Table 4.

Technology readiness assessment of the BCI-hand robot systems

Levels	Description	Studies
TRL 1	Lowest level of technological readiness Literature reviews and initial market surveys Scientific application to defined problems
TRL 2	Generation of hypotheses Development of research plans and/or protocols
TRL 3	Testing of hypotheses – basic research, data collection and analysis Testing of design/prototype – verification and critical component specifications Initial proof-of-concept in limited amount of laboratory/animal models	Most studies from the prototype group (N = 18) [86–100, 102–104]
TRL 4	Proof-of-concept of device/system in defined laboratory/animal models Safety testing – problems, adverse events and potential side effects	Witkowski et al., 2014 [101]
TRL 5	Comparison of device/system to other existing modalities or equivalent devices/systems Further development – testing through simulation (tissue or organ models), animal testing Drafting of Product Development Plan	Barsotti et al., 2015 [76], Ono et al., 2016 [81], Chowdhury et al., 2018-b [78], Tsuchimoto et al., 2019 [84]
TRL 6	Small scale clinical trials (Phase 1) – under carefully controlled and intensely monitored clinical conditions	Carino-Escobar et al., 2019 [85], Chowdhury et al., 2018-c [79], Norman et al., 2018 [82], Wang et al., 2018 [83]
TRL 7	Clinical trials (Phase 2) – safety and effectiveness integration in operational environment	Ang et al., 2014 [75], Frolov et al., 2017 [80]
TRL 8	Clinical trials (Phase 3) – evaluation of overall risk–benefit of device/system use Confirmation of QSR compliance Awarding of PMA for device/system by CDRH or equivalent agency
TRL 9	The device/system may be distributed/marketed

QSR Quality System Requirements, PMA Premarket Approval, CDRH Center for Devices and Radiological Health