Cross-modal Neuromodulation to Improve Balance and Cognition in Older Adults With Glaucoma: A Randomized Trial of Cerebellar Transcranial Electrical Stimulation

Sponsor
The Hong Kong Polytechnic University
Study ID
NCT07771699
Status
Recruiting
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Conditions

Eligibility Criteria

Sex
ALL
Age
55 Years - N/A
Healthy Volunteers
Not accepted

Interventions

  • transcranial electrial stimulation — OTHER
    This intervention is uniquely designed to enhance balance function in patients with glaucoma using non-invasive cerebellar Transcranial Electrical Stimulation (tES), encompassing both transcranial Direct Current Stimulation (tDCS) and transcranial Alternating Current Stimulation (tACS). Glaucoma-induced visual field loss disrupts the visual feedback critical for postural control, forcing patients to rely heavily on sensory re-weighting (integrating vestibular and proprioceptive inputs). The cerebellum is the central hub for this multi-sensory integration and motor adaptation. By modulating cerebellar excitability and neural oscillations, this intervention aims to facilitate sensory re-weighting, optimize vestibular-ocular/spinal reflexes, and ultimately improve dynamic and static balance.

Study Details

The goal of this clinical trial is to use different tES techniques to constantly stimulate the cerebellum in older glaucoma patients. The main questions aim to answer : 1. If the different types of tES targeting the cerebellum can modulate glaucoma patients' balance function and visual-cognitive function? 2. Which tES techniques among the two types can benefit most? Participants will be required to receive the stimulation 15 times (3 sessions, 5 continuous days/session, 1-week interval between each session), and complete the balance and visual-cognitive function outcome measurements before and after each session.

Key Dates

First listed
Aug 18, 2026
Start date
Jul 1, 2026
Status verified
Aug 2026
Primary completion
Nov 1, 2029
Completion
Nov 1, 2029

Study Design

Enrollment
36 participants (estimated)
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
TREATMENT

Arms

  • Experimental: tDCS
    The tDCS stimulation session will be performed over five consecutive days. The tDCS protocol used in this study will involve the application of a low direct current of 2 mA for 20 minutes using a Nurostym tES device (Neuro Device Group SA, Poland). It begins with a 30-second ramp-up period and employs two 5 cm × 5 cm electrodes that are housed in saline-soaked sponges. The anode and the cathode electrodes will be placed bilaterally over the cerebellum (1 cm below the inion of the occipital bone) and the right shoulder, respectively. This electrode montage is based on previous studies and is designed to target cerebellar regions implicated in balance and motor control.
  • Experimental: tACS
    The tACS stimulation session will be five consecutive days. tACS protocol used in the study will be delivered using the Neurostym tES device (Neuro Device Group SA, Poland) with two 5 × 5 cm electrodes. The anode and the cathode electrodes will be placed bilaterally over the cerebellum (1 cm below the inion of the occipital bone) and the right shoulder, respectively. The tACS will be administered at a current of 2 mA with a stimulation frequency of 50 Hz. There will be a 30-second ramp-up and ramp-down period to minimize discomfort at the onset and offset of stimulation.
  • Sham Comparator: Sham
    The sham protocol will mimic the same electrode placement as the other experimental group setting to maintain blinding. During sham stimulation, the stimulator will deliver 2 mA current for the first 30 seconds, after which the current will be turned off for the remainder of the session. To further enhance blinding, the current will be reactivated at 2 mA for the final 30 seconds of the stimulation and then gradually taper off thereafter. The total duration of the sham stimulation will match that of the active stimulation protocols (20 minutes). Each stimulation session will be five consecutive days.

Primary Outcome Measure

Dynamic Balance Performance-The dual task Narrow Path Walking Test [ Time Frame: The outcome will be assessed 6 times: before and after each stimulation session (tDCS, tACS, Sham session ) (each session length = 5 consecutive days). Therefore, there will be tDCS-pre, tDCS-post; tACS-pre, tACS-post; Sham-pre, Sham-post. ]

Central Contacts

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