Evidence for a link among cognition, language and emotion in cerebellar malformations

We compared the neurobehavioral profiles of children with Joubert syndrome (JS participants), a rare autosomal recessive condition characterized on magnetic resonance imaging (MRI) by hypoplasia of the cerebellar vermis and midbrain-hindbrain malformations, and children with malformations confined to the cerebellar vermis and one or both hemispheres (Cerebellar malformations--CM participants). We aimed at investigating the influence of anatomo-clinical similarities (vermian malformation) and differences (intact cerebellar hemispheres vs sparing of the pons, respectively) with respect to cognitive, linguistic and emotional development, assuming as a reference framework the Cerebellar Cognitive Affective Syndrome (CCAS). Results show that severe to moderate mental retardation is infrequent in JS children, while it is present in more than half the sample of CM children. Affect development was generally preserved in JS, in high-functioning CM individuals and also in some of the CM children with moderate mental retardation, which raised questions as to the role of a cerebellar vermis lesion in determining affect disorders. Further, cognitive and linguistic profiles on both intellectual and neuropsychological evaluations provided evidence for distinct patterns of peaks and valleys in the two groups, with JS children being significantly more impaired in language and verbal working memory and CM individuals showing a significant impairment of executive functions and emotional development. The overall evidence provides support for an important role of cerebellar structures per se in shaping emotional, cognitive and linguistic development, when vermian lesions are associated to cerebellar hemispheric lesions. Cerebellar vermis and brainstem lesions instead appear to have a major impact on motor-related skills, including oro-motor abilities and verbal working memory.