Footnotes

• CS and ESL contributed equally.

• Contributors MMM, CS, ESL and PMV conceived the study. CS, ESL and BJB analysed the data. All authors discussed and interpreted the results. CS, ESL and MMM drafted the manuscript. All authors provided critical feedback and input to the manuscript.

• Competing interests None declared.

• Funding This work received support from the James S McDonnell Foundation, Tiny Blue Dot Foundation and the Brain Injury Research Center (BIRC) at UCLA. 

• Patient consent Not required.

• Ethics approval The protocol was approved by the University of California at Los Angeles Institutional Review Board.

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