Preoperative Speech Impairments as Precursors of Posterior Fossa Syndrome in Children with Brain Tumours.

Preoperative speech deficits in children with posterior fossa tumours (PFTs) may be linked to postoperative speech impairment (POSI), a hallmark of posterior fossa syndrome, yet this relationship remains underexplored. POSI is characterized by mutism or markedly reduced speech that resolves within weeks to months but often leaves persistent motor-speech deficits. Most existing literature has focused on postoperative outcomes, with limited attention to preoperative speech function. We therefore systematically investigated this association by analyzing perceptible motor-speech features in a large cohort of patients scheduled for surgery within the European Study of Cerebellar Mutism Syndrome. We included data from 135 children which formed three age-and sex- comparable groups: 16 patients who later developed POSI, 11 were mute and five had severely reduced speech (3;9-14;4 years), 62 patients with habitual speech (3;2-17;11 years), and 57 healthy controls (3;0-18;1 years). Patients were Italian-, Dutch-, and English-speaking, while controls were Dutch- and Italian-speaking. Four speech-language therapists rated participants' narrative recordings on 23 speech features (e.g., distorted vowels, imprecise consonants, stuttering, and hoarseness). Group comparisons revealed significant preoperative differences between the children who later developed POSI and the children with habitual speech in both hypernasality and in phonation-respiration (e.g., leaky, hoarse, and strained voice). In addition, patients who later developed POSI showed impairment compared to healthy controls in prosody (e.g., speech rate, excess and equal stress) and articulation (e.g., distorted vowels, imprecise consonants, sequencing errors). Patients with habitual speech differed from the controls in hypernasality and prosody. Moreover, age influenced the severity of articulatory and prosodic symptoms, with younger patients showing greater impairment. Children with PFT show signs of speech impairment preoperatively relative to healthy controls. When comparing patients, those later developing POSI show more severe impairments related to resonance and voice quality. This suggests possible differences in the degree to which speech-related underlying anatomical substrates were compromised, and these early differences may represent potential predictors of later POSI. These findings highlight the value of preoperative assessment for identifying children at a heightened risk of POSI, opening opportunities for prehabilitation - targeted early intervention in the form of speech therapy - to strengthen the speech-motor networks.