Normally functioning vocal cords expand and contract during speech, but for a patient with SD, these movements are exaggerated or improperly timed, causing speech to be impaired. The result is speech that sounds strained, strangled, or staccato. Abductor Spasmodic Dysphonia is a type of SD in which the patient's vocal cords expand too far, producing short, breathy breaks in speech. The most effective treatment, particularly for adductor SD, is the injection of a minute amount of botulism toxin into the vocal cords. This chemical, often referred to as botox, is produced by the bacteria that cause botulism.
Surgery offers temporary relief for some SD patients, but symptoms usually return.
An editor's remarks about an expanded definition Nancy - Although you're not describing the actual process of how a thermocline develops, you need to use more expansion methods in order to cover the kinds of questions readers might have about the term you're defining. As you've defined the term, it seems to be merely a layer of water colder than the warmer air above, and warmer than the colder water below. Because you leave too many questions about thermoclines unanswered, your readers won't get a clear sense of what they are, how they occur, and why they play a significant role in weather patterns. I just did a quick search and found 18 sites that might help you. Here are a few comments on specific parts of your current definition.