Narrative Ability in Swedish Children Treated for Posterior Fossa Tumours: Macro- and Microstructural Performance...

Posterior fossa tumours (PFT), among the most common childhood brain tumours, place children at risk of speech, language, and communication difficulties, often described in relation to cerebellar mutism syndrome (CMS) but also seen in children without mutism. Narrative ability refers to the capacity to understand, create, and share stories. Narratives can be analysed at the macrostructural level, capturing structure and content, and the microstructural level, reflecting, for example, morphosyntax and lexicon. Narrative ability has not previously been investigated in children with PFT at both levels, including pre- and postoperative data, or in relation to CMS or dysarthria.

The aims were to investigate narrative ability at macrostructural and microstructural levels in children with PFT compared with typically developing (TD) peers, to investigate pre- to postoperative changes at both levels in children with PFT, and to examine relations between macro- and microstructure and the presence of CMS and dysarthria.

A story-generation task from the Expression, Reception and Recall of Narrative Instrument (ERRNI) was administered pre- and postoperatively, in the early postoperative phase (1-4 weeks after surgery). Macrostructure was analysed using ideascore, and microstructure using mean length of utterance in words (MLUw), grammaticality (GY), subordination index (SI), lexical diversity (MATTR), and words per minute (WPM). Group comparisons and associations with CMS and dysarthria were analysed using linear regressions, and changes over time with mixed-effects models.

Children with PFT scored significantly lower than TD peers on the macrostructural measure ideascore and on several microstructural measures, including MLUw, GY, and WPM, both pre- and postoperatively (all p < 0.05). SI and MATTR did not differ between groups. Difficulties were most pronounced among older children. No significant pre- to postoperative changes were found, although individual variability was evident. The small group of children with CMS did not differ significantly from other children with PFT, while those with postoperative dysarthria showed a decline in both macro- and microstructure (p < 0.05).

Children with PFT showed pre- and postoperative difficulties at macro- and microstructural levels, producing narratives with fewer story elements, shorter utterances, and more grammatical errors compared with TD peers. The age-related differences suggest that narrative difficulties become more prominent as language and cognitive demands increase. The findings underline the clinical importance of including narrative tasks encompassing macro- and microstructural aspects, together with motor-speech evaluation, in assessment and follow-up of children treated for PFT to guide appropriate interventions.

What is already known on this subject Previous studies have described speech, language and/or communication difficulties following posterior fossa tumour surgery, particularly in association with cerebellar mutism syndrome (CMS). One aspect of language that may be affected is narrative ability, which can be analysed at two levels: the macrostructural level (content) and the microstructural level (form). Still, little is known about narrative ability in children with posterior fossa tumours (PFT), although a small study based on postoperative data has shown microstructural difficulties in children undergoing PFT surgery. What this paper adds to existing knowledge Our study adds new knowledge about language profiles in children with PFT, showing that they have narrative difficulties at macro- as well as at microstructural levels, present both pre- and postoperatively. These difficulties are most evident among older children and show individual variability. We did not find more pronounced difficulties in the small group of children with CMS compared with the other children undergoing PFT surgery. What are the potential or actual clinical implications of this work? The findings underline the importance of including narrative assessment in the evaluation and follow-up of children treated for PFT. Assessing macro- and microstructural aspects together with motor-speech evaluation can help identify children in need of interventions. Regular follow-up assessments are essential, as narrative difficulties may become more apparent as language and cognitive demands increase.