CatWalk XT gait analysis versus treadmills
Traditionally, there are two fundamentally different ways to perform gait analysis in animals. One can either observe or measure gait in a forced manner, as seen when using a treadmill or treadwheel, or in an unrestricted manner, such as with CatWalk XT.
CatWalk XT gait analysis versus treadmills
In this blog post we will discuss the pros and cons of different gait assessing methods, and compare them to the CatWalk XT gait analysis method.
Unforced gait analysis
The unforced way of assessing gait ability is what we see in many daily practices of physicians- watching closely as the patient moves to and from them. In lab animals this is translated into traditional methods such as BBB scoring and paw inking. The main advantage of unforced gait analysis is that the animal is allowed to move at a speed that its gait (ab)normality or endurance will allow.
Variety between treatment groups
When analysing gait, there is often variety within and between treatment groups, such as speed of movement. Since speed of movement influences a lot of gait parameters, researchers find it important to adjust for speed even though it is the most obvious gait phenotype.
Adjusting for speed
The most obvious method of regulating speed is using a motorised treadmill or treadwheel system, which eliminates variations in speed within treatment groups… or does it?
The only thing you can be sure of is that the animals all walk with the same average speed; the speed to which the treadmill system is set. However, they typically reach this average speed by constantly varying their speed moving up and down the treadmill.
Furthermore, animals with different stress levels, different endurance levels or type of injury will have different strategies to ‘stay up to speed’, which can eventually result in huge variations in walking speed, jumping and limping behavior, etc.
The stress to keep up in forced gait analysis
Generally speaking, a treadmill does not frighten a human patient, because they can be told what is going on, and they can stop the treadmill if necessary. Animals, however, cannot comprehend what is going on, potentially leading to increased stress levels. The researcher sets a speed for them and they have to keep the pace, or they will fall.
Their natural instinct is to do whatever it takes to keep up, possibly introducing gait artefacts. While this set speed potentially reveals deviations in gait, it might also mask those subtle changes in gait that are the focus of your research.
The CatWalk XT gait analysis system
CatWalk XT successfully gives you the best of both worlds by combining a walkway system and advanced software program. CatWalk XT allows animals to walk at their own intrinsic speed in an unforced manner, guided in a straight line due to the restriction introduced by the walls of the corridor.
Afterwards, the software allows you to adjust for speed and speed variations. This way you can detect artefacts in gait in a non-artificial manner, all while introducing the least amount of stress on the animal.
Motivating the animal
Of course, this straight line does not solve all problems of standardisation. First, animals might not want to walk. Although training helps, motivation often works even better. That is why CatWalk XT uses a goal box at the end of the runway. This way, animals are motivated by the prospect of their home cage or some other reward.
The CatWalk XT goal box makes it easier to train your animals to get straight runs along the 70 cm glass plate. This results in faster data collecting and an overall smooth experiment. Curious on how an experiment with the CatWalk XT goal box looks like? Watch the video below!
Capturing footprints in detail
The biggest advantage of CatWalk XT is the way in which it measures the footfalls. CatWalk XT uses a technology called Illuminated Footprints. The animal traverses the glass walkway with a high speed camera mounted underneath. Light shines through this walkway, reflecting the footprint only when it touches the glass.
This results in a very precise recording of the actual placement of the feet. Belt driven systems are far less accurate, often detecting part of the feet that are not actually touching the walkway. Do you want to know more about the CatWalk XT? Our product manager Reinko Roelofs is happy to tell you all about it in the product video below!
CatWalk XT gait analysis in different studies
The CatWalk XT gait analysis has been validated in research and experimental procedures for several (neurological) disorders and lesions. The study of Hofman et al. is one of them. They were the first to use the CatWalk XT gait analysis system to establish an accurate gait analysis method for fracture healing research in small animal models and evaluate the influence of a lower extremity fracture on gait pattern. After their studies, Hofman et al. concluded the following big advantages that the CatWalk XT offers compared to treadmill-based gait analysis in small animals:
- Due to the runway set-up, the CatWalk XT system resembles the normal gait of animals;
- Both static and dynamic gait parameters can be evaluated in one analysis with the CatWalk XT system
- The registration of the CatWalk XT system is very accurate when animals are trained well. This provides clinically relevant and extensive data on gait behavior.
As you can see, the need for a forced gait analysis system is no more. Because all in all, the CatWalk XT is a complete and easy to use gait analysis system for quantitive assessment of footfalls and locomotion in small animals.
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