Q: When and how is a diagnosis of cerebral palsy usually made?

A: If a child has significantly delayed motor and mobility functions at 2 years of age, cerebral palsy may be diagnosed. This diagnosis will be made based on the discovery of a break in the profile of skills across defined functional and developmental domains.

For a child to be diagnosed with cerebral palsy, the following must be identified: movement and posture disorder through the analysis of abnormal motor development, abnormality in the development of the brain based on medical evaluation and etiological testing, and the absence of a non-progressive neurodegenerative condition. Cerebral palsy can be further sub-categorized based on the area of motor decrement and the type of abnormal movements displayed. The evaluation of a child's basic sensory and motor processes occurs at a clinical visit while the evaluation of integrated processes, including everyday skills, occurs through family and teacher interviews.

It is important to differentiate between cerebral palsy and other neurological disorders that mimic many of the traits characteristic of cerebral palsy. Magnetic resonance imaging and analysis of the child's personal and genetic history can help avoid misdiagnosis


The Cerebral Palsies - Diagnosis

In the absence of any specific diagnostic test the diagnosis of cerebral palsy remains an exercise of clinical skills. Although the diagnosis may be suggested by abnormal neuro-imaging, such tests do not predict the extent of disability and may be normal even in severe cases. The diagnostic process always involves, to some degree, the exclusion of many other conditions, some acute and transient, others remorselessly progressive, which mimic the clinical appearances of the cerebral palsies at some stages of their evolution. Where there is an obvious story of complicated delivery with clear evidence of birth injury, or of low-birth weight, the diagnosis may be made on the basis of overwhelming probability, but in many other cases the process of exclusion is absolutely necessary. Cerebral palsy implies permanent and significant disability, with some loss of hope and grief for the parents; in the absence of certainty, it is better to make a “working diagnosis” and to provide appropriate support for the child and family until the true diagnosis becomes clear.

The diagnosis of cerebral palsy is made on the basis of (1) delay in reaching motor milestones, (2) abnormal neurological signs indicating either an upper motor neuron lesion or a movement disorder, or both, usually with persistence of primitive reflexes and (3) exclusion of progressive or transient neurological disorder. The clinician should identify the “type” of cerebral palsy as described below, and should, so far as is feasible, attempt to identify the pathological processes that have lead to the clinical outcome. Increasingly, “cerebral palsy” is regarded as an unsatisfactory diagnosis in terms of its ability to explain what has happened to a disabled child or to predict the outcome in an individual case. Ideally, it is preferable to speak of “Right spastic hemiplegic cerebral palsy due to a left middle cerebral artery thrombosis associated with low birth-weight and disseminated intravascular coagulopathy due to maternal antithrombin III deficiency” than to use a less informative term which gives no hint as to how to prevent recurrence in subsequent pregnancies, but such precision is all too rarely achieved even in the most highly developed health services where there are no financial restraints upon investigation and treatment. Nevertheless, the physician should strive for the greatest degree of accuracy practical because behind plain “cerebral palsy” can hide a growing number of medically treatable and preventable conditions.

There is no “test” for cerebral palsy. Neonatal ultrasounds can be helpful in the management of premature neonates, and the finding of cystic periventricular leukomalacia or severe intra-ventricular hemorrhage may strongly predict, but cannot with certainty diagnose, later cerebral palsy. The same applies to neuro-imaging later in life; the chance discovery of abnormalities in somebody who clearly does not have cerebral palsy is not too uncommon, and about half of all children with cerebral palsy have normal CAT-scans. CAT-scans and MRIs may help to explain what has happened, and when it happened, but correlate only loosely with type and clinical course of cerebral palsy and may be normal even in severe cases; fairly substantial abnormalities on neuro-imaging may not be associated with significant functional loss.


Early diagnosis refers to the identification of cerebral palsy or similar clinical presentations in the first year of life. Whilst there is little evidence that early rehabilitation influences the severity of the abnormal neurological signs and symptoms, early intervention has a strong role in supporting parent-child relationships, improving the ease and confidence with which the child can be handled and fed, avoiding the unintentional neglect and stimulus deprivation which often occurs if the brain damaged infant is simply “left alone” and which magnifies the effects of the neurological injury, and preventing the child developing maladaptive abnormal movement patterns which can promote contractures and diminish the potential for later motor learning. Early intervention is associated with a better outcome in terms of quality of life and participation in society, although not always with a better locomotor outcome.

The first step in early diagnosis is the establishment of the degree of risk for each infant. High-risk infants should be placed in a developmental surveillance program. In the industrialized world only about half of all children with cerebral palsy have known risk factors so that some level of surveillance is recommended for all children.

The first surveillance session should be no earlier than four months after term. Before that time many infants still show the transient signs of a mild gestational or prenatal insult which will leave no permanent injury. It is very helpful if somebody who observed the infant in the neonatal period, other than the mother, can be present so that a trajectory can be established - are the abnormal findings improving, getting worse or unchanged? Improving signs are encouraging although they by no means exclude later cerebral palsy. Lack of improvement of neuro-behavioral (feeding, sleeping, irritability, apathy) or motor (asymmetry or other abnormality of movement, tone, deep tendon reflexes, or abnormally strong primitive reflex activity) difficulties by this time raises the likelihood of cerebral palsy. A normal neurological examination at four months post-term gives a 95% chance of long-term normality. The neurological examination should be graded as “normal”, “questionable” or “abnormal”.

A four months post-term infant with a normal neurological examination will show normal sociability and alertness, smiling in response to the examiners smile, vocalizing in turn with the parent or examiner when the adult, having cooed and made other appropriate baby noises, is silent, and will, when awake, give the impression of “listening” to conversations and demanding adult attention. There will be “brightening” or eye-turning toward a soft sound. The infant will fixate on a bright light or a red or yellow ring and will follow such an object vertically and horizontally. Ophthalmoscopy will at least show a “red reflex”. Observed quietly awake in supine all four limbs will move smoothly from one position to another in gentle, predictable movement patterns suggesting a good “quality of movement”. The examiner will observe no asymmetry of movement or posture and the mother will have noticed no “hand preference”. The hands will be open almost all the time, and the baby will make fairly accurate movements towards an object of interest such as a rotating red ring. After prolonged observation, the examiner will touch the infant and confirm that muscle tone is as normal as it looks. Because the asymmetric tonic neck response can be normal at this age the infants head should be gently held in midline while tone and reflexes are tested. The most discriminating way of identifying abnormal tone is by eliciting passive movements at the knees, hips and shoulders - too floppy a baby with too large movements indicates hypotonia whilst recognition of the stiffer, more rigid and more restricted flapping of the hypertonic baby requires only a little experience. Deep tendon reflexes are normal or may be difficult to elicit. Pulled from supine into sitting, the examiner grasping the baby by the outstretched arms whilst offering support for the neck, the infant shows good “head control”, the head remaining in the same plane as the trunk throughout the maneuver and showing minimal “wobble” when in supported sitting. If an attempt is made to make eye contact and interact socially with the baby he will, if his other has played the same “game” with him, usually anticipate the procedure by elevating the shoulders. Tilting the trunk to either side, first gently and then more rapidly, will not alter the infants distribution of muscle tone and may elicit extension of the fingers or even a movement of the whole arm on the side tilted toward the ground. Such movements, together with any compensatory movements of the head which tend to keep it in a constant position on the neck and shoulders (“righting response”), will be symmetrical. Rolling the infant from supine to prone by rotating one leg over the other will also elicit no abnormality or asymmetry of tone, but rather a smooth, segmental assistance of the rolling motion (“derogative righting response”). Once in prone, the infant will be fairly comfortable although he may protest after a few minutes. The prone posture of the normal infant at this age includes some elevation of the chest off the horizontal and some support for the chest on the outstretched arms. Elevated into supported standing in the vertical position, the normal infant again shows no distress or change of tone. “Bounced” on the ground five times with the examiner directing weight through the hips to the soles generates no increase in tone and if the pressure is maintained the infant bends the knees. If the infant is tilted forward a little with the soles flat on the ground reflex stepping may be elicited and is still normal at this age. With the examiners hand carefully supporting the neck and abdomen, the infant is tilted head down toward the ground; early protective responses may be seen, but at least there will be no sudden tensing or tone disturbance indicating subtle Spasticity ion the anti-gravity muscles. Even a normal examination of this type can be quite stressful for the baby, who may need a little time with mother to recover. If the baby starts to cry during the procedure the physician should return this patient to the mother for more comforting.

In a “questionable” neurological examination at this age the child may show one or more of diminished sociability, irritability, lack of visual interest, strabismus, mild or intermittent movement asymmetry, a single very strong primitive reflex, questionable or subtle tone changes in response to changes in position in space, or motor delay. One or both hands may be fisted intermittently. Note that most minor asymmetries are not associated with ongoing problems.

An “abnormal” neurological examination would include one or more of: cranial nerve abnormality other than strabismus; marked lack of social responsiveness, no apparent visual attention or response to soft sounds; obviously poor quality of movement with awkward changes of posture, jerkiness, and repetitiveness; marked asymmetry of movement, tone or deep tendon reflexes; abnormally low or high tone; hyper-reflexia; strong primitive reflexes which dominate the infants movements and from which the infant cannot appear to free himself. Fisting of one or both hands indicates hypertonia, and retention of the thumb within the fist may indicate cortical injury. About half of all infants with an abnormal neurological examination at this age will have permanent difficulties and some sort of intervention should be discussed with the parents.

The best time for a second surveillance examination is at seven or eight months eight months since almost all normally developing infants can by this time sit for five minutes without any support and clear failure to approach this milestone is definite evidence of delayed motor development. The ability to reach the sitting position from supine or probe comes later, or to leave it in controlled fashion, without falling, for crawling or some other mode of mobility, comes a little later. The hands are open all the time and, without obvious preference, are used for reach and grasp activities to either side and across the midline. No abnormal hand posturing or asymmetric involvement in protective responses can be observed. The infant has been rolling from prone to supine and back for a month or so. The infant will locate a soft noisemaker at the level of the ear-hole by turning the head. There is no abnormality of tone or reflexes and primitive reflex activity cannot be elicited by routine procedures. If resources do not allow surveillance at this time the seven month session can be omitted in medium or low-risk infants whose four month neurological examination was normal.

By ten to twelve months almost all cases of cerebral palsy in high-risk infants can be identified, although it may not yet be possible accurately to predict the type and severity. The “honeymoon period” is now over and the apparently normal or questionable neurological examination sometimes seen between four months and a year is replaced by definitely abnormal findings. Motor delay without abnormal neurological signs is more likely to indicate mental retardation, intercurrent illness or malnutrition. Although normal children follow a number of different paths to walking, and in the absence of abnormal neurological signs or evidence of slow development outside the motor area such delay is of no significance, abnormal preferred locomotion patterns in cerebral palsy have some implications. Reciprocal crawling suggests a good prognosis for walking. Diplegic children with moderately severe motor impairment may creep or crawl, but a group of severe diplegics, often eventually diagnosed as mild quadriplegics, creep without ever walking. Bottom-shuffling is the classic alternate pathway to walking and in children without cerebral palsy tends to be familial; in cerebral palsy it can be a compensatory mode of ambulation for hemiplegics, ataxics and others with only mild motor problems. Bunny hopping, classic in diplegia, is also seen in more severely dyskinetic children but rarely in the mentally retarded. Locomotion in supine, often arching between occiput and the lower spine, although seen occasionally as a normal variant, may suggest an element of ataxia. The outcome of hypotonia at this age is particularly difficult to predict. Apparent hemiplegias may evolve into mild quadriplegias, as may some of the more severe diplegias.

If the history or earlier neuro-imaging findings are strongly suggestive of cerebral palsy, the prudent physician might wait until fifteen months after term before declaring the child out of danger. The lower the birth weight the longer it can take to be sure that cerebral palsy is not going to develop. It is essential to “correct for prematurity” when assessing the development of infants born more than six weeks early - one uses corrected age, based not on the date of birth but on the calculated date of full term, to plan surveillance visits and base expectations for progress. Such corrections should be continued for the first 12 months in infants born weighing 1501 to 2500 grams, for 18 months for 1001 to 1500 grams and for up to three years for infants below 1000 grams. Severe and prolonged neonatal or post-natal illness may also require deduction from the “calendar or birthday age” of the child - so that an infant whose respiratory difficulties required ventilator or hospital care until six months post term could not be expected to catch up immediately the lungs matured. Note that in low risk infants very mild cerebral palsy, usually diplegic, can take up to four years to declare itself.

It will be apparent from the later section on prognosis below that a surveillance examination at 24 to 30 months will be invaluable in providing accurate predictions of motor outcome, The same age is appropriate for identification of significant language delay, since any child with an understanding of much less than 200 words, or unable to execute two-concept instructions (put the baby in the cup, put the pencil in the bed) employing miniature representations of common objects can be assumed to require remediation of a receptive language delay. Expressive language milestones show more variation and in the presence of the motor speech difficulties (dysarthria) which are common in cerebral palsy may be difficult to assess. Imaginative play implies a cognitive level of around 18 months and if definitely present for some months in the child with cerebral palsy provides an encouraging suggestion of normal intelligence.