Reflexes are involuntary responses to specific sensory stimuli that are generally tactile, proprioceptive, or vestibular in nature (Colangelo, 1999). Newborns' reflexive behaviors dominate movement, allow for survival, and set the stage for early primitive learning (Allen & Marotz, 1994).
Certain reflexes, such as swallowing, gagging, coughing, and yawning, remain present throughout a person's lifetime (Allen & Marotz, 1994). Other reflexes, however, begin to be integrated into volitional motor responses by 4 months of age. For example, the reflexive grasp at birth becomes a voluntary grasp by 4 months.
Motor Development and Movement, Carla J. Brown,Tanni L. Anthony,Susan Shier Lowry, Deborah D. Hatton
The continued presence of primitive reflexes above the age of six to twelve months and the absence, or under development, of postural reflexes beyond three and a half years of age are reliable indicators of neurological dysfunction and immature postural, motor, and visual functioning.
A large majority of children with deafblindness have other disabilities as well, and may have aberrant reflexes that adversely affect posture and movement.
There are many primitive reflexes but we will consider three that significantly affect posture and movement and are seen in many children with multiple disabilities.
Moro Reflex: startle reflexes
Emerges at 9 weeks in utero and normally resolves at 2-4 months of life
The earliest form of "fight or flight"
Stimulus is sudden change in position
The response is extension of the arms and flexion of the legs as in a protective posture.
Signs of aberrant or retained Moro reflex
Stimulus bound- can't ignore external stimuli
Chronic fatigue; constant hunger; weak immune systems due to over production of stress hormones
Hyper-sensitive to change, light, sound or touch
Emotionally inappropriate, impulsive, unable to attend to tasks
Tonic Labyrinthine Reflex (TLR)
Emerges at birth and is resolved gradually from 6 weeks to 3 years
Position of flexion: the baby's legs are curled up and flexed into the fetal position
TLR stimulus is a change in head position (forward or backward)
TLR response is a change in muscle tone (flexion or extension)
Reflex is needed to help babies through the birth canal.
Signs of aberrant or unresolved TLR reflex
When retained it can lead to spatial problems, motion sickness, poor posture, muscle tone, and visual perception difficulties.
In supine position, the severely involved child is in stiff extension and cannot lift head, bring hands to midline or turn over.
In prone position, the child is in excessive flexion and may not be able to lift or turn the head to clear the air passage. For example, a child sitting and lifting his head would cause the body to hyper-extend, causing the child to slip right out of the chair. Good practice would be to get down on the child's level and address them eye to eye. This will help avoid posture and muscle tone change due to unresolved TLR reflex.
Asymmetrical Tonic Neck Reflex (ATNR)
ATNR reflex develops in utero and is strongest at 2 months of age; usually suppressed by 5-7 months of age.
The ATNR is stimulated by a rotation of the head left or right and is also refered to as the "fencing" reflex because of the body position. The response is an extension of the limbs on the same side of the body as the chin is facing; the limbs on the other side of the body will curl or flex.
Signs of aberrant or unresolved ATNR
Children with aberrant ATNR are stuck in the positioning until a head turn releases the reflex. With no motivation to turn their head, a deafblind child can be stuck in this position for a very long time.
Because in this position the muscle tone is different on both sides on the body, the student will have difficulty with bilateral skills (Balance, running, and jumping are all skills that require the balanced use of both sides of the body.)