Research on Primitive Reflexes in Child Development

Insights into the Role of Primitive Reflexes in Neurodevelopment

Link Between Retained Primitive Reflexes and Attention Difficulties in Children

Primitive Reflexes and Attention-Deficit/ Hyperactivity Disorder: Developmental Origins of Classroom Dysfunction

Published in 2004 in International Journal of Special Education

This study explored the connection between retained primitive reflexes and attention-related behaviors in boys aged 7 to 10. Researchers assessed four specific reflexes — the Moro, Tonic Labyrinthine (TLR), Asymmetrical Tonic Neck (ATNR), and Symmetrical Tonic Neck (STNR) — in a group of 109 boys. Among them, 54 had been diagnosed with ADHD, 34 showed milder symptoms, and 21 had little to no signs of the condition. Using standardized tools to measure attention difficulties and academic performance, the study found that boys with ADHD had significantly higher levels of primitive reflex retention. There were also notable links between retained reflexes and challenges in math achievement. Interestingly, the Moro reflex appeared to play a central role, potentially influencing the suppression of the other reflexes.

Asymmetric Tonic Neck Reflex and Symptoms of Attention Deficit and Hyperactivity Disorder in Children

Published in 2013 in International Journal of Neuroscience

This study focused on the role of the Asymmetrical Tonic Neck Reflex (ATNR), a primitive reflex that typically fades as the brain matures after birth. Researchers explored whether the continued presence of ATNR might be linked to attention deficit and hyperactivity disorder (ADHD) in children. The study examined 60 children aged 8 to 11 with symptoms of ADHD and compared them to 30 typically developing peers. Results revealed a strong association between persistent ATNR and ADHD symptoms. The findings suggest that some ADHD behaviors may stem from incomplete neurological development related to reflex integration — specifically, the delayed suppression of ATNR.

Retained Primitive Reflexes and ADHD in Children

Published in 2012 in Activitas Nervosa Superior

This study investigated whether children with ADHD are more likely to retain the Moro and Galant reflexes—two primitive reflexes typically integrated during early development. Researchers examined children aged 8 to 11, comparing those diagnosed with ADHD to a control group of the same age. The results showed that children with ADHD had a significantly higher occurrence of these retained reflexes. The findings suggest that persistent Moro and Galant reflexes may be linked to ADHD symptoms, potentially reflecting incomplete neurological development during early childhood.

Delayed Motor Development Is Associated With Retained Primitive Reflexes

Persistence of Primitive Reflexes and Associated Motor Problems in Healthy Preschool Children

Published in 2018 in Archives of Medical Science

This study explored how retained primitive reflexes affect psychomotor development in typically developing children aged 4 to 6. Findings revealed that children with higher levels of reflex retention demonstrated reduced motor efficiency and poorer psychomotor skills. The researchers observed a clear link between the intensity of retained reflexes and developmental delays. Based on these results, the study recommends routine screening for primitive reflexes in early childhood and the use of targeted therapies to support proper reflex integration.

Retained Primitive Reflexes Are Associated With Reading Challenges

Primary Reflex Persistence in Children With Reading Difficulties (Dyslexia): A Cross-Sectional Study

Published in 2007 in Neuropsychologia

This study explored how the persistence of the Asymmetrical Tonic Neck Reflex (ATNR)—a primitive reflex typically inhibited in the first year of life—affects reading development in children. Researchers assessed 739 children aged 7–9 in mainstream schools using standardized literacy tests and clinical assessments for ATNR. The results showed that children with retained ATNR performed significantly worse in reading, spelling, non-word reading, and verbal IQ. There were no significant differences between dyslexic and non-dyslexic poor readers, suggesting they share similar underlying difficulties. Boys and children from disadvantaged backgrounds were more likely to retain the reflex. The findings suggest that retained primitive reflexes may hinder the development of core literacy skills and challenge traditional distinctions between dyslexia and other forms of reading difficulty.

Prevalence of Persistent Primary Reflexes and Motor Problems in Children With Reading Difficulties

Published in 2004 in Dyslexia

This study examined the link between retained primitive reflexes—specifically the Asymmetrical Tonic Neck Reflex (ATNR)—and reading ability in children aged 9–10 in mainstream primary schools in Northern Ireland. Researchers compared three reading-level groups (top, middle, and bottom 10%) and found that children in the lowest reading group had significantly higher levels of retained ATNR and more motor difficulties than their peers. Notably, 17% of poor readers had very high levels of ATNR, while none in the higher groups did. Boys were more likely to show ATNR persistence, but social deprivation was not significantly related. The study also found no significant motor skill differences between dyslexic and non-dyslexic poor readers. These findings suggest a strong association between reading difficulties, motor challenges, and retained reflexes, though the authors caution against assuming a direct causal relationship.

Increased Startle Reflex May Be an Early Indicator of Anxiety and Depression

Startle Modulation in Children at Risk for Anxiety Disorders and/or Alcoholism

Published in 1997 in Journal of the American Academy of Child & Adolescent Psychiatry

This study investigated whether the startle reflex could serve as a vulnerability marker in children aged 10 to 17 with a family history of anxiety disorders and/or alcoholism. Researchers measured startle responses and how they were influenced by prepulse stimuli. The findings showed that children of parents with anxiety disorders had heightened startle responses, while those with alcoholic parents showed reduced habituation and impaired prepulse inhibition. These distinct patterns suggest that startle reflex characteristics may help identify children at higher risk for developing anxiety or alcohol-related disorders.

Families at High and Low Risk for Depression: A Three-Generation Startle Study

Published in 2005 in Biological Psychiatry

This study explored whether heightened startle reflexes could indicate vulnerability to major depressive disorder (MDD) in children and grandchildren of individuals with MDD. Researchers measured startle responses during anticipation of a sudden air blast and in darkness among high-risk (with family history of MDD) and low-risk groups. Results showed that high-risk children exhibited increased startle magnitude, and high-risk girls among the grandchildren also showed elevated startle responses, while boys did not. These findings suggest that increased startle reactivity in threatening situations may serve as a biological marker of vulnerability to both anxiety and depression, indicating shared underlying mechanisms between the disorders.