revision preference src: A clinical history can also help determine what kind of disorder one has. Events such as respiratory infection and head trauma are usually indications of parosmia where as phantosmias usually have no history of such events and occur spontaneously. <SEP> tgt: A clinical history can also help determine what kind of disorder one has because events such as respiratory infection and head trauma are usually indications of parosmia where as phantosmias usually have no history of such events and occur spontaneously.