Detecting Sensory Dysfunction, Arousal, and Retained Primitive Reflexes When Working with Children

Sensory Processing Disorder

Various factors contribute to how we process sensory information. Sensory dysfunction may be the result of neurodevelopment, complex trauma, and secondary to insult or injury.

As an occupational therapist, it is crucial to connect underlying dysfunction to function. This means that our concerns should relate not solely on the detection or acknowledgement of a disorder, but rather on how the child is impacted in their daily function. What is their resulting arousal level following sensory input from their natural environments?

While I’ll be outlining some steps you may want to include in your consultation or assessment, it is important to remember to use your clinical reasoning to make the connection to function. We’ll start by reviewing how biomarkers and retained primitive reflexes can impact or provide insight on one’s sensory processing and arousal.


Some physiological functions may have a correlation to sensory dysfunction and arousal:

  • Some children have elevated respiratory rates and resting heart rates when presenting with high arousal levels or a diagnosis such as ADHD.1
  • Changes in the eye’s pupil occur secondary to light stimulation. Pupillary dilation (widening of the pupil) occurs during periods of excitation such as fight or flight. Abnormal pupillary reactions may be connected with disorders such as autism.2
  • Some children, with high arousal levels, have dilated pupils on a regular basis. Therefore, changes in size, as when a light is shined at the child’s eyes, would be minimal. In addition, irregular eye motor responses may be limited. If we do not see typical responses, there may be a need to seek further medical evaluation.

Primitive Reflexes

Primitive reflexes serve a vital purpose. They help a baby move through the birthing canal and develop early motor skills. Retained primitive reflexes may pose challenges with a child’s performance. Reflex retention may have a connection to ADHD symptoms. Such primitive reflexes may contribute to hyperactivity and impulsivity.3

Resources for testing and addressing the Moro reflex, tonic labyrinthine reflex, asymmetrical tonic neck reflex (ATNR), and symmetrical tonic neck reflex (STNR) can be found in my Medbridge course, “Self-Regulation in Children and the Neurological Connection,” as well as my book, Self-Regulation and Mindfulness: Over 82 Exercises & Worksheets for Sensory Processing Disorder, ADHD, & Autism Spectrum Disorder.

Pediatric courses

What Are Some Basic Biomarkers We Can Test?

Post-Rotary Nystagmus

Have the child close their eyes, tilt their head forward approximately 30 degrees, and spin in a chair 10 times to the left. Identify if the nystagmus was more or less than 10 seconds. Use a timer to see how long it takes for the eye movements to become inconsistent. Repeat again to the right. Additionally, assess whether the fast phase was in the opposite direction of the movement, and if the slow phase is within the same direction of the movement.

If no movement is identified, have them repeat the procedure and document the number of repetitions. A prolonged or absent post-rotary nystagmus may tell you something about their threshold to sensory input—specifically vestibular.

Resting Heart Rate and Respiratory Rate

Using a stopwatch, record a 60-second interval, counting the rises and falls of the child’s chest during breathing. Taking the child’s pulse on their wrist provides an indication of heart rate. Both of these should be assessed before and after physical activity or exposure to specific sensory stimuli.

A pulse oximeter is another option. Locate a breath rate and heart rate age chart online (such as this one) to compare your results.

Central Vision

Assess appropriate pupil dilation and constriction by increasing and decreasing the input of light into the eyes. This may be achieved through use of a flashlight, turning the lights on and off, or simply covering and uncovering the eyes. Also, have them maintain a fixed gaze for on an object for approximately 20 seconds, noticing whether this was accomplished without the child breaking their gaze.

Primitive Reflexes

Have the child perform a reach-and-grasp task while supine on the floor or mat. Place an item within arm’s reach at the child’s side and have them reach for the item with their most lateral side. Is ATNR present?

You can also assess for STNR by having them perform a Schilder’s arm extension test. Have them move into a quadruped position and reach for an item placed in front of them. Are able to maintain the position or do they fall to their feet?
Perform exercises requiring alternating sides of the upper body and lower body to move simultaneously to see the child’s ability to isolate right-left as well as upper body-lower body movements.

Tactile Processing

Have the child close their eyes and stimulate the dermatome areas of the hands and arms. Use both light touch and sharp touch, such as a pinprick, to have them identify the stimulus location. Lastly, with eyes still closed, have the child identify five basic items such as a pencil, comb, key, fork, or toothbrush. Note whether you suspect hypo- or hyper-reactivity.


Play both high-frequency and low-frequency music to document the child’s response. You can also try an auditory bingo game. There are a lot of free online videos that present various sounds. Many video creators have already done the work for you in the form of “guess the sound” games. You can make a bingo card with various pictures matching the presented sounds and have the child identify them. Be careful to present an enjoyable stimulus following any adverse responses.

Remember, this is just the start. The presence of dilated pupils or retained reflexes are not guarantees that the child has dysfunction related to sensory processing or their arousal. Be sure to take all the necessary steps within your scope of practice to assess your clients. The previous activities may not be age or developmentally appropriate for all.

  1. Novak, C., & Gill, P. (2016). Pediatric vital signs reference chart.
  2. Daluwatte, C., Miles, J. H., Christ, S. E., Beversdorf, D. Q., Takahashi, T. N., & Yao, G. (2013). Atypical pupillary light reflex and heart rate variability in children with autism spectrum disorder. Journal of Autism and Developmental Disorders, 40, 1910–1925.
  3. Taylor, M., Houghton, S., & Chapman, E. (2004). Primitive reflexes and attention-deficit/hyperactivity disorder: developmental origins of classroom dysfunction. International Journal of Special Education, 19(1), 23–27.