# Clinical, Cognitive and Behavioural Assessment in Children with Cerebellar Disorder
## 4 Diagnostic Approach
Such situations can be encountered both in static encephalopathies and in neurodegenerative diseases and neurometabolic disorders [76]. As mentioned previously, cerebellar anomalies can affect different regions (part or all of the cerebellar vermis or one or both of the cerebellar hemispheres), or they may involve the whole of the cerebellum. It is important to distinguish between these various forms because each of them specifically characterises a different disorder [77]. On MRI, cerebellar hypoplasia can also be differentiated from atrophic changes, this distinction orients the clinician towards a given general pathological category (congenital or metabolic-degenerative). More precisely, in the various anatomical regions, we may find a picture of hypoplasia (a reduction in the number of adequately-sized cells), dysplasia (due to the absence of a part of the cerebellar structure or a disorder of cerebellar neural migration), or atrophy (caused by progressive cell depletion) [78; 79]. These three situations can easily be distinguished if the same subject is examined repeatedly at different times; hypoplasia and dysplasia present a static picture, remaining unchanged, whereas the involutional process of atrophy progresses, becoming increasingly evident over time. Even if only one neuroradiological examination has been conducted, a careful analysis provides clinicians with important information, enabling them to distinguish between a cerebellum, of small size but normal shape (hypoplasia), and an 'involved' cerebellum with the typically accentuated arborisation of the vermis lobules in sagittal sections, or an increase in the size of the intra-hemispheric fissures (atrophy) [80; 81]. With regard to the cognition and behaviour, a comprehensive age-appropriate assessment should always be implemented at the time of diagnosis and at follow-ups, to update the functional profile in order to detect special needs and define appropriate therapeutic and educative interventions in a developmental perspective. The evaluation should include the investigation of psychomotor and intellectual abilities but also of higher cognitive functions, in particular verbal fluency, procedural learning, visual and auditory sequential memory, executive functions (including planning, processing speed, working memory, set shifting and visual attention) together with affect and behaviour regulation, emotional modulation, social and adaptive skills. It is important to adapt the protocol to the clinical and neurological condition of each patient (Table 1). Through the evaluation of clinical and neuroradiological data, it is therefore possible to formulate diagnostic hypotheses, distinguishing acquired causes (vascular, inflammatory, infectious) and genetic causes. In the genetic field, it is possible to distinguish malformations forms in which the MRI usually shows hypoplasia or dysplasia: among these, the most common are Joubert syndrome and related syndromes and some syndromes as Fragile X and Williams syndrome and pontocerebellar hypoplasia. Among the degenerative forms, characterized by cerebellar atrophy at brain MRI, we mention Atxia-telangiectasia,congenital disorders of glycosylation (CDG), spinocerebellar ataxias (SCA). These last ones have a more typical onset in adulthood, although some forms can start also in pediatric age as SCA6, SCA1 and SCA2, particularly for anticipation mechanism. Therefore these conditions should be investigated in case of familial cases. If a genetic disease is suspected, it is indicated to proceed with the investigation of the specific genetic mutation or in case of less clear hypothesis by next generation sequencing techniques (NGS) of specific groups of genes or of the whole exome.