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NCT Number: NCT06951906

Imaging Biomarkers of FOG Response to DBS

For this study, the investigators are recruiting 54 individuals with Parkinson's Disease and Freezing of Gait (FOG) who are planning to undergo Deep Brain Stimulation (DBS). The objective of this study is to better understand the FOG response to DBS. Prior to DBS, participants will undergo an MRI scan, behavioral assessment related to walking, a cognitive evaluation, and assessment of other Parkinson's disease symptoms. Following DBS, participants will repeat these assessments at multiple timepoints over the period of one year. Overall, participants will complete a total of 7 visits over a period of approximately 1 year.

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Key information

Conditions

Freezing of Gait Symptoms in Parkinson's Disease Basal Ganglia Diseases Brain Diseases Central Nervous System Diseases Deep Brain Stimulation Movement Disorders Nervous System Diseases Neurodegenerative Diseases Parkinson Disease Parkinsonian Disorders Synucleinopathies

Age range

40 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 4

Primary location

Medical University of South Carolina

Charleston, South Carolina, 29425, United States

Location status: Recruiting

Location contact

Gonzalo J. Revuelta, MS, DO, FANA

PRINCIPAL_INVESTIGATOR

Mahdi Sowlat, M.D.

CONTACT

[email protected]

8438766410

Niloufar Malakouti, M.D.

CONTACT

[email protected]

843-792-0235

About this study

The long-term goal of this research is to develop an individualized approach for the treatment of Freezing of Gait (FOG) with Deep Brain Stimulation (DBS). In pursuit of this goal, the investigators have preliminary findings which show that:

  • Effective subthalamic nucleus DBS (STN-DBS) activates the globus pallidus interna (GPi) and decreases cortical activation in Parkinson's Disease (PD);
  • Structural connectivity to the GPi, supplemental motor area (SMA), and primary motor cortex (M1) is associated with DBS response in FOG; and
  • Decreased microstructural integrity of the GPi is associated with decreased DOPA response in FOG.

The investigators propose a conceptual framework whereby engaging a specific FOG response network depends on the structural integrity of the network, as well as lead placement and stimulation parameters. The investigators propose to recruit 54 individuals with FOG who are identified as appropriate STN-DBS candidates to undergo a prospective longitudinal imaging and behavioral study of FOG response to STN-DBS. Baseline behavioral assessments will characterize FOG behavior, severity, subtype, as well as the cognitive profile, non-FOG motor severity, and other demographics of the enrolled participants that may contribute to DBS response. Baseline imaging will utilize advanced diffusion MRI metrics to determine which brain areas are structurally connected to the stimulation target and their structural integrity. Post-operative assessments will include behavioral measures of FOG response and imaging measures of neural response to stimulation. Pre- and post-operative data will be used to evaluate the association between structural integrity, connectivity, and behavioral response.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • >40 years of age.
  • diagnosis of PD based on UK Brain Bank diagnostic criteria.
  • presence of FOG, defined as a score of 1 on part 1 of the nFOGQ and confirmed by objective evaluation (a score of 1 represents a positive response of having experienced such an episode over the last month).
  • clinically selected at the MUSC DBS Conference to undergo STN-DBS surgery.

Exclusion criteria

  • a history of other significant gait impairment unrelated to PD (e.g. orthopedic deformities).
  • inability to complete gait assessments (timed-up-and-go task) in the OFF state without assistance or assist devices.
  • contraindications to MRI, including inability to lie supine in the scanner environment, pregnancy, and non-MRI compatible metal implants.
  • implantation of non-3 T MRI-compatible DBS devices.

Treatment and study plan

fMRI

Diagnostic Test

Baseline imaging will utilize advanced diffusion MRI metrics to determine which brain areas are structurally connected to the stimulation target and their structural integrity. Post-operative assessments will include behavioral measures of FOG response and imaging measures of neural response to stimulation. Pre- and post-operative data will be used to evaluate the association between structural integrity, connectivity and behavioral response.

Primary outcomes

  1. Turn Duration

    Time frame: Assessed at Baseline (Visit 3) and at 12 months post-activation (Visit 7)

    Turn duration is measured during the timed up and go (TUG) task. Subjects are instrumented with inertial measurement units (IMUs), and turn duration is measured from the first step onto a marked box to the last toe off the box during the turn.

  2. Difference in BOLD Response to STN-DBS

    Time frame: Assessed post-operatively at 6 months (Visit 5) and 12 months (Visit 6).

    Whole-brain activation is assessed via BOLD signal changes associated with T2*-relaxation rate during combined Deep Brain Stimulation and functional MRI (DBS-fMRI). This involves cycling the DBS device ON and OFF during resting-state scans

  3. Difference in Structural Connectivity

    Time frame: Based on baseline diffusion MRI data (Visit 4) and analyzed in relation to DBS response determined at 12 months post-activation.

    Structural connectivity profiles are determined using individual structural connectivity data and the Volume of Tissue Activated (VTA) model, which accounts for stimulation settings and lead placement. The outcome is the comparison of VTA connectivity to specific brain regions (e.g., GPi, SMA, M1, GPe) between STN-DBS responsive and unresponsive participants.

  4. Difference in Structural Integrity

    Time frame: Based on baseline diffusion MRI data (Visit 4) and analyzed in relation to DBS response determined at 12 months post-activation.

    Microstructural integrity of brain structures (e.g., STN, GPi, PPN) is assessed using advanced diffusion MRI metrics, specifically Diffusional Kurtosis Imaging (DKI). The outcome is the comparison of these metrics between STN-DBS responsive and unresponsive participants.

Sponsors and collaborators

Lead sponsor

Medical University of South Carolina

Other

Collaborators

  • National Institute of Neurological Disorders and Stroke (NINDS)

Registry information

Official study title

Imaging Biomarkers of Freezing of Gait Response to Deep Brain Stimulation

Important dates

Study start
2024
Primary completion
2029
Study completion
2030
First posted
Apr 30, 2025
Registry last updated
Aug 6, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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