AbstractIntroductionDown syndrome (DS) is a genetically determined form of Alzheimer’s disease (AD) and a specific form of epilepsy is strongly associated with AD in DS (DSAD), late onset myoclonic epilepsy (LOMEDs), but, there are no clinical trials evaluating the efficacy and tolerability of antiseizure medications in this epilepsyAimsTo describe our experience in the treatment of LOMEDs.Material and MethodsWe recruited patients with symptomatic AD (prodromal –pAD‐ or AD dementia –dAD‐ stages) in the context of a health plan for adult population with DS between January 2013 and November 2021. This health plan included semiannual follow‐ups (or as clinically needed) and an anamnesis and structured questionnaire including the personal history of epilepsy (duration of epilepsy, semiology, frequency, efficacy and tolerability of ASM).ResultsThe study included 72 patients with pAD (48.6% females) and 257 with dAD (50.6% females). Bilateral tonic‐clonic seizures (BTCS) were the most frequent type (85.7% in pAD and 70.7% in dDS) and frequentlly coexisted with myoclonic seizures (16.7% and 57.6% in pDS and dAD respectively). The most frequent treatment after the first seizure was levetiracetam (LEV) (61.5%) followed by valproate (VPA) (19.6%). During follow‐up, 75.8% were on monotherapy with LEV (56.3%), VPA (25.5%) or brivaracetam (BRV) (8.2%). LEV was discontinued due to irritability in 21.9% of patients (interestingly 48% tolerated BRV after LEV discontinuation).VPA was abandoned in 14% due to motor worsening. Seizure control at one year was achieved in 65.9%, when considering BTCS, but only 30.2% were free of of myoclonic seizures.DiscussionLOMEDs is a very common comorbidity in DSAD that responds partially to treatment. BTCS seem to have a better response to treatment compared to myoclonic seizures.