Amyotrophic lateral sclerosis (ALS), sometimes called Lou Gehrig's disease, is a rapidly progressive, invariably fatal neurological disease that attacks the nerve cells (neurons) responsible for controlling voluntary muscles.
The Alpine Scheitholt furnishes an example of this older type of European zither. By the late 18th century, two principal varieties of European concert zither had developed, known as the Salzburg zither (with a rounded side away from the player), and the Mittenwald zither (with both sides rounded).
Types of VAD. VADs are usually classified according to the mode of blood flow, namely pulsatile or continuous. Continuous types can be further subdivided based on the biomechanics of the pump: centrifugal or axial. Some continuous VADs can create pulsatile waveforms by periodically changing the pump speed.