Treadmill walking in the gait rehabilitation in Parkinson's diseaseneurophysiological mechanisms and their combination with the non-invasive brain stimulation

Resum

Parkinson's disease (PD) is a neurodegenerative disease characterized by a set of motor and non-motor symptoms. Gait disorders are among the most disabling motor impairments in PD patients, as they severely affect their quality of life. In recent decades, the treadmill has been explored as a tool for improving gait in PD. Understanding the mechanisms underlying these improvements will ameliorate the efficacy and prescription of physical therapy in PD. However, in spite of the growing body of evidence that links gait to cognitive function, the role played by attention in the gait improvements associated to treadmill walking in PD is still unknown. In the same way, the possible associated neurophysiological mechanisms have never been explored. However, transcranial direct current stimulation (tDCS), a form of non-invasive brain stimulation, has been explored recently in order to improve gait in PD, and offers a promising tool in increasing the efficacy of rehabilitative interventions. It could also enhance our understanding of PD-pathophysiology. Nevertheless, the combined use of tDCS and the treadmill in PD has not yet been investigated. The work presented here consists of three studies. The first explores the attentional demands involved in gait improvements associated with the treadmill in PD. The second investigates the immediate kinematics and neurophysiological effects of a single treadmill walking session on PD. The third study investigates the kinematic and neurophysiological effects of the combined use of tDCS and treadmill walking in patients with PD. The results of this thesis do not support attentional resources as a possible mechanism for treadmill-associated gait improvements in PD. Likewise, a specific therapeutic effect of a single treadmill walking session on gait in PD was observed, with no associated neurophysiological changes in the outcomes measured. However, the combination of tDCS and treadmill resulted in a specific spinal excitability modulation. Further studies would be recommended to explore the role of belt displacement and constant speed as main underlying mechanisms. Additional studies are also needed to investigate the functional significance of the interaction of tDCS and treadmill walking in PD.