Transcranial sonography in restless legs syndrome.

Restless legs syndrome (RLS) is one of the most common neurological disorders. The diagnosis is mainly based on the patient's report of the characteristic symptoms and further on the response to dopaminergic treatment. In the past years, transcranial B-Mode sonography (TCS) of the mesencephalic brainstem has been introduced as a promising new method to assist the diagnostic approach to RLS. This review of literature describes the typical TCS findings in RLS including hypoechogenicity of the substantia nigra and raphe as well as hyperechogenicity of the red nucleus. The diagnostic parameters for patients with idiopathic and various forms of symptomatic RLS will be discussed as well as the current knowledge about the pathophysiology underlying these sonographical abnormalities.