For decades, families who raised concerns in the first year were told to wait and see. Cerebral palsy was typically diagnosed somewhere between 12 and 24 months, often later. The reason is the accepted wisdom at the time was you simply couldn't be sure before that time.
That's no longer true. A landmark 2017 paper in JAMA Pediatrics by Novak and colleagues showed that a combination of three assessments can identify cerebral palsy with high accuracy in the first months of life. The American Academy for Cerebral Palsy and Developmental Medicine turned that evidence into a formal care pathway in May 2020, and the pathway explicitly advises against conservative wait-and-see monitoring.
Here's what the three tests are, when each one is used, and what the results mean for your child.
“An early diagnosis does not change how severe a child’s cerebral palsy will be. It changes how early the work can start, and the first year is the year the brain is most ready for it.”
— Cerebral Palsy Center Editorial Team
A note on corrected age
Every age threshold below is a corrected age, which means age adjusted for prematurity. For example, a baby born three months early who is six months old by the calendar has a corrected age of three months. It's important to account for this for consistency, since the tests switch over at a specific point.
Test one: Prechtl’s General Movements Assessment
This is the test used before five months corrected age, and it's far gentler than most parents expect. A short video is taken of a baby lying awake and undisturbed, moving on their own. A trained observer then watches how the baby moves, not whether the baby can perform any task.
What the observer is looking for at this stage are fidgety movements, small, continuous, elegant movements of the neck, trunk, and limbs that healthy infants produce around three to five months. If they don't see these it can be a red flag. The assessment is reported as roughly 98% sensitive, and nothing about it is invasive: no needles, no sedation, no equipment beyond a camera.
Test two: the Hammersmith Infant Neurological Examination
After five months corrected age, the General Movements Assessment gives way to the HINE, usually performed at 6, 9, or 12 months. This is a structured 34-item examination covering muscle tone, motor patterns, spontaneous movement, reflexes, and visual and auditory attention and behavior.
The HINE produces a score, and the score has published thresholds. A result below 73 indicates risk of cerebral palsy. A result below 40 indicates an abnormal outcome. Used on its own, the examination is reported as more than 90% accurate.
Test three: MRI
Brain imaging can confirm whether there is damage in the motor areas of the brain. Reported sensitivity sits in the range of 86%–89%. An MRI usually requires sedation in an infant, which is the main reason it is not automatic in every case. Care pathways treat MRIs as appropriate when safe and available, rather than being mandatory.
The most telling result is a combination of findings. The General Movements Assessment paired with an abnormal MRI is reported as more than 95% predictive. Combining the General Movements Assessment, the HINE, and neuroimaging has been reported at a sensitivity of 97.86% and a specificity of 99.22%.
What an early diagnosis can do
It's worth noting that detecting cerebral palsy early doesn't change how severe a child’s cerebral palsy will be. It's not a prognosis, and it won't tell you at four months whether your child will walk.
What it can change is timing. A diagnosis, or even a formal designation of high risk, is what opens the door to targeted therapy during the months when the developing brain is most able to reorganize. It also ends the limbo, which has its own value for families who have spent months being told not to worry while quietly worrying.
What to ask for
If your baby was born very preterm, spent time in a NICU, had a difficult delivery, or was treated for hypoxic-ischemic encephalopathy, these are reasonable questions:
- Has a General Movements Assessment been done? If your baby is under five months corrected, ask directly.
- Is anyone here trained in the HINE? It requires specific training, and not every clinic has someone certified.
- Is there an early detection clinic we can be referred to? The Cerebral Palsy Foundation runs an Early Detection and Intervention Network that can help you find one.
- If we are not doing these tests, what is the reason? There may be a good reason, however it's still worth hearing it out loud.
Once a concern is identified, the next question is what to do with the time. Our guide to early intervention for cerebral palsy covers what those first months of therapy look like.
