Troubles de la marche chez la personne âgée: aspects physiologiques et sémiologiques

Abstract

Human beings have the unique ability to walk in a bipedal manner, which, like language, makes them differ so much from even highly evolved animals. From a neurological point of view, the importance of gait analysis increased very much during the nineteenth century, through eminent clinicians like Romberg, Bruns or Parkinson. It became clear that certain structures were essential in the complex sequence of events that permitted bipedal walking, the localisation of which was deduced from abnormal gait patterns in patients with particular neurological lesions. The importance of the lobes was first underlined by Bruns in 1892 who described frontal ataxia. In the last century, further progress was made in the understanding of gait and gait disorders' mechanisms with the use of technical means like electromyography, stroboscopic video, accelerometers, gyroscopes and computers. Gait disorders is a major problem in our old-growing population, being responsible for significant morbidity and even mortality, mainly through falls and bone fractures. It has been reported that more than 20% of old people fall each year. This article mentions some of the epidemiological data regarding this issue, underlining its public health relevance. The gait cycle is detailed, along with the main centres that are known to be involved in its processing, in animal experience and in the human being. The main gait disorders' patterns are reviewed from a clinical point of view, beginning with level - often seen in patients with peripheral nervous system disease like polyneuropathy and characterised by an increased base of support, irregular steps and a positive Romberg's sign. In the so-called middle level gait disorders, cervical myelopathy due to degenerative spondylosis is the most frequent and often overlooked cause, leading to slowly progressive spastic paraparesis, with lower motor neuron signs in the superior limbs, sensory abnormalities and sometimes urinary incontinence. Parkinsonian gait pattern is frequently encountered, with its small and shuffling steps, its stooped posture and the associated parkinsonism in the form of rest tremor, brady-kinesia and rigidity. Many higher level gait disorders can mimic parkinsonian gait, for example in the first stage of normal-pressure hydrocephalus or in any lesion leading to a gait disorder. This gait pattern often leaves superior limb movements quite unaffected - best exemplified by arm swing, and clinical examination frequently displays associated signs like dementia or urinary incontinence. Other higher level gait disorders include dysequilibrium - both and subcortical, gait ignition failure, cautious gait and psychogenic gait disorders that are briefly discussed. The article ends with some practical information on how to deal with a patient presenting with gait disorders.