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

N/ANot Yet RecruitingNCT07830745

Clinique Les Trois Soleils30 enrolled

Overview

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.

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

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

Interventions

Optokinetic stimulation without reading taskOTHER

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.

Optokinetic stimulation with reading taskOTHER

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.

Eligibility

Sex: ALLMin age: 18 Years

Medical Language ↔ Plain English

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)

Outcomes

Primary Outcomes

Change in reading speed on paper

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.