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

NCT07771699 | Recruiting DMC

• 1 other identifier: HSEARS20250611004
• Study Type: interventional
• Target: 36
• Locations: 1 country
• Sites: 1

Brief Summary

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. 1.If the different types of tES targeting the cerebellum can modulate glaucoma patients' balance function and visual-cognitive function?
2. 2.Which tES techniques among the two types can benefit most?

Conditions

Glaucoma

Keywords

balance; glaucoma; visual attention; transcranial electrical stimulation

Outcome Measures

Primary Outcomes (1)

• Dynamic Balance Performance-The dual task Narrow Path Walking Test

  The Narrow Path Walking Test (NPWT) is a modified version of the Time Up and Go Test (TUGT) that assesses dynamic balance function during gait in a more challenging environment. In the TUGT, subjects stand up from a 46 cm-tall chair, walk 3 m at their normal walking speed, bypass an obstacle, return, and sit down. NPWT requires participants to perform the same procedure as the TUGT. In NPWT, a 40 x 300 cm green mat with 24% Michelson contrast against the walking path to create a challenging environment, dividing the path into two 20 cm-wide narrow pathways to test mediolateral dynamic balance. The NPWT time will be measured. To add difficulty, the dual task of the serial subtraction will be added in the walking procedure.To achieve stable performance, each test will be repeated 3 times, and the results will be averaged to ensure consistency. The recording parameters for NPWT will include trial time, mistakes, cognitive performance, and dual-task cost.

  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.

Secondary Outcomes (4)

• Balance performance - Mini-BESTest

  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.

• Sensory Organization Test

  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.

• Visual cognitive function-Useful Field of View test

  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.

• Visual cognitive function-reaction time test

  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.

Other Outcomes (1)

• The Optic blood Flow

  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.

Study Arms (3)

tDCS

EXPERIMENTAL

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.

Other: transcranial electrial stimulation

tACS

EXPERIMENTAL

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.

Other: transcranial electrial stimulation

Sham

SHAM COMPARATOR

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.

Other: transcranial electrial stimulation

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.

Sham; tACS; tDCS

Eligibility Criteria

• Age: 55 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Age over 55 years old;
• Diagnosis of primary open-angle or normal-tension glaucoma with relative scotoma in both eyes;
• Humphrey Field Analyzer visual field loss (mean deviation of ≤- 6 dB) using the 24-2 testing protocol for both eyes;
• Best-corrected distance visual acuity of 6/12 (equivalent to 0.3 logMAR) or better;
• Cognitive functional score of 22 or above in the Montreal Cognitive Assessment -Hong Kong version (HK-MoCA).
• Only the right-handed population will be recruited (screening by the Edinburgh Handedness Inventory).

You may not qualify if:

• Have musculoskeletal disorders or neurological diseases that can affect the balance or nervous system.
• Ocular diseases other than glaucoma (e.g., age-related macular degeneration, diabetic retinopathy, moderate to severe cataract) or severe hearing impairment (to ensure that participants can hear the instructions clearly during assessments and training)
• Have any contraindications for tES

Sponsors & Collaborators

• The Hong Kong Polytechnic University: lead

Study Sites (1)

Hong Kong Polytechnic University

Kowloon, Hong Kong, 000000, Hong Kong

RECRUITING

MeSH Terms

Conditions

Glaucoma

Condition Hierarchy (Ancestors)

Ocular Hypertension; Eye Diseases

Study Officials

• Allen Ming yan Cheong, PhD

  The Hong Kong Polytechnic University

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Yihong PENG, Phd student

CONTACT

+852-53937970; 22117438r@connect.polyu.hk

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, OUTCOMES ASSESSOR
• Masking Details: Participant Masking: The sham stimulation is pre-programmed to deliver 30 seconds of ramp-up and ramp-down current to generate the same somatosensory sensation as the active stimulation, without therapeutic effect. Active and sham electrode montages are identical. Outcome Assessor Masking: The stimulation device is configured in "study mode" with pre-set randomization codes. The outcome assessor inputs a specific numeric code assigned to each participant into the stimulator, which automatically delivers either active or sham stimulation. Therefore, the outcome assessor remains fully masked to the stimulation condition throughout the recruitment, intervention, and balance testing phases.
• Purpose: TREATMENT
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Head(Academic Programmes and Clinical Training), Prog. Leader (BSc (Hons) in Optometry; MSc in Vision Science and Innovation) & Professor

Study Record Dates

• First Submitted: July 28, 2026
• First Posted: August 18, 2026
• Study Start: July 1, 2026
• Primary Completion (Estimated): November 1, 2029
• Study Completion (Estimated): November 1, 2029
• Last Updated: August 18, 2026

Record last verified: 2026-08

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ICF
• Time Frame: IPD will be available no later than 6 months following publication and for 1 year
• Access Criteria: IPD will be shared with investigators who provide a methodologically sound proposal

Locations

HK (1)