Spinal cord stimulation (i.e. the electrical stimulation of the dorsal columns of the spinal cord) isincreasingly used for the treatment of intractable pain syndromes due to vascular or neurogenicdisorders. Despite well-established safety and efficacy in properly selected cases, the use of SCS is stilllimited and its acceptance by the medical community remains somewhat restricted. This is due toseveral factors including an unclear mechanism of action and difficulties in determining objective endpointsto assess pain intensity and quality of life improvements in chronic pain patients. We propose areliable measurement of the spontaneous physical activity, a fundamental determinant of the quality oflife. Measurements have been performed in the condition of every day life, before and after theimplantation of the spinal cord stimulator.