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Essential TremorNCT06899022

Attention and Eye Movement in Parkinson's Disease

A study testing Normal therapeutic DBS, Reduced current DBS and Reduced frequency DBS in people with Essential Tremor and Parkinson's Disease (PD), run by University of Nebraska at 1 site in United States.

Recruiting

Looking for participants now. Contact the study team or a site below to ask about taking part.

Sites and contacts
Official record
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Trial summary

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). Read more about this study

Who is it for?
Ages 19 to 90 yearsHealthy volunteers can take part
What is being tested?
Normal therapeutic DBS, Reduced current DBS and Reduced frequency DBS
Could I receive a placebo?
No, everyone receives an active treatment
How many people
138 participants
Where
1 siteUnited States
Study dates
22 Sep 2025to Aug 2028
Phase
Interventional
Are there results?
Not yet: the study is under way

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 19 to 90 years
  • All sexes
  • Healthy volunteers accepted
  • Adult, Older adult

Who may be able to join

  • 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).
Show all 21Show fewer
  • 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

Who cannot join

  • 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):
Show all 16Show fewer
  • 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

Trial locations and contacts

1 site in 1 country. Contact the study team or a site near you to ask about taking part.

Christopher K Kovach, PhD contact

319-471-3372

ckovach@unmc.edu

Dulce Maroni, PhD contact

402-836-9751

dmaroni@unmc.edu

United States1 site, 1 recruiting

  • University of Nebraska Medical Center

    Omaha, Nebraska, 68198

    Dulce V Maroni, PhD, 402-836-9751, dmaroni@unmc.edu

    Christopher K Kovach, PhD

    Recruiting

Other trials in United States

About this study

Official title: Investigating the Role of Attention in Perceptual and Cognitive Consequences of Parkinson's Disease

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?
Read more

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).
Read the detailed description

Parkinson's disease (PD) is the second most common age-related neurodegenerative disorder, with approximately 90,000 new cases diagnosed annually in North America. Although motor symptoms define the disorder, PD also leads to cognitive and emotional changes, such as difficulties in recognizing facial expressions and regulating attention, which often overshadow motor issues as the disease progresses. The goal of this study is to better understand the link between attention, eye movement, and emotional perception in PD, testing the hypothesis that disrupted attention leads to altered perception of facial emotions. The study will also investigate how deep brain stimulation (DBS) of the subthalamic nucleus (STN) affects these processes, providing critical insights into the cognitive and perceptual consequences of the treatment.

This research addresses a critical gap in understanding non-motor symptoms of Parkinson's disease by exploring how attention, eye movement, and perception interact. Findings will provide evidence on whether cognitive and emotional symptoms in PD stem from impaired attentional control, offering a new framework for treating these deficits. Additionally, the study will shed light on how different DBS frequencies affect perception and cognition, potentially guiding personalized stimulation strategies to alleviate both motor and non-motor symptoms. The insights gained may influence future therapies for PD, advancing both scientific knowledge and patient care.

Participants will be divided into three groups: PD undergoing DBS, non-PD movement disorders, essential tremor (ET) and dystonia (DT) undergoing DBS (as a comparison group for non-PD DBS effects) and healthy age- and sex-matched controls. Participants will complete facial morph rating tasks (rating faces as happy, neutral, or sad) and visual search tasks (finding faces among distractors), while their eye movements are tracked.

The first study aim is to measure how altered attention influences facial emotion perception in PD by tracking eye movements while participants view and categorize emotional face stimuli. The second aim is to characterize brain activity in the STN related to attentional and perceptual processes during awake DBS surgery by capturing microelectrode recordings (MER) of neural activity while participants view emotional faces, allowing researchers to map STN's role in guiding attention and eye movements. The third aim is to test how DBS stimulation at different frequencies (high, low, or off) affects attention, eye movement, and emotional perception by having participants perform visual and perceptual tasks under varying DBS settings to evaluate how brain stimulation influences cognitive and perceptual functions.

Being tested
Normal therapeutic DBS, Reduced current DBS, Reduced frequency DBS
Keywords
Deep Brain Stimulation, Attention, Perception, Eye movement
Medical subject headings
Essential Tremor, Dystonic Disorders

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Normal therapeutic DBSOther

    Participants will receive deep brain stimulation delivered at the clinically determined therapeutic frequency and current over approximately 20 min.

  • Reduced current DBSOther

    Participants will receive deep brain stimulation delivered at the clinically determined therapeutic frequency and reduced (50%) current over approximately 20 minutes.

  • Reduced frequency DBSOther

    Participants will receive deep brain stimulation delivered at the clinically determined therapeutic current and reduced (4 Hz) frequency over approximately 20 min.

Study groups in NCT06899022
Study groupRoleWhat they receive
Acute alteration of DBSExperimentalAll participants in the single arm of this study will undergo acute alteration of DBS stimulation under three conditions in randomized order over the course of 1 hour.
Receives: Other: Normal therapeutic DBS; Other: Reduced current DBS; Other: Reduced frequency DBS

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Facial Expression Rating

    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.

    Measured: 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).

  2. Eye Tracking

    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.

    Measured: 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).

  3. Intraoperative Microrecordings

    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.

    Measured: Intraoperative (Day 0; day of DBS implantation surgery).

Secondary outcomes (7)

  1. EEG beta-band power during emotional face rating

    Spectral power in the beta frequency band (12-30 Hz), expressed in microvolts squared (µV²) and normalized to a pre-stimulus baseline, computed from non-invasive scalp EEG over posterior electrodes during the emotional face rating component of the task. Measurement tool: 64-channel research-grade scalp EEG with time-frequency decomposition (demodulated band transform). Group comparisons across PD, ET, DT, and healthy controls and within-participant comparisons across DBS conditions will be made using mixed-effects linear models, comparing power at baseline and modulation of power within a -0.5 to 0.5 s peri-saccade window.

    Measured: Single experimental visit during the Aim 3 study session (third study visit; through study completion, an average of 6 months).

  2. EEG event-related potential (ERP) amplitude at saccade onset

    Mean amplitude (µV) of the stimulus-locked event-related potential at saccade onset, measured over occipito-temporal electrodes during the 100-300 ms post-stimulus interval (encompassing the N170 component). Measurement tool: 64-channel research-grade scalp EEG with stimulus-locked averaging.

    Measured: Single experimental visit during the Aim 3 study session (third study visit; through study completion, an average of 6 months).

  3. EEG beta burst rate, frequency and amplitude during emotional face viewing

    Modulation of beta band activity (12-30 Hz), will be studied in scalp EEG recordings using a published method (Kovach 2026) for identifying oscillatory bursts based on estimation and decomposition of the fourth order spectrum (trispectrum). Group comparisons across PD, ET, DT, and healthy controls and within-participant comparisons across DBS conditions will be made using mixed-effects linear models, comparing burst rate, amplitude and frequency comparing power at baseline and modulation of power within a -0.5 to 0.5 s peri-saccade window.

    Measured: Single experimental visit during the Aim 3 study session (third study visit; through study completion, an average of 6 months).

  4. LFP beta-band (12-30 Hz) power during emotional face viewing

    Spectral power in the beta band (12-30 Hz), expressed in microvolts squared (µV²), recorded from chronically implanted DBS electrodes targeting the subthalamic nucleus during eye-tracked task performance. Measurement tool: voltage telemetry through clinical leads using the BrainSense capability of the Medtronic Percept implantable pulse generator. Power will be computed via time-frequency decomposition (demodulated band transform) and compared across DBS conditions (normal therapeutic, reduced current, reduced frequency) and across movement-disorder populations using mixed-effects linear models.

    Measured: Single experimental visit during the Aim 3 study session (third study visit; through study completion, an average of 6 months).

  5. LFP beta burst rate, frequency and amplitude during emotional face viewing

    Modulation of beta band activity (12-30 Hz), will be studied in intracranial LFP recordings using a published method (Kovach et al. 2026) for identifying oscillatory bursts based on estimation and decomposition of the fourth order spectrum (trispectrum). Group comparisons across PD, ET, DT, and healthy controls and within-participant comparisons across DBS conditions will be made using mixed-effects linear models, comparing burst rate, amplitude and frequency comparing power at baseline and modulation of power within a -0.5 to 0.5 s peri-saccade window.

    Measured: Single experimental visit during the Aim 3 study session (third study visit; through study completion, an average of 6 months).

  6. LFP theta-band (4-8 Hz) power during emotional face viewing

    Spectral power in the theta frequency band (4-8 Hz), expressed in microvolts squared (µV²) and normalized to a pre-stimulus baseline, computed from non-invasive scalp EEG over fronto-central electrodes during presentation of morphed emotional face stimuli in the affective bias task (Bijanki et al., 2014). Measurement tool: voltage telemetry through clinical leads using the BrainSense capability of the Medtronic Percept implantable pulse generator.Group comparisons across PD, ET, DT, and healthy controls and within-participant comparisons across DBS conditions will be made using mixed-effects linear models, comparing power at baseline and modulation of power within a -0.5 to 0.5 s peri-saccade window.

    Measured: Single experimental visit during the Aim 3 study session (third study visit; through study completion, an average of 6 months).

  7. EEG-LFP coherence during emotional face viewing

    Coherence between scalp EEG recordings and intracranial LFP recordings will be examined across multiple frequencies from 1 Hz to 30 Hz using a time-frequency decomposition (demodulated band transform, Kovach 2016) with 1 Hz frequency bins. Measurement tool: 64 channel scalp EEG and concurrent voltage telemetry through clinical leads using the BrainSense capability of the Medtronic Percept implantable pulse generator. Group comparisons of subject-level coherence values across PD, ET, DT, and healthy controls and within-participant comparisons across DBS conditions will be made using mixed-effects linear models, comparing power at baseline and modulation of power within a -0.5 to 0.5 s peri-saccade window.

    Measured: Single experimental visit during the Aim 3 study session (third study visit; through study completion, an average of 6 months).

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted27 Mar 2025
  2. Study start22 Sep 2025
  3. Primary completionFeb 2028 (estimated)
  4. Study completionAug 2028 (estimated)

Resources

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
Model description
The interventional component of the study examines whether and how altered level and frequency of deep brain stimulation (DBS) acutely affects eye movement and perception of facial emotion. Participants will be tested in 3 stimulation conditions in random order: normal therapeutic DBS, reduced (50%) current DBS at the normal therapeutic frequency and reduced frequency (4 Hz) at the normal therapeutic current.
Masking
None (open label)
Enrolment
138 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT06899022
Sponsor's protocol ID
0082-25-FB
Other IDs
P20GM130447
Status last verified
Mar 2026
First submitted
14 Mar 2025
Last updated
5 May 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
No

Publications

  • McIntyre CC, Hahn PJ. Network perspectives on the mechanisms of deep brain stimulation. Neurobiol Dis. 2010 Jun;38(3):329-37. doi: 10.1016/j.nbd.2009.09.022. Epub 2009 Oct 3.

    PubMed 19804831

  • Sugita Y. Face perception in monkeys reared with no exposure to faces. Proc Natl Acad Sci U S A. 2008 Jan 8;105(1):394-8. doi: 10.1073/pnas.0706079105. Epub 2008 Jan 2.

    PubMed 18172214

  • W. Penny and A. Holmes. Random effects analysis. Statistical parametric mapping: The analysis of functional brain images, 156:165, 2007.

  • Kovach CK, Howard MA 3rd. Decomposition of Higher-Order Spectra for Blind Multiple-Input Deconvolution, Pattern Identification and Separation. Signal Processing. 2019 Dec;165:357-379. doi: 10.1016/j.sigpro.2019.07.007. Epub 2019 Jul 26.

    PubMed 41647176

  • C. Kovach, J. Moreira, J. Berger, M. Howard III, L. Gwilliams, A. Fallah, L. Comstock, and E. Mendes. Higher-order spectral decomposition applied to spike sorting. Feb. 2023.

  • Tottenham N, Tanaka JW, Leon AC, McCarry T, Nurse M, Hare TA, Marcus DJ, Westerlund A, Casey BJ, Nelson C. The NimStim set of facial expressions: judgments from untrained research participants. Psychiatry Res. 2009 Aug 15;168(3):242-9. doi: 10.1016/j.psychres.2008.05.006. Epub 2009 Jun 28.

    PubMed 19564050

  • X. Fan, M. Mocchi, B. Pascuzzi, J. Xiao, B. A. Metzger, R. K. Mathura, C. Hacker, J. A. Adkinson, E. Bartoli, S. Elhassa, et al. Brain mechanisms underlying the emotion processing bias in treatment- resistant depression. Nature Mental Health, pages 1-10, 2024.

  • Metzger BA, Kalva P, Mocchi MM, Cui B, Adkinson JA, Wang Z, Mathura R, Kanja K, Gavvala J, Krishnan V, Lin L, Maheshwari A, Shofty B, Magnotti JF, Willie JT, Sheth SA, Bijanki KR. Intracranial stimulation and EEG feature analysis reveal affective salience network specialization. Brain. 2023 Oct 3;146(10):4366-4377. doi: 10.1093/brain/awad200.

    PubMed 37293814

  • Bijanki KR, Kovach CK, McCormick LM, Kawasaki H, Dlouhy BJ, Feinstein J, Jones RD, Howard MA 3rd. Case report: stimulation of the right amygdala induces transient changes in affective bias. Brain Stimul. 2014 Sep-Oct;7(5):690-3. doi: 10.1016/j.brs.2014.05.005. Epub 2014 May 24.

    PubMed 24972588

  • Marneweck M, Loftus A, Hammond G. Psychophysical measures of sensitivity to facial expression of emotion. Front Psychol. 2013 Feb 20;4:63. doi: 10.3389/fpsyg.2013.00063. eCollection 2013.

    PubMed 23431121

  • Sprengelmeyer R, Young AW, Mahn K, Schroeder U, Woitalla D, Buttner T, Kuhn W, Przuntek H. Facial expression recognition in people with medicated and unmedicated Parkinson's disease. Neuropsychologia. 2003;41(8):1047-57. doi: 10.1016/s0028-3932(02)00295-6.

    PubMed 12667540

  • Hershey T, Campbell MC, Videen TO, Lugar HM, Weaver PM, Hartlein J, Karimi M, Tabbal SD, Perlmutter JS. Mapping Go-No-Go performance within the subthalamic nucleus region. Brain. 2010 Dec;133(Pt 12):3625-34. doi: 10.1093/brain/awq256. Epub 2010 Sep 20.

    PubMed 20855421

  • McIntosh LG, Mannava S, Camalier CR, Folley BS, Albritton A, Konrad PE, Charles D, Park S, Neimat JS. Emotion recognition in early Parkinson's disease patients undergoing deep brain stimulation or dopaminergic therapy: a comparison to healthy participants. Front Aging Neurosci. 2015 Jan 21;6:349. doi: 10.3389/fnagi.2014.00349. eCollection 2014.

    PubMed 25653616

  • Albuquerque L, Coelho M, Martins M, Guedes LC, Rosa MM, Ferreira JJ, Cattoni MB, Carvalho H, Ferreira AG, Martins IP. STN-DBS does not change emotion recognition in advanced Parkinson's disease. Parkinsonism Relat Disord. 2014 Feb;20(2):166-9. doi: 10.1016/j.parkreldis.2013.10.010. Epub 2013 Oct 18.

    PubMed 24182523

  • Berney A, Panisset M, Sadikot AF, Ptito A, Dagher A, Fraraccio M, Savard G, Pell M, Benkelfat C. Mood stability during acute stimulator challenge in Parkinson's disease patients under long-term treatment with subthalamic deep brain stimulation. Mov Disord. 2007 Jun 15;22(8):1093-6. doi: 10.1002/mds.21245.

    PubMed 17394245

Questions about this trial

What is this clinical trial studying?

A study testing Normal therapeutic DBS, Reduced current DBS and Reduced frequency DBS in people with Essential Tremor and Parkinson's Disease (PD), run by University of Nebraska 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 21 inclusion and 16 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: looking for participants now, as of the sponsor's last update on 5 May 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?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

Contact Christopher K Kovach, PhD (319-471-3372, ckovach@unmc.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

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).). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT06899022, which also lists 104 linked publications.

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 5 May 2026.

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