Table 4.

The results of the SMR waves examination (waves from C3, C4 channels).

Mode		Pre-COVID	Post-COVID	p
C3, eyes open	mean ± SD	4.33 ± 0.2	3.19 ± 0.23	p < 0.001 *
	Median	4.38	3.16
	Quartiles	4.2–4.45	3.05–3.19
C4, eyes open	mean ± SD	4.3 ± 0.33	4.53 ± 0.69	p = 0.332
	Median	4.23	4.48
	Quartiles	4.05–4.4	4.23–4.61
C3, eyes closed	mean ± SD	4.69 ± 0.64	4.2 ± 0.43	p = 0.011 *
	Median	4.44	4.16
	Quartiles	4.28–4.99	4.05–4.19
C4, eyes closed	mean ± SD	5.01 ± 0.64	4.63 ± 0.46	p = 0.017 *
	Median	4.85	4.56
	Quartiles	4.4–5.73	4.31–4.73

p-Wilcoxon paired test. * statistically significant (p < 0.05).