Proximal Dentatothalamocortical Tract Involvement in Posterior Fossa Syndrome

In a recent study, researchers from the United States have made significant discoveries about the underlying causes of posterior fossa syndrome, a condition characterized by cerebellar dysfunction, oromotor/oculomotor apraxia, emotional lability, and mutism in patients after infratentorial injury. The study, conducted at St. Jude Children's Research Hospital, aimed to investigate the involvement of proximal dentatothalamocortical tracts in patients who developed posterior fossa syndrome following tumor resection. The researchers found that initial tumor residence higher in the 4th ventricle, postoperative magnetic resonance signal abnormalities in the superior cerebellar peduncles and midbrain, and decreased fractional anisotropy in the bilateral superior cerebellar peduncles, fornices, and cerebral cortex were associated with the development of posterior fossa syndrome.

Key Takeaways:

• The study found that posterior fossa syndrome is characterized by cerebellar dysfunction, oromotor/oculomotor apraxia, emotional lability, and mutism in patients after infratentorial injury.
• The researchers used pre- and postoperative neuroimaging to investigate proximal dentatothalamocortical tract involvement in childhood embryonal brain tumor patients who developed posterior fossa syndrome following tumor resection.
• Initial tumor residence higher in the 4th ventricle (p=0.035) was observed in patients who developed posterior fossa syndrome.
• Postoperative magnetic resonance signal abnormalities within the superior cerebellar peduncles and midbrain were observed more often in patients with posterior fossa syndrome (p=0.030 and 0.003, respectively).
• Decreased fractional anisotropy of water was observed in the bilateral superior cerebellar peduncles, bisexual fornices, white matter region proximate to the right angular gyrus, and white matter region proximate to the left superior frontal gyrus.
• The researchers concluded that multiple bilateral injuries to the proximal dentatothalamocortical pathways may predispose the development of posterior fossa syndrome.

Statistics:

• 26 pediatric patients were evaluated in the study.
• 13 patients were prospectively diagnosed with posterior fossa syndrome, and 13 non-affected patients were evaluated.
• The study was published in Brain (Proximal dentatothalamocortical tract involvement in posterior fossa syndrome. Brain, 2009;132(Pt 11):3087-95).

Sources:

• E.B. Morris et al., "Proximal dentatothalamocortical tract involvement in posterior fossa syndrome," Brain, 2009;132(Pt 11):3087-95.
• Cancer Weekly editors, "Proximal dentatothalamocortical tract involvement in posterior fossa syndrome," NewsRx.com, 2009.
• St. Jude Children's Research Hospital, Division of Cancer Survivorship, Memphis, TN 38105 USA.