BACKGROUND: The preoperative evaluation in dystonia aims at characterizing the 
severity and topography of motor symptoms in patients, who have previously been 
selected for deep brain stimulation (DBS).
METHODS: The literature search was performed using PubMed, CINAHL, and the 
Cochrane Collaborative databases.
RESULTS: Commonly used scales for clinical assessment are the Burke-Fahn-Marsden 
dystonia rating scale for generalized dystonia and the Toronto Western Spasmodic 
Torticollis Scale for cervical dystonia. Motor assessment is completed by 
quality of life and functional scales, such as the Short-Form Health Survey 
(SF-36) or the Parkinson's Disease Questionnaire 39. Validated rating scales for 
cranial or upper limb dystonia are lacking.
DISCUSSION: In common clinical practice, these outcome measures can be 
administered in an open-label fashion because double blind assessment is only 
required for ascertaining new treatment indications or research purposes. The 
same measures are to be used postoperatively to revaluate outcome after DBS. 
Brain MRI is required to confirm diagnosis and assess structural abnormalities. 
Other imaging techniques, particularly functional imaging, are used for research 
purposes.