Table 5.

The results of the Beta 1 waves examination (waves from C3, C4 channels).

Mode		Pre-COVID	Post-COVID	p
C3, eyes open	mean ± SD	4.53 ± 0.33	4.32 ± 0.52	p = 0.191
	Median	4.4	4.58
	Quartiles	4.25–4.77	3.74–4.73
C4, eyes open	mean ± SD	4.45 ± 0.33	5.23 ± 0.72	p = 0.001 *
	Median	4.46	5.36
	Quartiles	4.39–4.53	4.47–5.68
C3, eyes closed	mean ± SD	4.48 ± 0.28	4.53 ± 0.45	p = 0.823
	Median	4.36	4.71
	Quartiles	4.25–4.61	4.47–4.76
C4, eyes closed	mean ± SD	4.55 ± 0.29	4.93 ± 0.49	p = 0.014 *
	Median	4.51	5
	Quartiles	4.45–4.62	4.47–5.39

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