thank you for posting your query in healthcaremagic.com.... well sudden increase in blood pressure can be associated with cardiac as well as cerebral abnormalities... so when you took your mother to ER, the doctors ran some tests to know the reasons of her symptoms but the results came normal... it can be because a TIA and sometimes it can not be detected..... also in the earlier states of an ischemia or infarction, sometimes it remains undetectable... i would ask you to consult a CARDIOLOGIST if the symptoms persist and he would prescribe some additional or changed medicines to keep her blood pressure down.... you can contact me for any further queries... hope this was helpful... regards