<s>[INST] my 55 year old downs syndrome brother has had about a dozen episodes over the past 3 years or so where he stiffens up and then goes limp and seems to have a very mild weakness on his right side for about 15 to 60 minutes.........he also is suffering some signs of dementia which is prominent in the family.........he also had a stroke at age 28 and another mild one 3 years ago...........he has recently had dvt s in both his legs and as he is not a candidate for blood thinners, had a mesh filter inserted into the vena cava.........is he having mini stokes or seizure activity........ [/INST] Hello Your brother is likely having Seizures or Scar Epilepsy from the previous stroke he suffered. The weakness of the Right side you mention is either due to Todd's Palsy or a residual effect of the Previous strokes getting accentuated.(you haven't mentioned which side he had stroke earlier.) Consult your doctor and add antiepileptic medications if he is not on them already or to adjust the dose if he is on them already. Hope this helps. Regards </s>