kimbotrav - this is important.
IF IT HAPPENS AGAIN, VIDEO IT
Then get yourself to the GP or A&E, show them the video, and ask whether they think it is
Infantile Spasms (aka West Syndrome)
I don't want to alarm you, but I do want you to get this seen without delay, so that you don't have the same situation as we did. Your description has rung huge alarm bells with me. Our little boy (also 29wks) started having spasms at 8m old. They consisted of a sudden spasm whereby he "crunched" his body, legs up to belly, sometimes lifting shoulders slightly, with a sharp cry. The first day, he only had one. The next day he had a couple. He was dopey and/or would sleep afterwards. The next day a couple more ...
On the third day we took him to the out-of-hours clinic (which happened to be on the main hospital campus here) on Saturday lunchtime, and described it to the GP. He wasn't sure, but was concerned enough to send us down to Paediatric A&E. Whilst we were sat there, Andrew took another seizure so we video'd it (on our phone). We showed the Registrar, and she recognised it as Infantile Spasms and immediately admitted him. He had an EEG which confirmed the epileptic trace on his brainwaves. They started treatment (steroids), and he had his last spasm on the day he started treatment. He was discharged a few days later.
The reason I don't want you to delay is because while the spasm is the first outward symptom of IS, the brain will have been having abnormal patterns for a while - and those abnormal patterns affect development. When we looked back, we could see that Andrew hadn't "been himself" for about two months beforehand, he hadn't really progressed at all and had become more insular.
All in all, Andrew is about three months delayed because of the IS (two months prior and one months when on steroids). Coupled with his three month actual-to-corrected age difference, it means his developmental age is around six months behind his actual age. And that hasn't improved, so we are now considering whether to delay his schooling.
If it is IS or any other form of epilepsy, the sooner it is diagnosed and controlled (in one so young), the better. And if it turns out that it wasn't IS and was just really bad constipation (which was our initial thought!) then at least you know.
Sorry to sound alarmist but your description really did sound familiar.