Introduction
respiratory problems, Parkinson's disease, tremors, respiratory dysfunction, PD, muscle rigidity
DISEASE, PARKINSON'S DISEASE, RESPIRATORY COMPLICATIONS, NEURODEGENERATIVE DISORDER, COMPLICATIONS
Parkinson's disease (PD) is a neurodegenerative disorder that is progressive and characterized by muscle rigidity, tremors, postural instability, bradykinesia, and autonomic dysfunctionsTherefore, treating respiratory problems in PD should be part of disease management to avoid complications in the respiratory system. However, no fixed respiratory protocols are suggested for respiratory problems as an intervention in patients with PD. According to a systematic review by Rodríguez et al.A few available types of equipment can be used as part of respiratory therapy that can improve ventilation and target lung expansion in patients with PD, thus preventing and treating respiratory complications. A volume-based incentive spirometer (IS) is a mechanical breathing device used in patients with respiratory dysfunction to aid in lung expansionAnother commonly used device for IMT is the threshold inspiratory muscle trainer (TIMT)Both devices (IS and TIMT) are used for IMT and use different mechanisms for their functioning. IS is a volume-based loading device, and TIMT is a pressure-based loading device; therefore, their effects may differ. Choosing the best from them will be an advantage for PD patients. No study has compared the effects of IS with the effects of TIMT when used for IMT in patients with PD. Therefore, the study aimed to compare the effectiveness of IS versus TIMT on maximum inspiratory pressure (MIP), 6-min walk distance (6-MWD), and pulmonary functions [forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), and peak expiratory flow rate (PEFR)] in patients with PD. We hypothesized that there is a significant difference between the effects of IS and the effects of TIMT on MIP, 6-MWD, FVC, FEV1, and PEFR in patients with PD.