Subthalamic Steering for Therapy Optimization in Parkinson's Disease (SANTOP)

June 1, 2026 updated by: Alireza Gharabaghi, MD, University Hospital Tuebingen
Twenty patients with idiopathic Parkinson's disease (PD) will be included into this single center randomized controlled double-blind clinical trial (RCT) in a cross-over design. The treatment consists of two different stimulation settings using (i) conventional omnidirectional stimulation of the subthalamic nucleus [STN_O] as active comparator and (ii) directional steering of STN stimulation via a segmented electrode contact [STN_D].

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Twenty PD patients will be enrolled in this cross-over double-blind RCT to evaluate both the safety and efficacy of directional STN stimulation [STN_D] compared with standard omnidirectional STN stimulation [STN_O]. The primary outcome measure is objectively quantified muscle rigidity of the upper extremity, i.e., surface EMG recordings of the biceps and triceps muscle during standardized extension/flexion of the elbow joint (Levin et al., 2009) assessed 6 months after implantation in cross-over design. The trial is designed to detect with an 80% power a change of 0.27 mA of the therapeutic stimulation threshold with two-tailed P < 0.05 (Wilcoxon rank sum test). Secondary outcome measures address clinical motor, non-motor, neurocognitive and neuropsychiatric symptoms, freezing of gait, and quality of life. Visits are scheduled at weeks 1 (V1), 6 (V2), 24 (V3), 27 (V4), and 30 (V5) from baseline (V0).

Study Type

Interventional

Enrollment (Actual)

20

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Germany
    • Baden-Wurttemberg
      • Tübingen, Baden-Wurttemberg, Germany, 72076
        • University Hospital Tuebingen, Dep. of Neurosurgery (Functional Neurosurgery) and Neurology (Neurodegenerative Diseases)

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 80 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Written informed consent
  • Idiopathic Parkinson's disease (according to the "British Brain Bank criteria" (Hughes, 1992) including genetic forms

Exclusion Criteria:

  • Cognitive impairment (Mini Mental State Exam < 20)
  • Suicidality, Psychosis
  • Other severe pathological chronic condition that might confound treatment effects or interpretation of the data
  • Pregnancy

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: STN_O
Omnidirectional Deep Brain Stimulation of STN
Device: Omnidirectional Deep Brain Stimulation of STN
Deep Brain Stimulation
Experimental: STN_D
Directional Deep Brain Stimulation of STN
Device: Directional Deep Brain Stimulation of STN
Deep Brain Stimulation

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Muscle Rigidity
Time Frame: 6 months post-operatively
Surface-Electromyography (EMG) of M. biceps brachii and M. triceps brachii
6 months post-operatively

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Clinical motor and non-motor symptoms (1)
Time Frame: 6 months post-operatively
MDS-UPDRS I
6 months post-operatively
Clinical motor and non-motor symptoms (2)
Time Frame: 6 months post-operatively
MDS-UPDRS II
6 months post-operatively
Clinical motor and non-motor symptoms (3)
Time Frame: 6 months post-operatively
MDS-UPDRS III
6 months post-operatively
Clinical motor and non-motor symptoms (4)
Time Frame: 6 months post-operatively
MDS-UPDRS IV
6 months post-operatively
Clinical motor and non-motor symptoms (5)
Time Frame: 6 months post-operatively
Bradykinesia evaluation
6 months post-operatively
Clinical motor and non-motor symptoms (6)
Time Frame: 6 months post-operatively
Tremor evaluation
6 months post-operatively
Clinical motor and non-motor symptoms (7)
Time Frame: 6 months post-operatively

Deep brain stimulation impairment scale (DBS-IS):

  • the scale consists of 22 questions and 6 subscales;
  • subscales: 1. postural instability and gait difficulties (range 0-20), 2. cognitive impaiment (range 0-20), 3. speaking problems (range 0-12), 4. apathy (range 0-12), 5. impulsivity (range 0-12), and 6. difficulties related to DBS device (range 0-12);
  • Ʃ 1-6 DBS-IS total range: 0-88;
  • Ʃ 1-5 DBS-IS total range: 0-76;
  • higher values represent worsening of symptoms
6 months post-operatively
Clinical motor and non-motor symptoms (8)
Time Frame: 6 months post-operatively
Clinical global impression self
6 months post-operatively
Neurocognitive and non-motor symptoms (1)
Time Frame: 6 months post-operatively
Modulation range
6 months post-operatively
Neurocognitive and non-motor symptoms (2)
Time Frame: 6 months post-operatively
Spatial with a visual Odd-Ball test
6 months post-operatively
Neurocognitive and non-motor symptoms (3)
Time Frame: 6 months post-operatively
Verbal Working Memory with an auditory Odd-Ball test
6 months post-operatively
Neurocognitive and non-motor symptoms (4)
Time Frame: 6 months post-operatively
Power of Attention (Cognitive Drug Research Battery)
6 months post-operatively
Neurocognitive and non-motor symptoms (5)
Time Frame: 6 months post-operatively
Digit Vigilance Accuracy (Cognitive Drug Research Battery)
6 months post-operatively
Neurocognitive and non-motor symptoms (6)
Time Frame: 6 months post-operatively
Executive functions with One Touch Tower of London (Cambridge Neuropsychological Test Automated Battery, CANTAB)
6 months post-operatively
Neurocognitive and non-motor symptoms (7)
Time Frame: 6 months post-operatively
Montreal Cognitive Assessment (MoCA)
6 months post-operatively
Neuropsychiatric symptoms (1)
Time Frame: 6 months post-operatively
Beck Depression Inventory (BDI)
6 months post-operatively
Neuropsychiatric symptoms (2)
Time Frame: 6 months post-operatively
Apathy Scale/Lille Apathy rating scale/Neuropsychiatric inventory
6 months post-operatively
Freezing of gait (1)
Time Frame: 6 months post-operatively
Capsit-PD
6 months post-operatively
Freezing of gait (2)
Time Frame: 6 months post-operatively
Freezing of Gait Assessment Course
6 months post-operatively
Quality of Life
Time Frame: 6 months post-operatively
Parkinson's Disease Questionaire (PDQ-39)
6 months post-operatively

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Electroencephalography
Time Frame: up to 6 months post-operatively
Electroencephalography (EEG)
up to 6 months post-operatively
Electromyography
Time Frame: up to 6 months post-operatively
Electromyography (EMG)
up to 6 months post-operatively

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University Hospital Tuebingen

Collaborators

Abbott

Investigators

  • Principal Investigator: Alireza Gharabaghi, MD, Division of Functional and Restorative Neurosurgery, Department of Neurosurgery, Tuebingen, Germany
  • Principal Investigator: Daniel Weiss, MD, Department for Neurodegenerative Diseases, Centre for Neurology, Tuebingen, Germany, and Hertie-Institute for Clinical Brain Research

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

April 19, 2018

Primary Completion (Actual)

December 31, 2023

Study Completion (Actual)

December 31, 2023

Study Registration Dates

First Submitted

April 18, 2018

First Submitted That Met QC Criteria

June 6, 2018

First Posted (Actual)

June 7, 2018

Study Record Updates

Last Update Posted (Actual)

June 3, 2026

Last Update Submitted That Met QC Criteria

June 1, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • SANTOP

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

product manufactured in and exported from the U.S.

Yes

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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