Unmet Needs in Clinical Practice: A Proposal and Application of A Diagnostic and Severity Scale to Grade Cerebellar Mutism Syndrome

BACKGROUND: The post-operative Pediatric Cerebellar Mutism Syndrome (CMS) affects about one-third of children and adolescents following surgical removal of a posterior fossa tumor (PFT). According to the Posterior Fossa Society consensus working definition, CMS is characterized by delayed onset mutism/reduced speech and emotional lability after cerebellar or 4th ventricle tumor surgery in children, with additional common features that include hypotonia and oropharyngeal dysfunction/dysphagia. The main objective of this work was to propose a diagnostic scale to grade CMS duration and severity.METHOD: Thirty consecutive subjects, aged 1-17 years (median 8 years, IQR 7) were evaluated with the proposed Post-Operative Pediatric CMS Survey after surgical resection of a PFT and, in cases of CMS, for the next 30 days after the onset (T0) or until symptom remission. At day 30th (T1), CMS was classified into mild, moderate, or severe according to the proposed Scale.RESULTS: CMS occurred in 13 patients (43.3%, 95% C.I.: 25.5-62.6%), with mild severity in 4 cases (31%), moderate in 4 (31%), and severe in 5 (38%). At T1, longer symptom persistence was associated with greater severity (p=0.01). Greater severity at T0 predicted greater severity at T1 (p=0.0001). Children with a midline tumor location and those aged under 5 years at diagnosis were at higher risk of CMS (p=0.025 and p=0.008, respectively).CONCLUSIONS: The proposed scale is a simple and applicable tool for estimating the severity of CMS at its onset, monitoring its course over time, and providing an early prognostic stratification to guide treatment decisions.