Effectiveness of STIL Orthosis in PD (STIL-PD)

The Effect of the STIL Orthosis on Action Tremor Severity in People With Parkinson's Disease

Parkinson's disease is a neurodegenerative condition that leads to uncontrollable shaking (tremor), which can substantially impair everyday activities. The goal of this clinical trial is to learn if the STIL Orthosis works as a treatment option for tremor in people with Parkinson's disease. The main questions it aims to answer are:

• Does the STIL Orthosis reduce tremor?
• Are users satisfied with the usability and comfort of the STIL Orthosis?
• Does the STIL Orthosis have any adverse effects?

Participants' tremor will be measured during three conditions:

• While wearing the STIL Orthosis
• While wearing an orthosis without dampening (sham)
• While wearing no orthosis (baseline)

Researchers will compare the severity of tremor while wearing the STIL Orthosis against tremor during sham and baseline.

Study Overview

• Status: Completed
• Conditions: Action Tremor; Parkinson&Amp;#39;s Disease
• Intervention / Treatment: Device: STIL Orthosis; Device: Sham

Detailed Description

• Background: Tremor is a common symptom in people with Parkinson's disease (PD), affecting 75% of patients. While PD tremor usually occurs at rest, 46-93% of patients also have action tremor. Action tremor often does not respond to dopaminergic medication, and stereotactic surgery is invasive and unsuitable for many patients. By interfering with daily activities, action tremor can reduce independence and quality of life, necessitating new treatments.
• STIL Orthosis: The STIL Orthosis, a CE-certified device, aims to reduce tremor by dampening wrist flexion-extension and forearm pronation-supination. It features dampeners that limit high-frequency movements, such as tremor, while maintaining voluntary movements. In patients with essential tremor (n=24), the STIL Orthosis reduced action tremor severity during daily activities by 65-87% compared to baseline. This suggests that it could be a promising treatment for PD action tremors.
• Design: In this study, 25 PD patients will be recruited to test whether the STIL Orthosis can be used to treat PD-related action tremor. Action tremor will be measured under three conditions: while wearing the STIL Orthosis (intervention), while wearing an orthosis without dampening (sham), and while wearing no orthosis (baseline). Severity of action tremor in all conditions will be assessed using the TETRAS scale.
• Primary outcome: The primary outcome of this study is action tremor severity, measured using the TETRAS scale. The main study endpoint is the difference in TETRAS scores between two conditions (intervention vs. sham and intervention vs. baseline).
• Secondary outcomes: As secondary outcomes, we will measure tremor severity using the MDS-UPDRS part III scale, focusing on items related to postural, kinetic, and rest tremor (3.15, 3.16, 3.17). We will also measure tremor power using surface electromyography (sEMG) and accelerometry. Furthermore, we will assess perceived change in tremor using the PGC-I, user satisfaction on relevant items from the D-QUEST, and product safety using an adverse events report form.
• Sample size calculation: The sample size calculation is based on a pilot study with 8 Parkinson's disease patients experiencing action tremor in the forearm, which showed an effect size of 1.24 1.86 for MDS-UPDRS part 3 (tremor items 3.15, 3.16, and 3.17) and 2.21 for TETRAS. Given that patients only benefit from a device that has a large effect on their tremor, an effect size Cohen's d=0.8 was chosen, which is also common practice in the medical literature. In total, two main comparisons will be done on the primary outcome (TETRAS score): intervention vs. sham, intervention vs. baseline. To adjust for multiple statistical tests, a Bonferroni correction of alpha = 0.05/2 = 0.025 is used. To achieve 80% power in a two-sided paired t-test, a minimum of 18 patients needs to be included. In order to compensate for possible drop-outs, 25 patients will be included for this clinical investigation.
• Statistical analysis: All analyses will follow the intention-to-treat principle. Paired-samples t-test will be used to test for intervention-related effects on action tremor severity. In the event that tremor severity scores are not normally distributed, Wilcoxon signed rank tests will be used instead.

• Study Type: Interventional
• Enrollment (Actual): 25
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Netherlands
  • Gelderland
    • Nijmegen, Gelderland, Netherlands, 6511EN
      • Donders Institute for Brain, Cognition and Behaviour

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Participant is at least 18 years of age.
• Willing to sign the informed consent.
• Diagnosed with Parkinson's disease by a neurologist or movement disorders specialist.
• Action tremor in one or two arms (clinical severity score of at least 2 on their dominant side, on MDS-UPDRS items 3.15 or 3.16).
• At least experiencing wrist flexion/extension or forearm pronation/supination tremor.

Exclusion Criteria:

• Diagnosed with any other neurological disorder, such as epilepsy, Essential tremor, functional tremor, physiologic tremor, cerebellar tremor, MS, spasticity, ataxia, dystonia, Alzheimer's disease or dementia, atypical parkinsonism, peripheral neuropathy affecting the arms (e.g., carpal tunnel syndrome).
• Disease duration of > 15 years.
• Experiencing severe bradykinesia/rigidity, to such an extent that the participant is unable to perform the ADL tasks (drinking, eating, pouring water).
• Limited movement or muscle function in the arm/hand (for contractures or muscle diseases), or loss of muscle function in one arm (e.g., due to paralysis, or amputation).
• Swollen, infected, inflamed areas, or skin eruptions, open wounds, or cancerous lesions of skin on the forearm or hand that would wear the orthosis during the clinical investigation.
• Consuming excessive alcohol (more than 21 glasses per week for men and 14 glasses per week for women), as defined in the GGZ guidelines on alcohol use.
• Having received a botulinum toxin injection to suppress hand tremor in the past six months, or planned in the coming 60 days.
• Previous or planned Deep Brain Stimulation (DBS) at time of study enrollment that interferes with testing.
• Change in any tremor medication in the past 30 days or planned during the period of testing.
• A hand circumference smaller than 170 mm, or larger than 250 mm.
• An upper arm circumference smaller than 180 mm, or larger than 350 mm.
• Patch/band-aid allergies.
• Participant is unable to communicate with the investigator and staff due to: (1) not mastering the Dutch and English language, (2) blindness, (3) deafness, (4) illiteracy.
• Pregnancy or anticipated pregnancy at time of study enrollment.
• Any health condition that in the neurologist's opinion should preclude participation in this study.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Baseline-Intervention-Sham; Order of tremor assessments: Baseline > STIL Orthosis > Sham	Device: STIL Orthosis; STIL Orthosis, a brace for the arm equipped with passive dampening designed to suppress high-frequency movements.; Device: Sham; A version of the STIL Orthosis that is visually indistinguishable from original, but which does not have the passive dampening mechanism.
Experimental: Baseline-Sham-Intervention; Order of tremor assessments: Baseline > Sham > STIL Orthosis	Device: STIL Orthosis; STIL Orthosis, a brace for the arm equipped with passive dampening designed to suppress high-frequency movements.; Device: Sham; A version of the STIL Orthosis that is visually indistinguishable from original, but which does not have the passive dampening mechanism.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
TETRAS	Tremor severity is assessed using the Tremor Research Group Essential Tremor Rating Scale (TETRAS), which is a validated scale specifically designed for essential tremor, the most common action tremor worldwide. TETRAS will be rated by two independent assessors, based on a video recording. The scale covers 7 postural and kinetic tasks (postural outstretched arms, postural wing beating, finger-to-nose maneuver, eating, drinking, pouring, Archimedes spiral), which are selected to accurately represent the difficulties that PD patients experience with per-forming ADL tasks. A TETRAS score is rated on the baseline, and for the sham and STIL Orthosis conditions. Tremor is rated on a 0 to 4 scale per task, with 0 indicating no visible tremor and 4 indicating a tremor with an amplitude exceeding 20 cm. Combining the 7 tasks from the TETRAS scale, a maximum sum score of 28 points can be achieved per condition.	Day 1

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
MDS-UPDRS part III tremor items	Tremor severity is also assessed using the MDS-UPDRS part III scale. Items 15, 16, and 17, of the MDS-UPDRS part III for postural, kinetic, and rest tremor will be used for assessment of the arm, respectively. Tremor is rated on a 5-point scale, with 0 indicating no tremor and 4 indicating a tremor with an amplitude of at least 10 cm. Note that the tasks for this rating are distinct from the TETRAS scale.	Day 1
Tremor power	Quantification of tremor power will be based on movement data from accelerometry and using surface electromyography (sEMG). Again, the same 7 tasks (postural out-stretched arms, postural wing beating, finger-to-nose manoeuvre, eating, drinking, pour-ing, Archimedes spiral) and resting posture are used to compare baseline, sham and in-tervention conditions. Tremor power is obtained through signal processing.	Day 1
PGI-I	Perceived change in tremor while wearing the sham and STIL Orthosis, using the Patient Global Impression of Improvement (PGI-I) scale. This questionnaire is a single-item scale that measures a patient's perception of improvement or deterioration in their condition following treatment. Answers range from 'very much improved' to 'very much wors-ened'.	Day 1
D-QUEST	User satisfaction is evaluated with a subset of the Dutch Quebec User Evaluation of Satisfaction with Assistive Technology (D-QUEST) (Demers et al., 2001 & 2002). This questionnaire consists of 8 questions regarding comfort and usability of the device itself and 5 questions about the service of the manufacturer. Only 4 questions about satisfaction of the device itself will be questioned. Satisfaction is measured on a 1-5 scale, ranging from 'completely not satisfied' to 'very satisfied'. Additional questions regarding comfort will be asked to examine possible adverse-effects more detailed.	Day 1
Adverse events	Product safety will be assessed using the Dutch version of NCCIH's Adverse Events Report Form. This form is used to report the severity, relationship to the study, taken action, outcome of the (S)AE and whether it was expected or not.	Day 1

Collaborators and Investigators

• Sponsor: Radboud University Medical Center
• Collaborators: The Dutch Brain Foundation

Study record dates

Study Major Dates

• Study Start (Actual): February 19, 2025
• Primary Completion (Actual): December 1, 2025
• Study Completion (Actual): December 1, 2025

Study Registration Dates

• First Submitted: March 3, 2025
• First Submitted That Met QC Criteria: March 14, 2025
• First Posted (Actual): March 20, 2025

Study Record Updates

• Last Update Posted (Actual): March 19, 2026
• Last Update Submitted That Met QC Criteria: March 17, 2026
• Last Verified: February 1, 2025

More Information

Terms related to this study

• Keywords: Orthosis; Parkinson's disease; Action tremor
• Additional Relevant MeSH Terms: Neurologic Manifestations; Nervous System Diseases; Dyskinesias; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Tremor
• Other Study ID Numbers: NL86972.091.24

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Data will be shared with other research sites upon approval of reasonable requests.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No