A Cochrane review included 10 studies with a total of 172 subjects. Six of the studies were placebo-controlled (pharmacotherapy) and 4 comparative (one stereotactic neurosurgery and three neurorehabilitation). No standardised outcome measures were used across the studies. In general, pharmacotherapies were unrewarding and data on neurosurgery or rehabilitation is insufficient to lead to a change in practice.
Comment: The quality of evidence is downgraded by imprecise results (limited study size for each comparison), by limitations in study quality (e.g. lack of blinding, high attrition rate) and by inconsistency (heterogeneity in outcome measures).