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Voice Disorders. A voice disorder is when the voice has a problem with pitch, volume, tone, and other qualities. These problems occur when the vocal cords don't vibrate normally. Your voice is the sound that air makes when it is forced out of your lungs and passes over your vocal cords.
Spastic dysphonia. This is a long-term voice disorder that causes the voice to fluctuate, seize up or sound quivery and strained. The voice changes are caused by uncoordinated movement of the muscles that control the vocal cords, but the exact cause of spastic dysphonia is not completely understood.