A glioma is a brain tumor that starts in the glue-like cells that hold nerve cells together. Because these cells are spread throughout the brain, symptoms depend on where the tumor is growing and how fast. Most people notice gradual changes, but sometimes the signs appear suddenly. Headaches are the most common complaint. They often feel dull and steady, and they may be worse in the morning or when you bend over. Seizures are another key warning—shaking, staring, or blacking out for no reason. If the tumor is pressing on the movement area, one arm or leg may feel weak... Learn more