This cross-sectional observational study aims to determine the frequency of falls in patients with myotonic dystrophy type 1 and to identify factors affecting dynamic balance. The study will also evaluate fear of falling, selected lower extremity muscle strength, and the relationship between muscle strength and fall frequency. The findings may contribute to a better understanding of fall risk and balance impairment in patients with myotonic dystrophy type 1.

Myotonic dystrophy type 1 is a multisystem neuromuscular disorder characterized by myotonia, progressive muscle weakness, and functional limitations. Distal muscle weakness, impaired postural control, and gait dysfunction may increase the risk of falls and negatively affect daily activities and quality of life. Although falls and balance impairment are clinically important in patients with myotonic dystrophy type 1, data on fall frequency and factors affecting dynamic balance remain limited.

This single-center, hospital-based, cross-sectional observational study will be conducted in patients with myotonic dystrophy type 1 who are followed at the Neuromuscular Diseases Center of Antalya Training and Research Hospital. The study aims to determine fall frequency and to investigate factors affecting dynamic balance. Fear of falling, lower extremity muscle strength, and dynamic balance performance will be assessed, and the relationship between muscle strength and fall frequency will be examined. The results are expected to improve the understanding of fall-related impairments in myotonic dystrophy type 1 and support more comprehensive clinical assessment and rehabilitation planning.

Inclusion Criteria:

• Adults aged between 18 and 60 years old
• Diagnosis of myotonic dystrophy type 1
• Ability to understand and follow study instructions
• Ability to ambulate, with or without an assistive device, sufficiently to perform the study assessments
• Willingness to participate and provide written informed consent

Exclusion Criteria:

• Severe cognitive impairment interfering with understanding or completion of the study assessments
• Severe visual impairment interfering with balance and mobility testing
• Severe sensory impairment, including markedly impaired vibration sensation, that may affect balance assessment
• Any additional neurological, musculoskeletal, vestibular, or other medical condition that could substantially affect gait, balance, or fall risk independently of myotonic dystrophy type 1
• Acute medical condition or unstable clinical status at the time of assessment
• Inability to complete the study evaluations

The study population will consist of adult patients with myotonic dystrophy type 1 who are followed at the Neuromuscular Diseases Center of Antalya Training and Research Hospital. Participants who meet the predefined eligibility criteria and are able to complete the balance, mobility, and muscle strength assessments will be included.

The investigators have not yet made a final decision regarding the sharing of individual participant data. Any future data sharing will be considered in accordance with institutional policies, ethics committee approval, and participant confidentiality requirements.