[Cerebellar cognitive affective syndrome and vertebrobasilar ischemia. From cerebello-cerebral diaschisis to "dysmetria of thought"]

Cerebellum, along with it' s role in coordinating motor functions, exercises a significant regulatory influence in fields of cognitive and affective functions. Therefore, studying the effect of cerebrovascular atherosclerotic pathology on mood and cognition should not be limited to stenotic dysfunctions of carotid arteries, but also extend its methodological framework to the consideration of the integrity of vertebrobasilar system (VBS), cerebellar perfusion and posterior cerebral circulation in general, as it has not been yet sufficiently addressed whether VBS insufficiency is associated with deterioration of patients' mental and emotional status and quality of life (QoL). Vertebrobasilar circulatory dysfunction has been pointed out, since decades, as a cause of progressive memory impairment and dementia, due to multiple infarcts in cerebral areas which are topographically critical for mental and emotional functions. Indicative of the pathophysiological and anatomic-functional association of VBS with these neuro-psychiatric domains are cerebellar cognitive-affective syndrome (CCAS) and crossed cerebello-cerebral diaschisis (CCCD). Mental and psychiatric components of CCAS, along with ataxic motor disability, constitute the conceptual hypothesis of "dysmetry of thought", while diagnostic significance of mental dysfunctions and psychopathological manifestations, in terms of symptoms preceding motor impairments that ascribe cerebellar malfunction in the epicenter of their pathophysiology, such as cerebellar ataxias, in which, early recognition of CCAS may facilitate therapeutic interventions aimed at improving QoL, reveal that cerebellar pathology, either of degenerative etiology or vascular substrate on the ground of vertebrobasilar insufficiency (VBI) or other surgical conditions of the posterior fossa, is associated with deterioration of patients' QoL which is related to significant impairments in their cognitive functions with (co)manifested emotional disorders. Studies in animal models also support these conclusions. Since VBI is responsible for a wide range of psychiatric and neurological symptoms, new findings concurred with current indications advocating that, without consideration of VBS disorders, it is impossible to clarify the connection of cerebral perfusion dysfunctions to neurocognitive deficits. The inclusion of cerebellar perfusion disorders in scientific research and clinical approaches to cognitive and affective disorders that may occur in patients with cerebrovascular lesions constitutes a paradigm of best clinical practices implementation and interdisciplinary convergence of neurosciences and vascular medicine.