Movement Analysis

The Movement Analysis (MA) service operates a 'state of the art' gait assessment laboratory, containing high tech equipment designed to assess a patients walking ability.  Results of the assessments are used to inform clinicians as to the best course of treatment for each individual patient. 

Assessment Types

For more information on each assessment type please click on the relevant heading above.

Conditions Treated

  • Cerebral Palsy
  • Falls & Instability
  • Foot Problems
  • Lower Limb Deformity
  • Neurological Conditions
  • Spina Bifida
  • Stroke

3D Gait Analysis

The ORLAU gait laboratories contain two types of cameras: video cameras and 3D tracking cameras (Vicon).  The tracking cameras do not see everything, so we cannot use them to take ordinary pictures.  They are designed to detect a particular type of reflective material.  We have a set of small markers coated in this material.  The camera system is able to track these markers in three dimensions, so we know exactly where each one is in the laboratory.  When we stick these onto patients’ limbs we are able to take accurate measurements of how the limbs are moving, for example during walking.
We use the term 'kinematics' to describe these movements.  We are also able to collect kinetic data, by adding in the loads (forces and moments) on the limb.  This is possible because we have force measuring equipment mounted in our laboratory floor.
We have speclialist software which is able to analyse the information from our camera and force measurement systems.  Instead of pictures we end up with a whole series of graphs describing exactly how the limb is moving.  Because we can measure movements and loads in numbers we can compare different patterns.  This helps us to identify specific problems and measure the effects of treatments.
Our camera system has many other uses.  Film and games software companies use the same techniques to produce their animations.

What does it involve?
A 3D Gait Analysis test is non-invasive.  We first need to take measurements of the limbs and pelvis, to allow us to scale our computer models.  We then attach markers over key points.  We collect camera data for standing still and for walking.  We may need several walks up and down the lab, but patients are able to have a rest of they need to.

Who should have the test?
This test is useful for measuring almost any walking problem.  It is, however, an in depth procedure so we usually save it for times when a thorough investigation is needed.  Not everyone is suitable for this kind of test.  Patients need to be able to accept the markers and walk unaccompanied, without bulky walking aids.  Sometimes we are able to collect kinematic information but not kinetics.

How long is the test?
If everything goes smoothly the test can be completed in under an hour.  Sometimes it does take longer if the patient walks very slowly and needs frequent rests.
Kinematic data needs to be processed through our software and this is done after the patient has left.  For this reason results are not available before the patient goes home.  A report is produced after one of our team meetings, usually within a month or so after the test.

What are the risks?
The risks are very low.  The adhesive tape we use is designed to be in contact with the skin and rarely produces any reaction.  It does however need to be removed at the end of the test, a process similar to removing a sticking plaster.

Dynamic Electromyography (EMG)

EMG is a way of recording the electrical activity in the muscles in your legs during walking. This can assist our clinicians in determining which muscles are not working at the right time. Muscles may be overactive, active at the wrong time or not active at all. This information can help us to find out what causes walking problems in patients with conditions such as cerebral palsy, stroke, head injury and spinal cord injury.

What does it involve?
EMG is a non-invasive test. Two small detectors (electrodes) are placed on the skin over each muscle to be assessed. These are then connected to a box that is carried in a small backpack that sends the signals from your muscles back to a computer. We may assess several muscles at one time.

How long is the test?
It depends on how many muscles we need to assess, but it usually takes less than one hour. Most of this time is spent attaching and checking the electrodes and setting up the rest of the equipment. The test itself only involves a few short walks, which can usually be done in a few minutes.

What are the risks?
Before we attach the electrodes we need to make sure that the area of skin under the electrodes is free of any dead skin. We also need to use a special gel under the electrodes. This can occasionally lead to some reddening and irritation of the skin in some people. This should fade within a couple of hours of the test. 

Energy Consumption Testing

The body uses energy to power the muscles used for walking.  People with walking problems often use more energy than normal.  They find walking tiring, limiting the distances they can cover.

There are two ways of measuring the energy used.  The best approach is to monitor the amount of oxygen the body uses.  The rise in heart rate during walking is also a useful indicator.  Our energy test combines these two methods into a single energy test. 

What does it involve?
An energy test is non-invasive.  The patient wears a face mask so that we can collect a sample of the air they breathe out.  From this we can calculate how much oxygen they have used.  A strap around the chest measures the heart rate at the same time.  The picture below shows a child wearing our test equipment.  The test procedure includes 4 tasks, sitting (5 minutes), standing (3 minutes), walking (8 minutes) and sitting (5 minutes).  Most patients perform the test barefoot.
All the data collected is analysed using computer software, giving us a series of numbers which describe the energy used during walking.

Who should have the test?
This test is useful for measuring almost any walking problem.  Patients will need to be able to walk unaccompanied, following a track marked out on the floor.  The full test procedure includes an 8 minute continuous walk.  This is too difficult for some of our patients and it is possible to stop the test early and still produce useful results.  We do, however, need at least a 2 minute walk. 
An energy test is particularly useful for showing how much a person's walking problem affects their ability to get about.  Some walking patterns which appear abnormal are actually quite efficient and we can show that with an energy test.  We also use energy testing before and after major treatments as it gives us a good way of measuring overall improvement.

How long is the test?
The test itself lasts 21 minutes.  We usually leave about 40 minutes in total to allow us to set up the equipment at the start and remove it at the end.

What are the risks?
The risks are very low.  Patients do need to wear a face mask, which fits fairly tightly.  This can leave a red mark which fades very quickly.

Some children do not like wearing the face mask.  They are often particularly worried if they have had an anaesthetic with a mask previously.  It is helpful for them to know that this test is doing something completely different.

Pedobarography (PBG)

What is Pedobarography?
Pedobarography (PBG) involves measuring the pressure under the foot during walking. This can be done when walking barefoot by using a plate mounted in the floor, or when walking in shoes by using special pressure measuring insoles.

What is it used for?
This information can help our clinicians in diagnosing foot problems and identifying parts of the foot that may be at risk of further problems. In-shoe measurements can help to determine if special footwear and insoles are effective in alleviating high pressures.

Which type of medical conditions can be assessed by pedobarography?
It can be used to assist in the treatment of a range of conditions that affect feet, including rheumatoid arthritis, diabetic foot problems and musculo-skeletal disorders.

What does the assessment involve?
Patients who are referred for pedobarography normally undergo a clinical assessment to examine the available range of movement and active muscle power in the foot and ankle. Barefoot measurements are routinely conducted on patients who attend with a foot problem. Patients are required to perform several walks until at least three measurements have been made for each foot. In-shoe measurements are usually carried out if bespoke footwear and / or special insoles are used to treat the problem.
 

Video Vector Assessment

Even though we have access to sophisticated tracking cameras we still take videos of our patients walking.  A video gives us extra detail and for some parts of the body, such as the back and feet, it is particularly useful. 

Both of our gait laboratories have force measuring equipment in the floor, allowing us to measure the force between the sole of the foot and the floor (ground reaction force).  When someone is standing still the force is the same as their body weight, but once they start moving the force changes its size and direction. 

Using our video vector system we are able to draw a line on the video film, showing the size, direction and position of this force.  Watching the video helps us to understand which muscles are working and diagnose balance and control problems.

We have video vector systems in both our laboratories and we have also made the technology portable.  A transportable system is taken out to clinics and schools to allow patients to be seen in the local community. 

What does it involve?
Video vector analysis simply requires the patient to walk in front of the video cameras.  We may need several walks up and down the lab, but patients are able to have a rest of they need to.  We do need patients to dress in a way that allows us to see the legs, pelvis and lower back.  Shorts and a crop top are ideal for this.
We do ask patients to walk barefoot if at all possible so that we can assess the effects of their splints and footwear.

Who should have the test?
Almost all of our patients, with the exception of those coming for foot pressure studies, will have video film taken.
Video vector analysis is particularly useful for setting up splints and shoes.  The therapist is able to see the patient standing and walking, along with the ground reaction force, and make any adjustments necessary to get the best effect.

How long is the test?
If everything goes smoothly the test can be completed in under an hour.  Sometimes it does take longer if the patient walks very slowly and needs frequent rests.
The video recording itself is available straight away and staff members sometimes use it as part of a discussion with the patient.  Often we will need to study the video tape in detail at one of our review meetings.  In this case a report is produced, generally within a month or so after the test.

What are the risks?
The risks are very low.  Patients do need to walk in the laboratory and there may be a risk of falling if they have problems with balance.  Some patients also find walking tiring or uncomfortable.  The risks here are less than walking in the community, as a gait laboratory provides a safe, level, uncluttered environment.