Immediate Effects of Active Prisms on Reading Automaticity and Motor Control in Young Adults With Developmental Dyslexia

NCT07868367 | Not Yet Recruiting

• 1 other identifier: D2025-1
• Study Type: interventional
• Target: 66
• Locations: 1 country
• Sites: 1

Brief Summary

Developmental dyslexia is associated with persistent difficulties in reading automaticity. AUTO-DYS investigates whether a single, brief intervention using active prisms changes the complexity of nonlinear movement dynamics and reading automaticity in young adults with dyslexia. This single-center, prospective, non-randomized controlled study will enroll 66 adults aged 18-30 years: 33 with developmental dyslexia and 33 typical readers. All participants will undergo reading, postural-control, and working-memory assessments before and after an experimental period during one visit. Only participants with dyslexia will receive individually selected active prisms; typical readers will repeat the assessments without active prisms. The main hypothesis is that modifying tonic muscle distribution with active prisms is associated with increased dynamic complexity and improved reading automaticity in participants with dyslexia.

Conditions

Developmental Dyslexia

Keywords

Developmental dyslexia; Reading automaticity; Proprioception; Prismatic lenses; Postural control; Eye tracking; Working memory; Nonlinear dynamics; Multisensory integration

Outcome Measures

Primary Outcomes (2)

• Change in Detrended Fluctuation Analysis Alpha Coefficient

  Change in detrended fluctuation analysis alpha coefficient (α-DFA), reflecting fractal self-similarity and the complexity and adaptability of nonlinear dynamics.

  Baseline and immediately after the intervention/control period, within the same approximately two-hour visit.

• Change in High-Frequency Word Reading Effect

  Change in the high-frequency word effect during silent reading, used to assess reading automaticity.

  Baseline and immediate post-test during one approximately two-hour visit.

Secondary Outcomes (8)

• Change in Postural Sway Path Length Measured Using the Polhemus Tracking System

  Baseline and immediately after the intervention/control period, within the same approximately two-hour visit.

• Change in Pupil Diameter

  Baseline and immediate post-test during one approximately two-hour visit.

• Change in First Fixation Duration During Silent Reading

  Baseline and immediate post-test during one approximately two-hour visit.

• Change in Gaze Duration During Silent Reading

  Baseline and immediate post-test during one approximately two-hour visit.

• Change in Total Fixation Duration During Silent Reading

  Baseline and immediate post-test during one approximately two-hour visit.

Other Outcomes (3)

• Baseline Tonic Symmetry Assessed With the Podal Convergence Maneuver

  Initial assessment during one approximately two-hour study visit, before the experimental intervention.

• Baseline Visual Scotoma Index (0-12)

  Initial assessment during one approximately two-hour study visit, before the experimental intervention.

• Baseline Proprioceptive Maddox Index (0-8)

  Initial assessment during one approximately two-hour study visit, before the experimental intervention.

Study Arms (2)

Active Prisms (Developmental Dyslexia)

EXPERIMENTAL

Participants with documented developmental dyslexia will undergo assessments before and after receiving individually selected active prisms (0.25-3 prism diopters).

Device: Individually Selected Active Prisms.

No Active Prisms (Typical Readers)

NO INTERVENTION

Typical readers will undergo baseline and repeat assessments while wearing their usual unmodified glasses or plain trial lenses, without active prisms.

Interventions

Individually Selected Active Prisms. DEVICE

Individually selected active prisms (0.25-3 prism diopters) will be worn during post-intervention assessments by participants with dyslexia to modify tonic muscle distribution. The intervention will take place during one study visit.

Active Prisms (Developmental Dyslexia)

Eligibility Criteria

• Age: 18 Years - 30 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Adults aged 18-30 years with normal or corrected vision.
• Dyslexia group: documented medical diagnosis of developmental dyslexia and an Alouette-R C index greater than two standard deviations, as specified in the protocol, on the study day.
• Control group: typical readers with an Alouette-R C index less than two standard deviations, as specified in the protocol, on the study day. Eligibility will be verified by the study physician.

You may not qualify if:

• Optical correction exceeding ±0.75 diopters
• known balance or psychiatric disorder
• another diagnosed neurodevelopmental disorder in the dyslexia group
• any diagnosed neurodevelopmental disorder or proprioceptive dysfunction in the control group
• pregnancy
• legal guardianship
• pathological near-vision Parinaud test (P2)
• refusal of consent.

Sponsors & Collaborators

• Lille University: lead

Study Sites (1)

Université de Lille, Federation for Research in Visual Sciences and Cultures (FR-SCV), Plaine Images, Bâtiment L'Imaginarium

Tourcoing, 59200, France

Location

Related Publications (3)

• Stergiou N, Decker LM. Human movement variability, nonlinear dynamics, and pathology: is there a connection? Hum Mov Sci. 2011 Oct;30(5):869-88. doi: 10.1016/j.humov.2011.06.002. Epub 2011 Jul 29.

  PMID: 21802756 BACKGROUND

• Quercia P, Seigneuric A, Chariot S, Bron A, Creuzot-Garcher C, Robichon F. [Proprioception changes induced by prismatic glasses wear in children suffering from developmental dyslexia]. J Fr Ophtalmol. 2007 Apr;30(4):380-9. doi: 10.1016/s0181-5512(07)89608-2. French.

  PMID: 17486030 BACKGROUND

• Virlet L, Sparrow L, Barela J, Berquin P, Bonnet C. Proprioceptive intervention improves reading performance in developmental dyslexia: An eye-tracking study. Res Dev Disabil. 2024 Oct;153:104813. doi: 10.1016/j.ridd.2024.104813. Epub 2024 Aug 19.

  PMID: 39163725 BACKGROUND

MeSH Terms

Conditions

Dyslexia

Condition Hierarchy (Ancestors)

Language Disorders; Communication Disorders; Neurobehavioral Manifestations; Neurologic Manifestations; Nervous System Diseases; Specific Learning Disorder; Learning Disabilities; Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Neurodevelopmental Disorders; Mental Disorders

Central Study Contacts

Cédrick Bonnet, PhD

CONTACT

+33 (0)6 16 89 41 75; cedrick.bonnet@univ-lille.fr

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: Two pre-existing groups (developmental dyslexia and typical readers) complete matched pre- and post-assessments at a single visit. Only the dyslexia group will receive individually selected active prisms between assessments.

Study Record Dates

• First Submitted: September 29, 2026
• First Posted: October 9, 2026
• Study Start: October 1, 2026
• Primary Completion (Estimated): May 31, 2028
• Study Completion (Estimated): May 31, 2028
• Last Updated: October 9, 2026

Record last verified: 2026-09

Locations

FR (1)