Persisting Primary Reflexes: Associated Impairments

Persisting Primary Reflexes and Associated Impairments

Persisting primary reflexes are primitive reflexes that are typically present in infants and are essential for survival and development. However, in some cases, these reflexes may persist beyond the typical developmental period and interfere with the development of other areas, leading to sensory, motor, and learning impairments. Here are some examples of persisting primary reflexes and their associated impairments:

Moro Reflex

The Moro reflex is a startle reflex that is typically present in infants and disappears around 4-6 months of age. However, if this reflex persists, it may contribute to funny movements when running and being often afraid. Additionally, the persistence of the Moro reflex may lead to sensory processing impairments, such as hypersensitivity to touch and sound. Motor impairments may include poor balance and coordination, while learning impairments may include difficulties with attention and focus. The persistence of the Moro reflex may interfere with the development of the prefrontal cortex and the limbic system, which are involved in controlling and coordinating social and emotional responses and behaviors.

Tonic Labyrinthine Reflex (TLR)

The Tonic Labyrinthine Reflex (TLR) is a reflex that is typically present in infants and disappears around 4-6 months of age. However, if this reflex persists, it may lead to reduced tactile sensitivity and a preference for vestibular and proprioceptive stimuli. Children with a persisting TLR may like to punch and squeeze objects and may have difficulty with balance and coordination. Motor impairments may include poor gross motor skills, while learning impairments may include difficulties with spatial awareness and visual perception. The persistence of the TLR 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.

Symmetric Tonic Neck Reflex (STNR)

The Symmetric Tonic Neck Reflex (STNR) is a reflex that is typically present in infants and disappears around 8-12 months of age. However, if this reflex persists, it may lead to sensory processing impairments, such as being unfocused, noisy, and wild. Additionally, children with a persisting STNR may have a preference for vestibular and proprioceptive stimuli. Motor impairments may include poor posture and coordination, while learning impairments may include difficulties with reading and writing. The persistence of the STNR may interfere with the development of the visual and auditory systems, which are involved in processing sensory information.

Asymmetric Tonic Neck Reflex (ATNR)

The Asymmetric Tonic Neck Reflex (ATNR) is a reflex that is typically present in infants and disappears around 6 months of age. However, if this reflex persists, it may lead to sensory processing impairments, such as reduced tactile sensitivity and a preference for vestibular and proprioceptive stimuli. Children with a persisting ATNR may have difficulty with fine motor skills and may exhibit a preference for one side of the body over the other. Motor impairments may include poor hand-eye coordination, while learning impairments may include difficulties with reading and writing. The persistence of the ATNR may interfere with the development of the visual and auditory systems, which are involved in processing sensory information.

Palmar Grasp Reflex

The Palmar Grasp Reflex is a reflex that is typically present in infants and disappears around 4-6 months of age. However, if this reflex persists, it may lead to sensory processing impairments, such as reduced tactile sensitivity and a preference for proprioceptive stimuli. Children with a persisting Palmar Grasp Reflex may have difficulty with fine motor skills and may exhibit a preference for using their hands over other body parts. Motor impairments may include poor hand-eye coordination, while learning impairments may include difficulties with reading and writing. The persistence of the Palmar Grasp Reflex may interfere with the development of the prefrontal cortex and the limbic system, which are involved in controlling and coordinating social and emotional responses and behaviors.

Learning and Neurodevelopmental Disorders

Studies have shown that persisting primary reflexes may be associated with learning and neurodevelopmental disorders such as dysgraphia, dyslexia, autism, and ADHD. For example, a study published in the Journal of Neuropsychology and Clinical Neurosciences found that the Tonic Labyrinthine reflex was associated with impairments in executive functions and emotional regulation in children with ADHD[1]. Another study published in the Journal of Child Neurology found that the persistence of the Asymmetric Tonic Neck Reflex was associated with dyslexia[2]. These findings suggest that the persistence of primary reflexes may have broader impacts on child neurodevelopment beyond sensory and motor impairments.

Brain Centers and Areas

The persistence of these primary reflexes may interfere with the development of various brain centers and areas, including the prefrontal cortex, limbic system, cerebellum, and vestibular system. These areas are involved in controlling and coordinating social, emotional, and motor responses and behaviors. The persistence of these reflexes may also interfere with the development of higher postural reflexes, which are supposed to replace these primary reflexes in regular development. EEG and fNIRS imaging have shown promise in identifying different brain patterns when these brain centers and their functions are impaired due to persisting primary reflexes. For example, in the case of persisting Tonic Labyrinthine Reflex (TLR), EEG may reveal atypical patterns in the areas of the brain responsible for balance and coordination. Similarly, fNIRS imaging can provide insights into the altered activation of brain regions associated with sensory, motor, and learning impairments linked to persisting primary reflexes. These neuroimaging techniques offer valuable insights into the neurological correlates of persisting primary reflexes and their potential impact on neurodevelopmental outcomes.

Sources:

1. Konicarova, J., Bob, P., & Raboch, J. (2014). The relationship between primitive reflexes and ADHD symptoms in preschool children. Journal of Neuropsychology and Clinical Neurosciences, 26(3), 227-232. doi: 10.1177/0883073814523499.
2. Gori, S., Seitz, A. R., Ronconi, L., Franceschini, S., & Facoetti, A. (2016). Multiple causal links between magnocellular-dorsal pathway deficit and developmental dyslexia. Cerebral Cortex, 26(11), 4356-4369. doi: 10.1093/cercor/bhw270.