Evaluating the Child with Cerebral Palsy

Original Editor - Kim Jackson as part of ICRC Cerebral Palsy Content Development Project

Top Contributors - Naomi O'Reilly, Kim Jackson, Admin, 127.0.0.1, WikiSysop, Simisola Ajeyalemi, Wendy Walker, Rucha Gadgil, Jess Bell, Aminat Abolade and Lenie Jacobs  

Introduction

Cerebral Palsy (CP) is a neurodevelopmental disorder marked by non-progressive motor function impairment originating from damage to the developing brain. The complexity of this condition necessitates an integrated rehabilitation approach, encompassing multiple professionals in the field. Knowledge of cerebral palsy and experience of managing neurological is necessary to ensure that treatable causes are identified. The team usually includes physiotherapists, occupational therapists, speech therapists, nutritionists, paediatricians, orthopaedic surgeons, and neurologists, each playing a distinct yet collaborative role in managing the unique challenges presented by CP.

The manifestations of CP often become clearer over time, meaning that a diagnosis may not be confirmed until several months to a year after birth, or even later in cases with milder symptoms. During this time, the child's growth and development are closely monitored, their medical history is reviewed, and physical examinations are conducted.

Clinical Assessment

The evaluation of a child with CP requires a comprehensive, multidimensional approach to accurately identify and address the individual's specific deficits and needs. The assessment process includes a thorough medical history, physical examination, functional assessment, and often, specialized evaluations. Importantly, the assessment extends beyond the child to incorporate the family, evaluating their needs and resources, as successful management often relies on family-centered care. 

Observing the child’s movements is the initial and a crucial part of the examination. Observe before you touch. If the child is young, apprehensive or tearful, let them stay on mother’s lap while you watch and talk to the mother. As the child adapts to the environment, slowly place them on the examination table or on the floor still close to the mother/carer and watch them move around. If the child cries a lot and does not cooperate, continue while they are in their mother’s lap. Tools required for the examination are very simple: toys, small wooden/different shaped blocks, and objects with different textures.

A comprehensive physical and biomechanical evaluation is paramount for a child with cerebral palsy (CP) who is ambulant, as it informs targeted interventions at specific joints and segment levels. Essential components of the clinical examination should include:

1. Postural Evaluation: This involves assessing the child's posture in various positions, such as prone lying, supine lying, sitting, standing, and walking. Variations in these postures may provide insights into underlying musculoskeletal imbalances or functional limitations.
2. Muscle Tone Assessment: This entails the evaluation of muscle tone in the extremities, trunk, and neck, along with deep tendon reflexes. CP often presents with muscle tone abnormalities, necessitating thorough and regular tone evaluations. Dystonia, characterised by involuntary intermittent muscle contractions leading to twisting movements or abnormal postures, can manifest in cases of hypertonia arising from an extrapyramidal brain lesion. Conversely, hypertonia associated with a pyramidal brain lesion often presents as spasticity, which is the defining motor disorder in approximately 80% of paediatric CP cases. Spasticity is typified by a velocity-dependent increase in tonic stretch reflexes (muscle tone) with exaggerated tendon jerks, resulting from stretch reflex hyperexcitability, a component of the upper motor neuron syndrome .
3. Muscle Strength Evaluation: Accurate muscle strength assessment is critical, given its profound influence on the functional abilities of the child.
4. Joint Range of Motion (ROM) Assessment: ROM should be evaluated at the hip, knee, ankle, sub-talar, and mid-tarsal joints. Joint angles identified during ROM testing, performed at slow, medium, and fast velocities, inform the position of the anatomical joint in any potential orthotic intervention. It further assists in identifying if mechanical joints should be included in the orthotic design and, if so, the specific type.

The identification and quantification of spasticity remain crucial in determining appropriate orthotic intervention, thereby necessitating detailed evaluations of muscle tone and ROM during clinical assessments.

Tone 

In the clinical assessment of children with CP, a comprehensive understanding of muscle tone and strength is paramount. Notably, these children frequently exhibit muscle tone alterations, which often coincide with signs of underlying muscle weakness. Muscle tone can vary substantially in this population, and its accurate evaluation guides the overall clinical intervention strategy. To reliably assess muscle tone and spasticity, clinicians use well-established tools such as the Tardieu Scale (TS), the Modified Tardieu Scale (MTS), and the Ashworth Scale (AS). Each tool adopts unique methodologies for this purpose, although potential sources of error should be considered, including individual variability, measurement tool inaccuracies, and variability in the attributes being measured.

Specifically, spasticity is a velocity-dependent increase in muscle tone, necessitating the application of tools that accommodate this aspect, such as the Tardieu Scale. The Tardieu Scale uniquely caters to this by incorporating passive muscle stretches at three different speeds, thereby providing a more comprehensive assessment of spasticity. Whereas the Ashworth Scale measures passive resistance to movement at just one speed.

The TS and MTS have displayed high intra and inter-rater reliability with adequate training, while the AS has shown inconsistent reliability (Fosang et al., 2003). Notably, the TS and MTS capture the velocity-dependent nature of spasticity, making them more suitable for accurately assessing this condition. Conversely, the AS measures passive resistance at a single speed, potentially leading to inaccuracies when identifying spasticity, particularly in the presence of muscle contracture.

Tardieu Scale

The Tardieu Scale (TS) measures spasticity (velocity-dependent) by passively moving the joints at three specified speeds - slow, under gravity, and fast. The muscle's reaction to stretch (X) is rated on a 6-point scale and the joint angle (Y) recorded at the point where the muscle reaction is first felt (Boyd & Graham, 1999).

Scoring

The scoring is done as follows

Quality of Muscle Reaction

0	No resistance throughout passive movement
1	Slight resistance throughout,with no clear catch at a precise angle
2	Clear catch at a precise angle followed by release
3	Fatiguable Clonus (< 10 secs) occurring at a precise angleFatiguable Clonus (< 10 secs) occurring at a precise angle
4	Unfatiguable Clonus (> 10 secs) occurring at a precise angle
5	Joint immobile

Velocity to Stretch

V1	As slow as possible
V2	Speed of the limb segment falling (with gravitational pull)
V3	At a fast rate (>gravitational pull)

Spasticity Angle

R1	Angle of catch seen at Velocity V2 or V3
R2	Full range of motion achieved when muscle is at rest and tested at V1 velocity

However, the TS's extensive nature often makes it time-consuming to perform. This led to the development of a more time-efficient variant - the Modified Tardieu Scale (MTS).

Modified Tardieu Scale (MTS)

This scale is an abbreviated version of the TS, focusing only on joint angles at fast and slow velocities. It takes into account the angle of muscle 'catch' at the highest velocity (R1) and the joint angle when the muscle length is at its maximum (R2), gauged by slow passive movement through full Range of Motion (ROM) (Patrick & Ada, 2006). The difference in degrees between R2 and R1, known as the dynamic component of spasticity, helps estimate the relative contribution of spasticity compared to muscle contracture.

Ashworth Scale

The Ashworth Scale (AS) is used to grade the intensity of muscle tone through joint ROM on a five-point scale at one non-specified speed. Despite the widespread use of the AS and its ability to identify general hypertonia, it is recommended that this tool no longer be used and that the TS or MTS be used to evaluate the muscle tone in ambulant children with Cerebral Palsy.  The Modified Ashworth Scale (MAS), a derivative of the AS, includes a 6-point grading scale and severity grading of muscle tone at an unspecified 'fast' speed.

Scoring

The scoring is done as follows

0	No increase in tone
1	Slight increase in tone giving a catch when slight increase in muscle tone, manifested by the limb was moved in flexion or extension
1+	Slight increase in muscle tone, manifested by a catch followed by minimal resistance throughout (ROM )
2	More marked increase in tone but more marked increased in muscle tone through most limb easily flexed
3	Considerable increase in tone, passive movement difficult
4	Limb rigid in flexion or extension

Thus, the evaluation of lower limb muscle strength is an essential part of the clinical picture in ambulant children with CP. Muscle strength has a direct bearing on a child's motor function, walking speed, energy expenditure, and gait characteristics.

Strength 

Muscle weakness is a key contributing factor in children with CP, often resulting in an imbalance across various joints. This imbalance is associated with the development of muscle shortening and rotational deformities, which can further impede a child's motor function. It is therefore important to carry out a comprehensive muscle strength assessment of the lower limb during an orthotic assessment for children with CP.

There are many tools available to assess muscle strength, but a widely recognised tool used for children with CP is the Oxford Scale (aka Medical Research Council Scale (MRCS)) for manual muscle testing, which grades muscle strength. Throughout this assessment, it's imperative to be mindful of any signs of non-cooperation, inability to isolate the muscle being tested, or comprehension difficulties in the child.

In cases where a more detailed quantification of muscle strength is needed, clinicians may resort to using handheld dynamometers . These instruments provide a more objective measure, enhancing the assessment's overall precision and reliability.

Oxford Scale

Muscle Groups Tested
Wrist Extension
Elbow Flexion
Shoulder Abduction
Ankle Dorsiflexion
Knee Extension
Hip Flexion

Muscle Grading Scores
0	No detectable muscle contraction (visible or palpation)
1	Detectable contraction (visible or palpation), but no movement achieved
2	Limb movement achieved, but unable to move against gravity
3	Limb movement against resistance of gravity
4	Limb movement against gravity and external resistance
5	Normal strength

Range of Movement 

Identifying and understanding the range of motion (ROM) in children with cerebral palsy is integral to their orthotic assessment and overall care. Secondary musculoskeletal issues, such as muscle contractures and bony deformities, frequently observed in children with cerebral palsy, can significantly reduce the available lower limb joint ROM. Reduced mobility, the presence of spasticity, and dystonia, as well as factors like age, gender, pain thresholds, health conditions, injuries, and levels and types of physical activity, can all have an impact on decreased ROM. Therefore, it becomes essential to evaluate and quantify both passive and dynamic lower limb joint ROM, as muscle and joint movement can impact the ability to move freely.

Torsional deformities, which arise from muscle imbalances and abnormal bone growth due to increased tone or weakness, are common in ambulatory children with CP. As such, a rotational assessment of the lower limb joints is necessary. This includes assessing the:

• hip's internal/external rotation
• degree of femoral ante/retro version
• degree of tibial torsion, sub-talar inversion/eversion
• mid-tarsal ab/adduction. Establishing this torsional profile aids in orthotic prescription by identifying if there is a torsional lever arm deficiency.

A thorough assessment of both range and torsional deformities is crucial when prescribing orthoses, evaluating the effectiveness of the intervention, and monitoring growth-induced changes​​.

Hip Joint

In the hip joint, the extent of available passive and dynamic ROM in flexion, extension, abduction, and adduction must be examined. It's important to note that hip flexion contractures are a common occurrence in children with a predominantly spastic presentation of cerebral palsy. Such contractures can adversely affect a child’s gait by altering the body's weight line during the stance phase, restricting heel contact at initial contact, changing the inclination degree of the femur and the tibia during stance phase, and reducing possible hip extension, thereby disrupting transfer through the second and third rockers of stance phase​​.

Knee Joint

The knee joint also requires evaluation for flexion and extension in both passive and dynamic ROM. The joint range of motion should also be assessed for passive, active, and velocity specific knee extension when the child is in a supine position with the hip flexed to approximately 30°. This position emulates the degree of hip flexion at initial contact during gait and establishes the extent of knee extension possible during the early stance phase​1​.

Ankle Joint

The evaluation of the ankle joint's range of motion (ROM), specifically focusing on dorsiflexion and plantarflexion, is an essential aspect of assessing children with cerebral palsy, especially those exhibiting spasticity. While assessing, it is crucial to keep the sub-talar joint in a neutral position. Any variation from this, such as moving the sub-talar joint into eversion or inversion during dorsiflexion, can alter the length of the gastrocnemius muscle, potentially resulting in an inaccurate measurement of available dorsiflexion ROM.

These tests are ideally conducted while the child is in a supine position. In some instances, children with a spastic presentation of cerebral palsy may exhibit a plantar extensor pattern in their lower limbs. This pattern often affects the gastrocnemius or soleus muscles due to increased muscle tone. Flexing the hip and knee to 90 degrees and then dorsiflexing the ankle can help to isolate the effects of the gastrocnemius muscle on the foot and ankle. This isolation allows for a more specific assessment of the ROM and muscle tone related to the soleus muscle.

For a more precise evaluation, passive non-weight-bearing goniometric measurements of dorsiflexion can be carried out with the knee extended to 0° and flexed to 45°. Measurements taken with the knee extended are intended to assess the flexibility of the gastrocnemius muscle. In contrast, measurements taken with the knee flexed are thought to provide insight into the flexibility of the soleus muscle​​.

When implementing an ankle-foot orthosis (AFO), the angle of the ankle within the device and the pitch of the heel sole differential play a significant role. The passive length of the gastrocnemius muscle, measured with the knee extended, determines the angle of the ankle in the AFO. If the ankle in the AFO is in plantarflexion, an adjustment is made to the AFO to achieve a vertical bench alignment​2​.

Assessments of this nature allow for a more comprehensive understanding of the individual's unique musculoskeletal dynamics, facilitating the creation of a more tailored and effective treatment plan. It's important to remember that the limitation in the motion of the ankle joint, specifically dorsiflexion and plantarflexion, is influenced by the joint capsule and surrounding ligaments and muscles, including the gastrocnemius and soleus muscles​​.

Goniometry

The most common method to assess passive or velocity-dependent lower limb joint ROM in children with CP is goniometry. The number of people conducting the assessment, the patient's level of cooperation, and the measurement technique chosen can all have an impact on the dependability and repeatability of these measurements.

Resources

Hambisela_Module_2_Evaluating_Your_Child   In: Getting to Know Cerebral Palsy: A learning resource for facilitators, parents, caregivers, and persons with cerebral palsy