How do parkinsonian signs return after discontinuation of subthalamic DBS?
OBJECTIVE
To study the reappearance of the clinical signs of PD when subthalamic nucleus (STN) deep brain stimulation (DBS) was turned off.


METHODS
The authors studied 35 patients treated with STN DBS 6.7 +/- 3.3 months (mean +/- SD) after implantation. All were clinically improved. Twenty-four had not required any antiparkinsonian medication for many months and 11 were in "practically defined off" conditions when studied. Unified Parkinson's Disease Rating Scale (UPDRS) motor scores were assessed at baseline and 5, 15, 30, 60, 90, 120, 150, 180, and 240 minutes after switching off STN DBS.


RESULTS
A sequential pattern of return of parkinsonian signs was observed, with a fast worsening of tremor within minutes, followed by a smoother, slower worsening of bradykinesia and rigidity over half an hour to an hour, and finally a slow and steady worsening of axial signs over 3 to 4 hours. Ninety percent of the UPDRS motor score worsening was reached after 2 hours. When switching STN DBS "on" again, all motor UPDRS subscores improved with a similar pattern, but faster than their rate of worsening, especially for axial signs.


CONCLUSIONS
STN DBS may act by different mechanisms on the four major parkinsonian signs. At least 3 hours off STN DBS is needed to estimate the clinical effect of stimulation.
Temperli
P
P
Department of Neurology, Centre Hospitalier Universitaire Vaudois, Lausanne-CHUV, Switzerland.
Ghika
J
J
Villemure
J-G
JG
Burkhard
P R
PR
Bogousslavsky
J
J
Vingerhoets
F J G
FJ
D018450:Disease Progression; D004599:Electric Stimulation Therapy; D006801:Humans; D018476:Hypokinesia / Q000209:etiology / Q000503:physiopathology; D008875:Middle Aged; D009043:Motor Activity; D009127:Muscle Rigidity / Q000209:etiology / Q000503:physiopathology; D010300:Parkinson Disease / Q000150:complications / Q000503:physiopathology* / Q000628:therapy*; D020127:Recovery of Function; D012008:Recurrence; D012074:Remission Induction; D012720:Severity of Illness Index; D020531:Subthalamic Nucleus / Q000503:physiopathology*; D013997:Time Factors; D014202:Tremor / Q000209:etiology / Q000503:physiopathology