# Clinical, Cognitive and Behavioural Assessment in Children with Cerebellar Disorder
## 3 Developmental Cerebellar Cognitive-Affective Syndrome
### Posterior Fossa Malformations Syndromes  
The incidence of posterior fossa malformations diagnosed during the newborn period is estimated to be 1 out of 5000 live births [35]. Hypoplasia, atrophy, or a global or partial dysplasia, are associated with 333 different genetic syndromes, including several metabolic diseases [24]. Neurosychiatric disturbances and cognitive-executive dysfunctions have been described in case series and in samples of children with congenital cerebellar malformations, including cerebellar agenesis, dysplasia, and hypoplasia, molar tooth sign [9; 36; 37; 38]. Congenital cerebellar malformations are associated in particular with neuropsychological deficits and/or neurodevelopmental disorders, intellectual disability, severe language impairments, and emotional-behavioral problems of varying entities to autistic-like pictures [36]. The type and extent of cerebral reorganization processes in the presence of cerebellar malformations are difficult to predict and may possibly account for the variability of clinical phenotypes. Therefore, it is more difficult to identify a defined syndromic picture just as it is the case with acquired cerebellar lesions [39]. Moreover, many cerebellar malformations are associated with genetic mutations and/or abnormal neuroembryology, thus potential extracerebral central nervous system effects make it difficult to draw conclusions about function [40]. The isolated inferior vermian hypoplasia and mega cisterna magna tend to have a positive outcome, while vermian hypoplasia and cerebellar agenesis malformations appear to show a moderate or severe degree of neurodevelopmental delay [41]. The behavioral developmental profile of 27 children and adults with congenital malformations confined to the cerebellum showed a pattern of deficits in agreement with the general CCAS profile [39], confirming that malformations of cerebellar hemispheres were associated with selective neuropsychologic deficits in executive functioning, visuospatial and linguistic abilities, while malformations affecting the vermis produced affective and social disorders evolving towards autistic-like pictures. Motor impairments were generally less severe and showed a slow and progressive improvement. Recently, hospital records and neuroimaging of 67 children with cerebellar congenital malformations (isolated vermis hypoplasia, global cerebellar hypoplasia, Dandy-Walker malformation, pontocerebellar hypoplasia, molar tooth malformation, rhombencephalospnapsis, unilateral cerebellar malformation) were systematically reviewed by [PERSON] and colleagues [37] and associations between specific imaging features and neurodevelopmental outcomes were assessed. 85% of the cohort had global developmental delay. Intellectual disability was present in 61% and autism spectrum disorder in 12 percent. Adjusting for suprateratorial malformations and presence of genetic findings, severe developmental delay was associated with global cerebellar and ponto-cerebellar hypoplasia, whereas children with vermis hypoplasia were confirmed to be less likely to have severe delay. A worse neurodevelopmental outcome was associated to the presence of epilepsy, but not to suprateratorial abnormalities [37]. Cerebellar and brainstem malformation recognizable on axial brain MRI as the \"Molar Tooth Sign\" (MTS) characterize Joubert syndrome (JS, MIM PS213300) [42; 43]. This appearance results from a combination of abnormalities: cerebellar vermis aplasia/hypoplasia, thick and horizontally-oriented superior cerebellar peduncles, and often, a deep interpetduncular fossa. Clinically, individuals with JS typically present as infants with hypotonia, abnormal eye movements, respiratory control disturbances, and as children or adults, ataxia and/or cognitive impairment [44]. Essentially all individuals with JS experience hypotonia and motor delays during infancy and early childhood, usually evolving to ataxia as they get older. Abnormal eye movements and abnormal respiratory control are also seen in most, but may be subtle.