Parkinson's disease (PD) is most commonly manifested by the
presence of motor symptoms. However, non-motor symptoms
occur several years before the onset of motor symptoms
themselves. Hallmarks of dysfunction of the respiratory system are
still outside the main focus of interest, whether by clinicians or
scientists, despite their indisputable contribution to the morbidity
and mortality of patients suffering from PD. In addition, many of
the respiratory symptoms are already present in the early stages
of the disease and efforts to utilize these parameters in the early
diagnosis of PD are now intensifying. Mechanisms that lead to the
development and progression of respiratory symptoms are only
partially understood. This review focuses mainly on the
comparison of respiratory problems observed in clinical studies
with available findings obtained from experimental animal models.
It also explains pathological changes observed in non-neuronal
tissues in subjects with PD.