Long-term cognitive deficits following posterior fossa tumour resection: A follow-up neuropsychological and functional neuroimaging study

The posterior fossa syndrome (PFS) consists of transient cerebellar mutism, cognitive symptoms and neurobehavioral abnormalities that typically develop in children following posterior fossa (PF) tumour resection. Although several hypotheses have been advanced, the pathophysiological substrate of the syndrome remains unclear. We investigated five children, age 3 to 11 years, who after PF tumour resection presented with a variety of linguistic, cognitive and behavioral disturbances. Four children presented with transient cerebellar mutism lasting between 7 and 35 days. On the motor speech level, mutism was followed by dysarthric speech. Linguistic symptoms, such as agrammatism (two patients), anomia (one patient), impaired verbal fluency (three patients), comprehension deficits (one patient), and reduced verbal output (four patients) were found as well. On the cognitive level, executive dysfunctions, concentration deficits, and visuo-spatial disorders were observed in four patients. In addition, all children presented with behavioral and affective disturbances, consisting of irritability, apathy and emotional instability. Functional neuroimaging studies during the phase of mutism by means of SPECT showed perfusional deficits in the anatomo-clinically suspected supratentorial areas subserving language dynamics, syntax, naming, executive functioning, affective regulation and behavior. A significant improvement of frontal perfusional deficits paralleled the clinical remission of mutism. These results add to the view that the PFS might represent a cerebello-cerebral diaschisis phenomenon, reflecting the metabolic impact of the cerebellar lesion on supratentorial cognitive and affective functions.