I had myoclonic jerks (limbs suddenly jerk) with severe vitamin B12 deficiency and full body myclonic seizures (as if hit by a single jolt of electricity) due to magnesium deficiency. From your description it sounds like you are suffering from myclonic seizures.
Excerpt from HerbProf: Magnesium - One of the Most Deficient Minerals in the American Diet...
"Symptoms of a magnesium deficiency are:
Arthritis, Insomnia, Fatigue, Body tension, Headaches, Heart-Disorders, Low Energy, High Blood Pressure, PMS, Backaches, Constipation, Kidney Stones, Osteoporosis, Irregular-Heartbeat, Anxiety, Muscle Cramps or Spasms, Irritability, Confusion, Poor digestion, Rapid heartbeat, Seizures, Can be synonymous with diabetes, Cause cardiac arrhythmia, Hypertension, Asthma, Chronic fatigue, Chronic pain syndrome, Formation of kidney stones."
Excerpt from Belief Net: Myoclonus...
"The exact mechanism triggering the abnormal electrical discharge depends on what is causing the myoclonus. Myoclonus is often a symptom of a nervous system or metabolic condition. Possible causes include:
A lack of oxygen or nutrients
Certain medications or toxins
Nervous system disorders such as:
Head or spinal cord trauma or injury
Tumors of the brain or spinal cord
Metabolic disorders such as:
Lipid storage disease (a congenital disorder that usually occurs in children)
Malabsorption syndromes such as Whipple's disease or celiac disease"