Brain Stimulation Effects on Orientation and Mobility Skills in Adults With Vision Impairment

NCT07341763 | Not Yet Recruiting

• 1 other identifier: REB #47153
• Study Type: interventional
• Target: 20
• Locations: 1 country
• Sites: 1

Brief Summary

This pilot clinical trial evaluates whether non-invasive brain stimulation improves the orientation and mobility (O\&M) skills of individuals with constricted visual fields in both eyes. The study is composed of three visits. The first visit is meant to confirm eligibility by performing a few clinical tests. Eligible participants will then complete two additional visits, one in which the participants receive active stimulation, and one in which the participants receive placebo (sham) stimulation. Stimulation will be administered in a randomized, double-blind order. To evaluate improvement, various measures of O\&M performance will be assessed on a standardized obstacle course featuring static natural and artificial obstacles at defined intervals after the intervention. The investigators hypothesize that the application of brain stimulation to region of the brain responsible for visual processing will improve the orientation and mobility skills of individuals with binocular constricted visual fields immediately following stimulation, and the results will inform the design of a future, larger-scale study.

Conditions

Visually Impaired Persons; Peripheral Visual Field Defect of Both Eyes; Glaucoma; Vision Loss Partial; Orientation; Mobility Difficulty; Rod Cone Dystrophy; Low Vision, Both Eyes; Mobility Limitation; Mobility and Independence; Retinitis Pigmentosa (RP)

Keywords

Retinitis Pigmentosa (RP); Rod Cone dystrophy; Advanced Glaucoma; Visually Impaired Persons; Peripheral Visual Field Defect of Both Eyes; Low Vision, Both eyes; Brain stimulation; tES; tRNS; hf-tRNS; transcranial electrical stimulation; transcranial random noise stimulation; high-frequency transcranial random noise stimulation; Long white cane; white cane; mobility cane; walking; orientation and mobility; orientation; mobility; low vision; vision loss partial; occipital pole; primary visual cortex; V1; neuroplasticity; mobility difficulty; mobility limitation; mobility and independence

Outcome Measures

Primary Outcomes (1)

• Percentage preferred walking speed (PPWS)

  * Change in Percentage preferred walking speed (PPWS (%)) before and right after (2 mins) active stimulation. * Change in Percentage preferred walking speed (PPWS (%)) before and 30-minutes after active stimulation. * Change in Percentage preferred walking speed (PPWS (%)) before and right after (2 mins) placebo/sham stimulation. * Change in Percentage preferred walking speed (PPWS (%)) before and 30-minutes after placebo/sham stimulation. * Behavioural Measure: The participant will first complete section #1, which is obstacle free. The time taken to complete the section and preferred walking speed in an unobstructed path (obtained from the completion time and length of the straight, flat path) will be measured. They will then proceed to complete section #2, which has obstacles. The time taken to complete the section, and preferred walking speed in an obstructed path will be measured. PPWS= (preferred walking speed course 1/ preferred walking speed course 2)\*100.

  The pre-test and post-tests will take roughly 2 hours to complete.

Secondary Outcomes (3)

• Visual detection distance (VDD)

  The pre-test and post-tests will take roughly 2 hours to complete.

• Visual identification distance (VID)

  The pre-test and post-tests will take roughly 2 hours to complete.

• Number of orientation and mobility errors.

  The pre-test and post-tests will take roughly 2 hours to complete.

Study Arms (2)

Active brain stimulation (study visit 2) and Placebo/Sham (study visit 3)

OTHER

Participants in this arm will be exposed to active stimulation for 20 minutes whilst seated quietly at treatment session 1 (study visit 2). They will then complete the orientation and mobility (O\&M) course 2-minutes and 30-minutes after stimulation. It is important to note that they will also complete the course before undergoing stimulation. In addition, individuals with constricted visual fields in both eyes who use a white cane for travelling will be encouraged to use their personal cane for the course, whereas those who do not use a cane will complete the course as they naturally would for any travel paths. Forty-eight hours later the same participants in this arm will be exposed to placebo/sham stimulation (study visit 3) and except for the treatment they receive that day, the same protocol from the previous visit will be executed, and the same outcome measures evaluated. Interventions: Active hf-tRNS at treatment (study visit 2); Placebo/sham hf-tRNS (study visit 3).

Device: Active hf-tRNS.; Device: Placebo/sham hf-tRNS

Placebo/sham (study visit 2) and Active brain stimulation (study visit 3)

OTHER

Participants in this arm will be exposed to placebo/sham stimulation for 20 minutes whilst seated quietly at treatment session 1 (study visit 2). They will then proceed to complete the orientation and mobility (O\&M) course 2-minutes and 30-minutes after stimulation. It is important to note that they will also complete the course before undergoing stimulation. In addition, individuals with constricted visual fields in both eyes who use a white cane for travelling will be encouraged to use their personal cane for the course, whereas those who do not use a cane will complete the course as they naturally would for any travel paths. Forty-eight hours later the same participants in this arm will be exposed to active stimulation (study visit 3) and except for the treatment they receive that day, the same protocol from the previous visit will be executed, and the same outcome measures evaluated. Interventions: Placebo/sham hf-tRNS at treatment (study visit 2); Active hf-tRNS (study visit 3).

Device: Active hf-tRNS.; Device: Placebo/sham hf-tRNS

Interventions

Active hf-tRNS. DEVICE

Active hf-tRNS: A weak alternating electric current is applied to the head through two electrodes to affect the cortical excitability of the targeted cells in the brain. Stimulation instrument: neuroConn DC Stimulator Plus 2019 (Direct current stimulator Model number 0021, power: 1.2 W, charger: 2.9 V (maximum 160 mA)) (neurocaregroup.com), or neuroConn DC Stimulator MC 2016 (Multi-channel stimulator Model number 0028, power: 24 W, rating: 12 V (maximum 2 A)) (neurocaregroup.com).

Active brain stimulation (study visit 2) and Placebo/Sham (study visit 3); Placebo/sham (study visit 2) and Active brain stimulation (study visit 3)

Placebo/sham hf-tRNS DEVICE

Placebo/sham hf-tRNS: The tRNS machine will be used as in active stimulation, except the electrical current will not be applied. Stimulation instrument: neuroConn DC Stimulator Plus 2019 (Direct current stimulator Model number 0021, power: 1.2 W, charger: 2.9 V (maximum 160 mA)) (neurocaregroup.com), or neuroConn DC Stimulator MC 2016 (Multi-channel stimulator Model number 0028, power: 24 W, rating: 12 V (maximum 2 A)) (neurocaregroup.com).

Active brain stimulation (study visit 2) and Placebo/Sham (study visit 3); Placebo/sham (study visit 2) and Active brain stimulation (study visit 3)

Eligibility Criteria

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

You may qualify if:

• Are healthy, capacitated adults with binocular constricted visual field loss (due to either retinitis pigmentosa (RP), rod-cone dystrophy, or advanced glaucoma) resulting in functional vision losses. These individuals with visual impairments can be those who have been previously trained by an Orientation and Mobility (O\&M) specialist to independently travel with the long white cane daily (since the length of the white cane and tip at the base are based on personal preference, they should be willing to use their own white cane for the study), and those who do not necessarily use a cane for travelling.
• Have binocular visual acuity or best corrected binocular visual acuity no better than 6/12 or 20/40 or +0.30 logMAR (inclusive) with no eccentric viewing, and visual fields no better than 70 degrees in total in each eye.
• Are over the age of 18 (inclusive) and has full legal capacity to provide informed consent.
• Have read and fully comprehends the information in the consent letter.
• Are willing and capable of adhering to instructions and maintaining the outlined appointment schedule.

You may not qualify if:

• Are involved in other recent eye-related studies, either clinical or research-related. To be eligible they would have to wait at least one week for studies not involving brain stimulation, and four weeks for studies in which they receive brain stimulation before they could participate in this study.
• Have been diagnosed with dementia or self-reported dementia with no formal diagnosis.
• Have been diagnosed with a cognitive impairment or self-reported cognitive impairment with no formal diagnosis.
• Have been diagnosed with physical or motor impairments resulting in walking and/or balancing issues or self-reported physical or motor impairments resulting in walking and/or balancing issues with no formal diagnosis.
• Have been diagnosed with vestibular disorders or dysfunctions which affects one's balance and/or mobility or self-reported vestibular disorders or dysfunctions which affects one's balance and/or mobility with no formal diagnosis.
• Are unable to follow the researcher's instructions.
• Are anticipating treatment (including ocular surgery) for any eye disease within the duration of the study.
• Have any ocular pathology in addition to retinitis pigmentosa (RP), rod-cone dystrophy, or advanced glaucoma, which can diminish their visual acuity and/or their visual field, however wearing glasses or contact lenses, as well as mild cataract of grade 2 or below is acceptable.
• Have severe hearing impairment.
• Are pregnant or trying to get pregnant.
• Fit any of the typical contraindicators for brain stimulation. See contraindicator section below.
• For all participants the contraindications for brain stimulation are:
• Diagnosed with epilepsy or have previously experienced an epileptic seizure.
• Implanted medication pump or implanted electronic device, including defibrillator or pacemaker.
• Any metal implants in the head (excluding tooth fillings).

Sponsors & Collaborators

• University of Waterloo School of Optometry and Vision Science: collaborator
• The Hong Kong Polytechnic University: collaborator
• University of Waterloo: lead

Study Sites (1)

University of Waterloo, School of Optometry and Vision Science

Waterloo, Ontario, N2L 3G1, Canada

Location

MeSH Terms

Conditions

Retinitis Pigmentosa; Cone-Rod Dystrophies; Vision, Low; Orientation, Spatial; Mobility Limitation; Glaucoma

Condition Hierarchy (Ancestors)

Eye Diseases, Hereditary; Eye Diseases; Retinal Dystrophies; Retinal Degeneration; Retinal Diseases; Genetic Diseases, Inborn; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Vision Disorders; Sensation Disorders; Neurologic Manifestations; Nervous System Diseases; Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Spatial Behavior; Behavior; Ocular Hypertension

Study Officials

• Benjamin Thompson, PhD

  University of Waterloo School of Optometry and Vision Science

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Benjamin Thompson, PhD

CONTACT

1+5198884567; ben.thompson@uwaterloo.ca

Melanie A Mungalsingh, PhD

CONTACT

melanie.mungalsingh@uwaterloo.ca

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Masking Details: Each participant will experience active brain stimulation and placebo (sham)stimulation. The participant and the researcher will be blind to which session the participant receives active brain stimulation and placebo.
• Purpose: TREATMENT
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Director and Professor, School of Optometry and Vision Science.

Model Details: The study is a randomized, double-blind, placebo-controlled pilot study. There will be two brain stimulation/intervention sessions. The participant will receive active stimulation at one session and placebo at another sessions. Intervention sessions will be separated by 48 hours. The order will be randomized so that neither the participant nor the researcher will know what the participant will receive at each session.

Study Record Dates

• First Submitted: January 5, 2026
• First Posted: January 14, 2026
• Study Start: June 1, 2026
• Primary Completion (Estimated): August 31, 2027
• Study Completion (Estimated): August 31, 2027
• Last Updated: April 28, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP
• Time Frame: The IPD will be available upon publication, and no more than 9 months after the publication.
• Access Criteria: The IPD will be shared to researchers who provide a methodologically sound proposal.

Locations

CA (1)