thank you for your query. I completely understand your difficulty and dilemma. from the symptoms, it appears likely that it may be a case of focal seizures (partial seizure), which may present with unilateral numbness or heaviness and spasms. the focus appears to be in the right fronto parietal lobe around the central sulcus. the history of episodic stiffness in childhood also points towards an seizure disorder. to diagnose this case with certainty, a continuous EEG monitoring (video EEG) needs to be done. Doing EEG when there is no symptoms is most likely to give a normal result (false negative). Moreover, since the episodes are once a month, its practically difficult to do continuous EEG for so long. If a patient with these symptoms would have come to me,I would have advised a continuous EEG monitoring. I could also have prescribed an antiepileptic like Oxcarbazepine or carbamazepine in low doses along with folic acid empirically after discussion with the patient and her guardian (with their consent of course). I would suggest you consult your Neurologist for the same and discuss the role of empirical treatment in this case. Please remember, every time a seizure occurs, it causes some permanent damage to the brain, along with increasing the risk of subsequent seizures (kindling effect). hope i ve been able to satisfy your query. please feel free to contact me. best of luck.