Neuropsychological changes between "off" and "on" STN or GPi stimulation in Parkinson's disease.
BACKGROUND
In a previous study on a consecutive series of 62 patients with PD, the authors showed that bilateral subthalamic or pallidal continuous high-frequency deep brain stimulation (DBS) affects neither memory nor executive functions 3 to 6 months after surgery.


OBJECTIVE
To investigate the specific effects of DBS by comparing the performance of patients with the stimulator turned "on" and "off."


METHODS
The performance of 56 patients on clinical tests of executive function was compared after 3 and 12 months of DBS of the subthalamic nucleus (STN; n = 48) or the internal globus pallidus (GPi; n = 8) with the stimulator "on" or "off." Global intellectual efficiency, verbal learning, and mood were also evaluated with the stimulator "on." The performance of another group of 20 patients was compared after 6 months of DBS of the STN (n = 15) or the GPi (n = 5) with the stimulator "on" or "off" on more experimental tests recently shown to be more sensitive to l-dopa therapy.


RESULTS
When the stimulator was "on," STN patients showed a mild but significant improvement in psychomotor speed and working memory. In comparison with the presurgical state, STN patients had no cognitive deficit at 12 months, except for lexical fluency. There was no differential effect of STN or GPi stimulation.


CONCLUSIONS
1) The specific effect of DBS seems to mimic the action of l-dopa treatment in the cognitive as in the motor domain; 2) the surgery associated with DBS does not appear to affect the cognitive performance of patients with PD 12 months later, except for a mild deficit in lexical fluency.
Pillon
B
B
INSERM EPI 007 and U 289, Fédération de Neurologie and Centre d'Investigation Clinique, Hôpital de la Salpêtrière, Paris, France. bernard.pillon@psl.ap-hop-paris.fr
Ardouin
C
C
Damier
P
P
Krack
P
P
Houeto
J L
JL
Klinger
H
H
Bonnet
A M
AM
Pollak
P
P
Benabid
A L
AL
Agid
Y
Y
D000328:Adult; D000368:Aged; D000978:Antiparkinson Agents / Q000008:administration & dosage; D003071:Cognition / Q000187:drug effects / Q000502:physiology*; D003131:Combined Modality Therapy; D004599:Electric Stimulation Therapy; D004567:Electrodes, Implanted; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007980:Levodopa / Q000008:administration & dosage; D008297:Male; D008568:Memory / Q000187:drug effects / Q000502:physiology; D008875:Middle Aged; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000188:drug therapy* / Q000503:physiopathology*; D014706:Verbal Learning
D000978:Antiparkinson Agents; D007980:Levodopa