Analysis of Presurgical Language in Children with Posterior Fossa Tumours Relative to Postoperative Speech Outcomes: Findings from the European CMS Study

Posterior Fossa Syndrome is a common complication in children following posterior fossa tumour surgery, typically marked by transient postoperative speech impairment (POSI; i.e., mutism or reduced speech). Previous studies suggest that children who develop POSI show different language profiles postoperatively compared to those who do not. It remains unclear to what extent these language difficulties exist preoperatively and whether preoperative language difficulties are related to postoperative speech status. This study provides the first comprehensive analysis of preoperative language samples, using data from the European study of Cerebellar Mutism Syndrome. Patients with and without POSI were compared to identify preoperative language characteristics that may be associated with POSI. Preoperative language samples of 34 patients aged 3-16 years were analysed (16 developed POSI; 18 did not). We compared global sample characteristics and language performance across four levels: the semantic, lexical, morphosyntactic, and phonological level. No significant preoperative language differences were found between the groups for the four levels of language processing (all p-values > 0.137). Children who developed POSI produced more unintelligible speech preoperatively (beta = -14.455, p = .024), with better intelligibility related to older age (age & times;group: beta = 0.152, p = .007), only for the group with POSI. While the main focus of this study was on language, these findings suggest that risk factors for POSI within the domain of verbal output may lie more in preoperative speech. A comprehensive analysis of preoperative speech may provide valuable insight into speech characteristics potentially related to POSI.