Cerebellar Transcranial Alternating Current Stimulation (tACS) to Modulate Parkinson's Disease Tremor

NCT ID: NCT06993571

Last Updated: 2025-05-29

Basic Information

• Recruitment Status: RECRUITING
• Clinical Phase: NA
• Total Enrollment: 10 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2025-04-16
• Study Completion Date: 2025-12-31

Brief Summary

Parkinson's disease (PD) is a prevalent neurodegenerative disorder characterized by different motor symptoms, including tremor, which is particularly difficult to manage. Common treatments, such as dopaminergic therapy, can have limitations in efficacy. Recent advancements in non-invasive brain stimulation, specifically phase-adaptive transcranial alternating current stimulation (tACS), offer a promising approach to reduce PD tremor. In the current project, a newly developed closed-loop system delivers precisely synchronized cerebellar tACS by aligning stimulation with the intrinsic hand tremor signal. The study will assess the efficacy of this novel approach to reduce hand tremor in PD patients.

Detailed Description

Parkinson's disease (PD) is the second most common neurodegenerative disorder, characterized by progressive neurodegeneration, especially in the substantia nigra. Clinically, PD is characterized by motor impairment, including bradykinesia, rigidity, postural instability, and tremor, with hand trem-or being particularly challenging due to its heterogeneity and the incomplete understanding of its underlying neurophysiological mechanisms. Emerging evidence suggests that pathological activity in the cortico-thalamo-cortical (CTC) network is associated with PD tremor amplitude. In recent years, the cerebellum has been recognized for its direct involvement in tremor dynamics within the CTC network. Addressing the abnormal oscillatory activity within this network could potentially modu-late tremor pathophysiology.

Current therapeutic approaches for PD tremor focus on dopaminergic replacement, however some patients exhibit minimal response to this treatment. Deep brain stimulation (DBS) has shown effi-cacy in alleviating tremor, but its invasive nature and associated risks limit its widespread use. Con-sequently, there has been growing interest in non-invasive brain stimulation techniques as poten-tial alternatives for tremor management. Among these techniques, transcranial alternating current stimulation (tACS) has gained significant attention due to its ability to modulate endogenous brain oscillations. Phase-specific tACS, which involves aligning the stimulation phase with the intrinsic tremor rhythms, has demonstrated potential in entraining and reducing PD tremor. However, the application of this technique has been constrained by the complexities associated with phase ad-justment algorithms and the need for a responsive closed-loop system capable of real-time phase synchronization.

For the current project, a novel closed-loop device has been developed together with the collabo-rator neuroConn GmbH that is specifically designed to target PD tremor. This device is capable of real-time monitoring of hand tremor, rapid signal processing, and delivering phase-locked tACS within safe operational parameters. The central hypothesis is that phase-locked tACS of the cere-bellum can modulate the oscillatory dynamics within the CTC network and thereby reduce tremor amplitude in PD patients.

The study will involve PD patients with moderate to severe hand tremor, as assessed using the Movement Disorders Unified Parkinson's Disease Rating Scale (MDS-UPDRS). The experimental design involves two sessions, both utilizing closed-loop tACS at an intensity of 2 to 4 mA.

In each session, a baseline recording of PD hand tremor will be collected before stimulation. In the first session, the phase alignment between the tremor and tACS signals will be systematically varied across 60° phase bins; plus a sham (zero stimulation amplitude) and an unlocked stimulation proto-col (open-loop). The data from this session will be analyzed to determine the optimal phase align-ment. In the second session, tACS will be applied using the optimal phase alignment identified in the first session. After each block of stimulation, a post-stimulation baseline recording will be con-ducted to evaluate the immediate effects of the intervention. This design enables the assessment of phase-specific effects of closed-loop tACS on PD hand tremor.

This study aims to assess the extent and duration of tremor reduction achieved by closed-loop phase-adaptive cerebellar tACS, enhancing our understanding of the CTC network and potentially offering new insights into non-invasive therapeutic strategies for managing PD tremor.

Conditions

Parkinson's Disease (PD); Tremor

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: CROSSOVER
• Primary Study Purpose: TREATMENT
• Blinding Strategy: DOUBLE

Study Groups

Active-tACS

Patients receive an active tACS stimulation with 2-4 mA amplitude

Group Type: EXPERIMENTAL

Active-tACS

Intervention Type: DEVICE

30 seconds of closed-loop tACS at 2-4 mA, with 6 alternating phase alignments and 1-3 repetitions. Phase alignment is adjusted to the patient's tremor frequency and rhythm in real time. Administered using the neuroConn LOOPIT device and 2 electrodes placed on the cerebellum and jaw, with an area of 5x5 and 5x7 respectively. The stimulation begins with a 3-second ramp-up and ends with a 3-second ramp-down.

Sham-tACS

Patients receive a tACS stimulation with 0 mA amplitude

Group Type: SHAM_COMPARATOR

Sham-tACS

Intervention Type: DEVICE

30 seconds of tACS at 0 mA and 1-3 repetitions. Administered using the neuroConn LOOPIT device and 2 electrodes placed on the cerebellum and jaw, with an area of 5x5 and 5x7 respectively. The sham protocol begins with a 3-second ramp-up and ends with a 3-second ramp-down.

Unlocked-tACS

Patients receive an active tACS stimulation with 2-4 mA amplitude but without phase alignment between tremor and tACS

Group Type: ACTIVE_COMPARATOR

Unlocked-tACS

Intervention Type: DEVICE

30 seconds of open-loop tACS at 2-4 mA, with no phase alignments and 1-3 repetitions. Administered using the neuroConn LOOPIT device and 2 electrodes placed on the cerebellum and jaw, with an area of 5x5 and 5x7 respectively. The stimulation begins with a 3-second ramp-up and ends with a 3-second ramp-down.

Interventions

Active-tACS

30 seconds of closed-loop tACS at 2-4 mA, with 6 alternating phase alignments and 1-3 repetitions. Phase alignment is adjusted to the patient's tremor frequency and rhythm in real time. Administered using the neuroConn LOOPIT device and 2 electrodes placed on the cerebellum and jaw, with an area of 5x5 and 5x7 respectively. The stimulation begins with a 3-second ramp-up and ends with a 3-second ramp-down.

Intervention Type: DEVICE

Sham-tACS

30 seconds of tACS at 0 mA and 1-3 repetitions. Administered using the neuroConn LOOPIT device and 2 electrodes placed on the cerebellum and jaw, with an area of 5x5 and 5x7 respectively. The sham protocol begins with a 3-second ramp-up and ends with a 3-second ramp-down.

Intervention Type: DEVICE

Unlocked-tACS

30 seconds of open-loop tACS at 2-4 mA, with no phase alignments and 1-3 repetitions. Administered using the neuroConn LOOPIT device and 2 electrodes placed on the cerebellum and jaw, with an area of 5x5 and 5x7 respectively. The stimulation begins with a 3-second ramp-up and ends with a 3-second ramp-down.

Intervention Type: DEVICE

Eligibility Criteria

Inclusion Criteria

• Clinical diagnosis of Parkinson's disease based on UK Brain Bank criteria
• Patient exhibiting moderate to severe hand tremor
• Provision written informed consent by the patient

Exclusion Criteria

• History of other neurological disorders such as vascular malformations, ischemic or haemorrhagic stroke, cerebral neoplasia, epilepsy, or major psychiatric illness
• Existence of heart pacemaker or metal implants in the body
• Pregnancy

• Minimum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Universitätsklinikum Hamburg-Eppendorf

OTHER

Sponsor Role: lead

Responsible Party

Simone Zittel

Dr. med.

Responsibility Role: PRINCIPAL_INVESTIGATOR

Locations

Universitätsklinikum Hamburg-Eppendorf

Hamburg, City state of Hamburg, Germany

Site Status: RECRUITING

Countries

Germany

Central Contacts

Simone Zittel, Dr. med.

Role: CONTACT

s.zittel-dirks@uke.de

+49 40 7410 53770

Facility Contacts

Simone Zittel, Dr. med.

Role: primary

s.zittel-dirks@uke.de

+49 40 7410 53770

Other Identifiers

Cereb_tACS_PD_TR

Identifier Type: -

Identifier Source: org_study_id