Mapping of long-term cognitive and motor deficits in pediatric cerebellar brain tumor survivors into a cerebellar white matter atlas

Frederik Grosse,Pablo Hernáiz Driever,Stefan Mark Rueckriegel,Ulrich-Wilhelm Thomale

doi:10.1007/s00381-021-05244-2

Abstract

PurposeDiaschisis of cerebrocerebellar loops contributes to cognitive and motor deficits in pediatric cerebellar brain tumor survivors. We used a cerebellar white matter atlas and hypothesized that lesion symptom mapping may reveal the critical lesions of cerebellar tracts.MethodsWe examined 31 long-term survivors of pediatric posterior fossa tumors (13 pilocytic astrocytoma, 18 medulloblastoma). Patients underwent neuronal imaging, examination for ataxia, fine motor and cognitive function, planning abilities, and executive function. Individual consolidated cerebellar lesions were drawn manually onto patients’ individual MRI and normalized into Montreal Neurologic Institute (MNI) space for further analysis with voxel-based lesion symptom mapping.ResultsLesion symptom mapping linked deficits of motor function to the superior cerebellar peduncle (SCP), deep cerebellar nuclei (interposed nucleus (IN), fastigial nucleus (FN), ventromedial dentate nucleus (DN)), and inferior vermis (VIIIa, VIIIb, IX, X). Statistical maps of deficits of intelligence and executive function mapped with minor variations to the same cerebellar structures.ConclusionWe identified lesions to the SCP next to deep cerebellar nuclei as critical for limiting both motor and cognitive function in pediatric cerebellar tumor survivors. Future strategies safeguarding motor and cognitive function will have to identify patients preoperatively at risk for damage to these critical structures and adapt multimodal therapeutic options accordingly.

Highlights

Almost half of all brain tumors in childhood are located in the infratentorial area and nearly a third arises in the cerebellum [1]
Planning capability was significantly compromised in Pilocytic astrocytoma (PA) (24%) and MB (39%) patients when compared to healthy peers (PA: p < 0.001, MB: p < 0.001) including prolonged planning time with increasing task complexity (PA: p = 0.025, MB: p < 0.001)
Using the atlas of cerebellar white matter tracts [37] for Voxel-based lesion symptom mapping (VLSM) of long-term sequelae in pediatric cerebellar tumor survivors, we demonstrated that lesions of the superior cerebellar peduncle (SCP) were critical for impaired motor as well as cognitive performance

Summary

Introduction

Almost half of all brain tumors in childhood are located in the infratentorial area and nearly a third arises in the cerebellum [1]. Postoperative cerebellar mutism syndrome and CCAS are associated with damage to structures composing the Guillain-Mollaret-triangle [13, 14] as well as diaschisis of cerebello-cerebral loops, which were described in animal studies [15] and confirmed in fMRI studies in humans [12, 16, 17]. The extent of lesion to the DN and the cerebello-thalamo-cerebral outflow tracts in the superior cerebellar peduncle (SCP) seem to be critical for pattern and severity of long-term deficits [20, 21]

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Conclusion