Title: Evaluation and facilitation of motor imagery in healthy persons and patients with Parkinson's disease
Other Titles: Evaluatie en facilitatie van motorische inbeelding bij gezonde personen en patiënten met de ziekte van Parkinson
Authors: Heremans, Elke
Issue Date: 4-May-2011
Abstract: Motor imagery (MI) can be defined as the mental rehearsal of a motor act in the absence of an overt motor output. This technique has already been used for many years by athletes to improve their performance. Recent studies suggest that motor imagery practice can also be of value in the rehabilitation of patients with neurological pathologies. The aim of this doctoral project was to tackle some important unsolved issues in this field, with specific interest in the implementation of motor imagery in the rehabilitation of patients with Parkinson’s disease (PD). First of all, when considering the application of motor imagery practice in PD patients’ rehabilitation program, there is a need to evaluate whether these patients are performing the imagery tasks correctly. It is not unlikely that a dysfunction of the basal ganglia, which is the core of the disease in PD, might affect imagery performance, since the basal ganglia were shown to be activated not only during physical execution but also during imagery of movements. Up to now, however, there is a lack of objective methods providing detailed information on the motor imagery process. Therefore, in chapter 2, we developed a method to monitor MI based on eye-movement registration. It was found that the participants’ eye-movement amplitude and duration, as well as their number of eye movements during imagery, nicely adapted to the to-be-imagined movements. These findings indicated that eye-movement registration can serve as an objective and real-time indicator to monitor the motor imagery process. We believe that this method may be a useful adjunct to monitor MI, mainly in a research context. In an additional study (chapter 3), we investigated the role of eye movements during MI in more detail. It was found that the occurrence of eye movements during MI was not a merely reflexive phenomenon, but instead had a functional role during the imagery process. The making of eye movements during motor imagery training was shown to be essential to achieve the highest gains from this type of training. In a next study, reported in chapter 4, we aimed to develop an alternative method to assess MI in a clinical context in which eye-movement registration is not available. Therefore, we assembled a test battery evaluating various aspects of motor imagery, such as accuracy, vividness and temporal organisation, as well as several types of MI, including visual and kinesthetic motor imagery. This battery was used to assess the imagery ability of a group of patients with middle and early stage Parkinson’s disease, in comparison to healthy age-matched controls. The results showed that the PD patients had preserved imagery vividness and accuracy and performed MI in accordance with general motor principles. However, they showed a profound slowness during MI, which might limit the potential benefits of MI training in this group. To overcome PD patients’ slowness during MI, in chapter 5 and 6 of this doctoral project, we investigated whether motor imagery quality could be positively affected by providing people with external task-related information during the imagery process. First, in chapter 5, a group of healthy participants was studied while performing motor imagery in the presence and absence of additional visual and auditory information. It was found that the provision of such external information significantly increased the participants’ imagery vividness and accuracy. In chapter 6, these positive effects of external information on MI were confirmed for patients with Parkinson’s disease. Providing these patients with additional visual information during MI significantly reduced their bradykinesia. In summary, the studies in the present doctoral thesis provide novel insights on methods to evaluate motor imagery ability and to increase motor imagery quality. We specifically focused on the use of motor imagery in patients with Parkinson’s disease. Although considerably more research is needed, we believe that the findings described in this thesis may contribute to the development of guidelines with regard to the implementation of motor imagery practice in neurorehabilitation, and, more specifically, in the rehabilitation of patients with Parkinson’s disease.
Publication status: published
KU Leuven publication type: TH
Appears in Collections:Movement Control & Neuroplasticity Research Group
Department of Kinesiology - miscellaneous
Department of Rehabilitation Sciences - miscellaneous
Research Group for Neuromotor Rehabilitation

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