Weakness that comes and goes

[inspiremichelle]

My grandmother is 88 years old and has many medical problems. Compression FX, Congestive Heart Failure,Diabetes, Femoral Stenosis, Spinal Stenosis, Heart Murmur, High Blood Pressure, High Cholesterol, Impaired Mobility, Neuropathy, Seizures, Server Osteoporosis, Urinary Track Infections. She recently had a pace maker put in. The problem she seems to be having is weakness in her arms and legs. They just give out without warning and then gain strength right back. An example would be picking up a spoon. She can hold it but when she raises it her hand will fall. But on the next try she is able to raise it. It like her hands and legs are jerking. Any ideas would be helpful. She has seen many doctors and she does both physical and occpational theraphy.