How to Test for a Retained Moro Reflex

Testing for a retained Moro reflex typically involves provoking a mild startle or a brief change in head position and watching for the distinctive arm-extension pattern that newborns display but that should fade by about four to six months of age. When the reflex persists beyond infancy, practitioners look for subtler versions of the same response in older children and adults, along with a cluster of sensory and behavioral signs that can suggest the brainstem circuit behind the reflex never came fully under higher-brain control. The testing itself is simple, but interpreting the results honestly requires understanding what the science does and does not support.

What the Moro Reflex Actually Is

In a healthy newborn, a sudden sensation of falling or a loud noise triggers a two-phase whole-body reaction. First the arms shoot outward with fingers splayed, the back arches, and the legs may extend. Then the arms pull inward in a clasping or embracing motion. This is the Moro reflex. Its neural center sits in the lower brainstem, roughly at the level of the pons and medulla, and it can even be triggered in infants born without higher brain structures, which tells researchers the reflex does not depend on the cortex at all.¹ As the brain matures during the first months of life, the cortex and other upper structures gradually inhibit this circuit, and the reflex disappears from everyday behavior.

The Moro reflex is not a single simple switch. Research suggests the reaction involves at least two neural systems: a fear-driven startle that produces the initial arm extension, and a separation-distress system that drives the clasping phase.² In an infant, the combination makes biological sense as a way to cling to a caregiver when startled. When this circuit is not adequately suppressed by the maturing brain, the body can keep producing fragments of the response well past infancy, sometimes in ways that are not immediately obvious.

The Standard Clinical Test in Infants

Pediatricians check for the Moro reflex during newborn and well-baby exams. The most common method is the head-drop technique: the examiner holds the infant in a semi-reclined position, supporting the head and upper body, then allows the head to drop back roughly 30 degrees while keeping the hands close enough to catch it. A normal Moro response is symmetrical, with both arms extending and then clasping. The examiner notes whether the response is present, whether both sides look equal, and how strong it is. An absent or asymmetrical Moro in a newborn can be a red flag for neurological injury or a clavicle fracture on one side.

Between about three and six months, the reflex should weaken and eventually stop appearing. If a pediatrician can still elicit a full Moro response at nine months or beyond, it raises questions about the pace of neurological maturation. At this age, the test itself is the same, though some clinicians use a sudden loud noise or a quick downward movement of the surface the baby is lying on instead of the head-drop.

Testing in Older Children and Adults

Retained primitive reflexes in school-age children and adults are not part of mainstream pediatric screening in most countries, so the testing protocols you are likely to encounter come from occupational therapy, neurodevelopmental therapy, and educational therapy traditions rather than standard medical exams. The approaches vary by practitioner, but they share a core logic: introduce a stimulus that would have triggered the Moro reflex in infancy and observe the body’s reaction.

One widely used approach has the person stand with feet together, eyes closed, and arms relaxed at their sides. The examiner, standing behind them, produces an unexpected auditory stimulus such as a sharp clap. A retained Moro may show as the arms suddenly flying outward, the shoulders hiking up, a sharp intake of breath, or a visible whole-body flinch that takes noticeably longer to recover from than a simple startle. The examiner is watching not just for the startle itself but for whether the person’s body completes the extension-then-clasping sequence, even in a muted form, and whether heart rate, breathing, and tension return to normal quickly or stay elevated.

Another method adapts the infant head-drop for older individuals. The person lies flat on their back on a padded surface. The examiner cradles the head a few inches above the surface and then lets it drop gently backward. In someone whose Moro reflex is still active, you may see the arms extend involuntarily, the fingers spread, or the body stiffen, even if the person is aware the drop is coming and is trying to stay relaxed. A third variation has the person stand with eyes closed and fall backward slightly from the ankles while the examiner supports them; the examiner watches for arm extension during the brief sensation of falling.

In each case, the examiner typically grades the response on a rough scale from zero (no visible reaction beyond a normal startle) to four (a full, uninhibited Moro pattern). A score of one or two suggests partial retention. This grading is subjective, which is one reason the field has been working on more standardized tools.

Behavioral and Sensory Signs to Watch For

The physical test is only one piece of the picture. Practitioners who assess retained Moro reflexes also look for a constellation of everyday signs that point toward ongoing activation of the reflex circuit. These are not diagnostic on their own, but when several cluster together alongside a positive physical test, they strengthen the case for retention.

Hypersensitivity to sensory input: Overreaction to sudden sounds, bright lights, or unexpected touch. A child who covers their ears at sounds other kids ignore, or who melts down when a classroom gets noisy, may be living with a hair-trigger Moro circuit.
Difficulty with balance and coordination: Because the Moro reflex involves the vestibular (balance) system, children with a retained version sometimes struggle with tasks that require steady posture, like riding a bike, catching a ball, or sitting still on a chair without fidgeting.
Poor emotional regulation: The reflex is tied to the fear and separation-distress systems, so its persistence can leave a child in a state of heightened anxiety or fight-or-flight readiness. Mood swings, difficulty calming down after being upset, and generalized anxiety that seems disproportionate to the situation are commonly reported.
Sleep difficulties: Many parents of children with a suspected retained Moro report trouble falling asleep, night waking, or a startle response when transitioning between sleep stages.
Motion sickness: Some clinicians note that children with an active Moro reflex are more prone to car sickness or other vestibular discomfort.

None of these signs are unique to a retained Moro reflex, and each can have other explanations. The value of the behavioral checklist is in prompting the physical test, not in replacing it.

Connections to ADHD, Learning Difficulties, and Eye-Movement Problems

A body of research has explored whether retained primitive reflexes, including the Moro, correlate with neurodevelopmental conditions. A study of 109 boys aged seven to ten found that those diagnosed with ADHD had significantly higher levels of Moro reflex retention than boys without the diagnosis, and that retention showed both direct and indirect relationships with ADHD symptoms and with performance in mathematics.³ Broader reviews have reported associations between persistent primitive reflexes and learning disabilities, autism spectrum traits, sensory processing difficulties, and dyslexia.⁴

There is also an interesting line of research on eye movements. A cross-sectional study of patients aged four to sixteen found that persistence of primitive reflexes, including the Moro, was associated with problems in fixation maintenance and saccade accuracy. After therapy aimed at inhibiting the retained reflexes, those eye-movement measures improved significantly.⁵ This matters because eye-tracking problems can contribute to reading difficulty and classroom struggles that might otherwise be attributed to attention or motivation.

The proposed mechanism linking all of these is cortical maturational delay. When the cortex is slow to develop certain long-range neural connections, the primitive reflex circuits in the brainstem are not fully suppressed, and the resulting disconnections can ripple through motor control, sensory processing, and attention.⁶ The reflexes themselves may not cause the learning or behavioral problem directly; rather, both the retained reflex and the developmental difficulty may share a common upstream cause in the way the brain wired itself during early development.

Formal Assessment Scales

One of the persistent criticisms of retained-reflex testing is that the grading has historically been examiner-dependent and unstandardized. Researchers have been working on more rigorous assessment tools. A recent effort developed a children’s primitive reflex integration assessment scale that breaks the Moro reflex dimension into specific observable items: whether movements are unsteady or lack fluidity, whether the child cannot tighten both legs, whether both legs cannot fully extend, and whether both arms cannot fully extend.⁷ Each item was tested for its ability to discriminate between children with and without retention. The resulting scale is a step toward making the assessment less dependent on one clinician’s subjective impression, though it is still relatively new and not yet universally adopted.

If you are seeking a formal evaluation, it is worth asking the practitioner which protocol or scale they use and whether it has published reliability data. A clinician who can describe their scoring criteria and cite a validated tool is operating on firmer ground than one who relies entirely on personal clinical judgment and a brief startle test.

Who Does the Testing

Because retained primitive reflexes sit at the intersection of neurology, occupational therapy, physiotherapy, and educational therapy, the professionals who test for them come from several backgrounds. Occupational therapists with training in sensory integration are probably the most common testers. Some physiotherapists and chiropractors who specialize in pediatric neurodevelopmental work also offer assessments, as do certain educational psychologists and developmental optometrists. In mainstream medical practice, a pediatric neurologist would evaluate primitive reflexes as part of a broader neurological exam, but they are less likely to frame a finding as “retained Moro reflex” and more likely to interpret it as a sign of neurological immaturity within their own diagnostic framework.

The landscape can feel confusing because no single professional license guarantees expertise in this area. A reasonable approach is to look for someone who has specific postgraduate training in neurodevelopmental reflex assessment, rather than assuming any OT or physio will be familiar with the protocols. Ask what training program they completed and how many children they have assessed.

How Reliable Is the Evidence

The research on retained primitive reflexes and their effects is growing but still patchy. Most studies are cross-sectional, meaning they show a correlation between reflex retention and a condition like ADHD at a single point in time. Correlation does not establish that the retained reflex caused the behavioral symptoms, and it leaves open the possibility that both are symptoms of the same underlying brain-maturation pattern rather than one causing the other.

Intervention studies exist but are limited in size and design. One trial comparing two reflex-integration programs in children with cerebral palsy found that both approaches led to improvements in gross motor ability and reflex control, but there was no significant difference between the two methods.⁸ That is encouraging in the sense that reflex-integration therapy seems to produce measurable changes, but the lack of a no-treatment control group in many of these studies makes it hard to rule out placebo effects or natural maturation. Children’s brains are developing rapidly, and some improvement would happen with or without therapy.

The honest summary is that the association between retained primitive reflexes and developmental challenges is well-replicated across multiple research groups and populations. The claim that specifically targeting these reflexes produces benefits above and beyond general occupational or physical therapy has weaker support so far. If your child tests positive for a retained Moro and a therapist recommends reflex-integration exercises, you are not being sold snake oil, but you are working with a treatment approach that is still building its evidence base.

What Happens After a Positive Finding

If testing suggests a retained Moro reflex, the typical recommendation involves a program of repetitive, rhythmic movements designed to replicate the developmental stages the reflex should have passed through. These exercises aim to give the brain the sensory input it needs to finally inhibit the brainstem circuit. A common exercise has the child (or adult) lie face-up and slowly open and close the arms and legs in the extension-flexion pattern of the Moro, performed daily over weeks or months, gradually giving the cortex practice at controlling the movement voluntarily.

Programs vary in their specifics. Some follow the Institute for Neuro-Physiological Psychology (INPP) model developed by Peter Blythe and Sally Goddard Blythe, which uses a standardized sequence of inhibition exercises. Others draw on the Masgutova Neurosensorimotor Reflex Integration (MNRI) approach, rhythmic movement training, or an occupational therapist’s own eclectic protocol. The study comparing sensory integration therapy to the MNRI approach found both produced improvements in reflex control and gross motor scores, suggesting that the specific brand of program may matter less than consistent, repetitive sensorimotor practice.⁸

Programs typically run for six to twelve months, with a brief daily home exercise routine and periodic clinic check-ins where the practitioner retests the reflex to track progress. Parents often report that behavioral and sensory improvements emerge gradually rather than all at once, and that sleep and emotional regulation tend to shift before academic performance does.

Testing Yourself at Home

You can get a rough sense of whether a Moro reflex might still be active by trying a simplified version of the startle test. Stand with your feet together, close your eyes, and have someone behind you clap loudly and unexpectedly. Pay attention to what your body does in the first half-second. A normal adult startle is brief: you may blink and your shoulders may rise for a moment, but your arms stay relatively still and you recover almost instantly. If your arms fly out, your fingers splay, your breath catches sharply, and your heart pounds for an unusually long time afterward, it is worth noting. Repeat the test on a different day to see if the response is consistent.

A home test like this cannot give you a clinical-grade answer. You cannot objectively observe your own body’s involuntary reaction, and the simple fact that you know the clap is coming (even if the timing is uncertain) can dampen the response. What a home test can do is help you decide whether a professional evaluation is worth pursuing. If the reaction is dramatic and repeatable, and you also recognize several of the behavioral signs described earlier, that combination is a reasonable basis for booking an assessment with a qualified practitioner rather than dismissing the idea out of hand.

When It Is Not the Moro Reflex

An exaggerated startle response can have causes that have nothing to do with a retained infant reflex. Anxiety disorders produce hypervigilance and heightened startle. Post-traumatic stress disorder is well known for an amplified startle response. Certain neurological conditions cause pathological startle reactions that look superficially similar to a retained Moro but have different underlying mechanisms. Sensory processing disorder, which many Moro-focused practitioners also screen for, can independently produce the sound sensitivity and emotional overreactivity that get attributed to the retained reflex.

This overlap is exactly why testing for a retained Moro should not happen in isolation. A thorough assessment includes a developmental history, a screen of multiple primitive reflexes (the Moro rarely persists alone; the asymmetric tonic neck reflex, symmetric tonic neck reflex, and tonic labyrinthine reflex are usually checked at the same time), and consideration of other explanations for the symptoms. A practitioner who tests only the Moro, declares it retained, and immediately prescribes a program without exploring the broader picture is skipping important steps. The reflex test is one data point, not a diagnosis in itself.