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

Sponsor
University of Waterloo
Study ID
NCT07341763
Status
Recruiting
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Conditions

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

Eligibility Criteria

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

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).
  • 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).

Study Details

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. We hypothesize that the application of hf-tRNS to V1 will improve the orientation and mobility skills of individuals with constricted visual fields immediately following stimulation as a results of enhanced periphery through modulation of the mechanisms responsible for crowding, thereby reducing crowding effects and improving contrast for individuals with rod-cone dystrophy and RP (genetic conditions), whereas for individuals with glaucoma (a neurogenerative condition), any improvement noted would be attributed to be enhanced processing of visual signal in the affected periphery. The results will inform the design of a future, larger-scale study.

Key Dates

First listed
Jan 14, 2026
Start date
Jul 1, 2026
Status verified
Apr 2026
Primary completion
Aug 31, 2027
Completion
Aug 31, 2027

Study Design

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

Arms

  • Other: Active brain stimulation (study visit 2) and Placebo/Sham (study visit 3)
    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).
  • Other: Placebo/sham (study visit 2) and Active brain stimulation (study visit 3)
    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).

Primary Outcome Measure

Percentage preferred walking speed (PPWS) [ Time Frame: The pre-test and post-tests will take roughly 2 hours to complete. ]

Central Contacts

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