Diagnosis Of Cerebral Palsy: Physical Examination, Developmental Assessments, And Imaging Tests

Introduction

Cerebral palsy (CP) is a group of disorders that affects your ability to move and maintain balance and posture. CP is the most common childhood motor disability. CP is caused by abnormal brain development or damage to the developing brain, which affects one’s ability to control their muscles. The exact cause of CP can vary, but it typically results from brain damage that occurs before, during, or shortly after birth. Common symptoms of CP are delays in reaching developmental milestones, movement that is too stiff or too floppy, weakness in the arms and legs, and random, uncontrolled movement. The intensity of CP symptoms greatly varies as some people are able to walk on their own while others may require assistance. This article will introduce and explain how cerebral palsy is typically diagnosed, including physical examination, developmental assessments, and imaging tests.¹  

Physical examination

Before any diagnosis by a medical professional begins, the first stage of CP diagnosis comes from parental observation. Generally, developmental delays become obvious to parents when their child does not develop specific skills within the expected time period. A child will typically reach for toys by 3 or 4 months of age, sit up by 6 or 7 months, and walk between 12 to 14 months.² Additionally, while a child being able to roll over is a significant milestone, having the ability to roll over too early can sometimes indicate abnormal reflexes or stiffness. Parents may notice that the child is stiff, cannot swallow properly, doesn’t appear to hear properly or has eyes that seemingly don’t focus. The child may have gastrointestinal issues or reduced oral-motor function. These signs usually indicate for a parent to bring their observations to the child's primary healthcare professional, who will then conduct a physical examination or direct the parents to a more specialised professional.^2,3 

The first medical stage in diagnosing CP involves a thorough physical examination conducted by a healthcare professional such as a paediatric neurologist or a paediatrician. The aim of this examination is to look at the child’s motor skills, muscle tone, posture, and reflexes for any characteristic symptoms of CP.^, They look at the child’s height, weight, reflexes, and age-appropriate behaviour. Any abnormal muscle tone such as stiffness or floppiness will be visible when the child moves, along with any involuntary movement or issues with coordination. Additionally, part of the examination will include examining the child’s reflexes. Sometimes CP can manifest with abnormal reflexes, such as exaggerated responses to stimuli or a lack of development from infant reflexes to more advanced reflexes. The doctor will also examine the child’s posture and check for any asymmetries or unusual positions that might suggest muscle imbalance or neurological impairment.⁴

A detailed medical history will be taken, including any complications, infections, or other factors like family background that can increase the risk of CP developing.

Developmental assessments

Developmental assessments are evaluations that focus on the child’s progress in attaining important developmental milestones such as sitting, crawling, walking, and talking. These assessments help identify any delays or abnormalities in motor skills, language development, social interaction, and cognitive abilities.⁵

During a developmental assessment, healthcare professionals use standardised tools and checklists to evaluate the child's abilities. They will observe how the child moves, interacts with others and responds to various stimuli. One common tool used in developmental assessments is the Ages and Stages Questionnaire (ASQ), which helps screen for developmental delays in children from one month to 5 ½ years old. Another tool is the Denver Developmental Screening Test, which assesses four areas: personal-social, fine motor-adaptive, language, and gross motor skills.⁶

The healthcare professional may also observe specific tests to assess muscle tone, reflexes, coordination, and balance. For example, they might ask the child to stack blocks, draw shapes, or walk a short distance. These activities look at their motor skills and coordination.³

Imaging tests

Imaging tests provide detailed pictures of the brain's structure and function. These pictures can then help identify any abnormalities or injuries that may have occurred before, during, or after birth, which can lead to developing CP. The most commonly used imaging tests include magnetic resonance imaging (MRI) and cranial ultrasound.

Magnetic resonance imaging (MRI)

MRI is one of the most precise imaging tests for diagnosing CP.  Unlike X-rays and CT scans, MRI scans do not use ionising radiation, making it safer to use in children. It uses strong magnetic fields and radio waves to create thorough images of the brain and spinal cord. Two types of MRIs are brain MRIs and spinal cord MRIs, which can be useful for children with leg spasticity, bowel complications, and improper bladder functioning.⁷ 

During an MRI, the child lies on a table that slides into a large tunnel machine. For an accurate image, the person being scanned must remain still for the whole exam, which can last approximately 30 to 45 minutes. It is also a very loud procedure that is harmless but can be extremely uncomfortable for children. The procedure requires the child to remain still for an extended period so sedation or anaesthesia can be used for young children. The MRI can show areas of the brain that are damaged or have developed abnormally, such as white matter damage, brain malformations, or bleeding. These images help determine the specific areas of the brain that are being affected by CP.^8,9

Cranial ultrasound

Cranial ultrasound is another imaging test used to diagnose CP in preterm infants or newborns. It can only be used on infants before the cranial bones are fully formed or after a fully formed skull is surgically opened. This is because the sound waves can pass through bones and therefore will not show anything. Cranial ultrasounds are useful for infants who cannot remain still for the amount of time required for MRI or CT scans because there is no need for any sedation, and it can be performed at the bedside instead of in a different machine. 

Cranial ultrasound uses high-frequency sound waves to create an image of the brain. During a cranial ultrasound, a small handheld instrument known as a transducer is moved over the head. The transducer sends sound waves through the soft regions in the skull and records the echoes that bounce back to create images of the brain on a monitor. Cranial ultrasounds can help detect conditions like bleeding in the brain or damage to the white matter around the brain's ventricles, which are commonly linked to CP. The cranial ultrasound is painless and the least intrusive of the possible techniques, but has a lower quality of results compared to MRI or CT scans. However, the results can still show abnormalities, cysts, and structures in the brain.

Cranial ultrasounds are done on premature babies if healthcare professionals suspect brain bleeding or damage.¹⁰

Additional imaging tests

Sometimes, other imaging tests like computed tomography (CT) scans or electroencephalography (EEG), may be used. A CT scan combined several X-rays taken from numerous angles to create a cross-sectional view of the brain. This can detect brain injuries or malformations and provides a better result than cranial ultrasounds. However, because of the exposure to radiation, CT scans are less commonly used compared to MRIs. EEG detects electrical activity in the brain and is utilised when there are concerns about seizures. Seizures sometimes occur with CP. This test involves small electrodes being put on the scalp to record brain wave patterns, which helps detect unusual activity.^7,9,10

Differential diagnosis

There is no single test that confirms or rules out CP, therefore there is always a chance that the child can have a different condition. Therefore differential diagnosis is crucial to distinguishing CP from other disorders and conditions that can appear as CP. Several conditions have symptoms that appear to be similar to the symptoms of CP, including genetic disorders, metabolic disorders, neurodegenerative diseases, and other developmental conditions. 

Genetic disorders

Some genetic disorders can have motor impairments and developmental delay symptoms similar to CP:¹¹

• Rett Syndrome generally affects girls and has normal early growth followed by a slowing of development, loss of purposeful hand skills, and severe cognitive impairment
• Angelman Syndrome causes severe developmental delays, balance issues, seizures, and a happy demeanour 
• Duchenne Muscular Dystrophy leads to progressive muscle weakness, primarily affecting boys, and can be mistaken for CP in the early stages

Metabolic disorders

Examples of metabolic disorders that can lead to similar symptoms to CP:

• Phenylketonuria (PKU) affects the metabolism of the phenylalanine amino acid, and if untreated can lead to cognitive impairments
• Mitochondrial Disorders affect the mitochondria, causing muscle weakness, developmental delays, and neurological issues

Neurodegenerative diseases

Neurodegenerative diseases progressively damage the nervous system and can initially look similar to CP:

• Spinal Muscular Atrophy causes muscle wasting and weakness because of motor neuron loss
• Leukodystrophies are disorders that affect the white matter inside the brain, leading to motor issues and cognitive decline

Other developmental conditions

Other developmental conditions include:

• Autism Spectrum Disorder can have motor delays and abnormal muscle tone but primarily involves social and communication deficits
• Developmental Coordination Disorder is characterised by motor skill difficulties that are not due to a neurological disorder like CP but can affect daily functioning¹¹

Summary

In summary, cerebral palsy (CP) is a group of disorders that affects an individual's ability to move and maintain balance and posture. This is due to abnormalities in the brain. A variety of tests can be used to diagnose someone with CP, including physical examinations, developmental assessments and imaging.