Functional Neurologic Symptoms in Multiple Sclerosis: Estimated Prevalence and Associated Comorbidities

Area of Science:

• Neurology
• Psychiatry

Background:

• Functional neurologic disorder (FND) presents with inconsistent neurologic symptoms unexplained by structural damage.
• Research on functional neurologic symptoms (FNS) in people with multiple sclerosis (PwMS) is limited.
• FNS can significantly contribute to disability in clinical practice.

Purpose of the Study:

• To estimate the prevalence of FNS in PwMS.
• To characterize the clinical features and comorbidities associated with FNS in PwMS.

Main Methods:

• Retrospective cohort study of adult PwMS at an Australian tertiary MS clinic (2024).
• Inclusion criteria: MS or clinically/radiologically isolated syndrome diagnosis, age 18-64.
• FNS defined by neurologist-documented FND, positive examination signs, persistent postural-perceptual dizziness, or functional cognitive disorder features.

Main Results:

• FNS identified in 15.1% of PwMS (62/411).
• PwMS with FNS were more likely female and experienced cognitive symptoms, functional fatigue, chronic pain, migraine, and polypharmacy.
• Higher prevalence of psychiatric comorbidities (anxiety, depression, PTSD) and increased emergency department use observed in PwMS with FNS.

Conclusions:

• FNS are prevalent in PwMS attending tertiary clinics, associated with significant medical and psychiatric comorbidities.
• Fatigue, cognitive symptoms, chronic pain, and migraines are key factors associated with FNS in PwMS.
• Further research is essential to understand the clinical impact and management of FNS in the PwMS population.