Footnotes

• Contributors ST conceived the idea, designed the study along with SS, and GB, analysed the data, drafted the manuscript, and had the final responsibility for all aspects of the study. MA, KS and CS recruited the cases, collected data and performed neurological assessments. AW advised on randomisation and supervised the data analysis. All authors contributed towards manuscript development and approved the final draft for publication. The study is compliant with the TRUST (Transparent Research Audit System) guidelines for ensuring research quality and integrity.

• Competing interests None.

• Patient consent Obtained.

• Ethics approval Ethics Committee, University College London.

• Provenance and peer review Not commissioned; externally peer reviewed.

• Clinical trials.gov No NCT01138176