Table 1.

Mean value ± SD of the evaluated central frequencies cf over 4 weeks [65]

Measurement	Central frequency (kHz)
m0	7.14 ± 3.29
m1	6.01 ± 3.73
m2	7.39 ± 3.35
m3	10.59 ± 2.85
m4	13.56 ± 2.52