The Effect of Proprioceptive Neuromuscular Facilitation on Trunk Mobility, Gait, Fear of Falling, and Quality of Life in Individuals Diagnosed With Parkinson's Disease

Parkinson's disease (PD) is a neurological disease that includes four main findings: resting tremor, bradykinesia, postural instability, and rigidity, in addition to many motor and non-motor symptoms . PD, the most common form of Parkinsonism, is a chronic and progressive disease characterized by the loss of dopaminergic neurons located in the pars compacta region of the substantia nigra. Its degenerative prognosis, characterized by motor and non-motor problems such as bradykinesia, tremor, rigidity, abnormal postural control, gait disorders, depression, and cognitive impairment, makes the management of the disease difficult . The incidence of PD, which typically begins around the ages of 55-60, varies between 15-250/100,000. Studies conducted in Turkey have indicated an incidence of 202/100,000 . In PH, as the disease progresses, there is a decrease in trunk mobility, forward flexion posture, and consequently loss of postural stability, particularly due to axial rigidity . Trunk stiffness and decreased trunk muscle strength are greater in individuals with PH compared to healthy controls. It has been noted that the decrease in trunk mobility impairs both anterior-posterior and lateral balance, and that individuals with PH experiencing these symptoms have difficulty in timing and scaling effective corrective movements, resulting in an increased risk of falls.

Gait disorders are considered one of the most disabling aspects of PH and can strongly affect the patient's independence and quality of life. The underlying mechanisms of gait disorders are multifactorial and usually result from a multisystem lesion involving both dopaminergic and non-dopaminergic mechanisms. In addition to the clinical and functional effects of gait disorders, a more important issue is that this impairment in gait can result in falls and trauma. The fact that gait disorders are affected by the motor and non-motor symptoms of the disease, and that they are parallel to longevity and cognitive decline, increases the importance of treatment . Therefore, rehabilitation interventions aimed at treating or alleviating gait disorders should be one of the main focuses in individuals with PH .

Falls are one of the most important causes of morbidity for PH . Approximately 60% of PH patients fall at least once a year, and falls are recurrent in at least one-third of these patients . Falls, which occur as a result of various factors, lead to injuries, fear of falling, decreased independence, decreased quality of life, and increased healthcare costs in patients. Fear of falling leads to a decrease in the patient's self-confidence, withdrawal from social life, and the choice of an inactive lifestyle, resulting in an increased risk of falling. This situation becomes a vicious cycle over time. While 28-55% of elderly people living at home fear falling, this rate increases to 50-65% in those who have fallen before . In PH patients, this rate is much higher than in healthy controls and is important in predicting future falls . Therefore, it is stated that fear of falling should be included in the assessment and treatment programs of individuals with PH.Quality of life is a multidimensional outcome measure consisting of three areas: physical, mental, and social, influenced by an individual's personal characteristics and environmental factors . Since chronic and progressive diseases affect every aspect of an individual's life, health-related quality of life is considered in the management of such diseases . PH affects an individual's ability to independently perform almost all daily living activities and leads to negative consequences in quality of life. PH affects the individual not only physically, mentally, and socially, but also economically for the individual and their family due to the additional financial burden of care and treatment costs . Therefore, evaluating the quality of life in individuals with PH is important and necessary.

Proprioceptive Neuromuscular Facilitation (PNF) is a method frequently used by physiotherapists to facilitate the emergence of a motor response through the stimulation of proprioceptors and to improve voluntary control in the central nervous system . The International PNF Association defines the PNF philosophy under 5 subheadings: positive approach (mental engagement in therapy), functional approach (integrating real tasks from daily life), mobilizing reserves (radiation principle), holistic treatment of the individual, motor learning, and control principles using motor learning. PNF fully complies with the International Classification of Functioning, Disability and Health (ICF) because it addresses the relevant patient along with their personal and environmental context components of deficiencies, activity limitations, and participation restrictions.Movements in the human body occur in oblique and rotational directions. In PNF, movements occur as a whole, rotationally and diagonally, and this common direction of movement is called a pattern. Applying PNF exercises in a patterned manner increases the effectiveness of the treatment . In PH, PNF can help individuals achieve efficient motor function and promote benefits related to physical aspects such as clinical condition, tremor, rigidity, bradykinesia, and balance disorders. Theoretical mechanisms for the effect of PNF include autogenic inhibition, reciprocal inhibition, and stress relaxation. These mechanisms could be used to treat rigidity and improve trunk mobility in PH, but there are very few studies reporting them in PH .

A meta-analysis examining PNF applications in individuals with PH included 6 studies. In these studies, PNF application was generally performed in combination with other methods (treadmill training, vibration, gait training), and the patterns were not applied in their pure form . This made it difficult to evaluate the effectiveness of PNF in isolation in individuals with PH. Furthermore, PNF applications in individuals with PH mostly involved lower extremity and pelvic patterns, often focusing on their effects on balance and gait parameters . However, the investigators anticipate that the combined use of upper and lower extremity patterns will have a positive effect on both trunk and gait and balance parameters, and the investigators believe that the PNF technique should be applied to the patient as a single exercise to determine its net effect in PH. The study's findings will contribute to determining the effectiveness of PNF in PH without the need for any additional methods or equipment, thus showcasing its applicability. Furthermore, a review of the literature reveals no studies examining the effects of PNF on trunk mobility, fear of falling, and quality of life. For all these reasons, the investigators believe that this planned study will both fill the gap in the literature and shed light on the treatment of PH patients for physiotherapists working in this field.