Effects of Optokinetic Stimulation Without a Reading Task in Patients With Hemianopic Alexia (OPTO)

September 15, 2026 updated by: Clinique Les Trois Soleils

The goal of this clinical trial is to investigate whether optokinetic stimulation delivered without a reading task can improve reading performance in adults with post-stroke hemianopic alexia. The main question it aims to answer is: does optokinetic stimulation without a reading task improve reading speed more than optokinetic stimulation with a reading task? Optokinetic stimlation with a reading task is considered the standard rehabilitation. These two conditions will be administered according to a randomized crossover design to determine wether the presence or absence of a reading task influences reading outcomes.

Participants will

  • receive 4 weeks of optokinetic stimulation without a reading task and 4 weeks of optokinétic stimulation with a reading task, with the order of these two interventions determined by randomization,
  • undergo assesments of reading performance, oculomotor behavior, visual field and rehabilitation tolerability before and after each intervention period,
  • undergo a follow-up assesment 1 month after completion of the interventions.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Stroke can cause a visual field defect known as homonymous hemianopia (HH). When this visual field loss involves the macula, the central area of vision, it may result in reading difficulties known as hemianopic alexia (HA).

The literature reports improved reading performance in these patients after repeated induction of horizontal optokinetic nystagmus (i.e., an oculomotor reflex consisting of horizontal saccades). To induce this nystagmus, previous studies have used a reading task involving text scrolling from right to left.

However, this type of exercise, which relies on reading, is cognitively demanding and may lead to frustration due to reading difficulties, fatigue, and reduced motivation and potentially the impact of rehabilitation. Therefore, the use of a non-reading task could help overcome these limitations.

The present study aims to compare the efficacy of optokinetic stimulation with reading to optokinetic stimulation without reading in patients with HA.

Study Type

Interventional

Enrollment (Estimated)

30

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • France
    • Île-de-France Region
      • Boissise-le-Roi, Île-de-France Region, France, 77310
        • Clinique Les Trois Soleils
        • Contact:
        • Principal Investigator:
          • Christophe Duret

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Time since lesion > 1 month
  • Diagnosis of homonymous hemianopia post-stroke without macular sparing
  • Reading complaint and/or reading impairment
  • Proficiency in reading French
  • Agreed to give informed consent
  • Afiliated with national health insurance

Exclusion Criteria:

  • History of neurological or psychiatric disorders
  • Visual impairment of peripheral origin (i.e., related to damage to the structures of the eye or the optic nerve)
  • Uncorrected visual acuity deficit
  • Reading disorder prior to the stroke (dyslexia)
  • Instability of reading impairment
  • Instability of homonymous hemianopia
  • Major cognitive that would limit the ability of the patient to participate in the study (unilateral spatial neglect, simultanagnosia, comprehension disorder, oral expression disorder)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Other: Group A

Patients receive 15 sessions of optokinetic rehabilitation with a reading task, followed by 15 sessions of optokinetic rehabilitation without an associated reading task.

The optokinetic rehabilitation sessions with reading are considered the standard of care, while optokinetic rehabilitation without an associated reading task is the experimental condition. Each patient undergoes both conditions sequentially and serves as their own control.
Other: Optokinetic stimulation without reading task

Participants are exposed to a horizontally moving optokinetic visual stimulus on a computer screen for 40 minutes per session. The task consists of viewing random sequences of letters scrolling from right to left. The sessions are spread out over 4 weeks, with 3 or 4 sessions per week, to achieve 10 hours (15 sessions) of optokinetic rehabilitation.

Other: Optokinetic stimulation with reading task

Participants are exposed to a horizontally moving optokinetic visual stimulus on a computer screen for 40 minutes per session. The task consists of reading aloud sentences scrolling from right to left. The sessions are spread out over 4 weeks, with 3 or 4 sessions per week, to achieve 10 hours (15 sessions) of optokinetic rehabilitation. The scrolling speed ranges from 85 to 275 words per minute, depending on the participant's reading accuracy.
Other: Group B

Patients receive 15 sessions of optokinetic rehabilitation without an associated reading task, followed by 15 sessions of optokinetic rehabilitation with a reading task.

The optokinetic rehabilitation sessions with reading are considered the standard of care, while optokinetic rehabilitation without an associated reading task is the experimental condition. Each patient undergoes both conditions sequentially and serves as their own control.
Other: Optokinetic stimulation without reading task

Participants are exposed to a horizontally moving optokinetic visual stimulus on a computer screen for 40 minutes per session. The task consists of viewing random sequences of letters scrolling from right to left. The sessions are spread out over 4 weeks, with 3 or 4 sessions per week, to achieve 10 hours (15 sessions) of optokinetic rehabilitation.

Other: Optokinetic stimulation with reading task

Participants are exposed to a horizontally moving optokinetic visual stimulus on a computer screen for 40 minutes per session. The task consists of reading aloud sentences scrolling from right to left. The sessions are spread out over 4 weeks, with 3 or 4 sessions per week, to achieve 10 hours (15 sessions) of optokinetic rehabilitation. The scrolling speed ranges from 85 to 275 words per minute, depending on the participant's reading accuracy.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in reading speed on paper
Time Frame: Baseline and end of each 4-week rehabilitation period: Week 0, Week 4, and Week 8

Change in the number of correctly read words per minute, assessed using the International Reading Speed Texts (IReST). For each participant, the change in reading speed will be calculated separately for the optokinetic rehabilitation condition with a reading task and for the optokinetic rehabilitation condition without a reading task. The within-participant changes obtained after each 4-week period will be pooled across the two randomized sequences and compared between conditions. A higher reading speed indicates better reading performance.
Baseline and end of each 4-week rehabilitation period: Week 0, Week 4, and Week 8

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in reading accuracy on paper
Time Frame: Baseline and end of each 4-week rehabilitation period: Week 0, Week 4, and Week 8

Change in the number and type of errors (paralexias, omissions) assessed using the International Reading Speed Texts (IReST).
Baseline and end of each 4-week rehabilitation period: Week 0, Week 4, and Week 8
Change in reading speed on screen
Time Frame: Baseline and end of each 4-week rehabilitation period: Week 0, Week 4, and Week 8

Change in the number of correctly read words per minute, assessed using a screen-based reading task
Baseline and end of each 4-week rehabilitation period: Week 0, Week 4, and Week 8
Change in reading accuracy on screen
Time Frame: Baseline and end of each 4-week rehabilitation period: Week 0, Week 4, and Week 8

Change in the number and type of errors (paralexias, omissions), assessed during a screen-based reading task
Baseline and end of each 4-week rehabilitation period: Week 0, Week 4, and Week 8
Change in subjective reading abilities
Time Frame: Baseline and end of each 4-week rehabilitation period: Week 0, Week 4, and Week 8

Change in the score on the Hemianopia Reading Questionnaire (HRQ)
Baseline and end of each 4-week rehabilitation period: Week 0, Week 4, and Week 8
Change in ocular fixations during reading
Time Frame: Baseline and end of each 4-week rehabilitation period: Week 0, Week 4, and Week 8

Change in the number of fixations and in the mean fixation duration (in ms) during the screen-based reading task, assessed with an eyetracker
Baseline and end of each 4-week rehabilitation period: Week 0, Week 4, and Week 8
Change in ocular saccades during reading
Time Frame: Baseline and end of each 4-week rehabilitation period: Week 0, Week 4, and Week 8

Change in the number and in the mean amplitude of saccades (in degrees) during the screen-based reading task, assessed with an eyetracker
Baseline and end of each 4-week rehabilitation period: Week 0, Week 4, and Week 8
Change in optokinetic nystagmus
Time Frame: Baseline and at the end of both rehabilitation: Week 0 and Week 8

Change of saccade amplitude and frequency during optokinetic stimulation
Baseline and at the end of both rehabilitation: Week 0 and Week 8
Change in visual detection during standard perimetry
Time Frame: Baseline and end of each 4-week rehabilitation period: Week 0, Week 4, and Week 8

Change in visual sensitivity (in dB) at each tested visual field location on automated static perimetry (Humphrey or Octopus)
Baseline and end of each 4-week rehabilitation period: Week 0, Week 4, and Week 8
Change in visual detection during screen-based perimetry
Time Frame: Baseline and end of each 4-week rehabilitation period: Week 0, Week 4, and Week 8

Change in number of correctly detected targets and mean reaction time (in ms) at each tested visual field location on screen-based perimetry
Baseline and end of each 4-week rehabilitation period: Week 0, Week 4, and Week 8
Tolerability of rehabilitation
Time Frame: Before and after each rehabilitation session

Score of fatigue, stress, and mood induced by the treatment, self-assessed using a numbered visual analogue scale
Before and after each rehabilitation session
Motivation for rehabilitation
Time Frame: End of each 4-week rehabilitation period: Week 4 and Week 8

Score obtained on the Situational Motivation Scale
End of each 4-week rehabilitation period: Week 4 and Week 8

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Clinique Les Trois Soleils

Collaborators

Laboratoire Mémoire Cerveau et Cognition, Boulogne-Billancourt, France

Investigators

  • Principal Investigator: Christophe Duret, Clinique Les Trois Soleils, Boissise-le-Roi, France

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

October 1, 2026

Primary Completion (Estimated)

June 1, 2027

Study Completion (Estimated)

June 1, 2027

Study Registration Dates

First Submitted

September 15, 2026

First Submitted That Met QC Criteria

September 15, 2026

First Posted (Actual)

September 21, 2026

Study Record Updates

Last Update Posted (Actual)

September 21, 2026

Last Update Submitted That Met QC Criteria

September 15, 2026

Last Verified

September 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2026-A00195-46
  • 26.02108.000598 (Other Identifier: SI (CPP))

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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