NCT06899022 · University of Nebraska
Attention and Eye Movement in Parkinson's Disease
What this study is about
The goal of this observational and interventional study is to understand how therapeutic deep brain stimulation (DBS) affects attention, perception and cognition in participants with Parkinson's disease (PD) and non-PD movement disorders, including essential tremor (ET) and dystonia (DT).
View original scientific description
The goal of this observational and interventional study is to understand how therapeutic deep brain stimulation (DBS) affects attention, perception and cognition in participants with Parkinson's disease (PD) and non-PD movement disorders, including essential tremor (ET) and dystonia (DT). The main questions it aims to answer are: * Does impaired control of attention and eye movement in PD alter how social cues are perceived and interpreted? * Does therapeutic DBS improve or worsen attentional and perceptual deficits for social cues in PD, ET and DT? * Can DBS be optimized to restore normal attentional control in PD while remaining an effective therapy for other aspects of the disorder. * What do parts of the brain targeted by DBS contribute to the control of attention? Using an eye tracking camera, investigators will study how participants with PD, ET and DT look at and perceive facial expressions of emotion before and after starting DBS therapy, in comparison to a group of healthy participants without ET, PD, DT or DBS. Participants with PD, ET and DT will see and rate morphed facial expressions on a computer screen in three conditions: * Before starting DBS therapy (over approximately 1 hour). * In the operating room, during the standard procedure to implant DBS electrodes, while the participant is awake (for no more than 15 minutes). * After starting DBS therapy, with brief experimental changes of DBS stimulation level and frequency (over approximately 1 hour).
Interventions
OTHER
Normal therapeutic DBS
Participants will receive deep brain stimulation delivered at the clinically determined therapeutic frequency and current over approximately 20 min.
OTHER
Reduced current DBS
Participants will receive deep brain stimulation delivered at the clinically determined therapeutic frequency and reduced (50%) current over approximately 20 minutes.
OTHER
Reduced frequency DBS
Participants will receive deep brain stimulation delivered at the clinically determined therapeutic current and reduced (4 Hz) frequency over approximately 20 min.
Primary outcome measures
Facial Expression Rating
Time frame: Baseline (within 2 weeks pre-DBS implantation), intraoperative (Day 0; day of DBS implantation surgery, and post-operative follow-up (2-3 weeks after DBS implantation, following clinical optimization of stimulation parameters).
Participants will rate facial expression along a continuous scale using a computerized slider, following the affective bias task (ABT) of Bijanki et al. (2014). The scale is anchored with three descriptors, "Very Sad" at slider value 0 (left), "Neutral", at position 0.5 (middle), and "Very Happy" at 1.0 (right). Responses are compared between two time points: (1) at the initial pre-surgical testing session and post DBS implantation and (2) at the post-implantation session following clinical optimization of therapeutic parameters, 2-3 weeks after surgery. The comparison will examine both the direction of any bias of the rating, against normative ratings, and the magnitude of average deviation from normative ratings. Finally, the ratings will be incorporated into a generalized linear model of gaze position (Kovach 2014) to identify the association between perceived facial expression and characteristic fixation patterns.
Eye Tracking
Time frame: Baseline (within 2 weeks pre-DBS implantation), intraoperative (Day 0; day of DBS implantation surgery, and post-operative follow-up (2-3 weeks after DBS implantation, following clinical optimization of stimulation parameters).
The location and duration of gaze fixations will be recorded with a remote eye tracking camera. The location of gaze fixations will be treated as the dependent measure within a generalized linear modeling (GLM) framework for spatial point processes, described in Kovach and Adolphs (2014). Parameter estimates of the model give the log relative risk of fixation at different locations in the visual scene as a function of the independent measures of the model. Independent measures include the main effect of (1) Fourier basis functions encoding scene location and its interactions with (2) image rating in the affective bias task of Bijanki et. al (2014), (3) session and (4) DBS stimulation state. Measures derived from the GLM model will also include the statistical deviation (e.g. Kullback-Leibler divergence) from the average distribution of fixations observed in healthy comparison subjects for each image.
Intraoperative Microrecordings
Time frame: Intraoperative (Day 0; day of DBS implantation surgery).
During the Aim 2 portion of the study, patients undergoing awake DBS surgery as part of standard clinical care will engage in a subset of the face rating tasks during the surgery. Invasive recordings will be obtained from DBS target structures, including STN, VIM, and GPi using microelectrodes that are placed as part of standard clinical practice. Spike sorting will be used to identify firing of individual cells and firing rate will compared to eye movements to identify responses associated with shifts of attention in the targeted deep brain structures . These measures will be compared across movement-disorders populations using mixed-effects linear modeling and other standard statistical procedures.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- All Participants (Aim 1):
- Ability and willingness to provide signed informed consent for this study
- Ability to express perceptual judgments through a button press or mouse- controlled computerized slider
- Age 19 - 90 years
- DBS Participants (Aim 1):
- Diagnosis of idiopathic Parkinson's disease (PD), essential tremor (ET) or dystonia (DT).
- Scheduled for new implantation of a therapeutic DBS device targeted to subthalamic nucleus (STN), ventral intermediate nucleus of thalamus (VIM) or internal globus pallidus (GPi)
- Comparison Participants (Aim 1): o Selection by age matching to participants in PD group
- Parkinson's disease (PD), essential tremor (ET) and dystonia (DT) Participants (Aim 2):
- Ability and willingness to provide signed informed consent for this study
- Ability to express perceptual judgments through a button press or mouse- controlled computerized slider
- Age 19 - 90 years
- Scheduled for awake DBS implantation with clinical micro-electrode recordings (MER)
- Willing and able to engage in tasks during an awake surgical procedure
- Parkinson's disease (PD), essential tremor (ET) and dystonia (DT) Participants (Aim 3):
- Ability and willingness to provide signed informed consent for this study
- Ability to express perceptual judgments through a button press or mouse- controlled computerized slider
- Age 19 - 90 years
- Willing to undergo acute manipulations of DBS
- Able to tolerate acute changes of DBS
Exclusion criteria
- All Participants (Aim 1):
- Corrected visual acuity insufficient to perceptually judge face stimuli
- Inability to understand task instructions or complete task requirements
- DBS Participants (Aim 1): o Insufficient therapeutic control of motor symptoms to engage in tasks requiring button press or use of a mouse to control a slider
- Healthy Comparison Participants (Aim 1): o History of neurodegenerative disorder
- Parkinson's disease (PD), essential tremor (ET) and dystonia (DT) Participants (Aim 2):
- Corrected visual acuity insufficient to perceptually judge face stimuli
- Inability to understand task instructions or complete task requirements
- Not undergoing awake DBS implantation
- Uncorrected visual acuity insufficient to perceptually judge face stimuli
- Parkinson's disease (PD), essential tremor (ET) and dystonia (DT) Participants (Aim 3):
- Corrected visual acuity insufficient to perceptually judge face stimuli
- Inability to understand task instructions or complete task requirements
- Failure of DBS to achieve a therapeutic effect on motor symptoms
Where
- Omaha, Nebraska
Collaborators
National Institute of General Medical Sciences (NIGMS)
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Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced May 5, 2026 · Source of record for eligibility and locations