<span>During a sleep study electrodes are attached to the scalp, near the chin, near the eyes, on the upper chest, and the lower legs. Sensors are also attached to the upper lip and either the finger or the ear. The electrodes on the scalp measure brain waves or EEG to monitor the different stages of sleep. The electrodes near the eyes record eye movement and the electrodes on the chin record muscle activity to also provide data for determining sleep stages. The upper chest electrodes monitor heart activity. The lower leg electrodes show leg muscle activity during sleep. The upper lip sensor monitors breathing. The sensor on the finger or ear tell the doctor about the oxygen levels in the patients blood. Various other sensors may be used for studying specific areas of concern t the discretion of the sleep lab technician.</span>
Constitutional amendments can be proposed by the Congress with a two-thirds majority vote in both the House of Representatives and the Senate. Constitutional amendments can also be proposed by a constitutional convention called for by two-thirds of the State legislatures; however, the first way is the one that has always been used.
It is the Article V of the Constitution the one that prescribes how an<em> amendment</em>, which means an improvement, a correction or a revision to the original content, can become a part of the Constitution.
