The posterior fossa syndrome (PFS) consists of transient cerebellar mutism, cognitive symptoms, and neurobehavioral abnormalities that typically develop in children following posterior fossa (PF) tumor resection. The pathophysiological substrate of the syndrome remains unclear. We investigated eight children of whom five presented with a variety of clinically relevant non-motor language symptoms associated with cognitive and behavioral disturbances after PF tumor resection. Four children developed transient cerebellar mutism followed by dysarthric speech. Non-motor language symptoms consisted of agrammatism, anomia, impaired verbal fluency, comprehension deficits, and a spontaneous speech. Neurocognitive deficits included executive dysfunctions, concentration deficits, and visuo-spatial disorders. In addition, all children presented with behavioral and affective disturbances. 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.

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Apraxic agraphia is a peripheral writing disorder caused by neurological damage. It induces a lack or loss of access to the motor engrams that plan and programme the graphomotor movements necessary to produce written output. The neural network subserving handwriting includes the superior parietal region, the dorsolateral and medial premotor cortex and the thalamus of the dominant hemisphere. Recent studies indicate that the cerebellum may be involved as well. To the best of our knowledge, apraxic agraphia has not been described on a developmental basis. This paper reports the clinical, neurocognitive and (functional) neuroimaging findings of a 15-year-old left-handed patient with an isolated, non-progressive developmental handwriting disorder consistent with a diagnosis of "apraxic dysgraphia". Gross motor coordination problems were objectified as well but no signs of cerebellar, sensorimotor or extrapyramidal dysfunction of the writing limb were found to explain the apraxic phenomena. Brain MRI revealed no supra- and infratentorial damage but quantified Tc-99m-ECD SPECT disclosed decreased perfusion in the anatomoclinically suspected prefrontal and cerebellar brain regions crucially involved in the planning and execution of skilled motor actions. This pattern of functional depression seems to support the hypothesis that "apraxic dysgraphia" might reflect incomplete maturation of the cerebello-cerebral network involved in handwriting. In addition, it is hypothesized that "apraxic dysgraphia" may have to be considered to represent a distinct nosological category within the group of the developmental dyspraxias following dysfunction of the cerebello-cerebral network involved in planned actions.

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This paper presents the case of a 17-year-old right-handed Belgian boy with developmental FAS and comorbid developmental apraxia of speech (DAS). Extensive neuropsychological and neurolinguistic investigations demonstrated a normal IQ but impaired planning (visuo-constructional dyspraxia). A Tc-99m-ECD SPECT revealed a significant hypoperfusion in the prefrontal and medial frontal regions, as well as in the lateral temporal regions. Hypoperfusion in the right cerebellum almost reached significance. It is hypothesized that these clinical findings support the view that FAS and DAS are related phenomena following impairment of the cerebro-cerebellar network.