Clinical features of adolescent-onset functional motor disorders in tertiary movement disorders centers 2026 Geroin et al

[Andy]

Abstract​

Background​

Functional Motor Disorders (FMDs) represent a diagnostic and therapeutic challenge in pediatric neurology, particularly among adolescents. Their clinical presentation is common but often nonspecific, leading to frequent misdiagnoses and diagnostic delays. We aimed to characterize FMDs in adolescents and to examine the frequency of isolated and combined phenotypes and their associations with demographic and clinical variables.

Methods​

In this observational study, data were obtained from the Italian Registry of FMDs, including patients with a clinically definite diagnosis of FMD consecutively enrolled at 25 Italian tertiary movement disorders centers.

Results​

Among 847 patients, 93 (10.9%) had adolescent-onset FMDs. Motor phenotypes did not differ significantly between adolescent- and adult-onset FMDs, with the exception of parkinsonism, which was observed only in the latter. Compared with adult-onset FMDs, adolescent-onset FMDs were associated with a longer disease duration, a higher number of medical consultations before diagnosis, and a higher frequency of functional seizures and infections, but with lower rates of insomnia, fatigue, and antipsychotic use. In multivariable analysis, adolescent-onset FMDs remained independently associated with a greater number of medical consultations (adjusted OR 1.07; 95% CI 1.02–1.13), the presence of functional seizures (adjusted OR 2.06; 95% CI 1.09–3.8), and with lower occurrence of insomnia (adjusted OR 0.49; 95% CI 0.27–0.92) and fatigue (adjusted OR 0.51; 95% CI 0.30–0.86). Pain was more likely to be associated with the combined FMDs phenotype.

Conclusions​

Adolescent-onset FMDs are common and are associated with several non-motor symptoms in tertiary movement disorders centers. Early and accurate diagnosis may help to reduce unnecessary investigations and inappropriate treatments.

Open access

 

[Andy]

"Among the non-motor symptoms, fatigue appeared to be more characteristic of the adult-onset FMDs group. In general, fatigue affects 45% to 93% of patients with FMDs [22, 49, 50], and in our sample it was more frequent in the adult-onset group (52.9%) and less common in the adolescent-onset group (41.9%). These findings are in line with a large international survey (n = 1048) reporting fatigue in up to 93% of patients with functional neurological disorders [51].

In our study, the lower occurrence of fatigue in adolescent-onset FMD may relate to the smaller sample size in this subgroup or to the challenges of identifying this symptom in adolescence, particularly when coexisting with psychiatric or neurological comorbidities. A significant proportion of FMDs patients experience fatigue, even when compared with individuals affected by other neurological disorders [50], and fatigue is strongly associated with reduced quality of life and lower self-rated health, regardless of FMDs severity. Its role should therefore be acknowledged in clinical practice and addressed with tailored interventions. The higher frequency of insomnia in the adult-onset FMDs group is consistent with previous reports, which indicate that sleep disturbances are common in adults, with rates up to 58% [52]. In pediatric populations, sleep disorders are not uncommon, but their prevalence has not been systematically investigated in a large cohort of adolescents with FMDs.

To date, the literature does not clarify how fatigue and insomnia influence disability or quality of life in FMDs, nor which therapeutic strategies may be most effective in addressing them. Other non-motor comorbidities, such as migraine, have been reported in pediatric FND, suggesting a potential clinical overlap [53]. However, in our cohort, migraine frequency did not differ between adolescent-onset and adult-onset FMD."