Hi,
How are you? Syncope or fainting,is generally caused by insufficient oxygen in the brain. This can be through cerebral hypoxia or through hypotension, and other medical conditions. One common type is vasovagal syncope. It may occur in scary, embarrassing or uneasy situations, or during blood drawing, coughing, laughing, urination or defecation. If it persists, have this checked by your doctor for proper management. Your complete medical history and physical examination are needed to determine the underlying cause. Take care and do keep us posted.
Jean-
I do not know whether or not your stroke could be affecting your current symptom. However, your post caught my eye because I was recently diagnosed with Narcolepsy with Cataplexy. Often in people who have this disorder, they experience loss of muscle tone which presents similarly to fainting after experiencing emotion (anger, excitement, surprise, laughter). In my case, I thought I was having fainting spells, but was actually experiencing Cataplexy, which is when your body actually abruptly enters a REM sleep cycle. Since we are paralyzed while we are in REM sleep cycles, it results in a sudden loss of muscle tone or fainting. I would recommend researching the disorder on your own or speaking to your doctor about it. Although there are no cures for the disorder, there are prescription medications that can help treat the symptoms.