To investigate the combined neuromodulatory effects of intermittent theta burst stimulation (iTBS) and probiotics on gut-brain axis in Parkinson’s disease – a randomized controlled trial.

Parkinson’s disease (PD) is a progressive neurodegenerative disease characterized by the loss of dopamine neurons in the substantia nigra pars compacta. Gastrointestinal (GI) dysfunction is one of the most common non-motor symptoms of Parkinson’s disease. Abnormal gastric motility and delayed gastric emptying occur in early-stage PD even prior to pharmacological treatment, which is attributed to alterations in gut microbiota.  Neurogenic orthostatic hypotension (nOH), is a potentially serious manifestation of cardiovascular sympathetic failure that occurs in approximately 30% of patients with PD. Recently, transcranial magnetic stimulation (TMS) has been used extensively to modulate the cortical plasticity via non-invasive magnetic stimulation applied to the motor cortex. Evidence suggests probiotics may decrease pro-inflammatory cytokines, oxidative stress, and potentially pathogenic bacterial overgrowth in patients with PD. The present study is designed to unravel the therapeutic role of single-session (excitatory) intermittent theta burst stimulation (iTBS) of motor cortex along with probiotics on gut brain axis and neurogenic orthostatic hypotension in PD patients. A Battery of questionnaires, blood pressure assessment, electrogastrography (EGG), cortical excitability will be recorded and correlated with the motor cortex excitability of the PD patients. Thus, the present study will be helpful in mitigating the disease complexity of PD by the novel, non-invasive combinatorial strategy over classical pharmacological based approaches.