# A Clinical-Based Diagnostic Approach to Cerebellar Atrophy in Children
## 3 Results
Impairment of the orobuccal motility (orobuccal dysppraxia) is present in 23% of patients, while two patients have dysphagia. All such signs do not appear to be specific to a particular disorder, but can be variably present--or not--in all the atax syndromes included in the cohort. Hypotonia is seen in 56% (29/52) and in some cases, particularly in children with DNA repair disorders, a truncal hypotonia is associated with distal limbs spasticity. Extracerebellar neurological degeneration is common. 65% have signs of pyramidal system involvement (spasticity, hyper-reflexia, clonus, Babinski sign). Extra-pyramidal movement disorders are found in 21% and may be dys/hyperkinetic movements (four patients), choreoatetoid movements (three, all affected by DNA repair defect disorders: 2 AOA1, 1 A-T), dystonia (7 patients: 1 Cockayne, 1 Mitochondrial, 2 NBIA, 1 PCH, the QARS1 patient, 1 SCA); bradykinesia is observed in one patient with mitochondrial disorder. Finally, a hypo-reflexia is present in 15%; five out of eight of these children have a definite neuropathy recorded at NCS (one did not have the investigation, the Wolfram child and one Cockayne had normal NCS study). Epilepsy affects 25% (14/52) children and in particular all children with NCL and PCH and 41% of those with DNA repair defect disorders. Brain MRI was performed more than once in all but eight patients (85%); a progression of the atrophy is present in 70% (31/54). Children with the absence of radiological progression had ARSACS (2/2 children affected by such disease), CMT2Z (1), FRDA (1), Gillespie syndrome (1/2), KIF1A mutation (1/2), mitochondrial disease (two of the six with available follow-up), PCH (1/2 with available follow-up), SCA (2/5 with available follow-up, one SCA6, one SCA5), and Wolfram Syndrome (1/1). CA affects cerebellar vermis in all patients, while hemispheres are spared in seven cases. In 38% (20/52), a cerebellar hyperintensity is present, affecting dentate nuclei (7/20), the cerebellar cortex (7/20), or both (6/20). Cerebellar hypoplasia is present in six children (12%): 3/5 CDG and 3/3 PCH; in these latter three children, hypoplasia spreads to the pons, showing the pathogenomic PCH pattern. A brainstem involvement is globally present in 29%. Atrophy was present also in the supratentorial areas in nine cases; in two NCL and in two out of five Cockayne, it is associated with WM abnormalities, with these latter globally present in 33%. One child with Cockayne syndrome and one with NCL also have basal ganglia alterations. In the majority of cases, neurophysiological studied have been conducted. All the children underwent at least one sleep-EEG, which demonstrated epileptic abnormalities not only in those patients suffering from epilepsy, but in an additional seven cases, so that the global prevalence of EEG abnormalities was 40% (21/52). BAEP and VEP were, respectively, pathological in 32% (15/47) and 20% (9/44) patients in which the exams were performed; both studies does not seem to correlate with any disorder; also, ERG alterations, present in 8 out of 47 patients (17%), are not typical of specific diseases, except for the fact that both CLN patients showed an abnormal retinal function. SEP study has been performed in a small number of patients (\(n=19\)) addressing specific clinical suspicions (mostly, a possible SCA diagnosis); in such children, 58% showed abnormalities. EMG and NCS were, respectively, performed in 27 and 35 patients. EMG was pathological in 37% of the tested patients and NCS abnormalities were just as common (37%). Children presenting EMG + NCS alterations are seven (26%, 7/27), more than a half with DNA repair defect diseases. Almost half of the patients underwent muscle biopsy. The exam showed non-specific alterations in 28%: minimal neurogenic alterations were present in three patients with DNA repair defects, while the exam revealed minor alterations in the structure of muscular fibers in four SCA patients.