Gait disturbances are important signs and symptoms in clinical neurology. Causes underlying gait disturbances are many like motoneuron disease, cerebellar disease, Parkinson's disease, stroke, pain. Among the traumatic causes of locomotor deficits, spinal cord injuries (SCI) take an important place. Clinically, an extensive and reasonably simple array of tests is available for the assessment of gait disorders. In animals (quadrupals), on the contrary, analysis of gait is not that simple.
Recently, an automated gait analysis system, named 'CatWalk', has been developed. The CatWalk was originally developed to assess functional recovery following spinal cord injury. The use of CatWalk allows detailed analysis of very fine locomotor aspects which were previously not detectable in SCI research.
Next to the assessment of locomotor recovery in SCI models, the CatWalk has been shown to be valid method for the objective assessment of mechanical allodynia in animal models of neuropathic pain. The most commonly used method for testing mechanical allodynia is the application of von Frey's filaments to the mid-plantar surface of the affected paw. Now a complete study on the use of the CatWalk in a model of neuropathic pain was performed by Vrinten and Hamers (2003). They tested rats with a Chronic Constriction Injury of the sciatic nerve (CCI) both with the well known von Frey filaments and the CatWalk. From the CatWalk data it was concluded that these rats minimize contact with the affected paw during locomotion, by reducing (1) the duration of the stance phase and (2) the pressure applied during stance. Moreover, these parameters show a high degree of correlation with mechanical withdrawal thresholds as determined by von Frey filaments. Our laboratory further extended research on the use of the CatWalk in both rat and mouse models of neuropathic pain, e.g. CCI in several mice strains and partial ligation of the sciatic nerve in rats (Seltzer-model). The most recent experiments using the CatWalk method as an objective tool in the investigation of mechanical allodynia in various mouse and rat neuropathic pain models will be presented.