Gait and movement laboratories are used to measure, evaluate and study human movement disorders. The Derby Gait and Movement Laboratory was set up in 1994 and consists of a specially equipped room containing a six camera 3-D Elite motion analysis system that incorporates a Kistler force plate.

It is used to document dynamic walking patterns so that informed decisions can be made about future treatments and management of ambulatory problems. Such treatments could include physiotherapy, orthotic management, surgical procedures and more recently Botulinum toxin injections to reduced spasticity in a range of movement. The Laboratory offers a multi-disciplinary professional team ensuring that the full potential to patients and referring professionals is realised and carries out substantial amounts of varied research work. This service has been fully audited by a european consortium (abcmale) and was accredited for clinical and research purposes by Prof J. Paul in 2000.

Marker and Marker Recogintion System

The basis of the Elite system as with many other motion analysis systems is the use of passive retro-reflective markers attached to a series of anatomical landmarks. This is in contrast to systems that use active markers, commonly light emitting diodes or LEDs, that are more restrictive to movement because of the necessary wires.

Reflective markers are attached to the anatomical landmarks used by the Elite system for motion analysis, in gait analysis this enables measurements of the ankle, knee, hip, pelvis and shoulders to be made.

The cameras situated around the room have a ring of infra-red emitting diodes around the lens. Each marker reflects the infra-red light which is picked up by the cameras that have a clear line of sight to it. Therefore each camera will only be able to ‘see’ some of the markers at any one time. As long as at least two of the six cameras can ‘see’ a marker at any one moment in time its absolute coordinates within the calibrated volume of the lab can be fixed. The cameras have a maximum acquisition speed of 100 Hz.

The Elite system uses a special purpose image processor for marker recognition which enables it to ‘see’ only the markers and removes erroneous reflections from the field of view of each camera. A second phase of processing utilises BTS software-implemented algorithms to determine a 3D coordinate for each marker for a series of frames that make up the recording time of the analysis. The coordinate of each marker is relative to the absolute reference system of the laboratory. 

Along with analysis, a full clinical history and examination is carried out by a Consultant in Paediatrics and Rehabilitation.

A fully qualified physiotherapist performs a full static examination of the range of movement of the lower limb joint angles.

Upper limb motion analysis

Over the past two years the Derby gait and motion analysis team have pioneered a unique software package to objectively analyse upper limb motion. The analyser simultaneously produces kinematic (degrees of movement in three dimensions) of all movements of the trunk, shoulder, elbow, wrist, index finger and thumb) which provides a unique opportunity to evaluate the use of pharmaceuticals believed to improve motion within the upper limb.

As in gait, passive reflective markers 10 mm in diameter are positioned on the affected limb. Each patients passive/active forward reach (mm) and available range of movement at the shoulder, elbow, wrist, and the index finger and thumb separation is measured. The degree of elbow extension, coupled with the pro/supination obtained on each reaching task, will be the primary outcome measures as they provide some indication as to the degree of spasticity within the biceps and brachio-radialis.