Persisting Primary Reflexes: Tonic Labyrinthine Reflex

Tonic Labyrinthine Reflex

The Tonic Labyrinthine Reflex (TLR) is a primitive reflex that is present in infants and should integrate by the age of 4-6 months. The persistence of the TLR may be correlated with neurodevelopmental disorders such as dyslexia and ADHD. Studies have found that children with dyslexia and ADHD are more likely to have a persisting TLR than typically developing children.

For example, a study published in the Journal of Child Neurology found that children with dyslexia were more likely to have a persisting Tonic Labyrinthine Reflex than typically developing children[1]. Another study published in the Journal of Attention Disorders found that children with ADHD were more likely to have a persisting Tonic Labyrinthine Reflex than typically developing children[2]. These findings suggest that the persistence of the Tonic Labyrinthine Reflex may be a risk factor for the development of neurodevelopmental disorders.

Persisting Labyrinthine Reflex

The persisting Tonic Labyrinthine Reflex (TLR) can lead to impairments in sensory, motor, and learning domains. In the sensory domain, individuals with a persisting TLR may have difficulty processing vestibular and proprioceptive information, leading to balance and coordination problems. In the motor domain, individuals may have difficulty with gross motor skills such as crawling, walking, and running, as well as fine motor skills such as handwriting and buttoning clothes. In the learning domain, individuals may have difficulty with attention, concentration, and spatial awareness. It is estimated that approximately 5-10% of children may have a persisting TLR after 6 months of age.

The Tonic Labyrinthine Reflex is assessed by observing the infant's response to changes in head position. The reflex is considered integrated when the infant can maintain a stable head position without the extension or flexion of the limbs. The assessment of the TLR is typically done by a pediatrician or a physical therapist.

Impacts on Neurodevelopment

The persistence of the Tonic Labyrinthine Reflex may interfere with the development of the cerebellum, which is involved in coordinating movement and balance, and the vestibular system, which is involved in spatial orientation and balance. The persistence of the TLR may also affect the development of the visual system, as the reflex can interfere with the ability to track moving objects. This can lead to difficulties with reading and writing, as well as problems with attention and concentration.

Recent studies have shown that the persistence of the Tonic Labyrinthine Reflex may be correlated with neurodevelopmental disorders such as dyslexia and ADHD. The findings suggest that the persistence of the Tonic Labyrinthine Reflex may be a risk factor for the development of neurodevelopmental disorders.

Imaging Technology for Diagnostic and Therapy

Functional near-infrared spectroscopy (fNIRS) and electroencephalography (EEG) are two neuroimaging techniques that have shown promise in identifying different brain patterns when the brain centers and their functions are impaired due to persisting primary reflexes such as the Tonic Labyrinthine Reflex (TLR).

These techniques have been used to identify atypical patterns of brain activation in the areas responsible for balance and coordination in individuals with a persisting TLR. EEG and fNIRS can provide valuable insights into the neurological correlates of persisting primary reflexes and their potential impact on neurodevelopmental outcomes.

Sources:

1. https://journals.sagepub.com/doi/abs/10.1177/08830738020170010501
2. https://journals.sagepub.com/doi/abs/10.1177/1087054705281129