Insights into emotions, learning and motor function in Parkinson’s disease to improve the multidisciplinary approach of the treatment

Quantitative methods are nowadays available to assess human balance by measuring movements of the body Center of Pressure (CoP) and Center of Mass (CoM) in static (i.e. posturography) or dynamic condition (i.e. walking). The CoP displacements are commonly recorded using force platforms, as CoP is the point of application of the resultant of ground reaction forces, while the CoM is usually extrapolated from the 3D coordinates of the body anatomical landmarks related to the kinematics through biomechanical models. The availability of such methods has improved over the years the knowledge of the physiological movement and of its alterations in pathological conditions in people with neurological diseases, such as Parkinson’s disease (PD). The strength of instrumented measurements lays in their ability to detect slight differences in movement patterns and motor control, not clinically detectable by a human observation, between PD patients at the early stage of the disease and healthy subjects, as well as in the possibility to capture the changes induced by rehabilitation. In addition, the usefulness of these measurements became fundamental for the management of individual patients, in particular for tailoring the therapeutic interventions on balance deficits in PD patients. Recent narrative reviews highlighted that a multidisciplinary approach, which include pharmacological, surgical, and non-pharmacological treatments (i.e., physiotherapy, occupational-therapy, and cognitive-emotional interventions), is essential for a positive effect on PD persons, especially when Freezing of Gait (FOG) symptoms occur. In light of the above consideration, this thesis has been divided into two main lines of research, that are: 1) the investigation of the effects of the emotional sphere on visual-spatial learning and gait initiation in persons with PD, with and without FOG symptoms, to advance the knowledge on PD pathophysiology and to provide useful data for a tailored therapeutic approach (Chapter 2 and 3); 2) the assessment of quantitative measures of movement, related to static and dynamic balance, during gait initiation and walking in persons with PD, using both wearable systems and optoelectronic instrumentation (Chapter 4 and 5). This thesis have the objective of adding a piece of knowledge about the neurophysiological basis of usual and complex gait in healthy subjects and in people with PD by means of movement analysis methodologies. Overall, our results highlighted some relevant findings regarding: (i) the protective strategy adopted by subjects with PD to manage their dynamic balance deficit; (ii) the development of home-based rehabilitation protocol based on a single wearable sensor to improve the anticipatory postural adjustments in subjects with PD; (iii) the effects of music evoked-emotions on visual-spatial learning in elderly and in subjects with PD; (iv) the correlates of emotions aroused by the common real-life sounds with the FOG symptom experienced in subjects PD. Although physiotherapy is considered an essential intervention to improve independence and quality of life of PD patients, the development of innovative, multi-domains, and personalized treatment, to support patients along the course of the disease is still needed. Nowadays, the availability of cost-effective technologies, able to detect movements in ecological settings (e.g. home, outdoor activities), allow researchers to deeply investigate motor and cognitive disturbances induced by PD. Humans are emotional beings. We have the ability to accept and give love, feel anger and fear, experience shame, guilt, and humiliation, transform with joy, pride, and elation, and so much more. Our ability to be emotional sets us apart from other living beings in the world. And it’s our emotional responses to stimuli in our world that can either bring out the best or the worst from us. The results reported in this project (Section 2 and 3) suggest that emotions play an important role in motor and cognitive ability in healthy subjects and in subjects with PD. In the more advanced stages of the disease more severe symptoms appear such as FOG, which is a very disabling episodic symptom. For this reason, a part of this thesis has been focused on trying to understand what the triggering factors of FOG may be. Based on the study of APAs, which are fundamental movements for dynamic balance and for the integrity of walking, it emerged that the unpleasant emotions can be among the triggering factors of the FOG symptom in subjects with PD. We compared behavioral data from a cohort of PD participants with or without the FOG symptom during gait initiation, to investigate which among the most realistic circumstances involving emotional factors may influence gait patterns. The main finding of our study was that the influence of auditory emotional stimuli on automatic movement during gait initiation is different in subjects with and without FOG. In particular, the negative-oriented auditory stimuli (i.e., unpleasant stimuli) reduced the APA generation in PD patients with FOG, while positive-oriented ones (i.e., pleasant stimuli) facilitate the APA displacement. In addition, we found that this emotion-evoked behavior was mainly associated with non-motor domain factors, such as depression, confirming the role of non-motor symptoms in the developing of the FOG. The results of cross sectional studies conducted in this project (Section 4 and Section 5) highlighted the possible lines of development on rehabilitation protocols to improve the dynamic balance in subjects with PD and increase their effects with testing protocols applicable in a home-based setting. The training as constant as possible could prolong the maintenance of the beneficial effects after the end of therapy. The availability of easy-to-administer tests for the evaluation of balance control and motor skills makes a realistic scenario the one in which similar solutions will be soon adopted in the tele-monitoring of community-dwelling healthy elderly and neurological patients, offering the possibility of an early diagnosis and fast intervention. The possibility to learn new motor strategies in a familiar domestic environment could be of high value for the patient, since it could enable the possibility to directly improve activities that are really conducted in that setting on a daily basis, thus assisting the final users in preserving their lifestyle, autonomy and health. Our results support previous finding, suggesting that emotional management (also known as emotion-focused therapy), which assumes that lacking emotional awareness or avoiding unpleasant emotions can cause harm, might be an adjunctive therapeutic intervention to improve gait and balance performance in PD patients and in particular in those who experience FOG. Future studies should investigate whether adding emotion-focused training to physiotherapy might reduce the effects of FOG in individuals with Parkinson's disease.