LEvetiracetam to Prevent Seizures in Symptomatic Alzheimer's Disease in Adults With Down Syndrome

Inclusion Criteria: * Diagnosed with Down Syndrome (DS), either with a karyotype or a compatible typical phenotype. * Age over 40 years at time of screening. * Symptomatic Alzheimer's Disease (AD) dementia, based on change in functionality and neuropsychological tests' results. Different cut-off points will be established to diagnose dementia depending on the level of intellectual disability of the individual, according to previous experience (Benejam et al; 2020): in adults with mild intellectual disability, a CAMCOG-DS score of 80 and an mCRT score of 29 will be chosen, whereas values of 56 and 28, respectively, will be used in subjects with moderate intellectual disability. Doubtful cases (e.g., with compromised functionality, but without alteration in the neuropsychological assessment) or those unable to complete the evaluation will be categorized by consensus among expert clinicians, using all available clinical information. * Willing and able caregiver who has daily contact with the study subject. * Subjects and caregivers must be able to comply with the prescribed regimen of study treatment throughout the course of the study and meet a minimum required time commitment of biannual in-person visits. * Any concurrent treatment for AD approved by the European Medicines Agency (EMA) must be stable for at least 30 days prior to screening and at least 60 days prior to study day 1. Other medications (except for those listed under exclusion criteria) are allowed as long as the…