STN DBS in PD: Effect of
Associative vs. Sensorimotor
Stimulation On Executive Function
Kalyn Horst, B.S.*, Laura Manning, M.S. ,
Edward Golob, Ph.D. , and Erich Richter, M.D.*
*Department of Neurosurgery, LSU Health Sciences Center, New Orleans, LA
Department of Psychology, Tulane University, New Orleans, LA
Background
DBS of the STN is a common treatment for
intermediate stage Parkinson’s disease patients
Effective for motor
symptoms
Tremor
Rigidity
Bradykinesia
May impair cognition,
particularly executive
function1
Rationale for Current Study
Hamani, et al. The subthalamic nucleus in the context of movement disorders.
Brain, 2004. 127: p. 4-20.
Hypothesis: cognitive deficits appearing after DBS
are due to the stimulation of the ventral region of
the STN
Methodology: Patient
Population & Measure Design
Two auditory conflict tasks5,6 using E-Prime
software
Seven subjects (male=6, female=1, aged 46-74)
and four controls (male=2, female=2, aged 21-30)
have participated to date
Methodology: Tasks Used
Stimulus
Response
Compatibility
(SRC)
Simon Effect (SE)
Stimulus
information
Spatial arrangement only
Spatial arrangement,
amplitude modulation
Response(s)
Two types of response:
Ipsilateral and contralateral
One type of response only
(amplitude modulation)
Measures
Motor function
Cognitive function
Preliminary Results
Motor Function Task:
Baseline Performance
1200
Control (Contra)
Study (Ipsi)
1100
Median Reaction Time (ms)
Control (Ipsi)
Study (Contra)
1000
900
800
700
600
500
400
Far Left
Left
Right
Stimulus Location
Far Right
Median Reaction Time (ms)
Median Reaction Time (ms)
1200
1200
Motor Function
Task: Task:
Motor
Motor Function
Function
Task:
BaselineBaseline
vs. Ventral
Dorsal Region
Region Stimulation
Stimulation
1100
1100
1000
1000
Ventral(Ipsi)
Dorsal
(Ipsi)
Baseline (Ipsi)
Dorsal (Contra)
Ventral
(Contra)
900900
Baseline (Ipsi)
Baseline (Contra)
Baseline (Contra)
800800
700700
600600
500500
400400
Left
FarFar
Left
Left
Left
Right
Right
Stimulus
Location
Stimulus
Location
Right
FarFar
Right
Motor Function Task Trends
PD population has greater reaction times
as compared to a healthy population
Stimulation of dorsal region did not yield
substantially different SRC task
performances
Stimulation of ventral region did not yield
substantially different SRC task
performances
Cognitive Function Task:
Baseline Performance
1200
Control (Left)
Control (Right)
Study (Left)
Median Reaction Time (ms)
1100
Study (Right)
1000
900
800
700
600
500
Far Left
Left
Right
Stimulus Location
Far Right
Cognitive
Function
Task: Task:
Cognitive
Function
Cognitive
FunctionTask:
Dorsal Region
BaselineBaseline
vs. Ventral
Region Stimulation
Stimulation
Median Reaction Time (ms)
1200
Dorsal (Left)
Ventral
(Left)
Baseline (Left)
1100
Dorsal (Right)
Ventral
(Right)
1000
Baseline (Left)
(Left)
Baseline
Baseline
(Right)
Baseline (Right)
(Right)
Baseline
900
800
700
600
500
400
Far Left
Left
Right
Stimulus Location
Far Right
Cognitive Function Task Trends
PD population has greater reaction times
as compared to a healthy population
Stimulation of dorsal region yielded
improved reaction times
Stimulation of ventral region worsened
reaction times when compared to baseline
Preliminary Results Summarized
Performances on the motor conflict task
were not substantially affected by
stimulation in either the dorsal or ventral
region
Performances on the cognitive conflict
task improved with stimulation of dorsal
region but worsened with ventral region
stimulation
Discussion
Cognitive decline, particularly in executive
function, is often observed following STN DBS in
PD patients.
For this target type of DBS, both dorsal and
ventral regions are stimulated.
Hypothesis: cognitive decline results from the
ventral region stimulation
Thus far, data suggest dorsal stimulation of the
STN is beneficial to patients’ PD symptoms
whereas ventral stimulation actually impairs
executive function
Limitations & Future Directions
A larger patient population is
needed to gain statistical power
Development of visual and
tactile complementary tasks
References
1.
2.
3.
4.
5.
6.
Smeding, H.M., et al., Neuropsychological effects of bilateral STN
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Yelnik, J., Modeling the organization of the basal ganglia. Rev Neurol
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Amick, M.M. and J. Grace, Deep brain stimulation surgery for
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