Cognitive impairment in the lateralized phenotype of corticobasal degeneration

Corticobasal degeneration (CBD) is a rare disorder, which normally includes a combination of neurobehavioural features, movement disorders and other manifestations. It is now recognized that CBD patients usually present with two phenotypes: the lateralized phenotype and the dementia phenotype. The aim of our work was to determine the nature and the progression of cognitive and behavioural impairment in 10 lateralized CBD patients. In our patients, the most salient aspects of cognitive impairment were: an evident alteration of rapid alternating operative strategies, associated with the evident impairment of set shifting, of executive operations, of operative and sequential procedure and of implementation of judgement and abstract reasoning. The self-activation of retrieval processes is partly preserved in CBD. As all the other types of subcortical impairments, even CBD encompasses both cognitive impairment as well as a wide range of behaviour disturbances, such as progressive alterations of sleep, depression, and of anxiety (with a remarkable incidence of somatic pain). This suggests that in addition to neuropsychological assessment, quantification of the personality behaviour disorder is important for standardizing the diagnosis of subcortical vascular dementia and distinguishing it from any other dementias.