clinical settings,
testing different LFP‐based adaptive strategies other than those controlled by the
beta activity to find the frequency that is more suitable to reflect patient clinical
state.7
In conclusion, the approach and device we used proved eligible for prolonged use in
a freely moving parkinsonian patient and disclosed new opportunities to study aDBS
during patients’ daily activities, providing new insights into how this novel DBS
strategy should improve patients’ quality of life. Although we await future studies
to confirm our findings and to test other aDBS LFP‐based algorithms, our observation
is a step toward developing a new generation of implantable aDBS devices for chronic
treatment of PD.
Video legend
Video: The video shows a section of patient clinical assessments performed 120 min
after the experiment began (T5) during standard DBS (cDBS) on the left and during
adaptive DBS (aDBS) on the right. Standard DBS was delivered at 2 V, 130 Hz, 60 µs;
aDBS was delivered at a stimulation voltage that automatically changes according to
the online LFP beta recording analysis (voltage range, 0‐2 V), 130 Hz, 60 µs. The
video shows the patient during the execution of items 29, 23, 24, and 31 of unified
parkinson's disease rating scale (UPDRS) III scale.
Manuela Rosa, MS,*1,2 Mattia Arlotti, MS,1,3 Gianluca Ardolino, MD,1 Filippo Cogiamanian,
MD,1 Sara Marceglia, MS, PhD,1 Alessio Di Fonzo, MD, PhD,1 Francesca Cortese, MD,1,2,4
Paolo M. Rampini, MD,1 and Alberto Priori, MD, PhD1,2
1Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
2Università degli Studi di Milano, Milan, Italy
3Department of Electrical, Electronic and Information Engineering ‘Guglielmo Marconi’,
Università di Bologna, Cesena, Italy
4Università la Sapienza di Roma, Polo Pontino, Latina, Italy
Author Roles
1. Research Project: A. Conception, B. Organization, C. Execution; 2. Statistical
Analysis: A. Design, B. Execution, C. Review and Critique; 3. Manuscript Preparation:
A. Writing the First Draft, B. Review and Critique.
M.R.: 1C, 2B, 3A
M.A.: 1C, 2B
G.A.: 1C, 3B
F.C.: 1C, 3B
S.M.: 2A, 2C
A.D.F.: 1C
F.C.: 1C
P.M.R.: 1A, 1B
A.P.: 1A, 1B, 3B
Financial Disclosures
Stock ownership in medically related field: Newronika s.r.l: Filippo Cogiamanian,
Sara Marceglia, Paolo M Rampini, Alberto Priori
Consultancies: None
Advisory boards: None
Partnerships: None
Honoraria: None
Grants: Italian Ministry of Health: Sara Marceglia, Alberto Priori; Fondazione IRCCS
Ca’ Granda, Ospedale Maggiore Policlinico, Milan, Italy: Alberto Priori
Intellectual Property Rights: MI2010A001265: Alberto Priori; US11766401‐070621: Alberto
Priori; EP1940508: Alberto Priori; US8078281: Alberto Priori. EP2328655: Sara Marceglia;
EP2155323: Filippo Cogiamanian; Sara Marceglia, Alberto Priori
Expert testimony: None
Employment: Fondazione IRCCS Ca’ Granda, Ospedale Maggiore Policlinico, Milan, Italy:
Filippo Cogiamanian, Gianluca Ardolino, Alessio Di Fonzo, Paolo M Rampini; Università
la Sapienza di Roma, Polo Pontino, Latina, Italy: Francesca Cortese. Universita' degli
Studi di Milano, Italy: Alberto Priori
Contracts: Fondazione IRCCS Ca’ Granda, Ospedale Maggiore Policlinico, Milan, Italy:
Sara Marceglia
Royalties: None
Others: None
Supporting information
Additional supporting information may be found in the online version of this article
at the publisher's web‐site.
Video legend: The video shows a section of patient clinical assessments performed
120 min after the experiment began (T5) during standard DBS (cDBS) on the left and
during adaptive DBS (aDBS) on the right. Standard DBS was delivered at 2 V, 130 Hz,
60 µs; aDBS was delivered at a stimulation voltage that automatically changes according
to the online LFP beta recording analysis (voltage range, 0‐2 V), 130 Hz, 60 µs. The
video shows the patient during the execution of items 29, 23, 24, and 31 of UPDRS
III scale.
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Supporting Information Figure 1
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Supporting Information
Click here for additional data file.