Functional neurological symptoms are a frequent and relevant comorbidity in patients with multiple sclerosis

Introduction: Functional neurological symptoms (FNS) in multiple sclerosis (MS)
have shown to be underinvestigated even though neurological diseases such as
MS represent a risk factor for developing FNS. Comorbidity of FNS and MS can
produce high personal and social costs since FNS patients have high healthcare
utilization costs and a quality of life at least as impaired as in patients with disorders
with underlying structural pathology. This study aims to assess comorbid FNS in
patients with MS (pwMS) and investigate whether FNS in pwMS are associated
with poorer health-related quality of life and work ability.
Methods: Newly admitted patients (234) with MS were studied during their stay
at Kliniken Schmieder, a neurological rehabilitation clinic in Konstanz, Germany.
The degree to which the overall clinical picture was explained by MS pathology
was rated by neurologists and allied health practitioners on a five-point Likert
scale. Additionally, neurologists rated each symptom reported by the patients.
Health-related quality of life was assessed using a self-report questionnaire and
work ability was assessed using the mean number of hours worked per day and
information regarding disability pension as reported by patients.
Results: In 55.1% of cases, the clinical picture was completely explained by
structural pathology due to MS. 17.1% of pwMS presented an overall clinical picture
half or less of which could be explained by underlying structural pathology. PwMS
with a higher comorbid FNS burden had a lower health-related quality of life and
reported fewer working hours per day than pwMS with symptoms explained
by structural pathology. Furthermore, pwMS with a full disability pension had a
higher comorbid FNS burden than pwMS with no or partial disability pension.
Discussion: These results show that FNS should be addressed diagnostically and
therapeutically since such symptoms are an important comorbidity in MS that is
related to poorer health-related quality of life and lower work ability.