Evaluating the Child with Cerebral Palsy

Introduction

Most of the information leading to the diagnosis of cerebral palsy is generally obtained from a thorough medical history and examination. The most critical tasks of the health care professional are to identify potentially treatable causes of a child's impairment. The health care professional evaluating the child with possible cerebral palsy should be experienced in neurological examination and assessment of impaired children and well-versed in the potential causes of cerebral palsy. Often, but not necessarily, this practitioner should be a pediatric neurologist. Once the examination is complete, depending on the findings, the practitioner may order laboratory tests to help in the assessment.

There is no single test to diagnose cerebral palsy. But since cerebral palsy is the result of multiple different causes, the tests performed are used to identify specific causes when possible. Other tests will be performed to assess the condition of the child (nutritional status for example) or to assess other concomitant conditions that the child might have.

Clinical Assessment

Evaluation of an ambulant child with CP requires a unified Multi-Disciplinary Team (MDT) often comprising of a medical doctor or paediatrician, rehabilitation consultant, neurologist, orthopaedic consultant, physiotherapist, occupational therapist, clinical scientist and orthotist.  The MDT needs to have a close working relationship with the parents or caregivers to ensure consent is provided for assessment or for any proposed interventions and to ensure the treatment is incorporated into everyday family life.
A thorough physical and biomechanical evaluation is necessary to decide the specific joints and segment levels to target any orthotic intervention. The physical examination of the ambulant child with CP should evaluate:

• Posture in Prone Lying, Supine Lying, Sitting, Standing and Walking;
• Muscle Tone of the Extremities, Trunk and Neck, Deep Tendon Reflexes;
• Muscle Strength; and
• Joint Range of Motion at the Hip, Knee, Ankle, Sub-talar and Mid-tarsal Joints.  

As Cerebral Palsy is a disorder of movement that commonly presents with muscle tone abnormalities, it is critical to perform an evaluation of muscle tone during the initial and any future physical evaluations. Hypertonia due to an extra pyramidal brain lesion is known as dystonia and presents as involuntary intermittent muscle contractions that cause twisting or repetitive movements of abnormal postures. Hypertonia where a pyramidal brain lesion exists presents as muscle spasticity. Spasticity accounts for 80% of paediatric Cerebral Palsy presentations and is defined as a motor disorder characterised by a velocity dependent increase in tonic stretch reflexes (muscle tone) with exaggerated tendon jerks.  It results from hyper excitability of the stretch reflex as one component of the upper motor neurone syndrome. The identification and quantification of spasticity is critical when determining appropriate orthotic intervention. Identifying the joint angles during joint Range of Motion (ROM), testing at slow, medium and fast velocities where an increase in muscle tone is first felt and also at the end of joint ROM, helps establish the angle the anatomical joint will be positioned within any potentially prescribed orthosis. It also determines if, and what type, of mechanical joints may be included in the orthotic design.

The measurement tools used to evaluate muscle tone in children with Cerebral Palsy can be divided into two main groups according to their assessment technique and method of quantification. The Tardieu Scale (TS) assesses spasticity by passively moving the joints at three specified velocities (slow, under gravity and fast) while the intensity and duration of the muscle reaction to stretch (X) is rated on a 6-point scale (Table.1), with the joint angle (Y) recorded at where the muscle reaction is first felt.

Velocity	Description
V1	As slow as possible (slower than the natural drop of the limb segment under gravity)
V2	Speed of the limb segment falling under gravity
V3	As fast as possible (faster than the rate of the natural drop of the limb segment under gravity)
Grade	Decsription
0	No resistance throughout passive movement
1	Slight resistance throughout, with no clear catch at as precise angle
2	Clear catch at a precise ankle followed by a release
3	Fatigable clonus (<10 seconds) occurring at a precise angle
4	Unfatigable clonus (>10 seconds) occurring at a precise angle
5	Joint immobile

TABLE 1: Definition of the velocities used and the 6-point scale used to grade the quality of muscle reaction when using the Tardieu Scale to assess spasticity

Due to the large amount of time required to perform the full TS, the Modified Tardieu
Scale (MTS) was developed. It records the joint angles during the fast and slow velocities only. It uses the most clinically significant parts of the TS: the angle of catch at the most rapid velocity (R1) and the joint angle when the muscle length is at its maximum (R2), assessed by moving the joint through full ROM using slow passive movement.[6] The MTS has been found to be a valid, reliable and sensitive abridged version of the TS.[5,7,8] The difference in degrees between the angles R2 and R1 is referred to as the dynamic component of spasticity and estimates the relative contribution of spasticity compared to muscle contracture.[5,6, 9]
The Ashworth Scale (AS) grades the intensity of muscle tone through joint ROM on a five-point scale at one non-specified velocity. (TABLE 2) Modifications of the AS are referred to as the Modified Ashworth Scale (MAS). Literature has also described the
MAS to include a 6-point grading scale, a grading for the severity of the muscle tone and also the assessment of the muscle tone at an unspecified ‘fast’ velocity. [4]

Objective Assessment

Objective examination of the child with movement problems has two basic purposes.

1. First, objective examination accompanying a detailed history enables an accurate diagnosis.
2. Second, it allows the physiotherapist to define the impairments and associated conditions, determine the functional prognosis and set treatment goals in children with Cerebral Palsy. These then help devise a treatment plan for each child. 

Clinical Observation:

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.

Musculoskeletal Observation:

• Joint Range of Motion 
• Deformities
• Contractures
• Muscle Control
• Balance
• Posture
• Sitting
  

Joint Range of Motion (ROM)

Especially measurable in Children with Cerebral Palsy Age Range 4 - 9 years old. Intra and inter-rater reliability is average. 

For children < 4 years, no literature evidence exists about reliability.  

Try to use goniometer at first. If poor cooperation of the child visual estimate.

LOWER LIMB
Hip Assessment:	Thomas Test (Flexion Contracture of Hip, compensated by increase Lumbar Lordosis) Adduction Contracture Ely Test (m. Rectus Femoris Tightness) Hip Rotations
Knee Assessment:	Position Patella Popliteal Angle (Hamstrings Contracture) Posterior Capsule Tightness
Ankle / Foot Assessment:	Silfverskiold Test (Triceps Contracture) Spastic Tibialis Anterior / Posterior causes Pes Equinovarus (Hind Foot Varus) Spastic Peroneus and Gastrocnemius causes Pes Valgus

UPPER LIMB
Shoulder Assessment:
Elbow Assessment:
Wrist Assessment:

Muscle Strength:

There are two main methods that are commonly used:

1. Manual Muscle Testing (MMT) e.g Medical Research Scale (MRC)

For use of MRC Scale it is necessary/mandatory that a child needs to be able to actively flex and extend the joint. It is only useful in children who can well make isolated and voluntary movements in a joint.

No research has been done about the reliability of use MRC Scale in Children with Cerebral Palsy and as such MMT is not always very reliable in measuring strength in children with Cerebral Palsy.

2. Hand Held Dynamometry (HHD) 

Disadvantage HHD: Time Consuming, Further training of Physiotherapist necessary

Functional Classification

Valid and Reliable Tool:
- Gross Motor Function Measure (GMFM 88) Evaluation on activity level

GMFM 88:
∗ It evaluates performance of motor skills on that day; useful for comparison over time
∗ Measures how much of a task the child can accomplish, rather than how well the task is completed (quantity, not movement quality)
∗ Appropriate for children 5 months – 16 years
∗ May be appropriate for children with other diagnoses (e.g. OI, Down Syndrome, leukemia)
∗ GMFM is appropriate for children whose motor skills are at or below those of a typical 5 year old
∗ Internationally accepted, considered best practice
∗ Useable as outcome measure
∗ No expensive equipment needed, usable in rural areas
∗ Can be used for assessing the effects of orthoses/ aids
∗ To measure small but important changes in motor function over time

General Neurological Assessment

Neurological assessment requires adequate knowledge about typical developmental stages.

- Focus on motor skills (strength, tone) and reflexes
- Spastic CP: significant reduced selective strength
- Differentiate 2 aspect spastic movement disorder:
1. Spasticity (speed dependent resistance during passive movements)
2. Hypertonia (resistance over total move-track during slow movements)

To differentiate 2 tools do exist:
1. Modified Ashworth Scale
2. Tardieu Scale

Disadvantage Ashworth: spasticity and hypertonia are not registered separately. Reproducibility is low.
Disadvantage Tardieu: very complicated and time consuming.

Spastic CP classification, at least 2 of 3 characteristics need to be shown:
1. Abnormal postural and/or movements
2. Increased muscle tone
3. Pathological reflexes (Babinski)

Despite the lack of useful, reliable and valid assessment tools to objectify and quantify spasticity, it is possible on the basis of clinical expertise to determine spasticity.
For objective estimation it is important to notify a difference in slow and fast movements in different muscle groups. Control spasticity by relaxing the child.

Systematic reviews have shown it is likely that there is no research that can establish reliable and valid assessment tools to classify spasticity as a characteristic phenomenon of a spastic CP. (Scholtes 2006, Damiano 2002, Haas 1996, Platz 2005)

Gait Analysis:

Ambulatory Children with Cerebral Palsy display various types of pathological gait. Efficient intervention depends on proper evaluation.
Stability in stance, progression and foot clearance in swing are necessary for efficient walking. Stability is disturbed in Cerebral Palsy because of impaired balance, increased muscle tone leading to contractures and muscle weakness.

Stance Phase:	Swing Phase:
The common problem in stance are equinovarus, jump knee, crouch knee and internal rotation of the legs.  Progression of the body is disturbed because of contractures and muscle weakness as well.	The common problems of swing are shortened step length and impaired foot clearance (as that which occurs in stiff knee gait).

The child’s walking pattern changes with age. Walking patterns are established at approximately 5 to 7 years of age.

The use of Classification Systems for Gait Analysis helps to:

1. Have clear communication between Physiotherapist and Prosthetist/Orthotist to improve Interdiscpilinary Teamwork
2. Conduct Treatment Plan
3. Evaluate Treatment

Examples Classification Systems used for Gait Analysis:

1. Observational Gait Scale (OGS) (Mackey, 2003)
2. Physician Rating Scale (PRS) (Maathuis 2005)
3. Edinburgh Visual Gait Analysis Interval Testing Scale (GAIT) (Maathuis 2005)
4. Gait Analysis Classification (Becher 2002, Verschuren 2004)

Types of Pathological Abnormal Gait:

Equinus	Femoral Anteversion Leading to In Toeing
Jump Gait	Spasticity Hip and Knee Flexors and Ankle Plantar Flexors
Crouch Gait	Tight Hip Flexors and Hamstrings, Weakness Quadriceps and Triceps Surae
Stiff Knee Gait	Spasticity Rectus Femoris
Scissoring Gait with Internal Hip Rotation	Hip Adductor and Medial Hamstring Spasticity, combined with Excessive Femoral Anteversion
Trunk Lurching	Due to Balance Deficiency Only remedy for trunk lurch is using a mobility device such as a walker or canes. Strengthening the Hip Abductors may also be helpful
Apparent Equinus	Hamstring Spasticity, Knee Flexion contracture causing Tiptoe Walking. Not due to Spasticity Gastrocnemius

Types of Hemiplegic Gait:

Type 1:	Foot in Equinus (No Active Dorsiflexion)  → brace needed to keep foot in neutral
Type 2:	Foot in Equinus (spasticity gastrocnemius, active m. Tib. Ant. present)  → lengthening m. gastrocnemius results in more functional gait
Type 3:	Problems observed in type 1 and 2 and in addition: abnormal activity rectus femoris and hamstrings present causing stiff knee of genua recurvatum
Type 4:	In addition to abnormal knee muscle activity, increased hip flexor and adductor spasticity or contracture present