Table 1.

Features definitions in frequency domain.

Symbols	Notation	Equations
FRδ	Ratio of the power of δ activity in total EEG frequency band (%)	$\mathrm{a}\mathrm{v}\mathrm{e}\left\{\frac{S_{\delta }\left(C3\right)}{S_T\left(C3\right)}\ast 100,\frac{S_{\delta }\left(C4\right)}{S_T\left(C4\right)}\ast 100\right\}$
FRθ	Ratio of the power of θ activity in total EEG frequency band (%)	$\mathrm{a}\mathrm{v}\mathrm{e}\left\{\frac{S_{\theta }\left(C3\right)}{S_T\left(C3\right)}\ast 100,\frac{S_{\theta }\left(C4\right)}{S_T\left(C4\right)}\ast 100\right\}$
FRα	Ratio of the power of α activity in total EEG frequency band (%)	$\mathrm{a}\mathrm{v}\mathrm{e}\left\{\frac{S_{\alpha }\left(O1\right)}{S_T\left(O1\right)}\ast 100,\frac{S_{\alpha }\left(O2\right)}{S_T\left(O2\right)}\ast 100\right\}$
FRβ	Ratio of the power of β activity in total EEG frequency band (%)	$\mathrm{a}\mathrm{v}\mathrm{e}\left\{\frac{S_{\beta }\left(C3\right)}{S_T\left(C3\right)}\ast 100,\frac{S_{\beta }\left(C4\right)}{S_T\left(C4\right)}\ast 100\right\}$

δ: 0.5–2 Hz; θ: 2–7 Hz; α: 8–13 Hz; β: 13–30 Hz; T: 0.5–30 Hz.