Hypometric anticipatory postural adjustments in dystonia are not affected by deep brain stimulation of globus pallidus internus.
Dystonia is a movement disorder with patterned, directional, and often sustained muscle contractions that produce abnormal postures or repetitive movements. Deep brain stimulation (DBS) of the globus pallidus internus (GPi) is an effective and safe treatment for medically refractory dystonia. However, recent studies reported gait problems, gait freezing and falls in patients treated with DBS. Because these symptoms may point to deficient gait initiation processes, we systematically assessed the anticipatory postural adjustments (APAs) prior to stepping in dystonia patients with GPi-DBS.



Thirteen patients with focal/segmental dystonia under GPi-DBS and twelve healthy control subjects were included in the study. Data were collected using pressure sensitive sensors and APAs were studied by centre of pressure measures. We compared APAs of both groups and analysed the influence of GPi-DBS on APAs in patients.



Medio-lateral and antero-posterior COP displacements, total COP path, maximal APA velocity and 1st step length were all smaller in patients for both ON (p=0.006, p=0.018, p=0.002, p=0.016, p=0.04) and OFF (p=0.001, p=0.01, p=0.001, p=0.03, p=0.024) condition compared to healthy subjects. GPi-DBS did not change APA parameters in patients.



Observations that APAs are impaired in dystonia and are at the same time not affected by the stimulation current are compatible with the assumption that APAs and dystonic symptoms may rely on distinct networks, possibly within the same cortical and basal ganglia structures. With no effect of stimulation on APAs it is unlikely that this would be a mechanism of impaired balance in the patients after the surgery.
Department of Neurology, Ludwig-Maximilian University, Munich, Germany; Department of Neurology, University Medical Centre Ljubljana, Ljubljana, Slovenia. Electronic address: gregor.brecljakob@kclj.si.
Gregor
G
Brecl Jakob
Department of Orthopaedic Surgery Physical Medicine and rehabilitation, Ludwig-Maximilian University, Munich, Germany. Electronic address: opelykh@med.uni-muenchen.de.
Olena
O
Pelykh
Department of Neurology, Ludwig-Maximilian University, Munich, Germany. Electronic address: Annika.Plate@med.uni-muenchen.
Annika
A
Plate
Department of Neurology, Ludwig-Maximilian University, Munich, Germany; 2nd Department of Neurology, School of Medicine, Comenius University, Bratislava, Slovak Republic. Electronic address: zuzanakosutzka@gmail.com.
Zuzana
Z
Košutzká
Department of Neurology, University Medical Centre Ljubljana, Ljubljana, Slovenia. Electronic address: zvezdan.pirtosek@kclj.si.
Zvezdan
Z
Pirtošek
Department of Neurology, University Medical Centre Ljubljana, Ljubljana, Slovenia. Electronic address: majatrost@yahoo.com.
Maja
M
Trošt
Department of Orthopaedic Surgery Physical Medicine and rehabilitation, Ludwig-Maximilian University, Munich, Germany. Electronic address: jilmberger@med.uni-muenchen.de.
Joseph
J
Ilmberger
2nd Department of Neurology, School of Medicine, Comenius University, Bratislava, Slovak Republic; Laboratory of Motor Control, Institute of Normal and Pathological Physiology, Slovak Academy of Sciences, Bratislava, Slovak Republic. Electronic address: Peter.Valkovic@gmail.com.
Peter
P
Valkovic
Department of Neurosurgery, Ludwig-Maximilian University, Munich, Germany. Electronic address: Jan.Mehrkens@med.uni-muenchen.de.
Jan H
JH
Mehrkens
Department of Neurology, Ludwig-Maximilian University, Munich, Germany. Electronic address: kboetzel@med.uni-muenchen.de.
Kai
K
Bötzel
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D046690:Deep Brain Stimulation / Q000379:methods; D004421:Dystonia / Q000628:therapy*; D005260:Female; D005684:Gait / Q000502:physiology*; D020233:Gait Disorders, Neurologic / Q000503:physiopathology*; D005917:Globus Pallidus / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology*
Anticipatory postural adjustments; Deep brain stimulation; Dystonia; Gait initiation; Globus pallidus