Saccade adaptation deficits in developmental dyslexia suggest disruption of cerebellar-dependent learning

Edward G. Freedman, Sophie Molholm, Michael J. Gray, Daniel Belyusar, John J. Foxe

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Background: Estimates of the prevalence of developmental dyslexia in the general population range from 5% to as many as 10%. Symptoms include reading, writing, and language deficits, but the severity and mix of symptoms can vary widely across individuals. In at least some people with dyslexia, the structure and function of the cerebellum may be disordered. Saccadic adaptation requires proper function of the cerebellum and brainstem circuitry and might provide a simple, noninvasive assay for early identification and sub-phenotyping in populations of children who may have dyslexia. Methods: Children between the ages of 7 and 15 served as participants in this experiment. Fifteen had been diagnosed with developmental dyslexia and an additional 15 were typically developing children. Five of the participants diagnosed with dyslexia were also diagnosed with an attention deficit hyperactivity disroder and were excluded from further analyses. Participants performed in a saccadic adaptation task in which visual errors were introduced at the end of saccadic eye movements. The amplitudes of primary saccades were measured and plotted as a function of the order in which they occurred. Lines of best fit were calculated. Significant changes in the amplitude of primary saccades were identified. Results: 12/15 typically developing children had significant adaptation of saccade amplitude in this experiment. 1/10 participants with dyslexia appropriately altered saccade amplitudes to reduce the visual error introduced in the saccade adaptation paradigm. Conclusions: Proper cerebellar function is required for saccadic adaptation, but in at least some children with dyslexia, cerebellar structure and function may be disordered. Consistent with this hypothesis, the data presented in this report clearly illustrate a difference in the ability of children with dyslexia to adapt saccade amplitudes in response to imposed visual errors. Saccadic adaptation might provide a noninvasive assay for early identification of dyslexia. Future work will determine whether reduced saccadic adaptation is pervasive in dyslexia or whether this identifies a sub-phenotype within the larger population of people identified with reading and language deficits.

Original languageEnglish (US)
Article number36
JournalJournal of Neurodevelopmental Disorders
Volume9
Issue number1
DOIs
StatePublished - Nov 9 2017

Fingerprint

Dyslexia
Saccades
Learning
Cerebellum
Reading
Language
Population
Aptitude
Brain Stem
Phenotype

Keywords

  • Adaptation
  • Cerebellum
  • Dyslexia
  • Eye movements
  • Reading
  • Saccades

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health
  • Pathology and Forensic Medicine
  • Clinical Neurology
  • Cognitive Neuroscience

Cite this

Saccade adaptation deficits in developmental dyslexia suggest disruption of cerebellar-dependent learning. / Freedman, Edward G.; Molholm, Sophie; Gray, Michael J.; Belyusar, Daniel; Foxe, John J.

In: Journal of Neurodevelopmental Disorders, Vol. 9, No. 1, 36, 09.11.2017.

Research output: Contribution to journalArticle

@article{25593ef7e072469e9b42ec9a1efa9961,
title = "Saccade adaptation deficits in developmental dyslexia suggest disruption of cerebellar-dependent learning",
abstract = "Background: Estimates of the prevalence of developmental dyslexia in the general population range from 5{\%} to as many as 10{\%}. Symptoms include reading, writing, and language deficits, but the severity and mix of symptoms can vary widely across individuals. In at least some people with dyslexia, the structure and function of the cerebellum may be disordered. Saccadic adaptation requires proper function of the cerebellum and brainstem circuitry and might provide a simple, noninvasive assay for early identification and sub-phenotyping in populations of children who may have dyslexia. Methods: Children between the ages of 7 and 15 served as participants in this experiment. Fifteen had been diagnosed with developmental dyslexia and an additional 15 were typically developing children. Five of the participants diagnosed with dyslexia were also diagnosed with an attention deficit hyperactivity disroder and were excluded from further analyses. Participants performed in a saccadic adaptation task in which visual errors were introduced at the end of saccadic eye movements. The amplitudes of primary saccades were measured and plotted as a function of the order in which they occurred. Lines of best fit were calculated. Significant changes in the amplitude of primary saccades were identified. Results: 12/15 typically developing children had significant adaptation of saccade amplitude in this experiment. 1/10 participants with dyslexia appropriately altered saccade amplitudes to reduce the visual error introduced in the saccade adaptation paradigm. Conclusions: Proper cerebellar function is required for saccadic adaptation, but in at least some children with dyslexia, cerebellar structure and function may be disordered. Consistent with this hypothesis, the data presented in this report clearly illustrate a difference in the ability of children with dyslexia to adapt saccade amplitudes in response to imposed visual errors. Saccadic adaptation might provide a noninvasive assay for early identification of dyslexia. Future work will determine whether reduced saccadic adaptation is pervasive in dyslexia or whether this identifies a sub-phenotype within the larger population of people identified with reading and language deficits.",
keywords = "Adaptation, Cerebellum, Dyslexia, Eye movements, Reading, Saccades",
author = "Freedman, {Edward G.} and Sophie Molholm and Gray, {Michael J.} and Daniel Belyusar and Foxe, {John J.}",
year = "2017",
month = "11",
day = "9",
doi = "10.1186/s11689-017-9218-5",
language = "English (US)",
volume = "9",
journal = "Journal of Neurodevelopmental Disorders",
issn = "1866-1947",
publisher = "Springer New York",
number = "1",

}

TY - JOUR

T1 - Saccade adaptation deficits in developmental dyslexia suggest disruption of cerebellar-dependent learning

AU - Freedman, Edward G.

AU - Molholm, Sophie

AU - Gray, Michael J.

AU - Belyusar, Daniel

AU - Foxe, John J.

PY - 2017/11/9

Y1 - 2017/11/9

N2 - Background: Estimates of the prevalence of developmental dyslexia in the general population range from 5% to as many as 10%. Symptoms include reading, writing, and language deficits, but the severity and mix of symptoms can vary widely across individuals. In at least some people with dyslexia, the structure and function of the cerebellum may be disordered. Saccadic adaptation requires proper function of the cerebellum and brainstem circuitry and might provide a simple, noninvasive assay for early identification and sub-phenotyping in populations of children who may have dyslexia. Methods: Children between the ages of 7 and 15 served as participants in this experiment. Fifteen had been diagnosed with developmental dyslexia and an additional 15 were typically developing children. Five of the participants diagnosed with dyslexia were also diagnosed with an attention deficit hyperactivity disroder and were excluded from further analyses. Participants performed in a saccadic adaptation task in which visual errors were introduced at the end of saccadic eye movements. The amplitudes of primary saccades were measured and plotted as a function of the order in which they occurred. Lines of best fit were calculated. Significant changes in the amplitude of primary saccades were identified. Results: 12/15 typically developing children had significant adaptation of saccade amplitude in this experiment. 1/10 participants with dyslexia appropriately altered saccade amplitudes to reduce the visual error introduced in the saccade adaptation paradigm. Conclusions: Proper cerebellar function is required for saccadic adaptation, but in at least some children with dyslexia, cerebellar structure and function may be disordered. Consistent with this hypothesis, the data presented in this report clearly illustrate a difference in the ability of children with dyslexia to adapt saccade amplitudes in response to imposed visual errors. Saccadic adaptation might provide a noninvasive assay for early identification of dyslexia. Future work will determine whether reduced saccadic adaptation is pervasive in dyslexia or whether this identifies a sub-phenotype within the larger population of people identified with reading and language deficits.

AB - Background: Estimates of the prevalence of developmental dyslexia in the general population range from 5% to as many as 10%. Symptoms include reading, writing, and language deficits, but the severity and mix of symptoms can vary widely across individuals. In at least some people with dyslexia, the structure and function of the cerebellum may be disordered. Saccadic adaptation requires proper function of the cerebellum and brainstem circuitry and might provide a simple, noninvasive assay for early identification and sub-phenotyping in populations of children who may have dyslexia. Methods: Children between the ages of 7 and 15 served as participants in this experiment. Fifteen had been diagnosed with developmental dyslexia and an additional 15 were typically developing children. Five of the participants diagnosed with dyslexia were also diagnosed with an attention deficit hyperactivity disroder and were excluded from further analyses. Participants performed in a saccadic adaptation task in which visual errors were introduced at the end of saccadic eye movements. The amplitudes of primary saccades were measured and plotted as a function of the order in which they occurred. Lines of best fit were calculated. Significant changes in the amplitude of primary saccades were identified. Results: 12/15 typically developing children had significant adaptation of saccade amplitude in this experiment. 1/10 participants with dyslexia appropriately altered saccade amplitudes to reduce the visual error introduced in the saccade adaptation paradigm. Conclusions: Proper cerebellar function is required for saccadic adaptation, but in at least some children with dyslexia, cerebellar structure and function may be disordered. Consistent with this hypothesis, the data presented in this report clearly illustrate a difference in the ability of children with dyslexia to adapt saccade amplitudes in response to imposed visual errors. Saccadic adaptation might provide a noninvasive assay for early identification of dyslexia. Future work will determine whether reduced saccadic adaptation is pervasive in dyslexia or whether this identifies a sub-phenotype within the larger population of people identified with reading and language deficits.

KW - Adaptation

KW - Cerebellum

KW - Dyslexia

KW - Eye movements

KW - Reading

KW - Saccades

UR - http://www.scopus.com/inward/record.url?scp=85033591069&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85033591069&partnerID=8YFLogxK

U2 - 10.1186/s11689-017-9218-5

DO - 10.1186/s11689-017-9218-5

M3 - Article

C2 - 29121855

AN - SCOPUS:85033591069

VL - 9

JO - Journal of Neurodevelopmental Disorders

JF - Journal of Neurodevelopmental Disorders

SN - 1866-1947

IS - 1

M1 - 36

ER -