This study investigates how obesity may affect the auditory system in individuals with Multiple Sclerosis (MS). Specifically, it examines the brain's ability to process and suppress sounds (contralateral suppression).

The test is painless and brief. It provides information about the condition of the auditory nerve pathways. The goal is to better understand how obesity may influence this system and to improve follow-up and support for individuals with MS.

This study investigates the potential impact of obesity on auditory efferent system function in individuals diagnosed with Multiple Sclerosis (MS). Specifically, it focuses on assessing contralateral suppression of Distortion Product Otoacoustic Emissions (DPOAEs), a non-invasive, objective method for evaluating the integrity of the cochlear outer hair cells and the medial olivocochlear (MOC) efferent system.

Participants will undergo a brief and painless auditory test, during which DPOAEs are recorded both in quiet and with contralateral acoustic stimulation. This approach allows for the assessment of the brainstem's ability to suppress cochlear responses, which reflects central auditory processing capabilities.

By comparing suppression patterns across participants with different body mass index (BMI) classifications, the study aims to identify whether obesity contributes to functional changes in the auditory efferent system among MS patients.

The outcomes of this research may enhance the understanding of how metabolic factors such as obesity interact with neurological conditions like MS, potentially guiding more personalized clinical monitoring and interventions.

Eligibility Criteria Minimum Age: 18 Years Maximum Age: 50 Years Sex: All Gender Based: No Accepts Healthy Volunteers: No

Inclusion Criteria:

Ability to cooperate with the applied scales and auditory tests

Normal findings in otoscopic examination (ear, nose, and throat evaluation)

Absence of any neurological, psychiatric, or metabolic disease other than Multiple Sclerosis (MS)

No history of significant noise exposure

For female participants: not pregnant and not in the menstrual period

Exclusion Criteria:

Presence of active middle ear pathology (e.g., otitis media, tympanic membrane perforation)

Abnormal tympanometric findings

Hearing loss exceeding 20 dB HL at any frequency between 500-4000 Hz

Neurological or psychiatric disorders other than MS

History of ear surgery or otologic trauma

Use of medications known to affect auditory function (e.g., ototoxic drugs)

Inability to cooperate with audiological testing

Pregnancy

Diagnosis of metabolic or endocrine disorders (e.g., uncontrolled diabetes, thyroid dysfunction)

Body Mass Index (BMI) below 18.5 (underweight) or above 40 (morbid obesity)

Data sharing is not planned prior to the publication of the study. Access may be considered after publication, upon request and subject to ethical approval.

This is an observational study with no intervention; therefore, no masking was applied. All participants and investigators were aware of the group assignments (obese vs. non-obese), and no parties beyond those listed were masked.