Parkinson's disease (PD) and Multiple sclerosis (MS) are neurological diseases characterized by motor impairment resulting in significant motor disability. Motor impairment in PD is thought to be due to changes in the activity of the basal ganglia leading to abnormal encoding of the motor output at primary motor cortex (M1) level. Cortical gray matter (GM) pathology contributes to MS patient's motor disability and predicts disease progression. Cortical neuronal loss within M1 may also play a role in the pathophysiology of motor impairment of MS patients. The concurrent use of transcranial magnetic stimulation and electroencephalography (TMS-EEG) allows to investigate the causal relationship between M1 activity and motor behavior in healthy subjects and neurologicla conditions. Developing non-invasive biomarkers of M1 dysfunction underlying motor disability may improve the prediction of the disease progression and response to therapy in individual patients with PD and MS.
The purpose of the present project is to investigate whether TMS-EEG can be used to identify non-invasive biomarkers of functional abnormalities of M1 activity underlying motor impairment in patients with PD and in patients with MS. In order to do so, we will enroll 51 patients with PD, 51 patients with MS, and 102 healthy controls. We will compare TMS-related spectral perturbations in the beta frequency range from M1 stimulation between PD patients OFF and ON medications and healthy controls (HC). Also, we will compare TMS-related spectral perturbations between healthy controls (HC) and patients with MS and will look for possible associations between TMS-related spectral perturbations from normal-appearing M1 and clinical progressions.
Identifying a non-invasive biomarker of functional alteration of the cortico-subcortical network underlying motor impairment in patients with PD could help in the field of early diagnosis, prognosis, and as an early response indicator for therapeutic interventions.
The identification of biomarkers of M1 functional impairment in patients with MS could allow us to identify cortical alteration before it results in cortical atrophy. Also, the availability of early markers of GM alterations in pwMS could help to tailor and to monitor therapeutic interventions thus reducing patients' long-term disability [19].
Overall, TMS-EEG biomarkers of motor cortical dysfunction underlying motor disability may improve the prediction of the disease progression and response to therapy in individual patients with PD and MS.
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