Spasmodic dysphonia can also be misdiagnosed as voice tremor. Slurred speech (dysarthria), and disordered vocal quality (dysphonia) are also common. Vocal tremor may also be seen in spasmodic dysphonia. Adductor spasmodic dysphonia is the most common type. Symptoms also vary across types of spasmodic dysphonia. Kennedy suffers from spasmodic dysphonia, which causes his voice to quaver and makes speech difficult. Linda was diagnosed with spasmodic dysphonia, preventing her from singing. Mixed spasmodic dysphonia is the most rare type. A mix and variance of these symptoms are found in mixed spasmodic dysphonia. Differences in treatment effectiveness are present even between the types of spasmodic dysphonia. They aid phonation (speech) by suppressing dysphonia. Linda lost her voice for the next two years as a result of spasmodic dysphonia. Traditional voice therapy is often used to treat muscular tension dysphonia. Surgical treatments may be recommended for patients having an organic dysphonia. Multiple treatments have been developed to address organic and functional causes of dysphonia.