The goal of this study is to investigate the effect of inspiratory muscle training (IMT) in Multiple Sclerosis (MS) patients on balance and postural control. The main question it aims to answer are:

• Is IMT effective in improving balance and postural control in MS patients? Participants will be randomly divided into two groups. One group will be given only balance exercises. The other group will be given IMT treatment in addition to balance exercises.

Multiple sclerosis (MS) is a chronic, inflammatory, demyelinating and neurodegenerative disease of the central nervous system (CNS). MS is a disease that usually progresses with attacks and can lead to progressive disability and severely restrict the quality of life in patients due to the accumulation of sequelae after attacks or the development of a progressive degenerative process. Somatosensory findings, motor findings, postural control-balance and coordination disorders, bladder-intestinal problems, visual, cognitive and psychiatric findings, fatigue and sleep disorders are seen in patients related to the CNS involvement site.

Balance, one of the International Classification of Functioning headings, is a skill included in activity and participation, expressing the body's ability to maintain its upright position against gravity, and reflects stability limits. Balance impairment is one of the most common problems in patients with MS and is one of the factors that cause disability. Lesions in the brain stem and cerebellum cause loss of postural control and balance. There are many causes of loss of balance: visual symptoms, optic neuritis, vestibular changes, somatosensory changes, ventromedial tract lesion, tone changes, loss of muscle strength, incoordination.

Respiratory dysfunction in individuals with MS is an important problem that starts from the early period of the disease, increases in severity with the progression of the disability and causes mortality. Considering the pathophysiology of respiratory problems in MS, unlike other neuromuscular diseases, demyelinating lesions are found and spread in one or more areas related to breathing in the brain and spinal cord. The location and size of the plaques were associated with muscle weakness.

One of the methods used in the field of pulmonary rehabilitation in MS patients is Inspiratory Muscle Training (IMT). The muscles responsible for primary inspiration are the diaphragm, external intercostal muscles, and scalene muscles. Inspiratory muscle training increases inspiratory muscle strength, type 1 muscle fibers, reduces dyspnea, increases maximum minute ventilation and 6-minute walking distance and quality of life. It is usually applied at 30% of the maximal inspiratory pressure (MIP) value for 30 minutes a day.

The effect of the core muscles is great in providing balance and postural control. The diaphragm forms the roof of the core muscles and plays an important role in the mobility of the thorax. Training the diaphragm muscle, like other muscles, is important for maintaining dynamic and static balance. IMT can help stabilize thoracic mobility by strengthening the diaphragm and scalene muscles, contributing to the stability of chest movements and improving transfer skills.

Inclusion Criteria:

• Having a diagnosis of relapsing-remitting MS with an EDSS of 1.5-5.5
• Having a Mini Mental Test score greater than 24
• Being between the ages of 18-65

Exclusion Criteria:

• Having a neurological disease other than MS
• Having an attack while working
• Problems other than MS that may affect balance
• Have a diagnosis of cardiac or pulmonary disease that will affect breathing

The IPD will not be shared with other researchers.