In brief
- Prechtl's General Movements Assessment (GMA) is a non-invasive, observational tool that evaluates the quality of an infant's spontaneous movements to predict neurodevelopmental outcomes, particularly cerebral palsy.
- It requires only a short video recording of the infant lying awake on their back. No special equipment, no needles, no handling by a clinician.
- Absent fidgety movements are a strong early warning sign of cerebral palsy. The 2017 international guideline reported the GMA's sensitivity for cerebral palsy at 98 percent.
- The GMA works in two developmental windows: the writhing period, from term age to about 6 to 9 weeks post-term, and the fidgety period, from about 6 to 9 weeks until about 20 weeks post-term. Its predictive value is highest at about 3 months post-term.
- It is recommended in international clinical guidelines for early CP detection, which now allow cerebral palsy to be diagnosed before 6 months' corrected age instead of the historical 12 to 24 months.
If your baby was born premature or had a difficult birth, and you have been told to wait and see whether motor problems develop, the General Movements Assessment is a test you should know about. It is one of the most accurate early predictors of cerebral palsy available, it is non-invasive, and it is scored from a short video.
What is the General Movements Assessment?
The General Movements Assessment (GMA) was developed by developmental neurologist Heinz Prechtl and colleagues at the University of Groningen in the Netherlands, building on decades of research into spontaneous movement in infants. Prechtl's group was publishing on the quality of general movements as a marker of neurological dysfunction by 1990, and his 1997 paper in Early Human Development surveyed the state of the method.
The GMA does not test what a baby can do when coaxed. Instead it evaluates what the baby does spontaneously, on their own, when they are awake and settled. The idea is that the quality of spontaneous movement reflects the functional integrity of the infant's nervous system, and that characteristic patterns of abnormal movement predict later neurological problems with high accuracy.
How it works
The assessment is scored from a short video, a few minutes long, of the infant lying on their back in minimal clothing such as a diaper, awake and not crying or fussing, with no one handling or playing with them. In research programs such as Australia's Baby Moves study, parents have also recorded these videos at home with a smartphone app for trained assessors to score remotely.
The GMA evaluates two distinct developmental periods:
The writhing period (term age to about 6 to 9 weeks post-term)
During this period, the infant's spontaneous movements are writhing in character, similar to the movements of a preterm baby but smaller and slower. A normal pattern looks complex, fluent, and variable. Abnormal patterns are classified as poor repertoire, cramped-synchronized (rigid movements in which the limbs and trunk contract and relax almost simultaneously), or chaotic. Cramped-synchronized movements are the most concerning: published figures put them at 70 percent sensitivity and 97 percent specificity for spastic cerebral palsy, meaning they are rarely seen in infants who do not develop it. Poor repertoire movements are less predictive.
The fidgety period (about 6 to 9 weeks until about 20 weeks post-term)
At about 6 to 9 weeks post-term, writhing movements gradually give way to fidgety movements: continuous small movements of moderate speed and variable acceleration involving the neck, trunk, and limbs. Think of them as a constant stream of tiny, gentle wiggles. They are usually most prominent at about 3 months post-term, which is when the GMA's predictive value is highest. The presence of normal fidgety movements at this age is strongly associated with normal neurological development. Absent fidgety movements are a strong early warning sign of cerebral palsy, and the 2017 international guideline reported the GMA's sensitivity at 98 percent.
How accurate is it?
A large 2017 systematic review and clinical guideline by Novak and colleagues, published in JAMA Pediatrics, examined the predictive validity of early movement assessments for cerebral palsy and found that the Prechtl GMA had the highest sensitivity of the early assessments it highlighted. Key figures from that review:
- General Movements Assessment: sensitivity around 98 percent for later cerebral palsy.
- Term-age MRI: sensitivity around 86 to 89 percent.
- Hammersmith Infant Neurological Examination: sensitivity around 90 percent.
What the numbers mean
Sensitivity tells you how often the test correctly identifies a child who will develop CP. Specificity tells you how often it correctly rules out CP in a child who will not develop it. A test with 98 percent sensitivity will miss about 2 children out of every 100 who actually have CP. That is not perfect, but it is far better than waiting until a child misses a walking milestone at 18 months. It is also important to know that these figures come from research settings with trained raters. Results in routine clinical practice may vary.
How it fits with other early assessments
The GMA is not the only tool used for early CP detection, and it is most accurate when used as part of a broader assessment pathway. International guidance, set out in the 2017 clinical practice guideline published in JAMA Pediatrics, recommends combining a standardized motor assessment such as the GMA with neuroimaging and the baby's history. It reports that, before 5 months' corrected age, the GMA plus MRI is more than 95 percent accurate.
Combining these assessments gives families the earliest possible window for intervention. An early detection finding is not a verdict. It is a head start.
What this means for you
If your baby was born early, or had a known risk factor for cerebral palsy such as neonatal encephalopathy, a brain bleed, or a birth defect, the GMA is something you can ask about now rather than waiting. It needs nothing more than a short video recording, but it must be scored by a trained assessor.
The key point is that the window for the fidgety period is limited. It runs from about 6 to 9 weeks until about 20 weeks post-term, and the assessment is most predictive at about 3 months. After that, general movements are replaced by the baby's own goal-directed movements, and the opportunity to assess them is gone. If your baby is approaching or past that window, other assessments such as the HINE or MRI are still available.
Ask your pediatrician or neonatal follow-up clinic whether they have access to a GMA-trained assessor.
This service is mentioned on our premature babies and NICU graduates page, which covers how CP can now be detected before 6 months and how DMI fits into early intervention.
What the GMA does not tell you
The GMA is a screening and prediction tool. It does not diagnose cerebral palsy. A finding of absent fidgety movements tells you the infant is at high risk and should be referred for intervention. It does not tell you the severity or type of CP that may develop, or whether the child's cognitive development will be affected. Those questions require ongoing follow-up and a full diagnostic assessment by a developmental pediatrician or pediatric neurologist.
The GMA also does not rule out all developmental problems. A normal GMA is reassuring but does not guarantee that no motor, cognitive, or behavioural differences will emerge later. The 2017 guideline also notes that some cases of hemiplegic cerebral palsy, which affects one side of the body, may be missed by the GMA. It is one piece of information, placed alongside the rest of the picture.
Where to find training and assessment
The General Movements Trust runs basic and advanced training courses in the GMA and issues certificates to those who complete them. Asking whether a provider has completed GMA training is a reasonable way to check who is qualified to score your baby's video.
The Idaho Infant Toddler Program serves children from birth to 3 years with a developmental delay or a condition, such as prematurity, that may lead to one. Its services are provided at no cost to families, and families can apply on their own or through a referral from their health care provider.
Sources
- Prechtl HFR. State of the art of a new functional assessment of the young nervous system. An early predictor of cerebral palsy. Early Human Development, 1997;50(1):1-11. PubMed
- Novak I, Morgan C, Adde L, et al. Early, accurate diagnosis and early intervention in cerebral palsy: advances in diagnosis and treatment. JAMA Pediatrics, 2017;171(9):897-907. PubMed
- Aizawa CYP, Einspieler C, Genovesi FF, Ibidi SM, et al. The general movement checklist: a guide to the assessment of general movements during preterm and term age. Jornal de Pediatria. 2021;97(4):445-452. PubMed
- Spittle AJ, Olsen J, Kwong A, Doyle LW, et al. The Baby Moves prospective cohort study protocol: using a smartphone application with the General Movements Assessment to predict neurodevelopmental outcomes at age 2 years for extremely preterm or extremely low birthweight infants. BMJ Open. 2016;6(10):e013446. PubMed
- General Movements Trust. The Prechtl General Movement Assessment: courses and certificates. General Movements Trust
- Idaho Department of Health and Welfare. About the Infant Toddler Program. idaho.gov
Nothing here is medical advice, and no single assessment should change your child's care on its own. Discuss anything you read here with your child's pediatrician or therapist.