Predictive factors for improvement of gait by low-frequency stimulation in Parkinson's disease.
BACKGROUND
After several years duration of Parkinson's disease, with or without deep brain stimulation, axial signs (such as postural instability, freezing of gait) may worsen. High-voltage, low-frequency stimulation has been shown to improve severe gait disorders in some patients.


OBJECTIVE
To identify predictive factors for the efficacy of low-frequency stimulation.


METHODS
We assessed the respective effects of low- and high-frequency stimulation using an acute stand-walk- sit test, and on motor performance in 22 patients with longstanding, bilateral sub-thalamic nucleus stimulation. We calculated the difference in the number of steps (delta steps) between high and low -frequency stimulation during the stand-walk-sit test. Our aim was to establish a profile for low-frequency responders, which was defined by a positive value for delta steps.


RESULTS
Low frequency responders presented higher age, a severe axial phenotype five years after surgery and a lower L-dopa responsiveness of (i) the Unified Parkinson's Disease Rating Scale part III score and its akinesia subscore before surgery and (ii) the axial subscore one year after surgery.


CONCLUSIONS
Here we defined a specific and severe axial profile of minority of patients who could benefit from low frequency stimulation parameters. Our findings challenge the conventional treatment approach (i.e. high-frequency stimulation) in patients who develop gait disorders after several years of stimulation.
Univ Lille Nord de France, Lille, France EA 1046, Lille, France Department of Clinical Neurophysiology, Lille University Medical Center, Lille, France.
Agnès
A
Annic
Univ Lille Nord de France, Lille, France EA 1046, Lille, France Department of Neurology, Lille University Medical Center, Lille, France.
Caroline
C
Moreau
Univ Lille Nord de France, Lille, France Department of Biostatistics, UDSL, EA 2694, Lille University Medical Center, Lille, France.
Julia
J
Salleron
Univ Lille Nord de France, Lille, France EA 1046, Lille, France Department of Clinical Pharmacology, Lille University Medical Center, Lille, France.
David
D
Devos
Univ Lille Nord de France, Lille, France EA 1046, Lille, France Department of Clinical Neurophysiology, Lille University Medical Center, Lille, France.
Arnaud
A
Delval
Univ Lille Nord de France, Lille, France EA 1046, Lille, France Department of Neurology, Lille University Medical Center, Lille, France.
Kathy
K
Dujardin
Univ Lille Nord de France, Lille, France Department of Neurosurgery, Lille University Medical Center, Lille, France.
Gustavo
G
Touzet
Univ Lille Nord de France, Lille, France Department of Neurosurgery, Lille University Medical Center, Lille, France.
Serge
S
Blond
Univ Lille Nord de France, Lille, France Department of Clinical Neurophysiology, Lille University Medical Center, Lille, France UMR 837 INSERM, JParc, IRCL, Lille, France.
Alain
A
Destée
Univ Lille Nord de France, Lille, France EA 1046, Lille, France Department of Neurology, Lille University Medical Center, Lille, France.
Luc
L
Defebvre
D000368:Aged; D046690:Deep Brain Stimulation; D005260:Female; D005684:Gait; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000175:diagnosis* / Q000503:physiopathology / Q000628:therapy*; D016896:Treatment Outcome
Parkinson's disease; deep brain stimulation; gait disorders; therapeutics