Impact of Von Willebrand Factor-platelet Aggregates in Patients With Type 2B Disease

Investigator will use an extensive series of neuropsychological tests that cover virtually all cognitive domains. A measurement of global cognitive function will be assessed by the Mini Mental State Examination (MMSE). The verbal memory function will be assessed by the Rey Auditory Verbal Learning Test (RAVLT). Visuospatial memory will be administered by the Rey's Complex Figure Test (RCFT). To evaluate speed of mental processes, Stroop test (three subtasks), the Paper and Pencil Memory Scanning Task (four subtasks), the Symbol-Digit Substitution Task will be used. To evaluate attention, the verbal series attention test (VSAT) will be used. To register subjective cognitive failures investigator will administer the Cognitive failures questionnaire (CFQ). The neurological evaluation will be completed with 3T (Tesla) Magnetic Resonance Imaging (MRI) with different MRI sequences including T1 3D SPACE, FLAIR 3D , 3D SWI (Susceptibility weighted imaging) and 2D EPI (Echo Planar Imaging) to address the presence of cerebral small vessel disease. The presence of each of the four MRI markers for cerebral small vessel disease (white matter hyperintensities, lacunes, cerebral microbleeds and perivascular spaces will be addressed.