Lay summary
·Introduction : In a previous study sponsored by the Swiss National Fund (# 3152-062006.00/1), to which the present application is an extension, we designed an original movement analysis system (MAS) based on kinematic sensors to assess the resting tremor, bradykinesia and gait impairment of patients with Parkinson’s disease (PD). Results from this study show that not only is the MAS able to identify these features accurately during long-term recordings, but also that the determination of their duration and severity may allow a clear distinction between ON and OFF periods in PD patients with levodopa (LD)-related motor fluctuations.

·Aims : The principal aim of the study is to test the long-term capacity of the MAS to detect, quantify and monitor abnormal hyperkinetic movements in extrapyramidal disorders, including dyskinesia in PD, chorea in HD, postural tremor in ET, dyskinesia and dystonia in TS and tics in GTS.Additional aims include a full validation of the MAS for the continuous assessment of motor fluctuations in PD and for an accurate discrimination between ON (with or without dyskinesia) and OFF periods over time ; and an improvement of technical aspects related to the MAS itself as well as determining specific algorithms for the detection of hyperkinetic movements.

·Methods: This two-year project comprises a clinical part and an engineering part which are superimposed during the whole project. The clinical part involved three separate studies during which patients mounted with the MAS will be assessed during four to six hours continuously and be simultaneously followed by raters using a specifically designed Pocket PC-based logging software. In the first study, PD patients with moderate to severe LD-induced dyskinesia will be assessed with particular emphasis on the presence, topography, duration and amplitude of dyskinesia. Analyses of these data will be focused on the delineation of the neurophysiological signature of these abnormal movements using various recognition methods. In the second study, provided dyskinesia have been accurately defined, we intend to validate the MAS by applying the method to PD patients with advanced disease and motor fluctuations, some of them having had a STN-DBS surgery. All features of PD will be analyzed in the long run and, more importantly, this information will be used to categorize ON and OFF periods with a sensitivity and specificity as high as possible. Other validity parameters, including face-to-face parameters, test-retest etc, will be calculated. Finally, in a third study, based upon methods derived from the analysis of tremor and dyskinesia, the detection capability of the MAS will be tested for various hyperkinetic movements, including postural tremor, chorea, dyskinesia-dystonia and tics, using a similar paradigm as described above. At the same time, technical modifications of the MAS, improvement of analysis algorithms and establishment of a robust data analysis method will be carried out.

·Value of the project : Complimentary to the first project, this research has the potential of providing the medical community with a unique instrument, the MAS, capable of assessing objectively a large variety of movements disorders with respect to their phenomenology, topography, duration and severity. Because of its relative simplicity, this tool is designed to be used by any clinician for the long-term and ambulatory monitoring of patients with any hypo- or hyperkinetic movement abnormality. Of particular interest will be the precise delineation of ON and OFF states distribution in PD over long periods of time, allowing personalized therapeutic interventions. In addition, many other medical and non-medical applications can be envisaged. Provided this versatile tool gains sufficient medical attention and is used on a routine basis, the MAS may replace most existing methods and may well become the ultimate instrumental method to assess movement disorders.