As per your explanation, looks she is weak due to long standing general health issues like low sodium, Parkinson, hospitalisation frequently, low diet etc. She is not able to walk much and feels better only when she is in bed and not comfortable while sitting and standing because for generalise weakness. Here your you want to know about whether she had mini stroke or not: let me tell you as per your explanation here you have done ct brain and that is normal. Which shows there was no mini stroke. How ever you can conform once again with MRI brain too. Now to prevent her from stroke I suggest to have check on her blood pressure and if its fluctuating a lot and remaining on higher side then do contact you physician for support. Apart from this give her good diet, and maintain all general health parameter like pulse rate, sodium level, O2 saturation in control. And also take her slowly gradually out of bed and do mobilization. Symptoms of stroke will be some times involuntary shaking of limb, or absence of movement in one part of body, loss of coordination, loss of balance, and not able to move legs or hands which ever body part is affeced, also some times loss of facial one half muscle action, also there may be symptoms of headache and vomiting. Here you need to understand one more thing each patient will have combination of all above symptoms but may not have all symptoms. I am sure this will be helpful. Take care.