The behavioral developmental profile of 27 children and adults (17 males and 10 females) with congenital cerebellar malformations was determined in a clinical, neuroradiological and neuropsychological study at the Scientific Institute 'E Medea', University of Milano, Italy. Of a total of 155 patients with cerebellar lesions, 128 (82.6%) with pathologies other than malformation were excluded (eg. acquired lesions, progressive pathology, metabolic disorders, cerebral involvement, Joubert syndrome, Arnold-Chiari syndrome, seizure disorders). The malformation was classified neuroradiologically as Type I. Complete cerebellar agenesis in 1 patient; Type II, complete or partial vermal agenesis in 5; Type III, Diffuse vermis and hemisphere cerebellar hypoplasia in 17; and Type IV, agenesis, hypoplasia or dysplasia of only the cerebellar hemispheres in 4 patients. Type I and II patients showed profound retardation of cognition, affect and language, and pervasive developmental disorder. Type III patients had variable cognitive and behavioral profiles, from normal to mild or moderate degrees of retardation. Type IV patients had largely normal cognition and affect, and mild language delay. Two patients had ADHD. Malformations affecting the cerebellar vermis were associated with affective and social disorders, autistic symptoms and a less favorable outcome. Patients with cerebellar hemisphere malformations had selective neuropsychological deficits involving mainly executive functions and visuospatial and liguistic abilities. Follow-up over time showed a gradual improvement in motor abilities and neuropsychological development, especially in patients with only hemisphere involvement. 
COMMENT. Acquired cerebellar lesions have been associated with a 'cerebellar cognitive affective syndrome, [CCAS].' . CCAS is characterized by disorders of executive cognitive functioning, visuospatial ability, expressive language, working memory, and affective behavior. Patients have impairment of planning, abstract reasoning, verbal fluency, working memory, impaired spatial cognition associated with distractibility, perseveration, and inattention, anomia, and personality change with blunting of affect or disinhibited or inappropriate behavior. Vermal lesions are associated with marked affective and communication disorders, or with post¬ surgical mutism and speech or language disorders. CCAS is described in both adults and in children with acquired cerebellar lesions. The above study has shown that CCAS also occurs with cerebellar malformations. It is noteworthy that 9 (33%) patients were diagnosed with PDD and 2 with ADHD. A structural brain pathology as the basis for ADHD is also supported by an N1H MRI study showing a smaller cerebellar vermis in boys with ADHD, particularly involving posterior inferior lobules VIII to X . The cerebellum controls not only motor functions but also cognitive, language, behavioral and affective functions.