Portable electroencephalography in early detection of depression: Progress and future directions

Table 1 Study quality assessment overview

Ref.	Bias risk assessment	Sample size assessment	Validation method assessment	Evidence level (OCEBM)	Overall quality score
Khan et al[44]	Low	Reasonable	Unreasonable	5	Medium
Wu et al[34]	Unclear	Unreasonable	Unreasonable	3	Low
Tian et al[45]	Low	Unreasonable	Reasonable	2	Medium
Tian et al[38]	Low	Reasonable	Reasonable	4	High
Sakib et al[43]	Unclear	Reasonable	Reasonable	5	Medium
Sharma et al[41]	Medium	Unreasonable	Unreasonable	4	Low
Lei et al[39]	Medium	Unreasonable	Unreasonable	4	Low
Morita et al[40]	High	Reasonable	Unreasonable	5	Low
Wang et al[46]	Medium	Unreasonable	Reasonable	5	Medium
Saleem et al[42]	Unclear	Reasonable	Unreasonable	5	Medium

OCEBM: Oxford Centre for Evidence-based Medicine.