Parkinson's DiseaseNCT01845883
Perceptual Decision Making Under Conditions of Visual Uncertainty
A study testing Deep Brain Stimulation (DBS) in people with Parkinson's Disease and Dystonia, run by University of California, Los Angeles at 1 site in United States.
Trial summary
In this proposal the investigators have three Specific Aims using human patient populations as model systems; 1) identify a role for the Basal Ganglia (BG) in perceptual decision making; 2) determine whether the Basal Ganglia contribute to decision making under conditions of visual uncertainty; 3) determine whether… Read more about this study
- Who is it for?
- Ages 18 to 80 yearsHealthy volunteers can take part
- Conditions the study is for
- Parkinson's Disease, Dystonia, Ataxia
- What is being tested?
- Deep Brain Stimulation (DBS)
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 0 participants
- Where
- 1 siteUnited States
- Study dates
- Apr 2013to Dec 2016
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 80 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Group 1 - Age and Sex matched healthy controls:
- Age 18-80 Years
- Group 2 - Patients with Parkinson's Disease - No DBS:
- "on meds" and "off meds" (tested in separate sessions) - total of 2 sessions
- Age 45-80 Years
- Unified PD rating scale (UPDRS)
Show all 35Show fewer
- Mini mental health Status (MMHS)
- Group 3 - Patients with Parkinson's Disease already consented for DBS (STN):
- Age 45-80 Years
- Unified PD rating scale (UPDRS)
- Mini mental health Status (MMHS)
- Group 4 - Patients with Parkinson's Disease already consented for DBS (GPi):
- Age 45-80 Years
- Unified PD rating scale (UPDRS)
- Mini mental health Status (MMHS)
- Group 5 - Patients with Cervical Dystonia - No DBS
- Age 30-80 years
- Fahn-Marsden dystonia rating scale (FMDRS)
- Mini mental health Status (MMHS)
- Group 6 - Patients with Generalized Dystonia (Ach) - No DBS:
- Age 30-80 years
- Fahn-Marsden dystonia rating scale (FMDRS)
- Mini mental health Status (MMHS)
- Group 7 - Patients with Dystonia already consented for DBS (GPi):
- Age 30-80 years
- Fahn-Marsden dystonia rating scale (FMDRS)
- Mini mental health Status (MMHS)
- Group 8 - Patients Cerebellar Stroke
- Age 30-80 Years
- Routine neuro exam
- Mini mental health Status (MMHS)
- Group 9 - Patients Cerebellar Ataxia
- Age 30-80 Years
- Routine neuro exam
- Mini mental health Status (MMHS)
Who cannot join
- Visual impairment or ocular motility disorder Inability to sit for the 30 minute task plus 20-30 minute instruction time, setup, and wait time.
- For Group 1 (Age Sex Matched Controls), there will additional exclusion criteria of other neurological disease and drug use
Trial locations and contacts
1 site in 1 country.
United States1 site
Neuroscience Research Building
Los Angeles, California, 90095
About this study
In this proposal the investigators have three Specific Aims using human patient populations as model systems; 1) identify a role for the Basal Ganglia (BG) in perceptual decision making; 2) determine whether the Basal Ganglia contribute to decision making under conditions of visual uncertainty; 3) determine whether the cerebellum plays a role in perceptual decision-making under conditions of visual uncertainty. The investigators designed experiments using healthy humans and humans with diseases known to affect the Basal Ganglia and the cerebellum, Parkinson's Disease, dystonia and non-dystonic cerebellar damage. With this approach the investigators will test the following hypotheses: 1) Patients with Parkinson's Disease and dystonia will have more difficulty than healthy controls making perceptual decisions when faced with sensory uncertainty; when sensory information is certain, patients will show improved decision-making but will still be impaired relative to healthy humans. Hypothesis 2: If ambiguous sensory information is aided by prior information, patients with Parkinson's Disease and dystonia will be unable to use the prior (bias/memory) information to inform their decisions. Hypothesis 3: Deep Brain Stimulation (DBS) of Basal Ganglia structures will improve the ability of patients to use prior information to inform their decisions when faced with sensory uncertainty. Hypothesis 4: Both cholinergic and dopaminergic medical therapies will improve the ability of patients to use prior information to inform their decisions. Hypothesis 5: Patients with non-dystonic cerebellar damage will be similar to healthy controls in performance of a perceptual decision making task in conditions of visual uncertainty. The overarching framework of this application is that the same mechanisms (D1 striatal synaptic plasticity) that operate in reward learning play a role in learning and using stimulus priors in a perceptual decision-making task when faced with uncertainty. Because Parkinson's Disease and dystonia share deficits in striatal circuitry, the patient deficits on this task will be similar. Because non-dystonic cerebellar patients do not have dysfunction of striatal circuits, they will show no deficits in the ability to use stimulus priors to guide choices in uncertain conditions. In the event these patients do show deficits, this is will provide evidence for an unexplored role for the cerebellum in perceptual decision-making.
Read the detailed description
In this study, the investigators aim determine whether patients with Parkinson's disease (PD) have altered perceptual decision-making. The results of these experiments will shed important light on some of the enigmatic symptoms seen in patients with disorders of movement.
In this study the subjects perform a computer generated visual task which involves reporting the direction of an arrow that is more or less difficult to see on the computer screen. Eye movements will be monitored using a video eye tracker. The system is completely non-invasive and positioned in front, out of the subject's line of sight to avoid interfering with their ability to perform the task.
Subjects will report their decision with either an eye movement in the same direction as the perception of the arrow direction. Trials will proceed as follows: a central point will appear on the screen. Subjects are asked to look at the fixation point. After this random delay time, a patch of spots will appear in place of the center fixation spot, embedded in the patch will be an arrow. The contrast between the arrow and the patch will vary from high values to low. At high contrasts the direction at which the arrow points will be very clear and at low contrasts it will be unclear. The task of the subject is to make a rapid eye movement as soon as they decide which direction the arrow points. A sound will be played to indicate a correct choice. On trials in which the sensory information is ambiguous subjects will be told to 'make their best guess' to which target the arrow points. Unknown to the subject the investigators will manipulate the probability that one of the targets is the correct one. This latter manipulation will test whether subjects can use probability information to inform their decisions. The investigators are particularly interested in whether this probability information is used preferentially when the sensory information is ambiguous.
The total number of subjects to be enrolled in the study is approximately 120. Subject groups are as follows: Healthy humans between the ages of 30 and 80 and those with PD (between ages of 45 and 80), dystonia (ages 30-80) and cerebellar lesions (ages 30-80) including those who have undergone DBS surgery to treat their PD or dystonia. The total duration of each session is approximately 2 hours. Each patient group including those with DBS will perform two sessions of the same task - one while on medication and one while off medication, hence the total duration of the study will be 4 hours for these groups (2 different sessions during different days). These patient groups are free to do these sessions at the same time as their routine physician visits or any other time that works best for them.
- Conditions
- Parkinson's Disease, Dystonia, Ataxia
- Being tested
- Deep Brain Stimulation (DBS)
- Medical subject headings
- Parkinson Disease, Dystonia, Ataxia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Deep Brain Stimulation (DBS)Procedure or surgery
Patients with DBS will participate to the study both when the stimulation is off and on.
| Study group | Role | What they receive |
|---|---|---|
| Deep Brain Stimulator | Other | Some of our subjects that participate to the study have Deep Brain Stimulation implanted. They will perform the behavioral task twice, with the stimulation ON or OFF. Receives: Procedure: Deep Brain Stimulation (DBS) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Choice performance - % correct responses out of total number of trials
data from each subject will be assessed at the end of each session to monitor and measure outcome measures.
Measured: at the end of each testing session - 2 hours
Secondary outcomes (1)
Reaction Time to make a choice - measured in milliseconds
data from each subject will be assessed at the end of each session to monitor and measure outcome measures.
Measured: at the end of each testing session - 2 hours
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted3 May 2013 (estimated)
- Study startApr 2013
- Primary completionDec 2015 (estimated)
- Study completionDec 2016 (estimated)
Why it stopped: Initiating PI has left the institution, and no participants have been enrolled for the interventional trial.
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Parkinson's DiseaseStudies of the same condition, open and under way.
- More trials run by University of California, Los AngelesThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 0 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of California, Los Angeles
- Sponsor type
- University, hospital or other
- Collaborators
- The Dana Foundation
- Responsible party
- Principal investigator, Barbara Knowlton, University of California, Los Angeles
- Investigators
- Michele Basso, PhD, Principal investigator, University of California, Los Angeles
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT01845883
- Sponsor's protocol ID
- 12-001589
- Status last verified
- Jul 2026
- First submitted
- 23 Apr 2013
- Last updated
- 4 Aug 2026
- Results posted
- No
- Data monitoring committee
- No
Study at a glance
From the registry record, last updated by the sponsor on 4 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Perceptual Decision Making Under Conditions of Visual Uncertainty
- ClinicalTrials.gov ID
- NCT01845883
- Acronym / sponsor ID
- 12-001589
- Conditions
- Parkinson's Disease, Dystonia, Ataxia
- Study type
- Interventional
- Recruitment status
- WithdrawnReason stopped: Initiating PI has left the institution, and no participants have been enrolled for the interventional trial.
- Enrolment
- 0 participants (actual)
- Lead sponsor
- University of California, Los AngelesUniversity, hospital or other
- Collaborators
- The Dana Foundation
- Study start
- Apr 2013 (actual)
- Primary completion
- Dec 2015 (estimated)
- Study completion
- Dec 2016 (estimated)
- First posted
- 3 May 2013 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
In this proposal the investigators have three Specific Aims using human patient populations as model systems; 1) identify a role for the Basal Ganglia (BG) in perceptual decision making; 2) determine whether the Basal Ganglia contribute to decision making under conditions of visual uncertainty; 3) determine whether the cerebellum plays a role in perceptual decision-making under conditions of visual uncertainty. The investigators designed experiments using healthy humans and humans with diseases known to affect the Basal Ganglia and the cerebellum, Parkinson's Disease, dystonia and non-dystonic cerebellar damage. With this approach the investigators will test the following hypotheses: 1) Patients with Parkinson's Disease and dystonia will have more difficulty than healthy controls making perceptual decisions when faced with sensory uncertainty; when sensory information is certain, patients will show improved decision-making but will still be impaired relative to healthy humans. Hypothesis 2: If ambiguous sensory information is aided by prior information, patients with Parkinson's Disease and dystonia will be unable to use the prior (bias/memory) information to inform their decisions. Hypothesis 3: Deep Brain Stimulation (DBS) of Basal Ganglia structures will improve the ability of patients to use prior information to inform their decisions when faced with sensory uncertainty. Hypothesis 4: Both cholinergic and dopaminergic medical therapies will improve the ability of patients to use prior information to inform their decisions. Hypothesis 5: Patients with non-dystonic cerebellar damage will be similar to healthy controls in performance of a perceptual decision making task in conditions of visual uncertainty. The overarching framework of this application is that the same mechanisms (D1 striatal synaptic plasticity) that operate in reward learning play a role in learning and using stimulus priors in a perceptual decision-making task when faced with uncertainty. Because Parkinson's Disease and dystonia share deficits in striatal circuitry, the patient deficits on this task will be similar. Because non-dystonic cerebellar patients do not have dysfunction of striatal circuits, they will show no deficits in the ability to use stimulus priors to guide choices in uncertain conditions. In the event these patients do show deficits, this is will provide evidence for an unexplored role for the cerebellum in perceptual decision-making.
Detailed description
In this study, the investigators aim determine whether patients with Parkinson's disease (PD) have altered perceptual decision-making. The results of these experiments will shed important light on some of the enigmatic symptoms seen in patients with disorders of movement.
In this study the subjects perform a computer generated visual task which involves reporting the direction of an arrow that is more or less difficult to see on the computer screen. Eye movements will be monitored using a video eye tracker. The system is completely non-invasive and positioned in front, out of the subject's line of sight to avoid interfering with their ability to perform the task.
Subjects will report their decision with either an eye movement in the same direction as the perception of the arrow direction. Trials will proceed as follows: a central point will appear on the screen. Subjects are asked to look at the fixation point. After this random delay time, a patch of spots will appear in place of the center fixation spot, embedded in the patch will be an arrow. The contrast between the arrow and the patch will vary from high values to low. At high contrasts the direction at which the arrow points will be very clear and at low contrasts it will be unclear. The task of the subject is to make a rapid eye movement as soon as they decide which direction the arrow points. A sound will be played to indicate a correct choice. On trials in which the sensory information is ambiguous subjects will be told to 'make their best guess' to which target the arrow points. Unknown to the subject the investigators will manipulate the probability that one of the targets is the correct one. This latter manipulation will test whether subjects can use probability information to inform their decisions. The investigators are particularly interested in whether this probability information is used preferentially when the sensory information is ambiguous.
The total number of subjects to be enrolled in the study is approximately 120. Subject groups are as follows: Healthy humans between the ages of 30 and 80 and those with PD (between ages of 45 and 80), dystonia (ages 30-80) and cerebellar lesions (ages 30-80) including those who have undergone DBS surgery to treat their PD or dystonia. The total duration of each session is approximately 2 hours. Each patient group including those with DBS will perform two sessions of the same task - one while on medication and one while off medication, hence the total duration of the study will be 4 hours for these groups (2 different sessions during different days). These patient groups are free to do these sessions at the same time as their routine physician visits or any other time that works best for them.
Study design
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Deep Brain Stimulator | Other | Procedure: Deep Brain Stimulation (DBS)Some of our subjects that participate to the study have Deep Brain Stimulation implanted. They will perform the behavioral task twice, with the stimulation ON or OFF. |
Who may qualify
- Ages
- 18 to 80 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (35 listed)
- Group 1 - Age and Sex matched healthy controls:
- Age 18-80 Years
- "on meds" and "off meds" (tested in separate sessions) - total of 2 sessions
- Age 45-80 Years
- Unified PD rating scale (UPDRS)
Key exclusion criteria (2 listed)
- Visual impairment or ocular motility disorder Inability to sit for the 30 minute task plus 20-30 minute instruction time, setup, and wait time.
- For Group 1 (Age Sex Matched Controls), there will additional exclusion criteria of other neurological disease and drug use
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Deep Brain Stimulation (DBS)Patients with DBS will participate to the study both when the stimulation is off and on. | Procedure or surgery | Deep Brain Stimulator |
Primary outcome
Choice performance - % correct responses out of total number of trials
Time frame: at the end of each testing session - 2 hours
data from each subject will be assessed at the end of each session to monitor and measure outcome measures.
1 secondary outcome
Reaction Time to make a choice - measured in milliseconds
Time frame: at the end of each testing session - 2 hours
Results and safety
The study was withdrawn before enrolling participants, so there are no results.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 4 Aug 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Michele Basso, PhD principal investigator
University of California, Los Angeles
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Deep Brain Stimulation (DBS) in people with Parkinson's Disease and Dystonia, run by University of California, Los Angeles at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 35 inclusion and 2 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: withdrawn, as of the sponsor's last update on 4 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study was withdrawn before enrolling participants, so there are no results.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Choice performance - % correct responses out of total number of trials (time frame: at the end of each testing session - 2 hours). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 4 Aug 2026.