Table 1.

Mean ± SE of subglottal pressure and laryngeal EMG muscle activity variables measured in five modules in single module (SMC) and composite calls (CC) demonstrated few differences (mixed effect linear regression)a

Flat N = (8, 309)Split N = (5, 117)Upward N = (1, 33)Complex N = (5, 143)Trill N = (8, 454)
Ps mean (kPa)
    SMC0.87 ± 0.090.87 ± 0.160.62 ± 0.010.93 ± 0.100.94 ± 0.10
    CC0.88 ± 0.090.88 ± 0.160.64 ± 0.010.93 ± 0.101.05 ± 0.11
z = 0.6, p = 0.61z = 0.4, p = 0.72z = 0.2, p = 0.85z = 4.34, p = 0
EMG mean (mV)
    SMC15.6 ± 2.319.4 ± 3.322.9 ± 0.934.6 ± 6.057.1 ± 5.5
    CC16.7 ± 2.320.7 ± 3.325.4 ± 1.137.2 ± 5.957.9 ± 5.5
z = 2.35, p = 0.06z = 1.49, p = 0.21z = 1.54, p = 0.24z = 0.74, p = 0.54
EMG CV
    SMC1.09 ± 0.051.06 ± 0.061.14 ± 0.031.51 ± 0.181.49 ± 0.07
    CC1.11 ± 0.051.09 ± 0.061.13 ± 0.031.62 ± 0.181.48 ± 0.07
z = 1.51, p = 0.22z = 1.51, p = 0.22z = 2.56, p = 0.04z = 0.98, p = 0.43
EMG burst rate (Hz)
    SMCNANANA96.1 ± 3.191.7 ± 0.76
    CC106.7 ± 3.090.5 ± 0.76
z = 5.93, p = 0z = 0.77, p = 0.558
EMG burst duration (ms)
    SMCNANANA1.57 ± 0.141.78 ± 0.06
    CC1.69 ± 0.141.88 ± 0.06
z = 2.04, p = 0.09z = 3.31, p = 0.005
EMG burst amplitude (mV)
    SMCNANANA130 ± 1.6232 ± 2.5
    CC148 ± 1.6226 ± 5.9
z = 2.35, p = 0.053z = 1.3, p = 0.28
No. of EMG bursts
    SMCNANANA3.76 ± 0.267.9 ± 0.48
    CC3.34 ± 0.256.63 ± 0.45
z = 2.31, p = 0.053z = 3.85, p = 0
  • aVariables were mean subglottal pressure (Ps mean), mean thyroarytenoid muscle EMG activity (EMG mean), CV of EMG activity (EMG CV), EMG burst rate, EMG burst duration, peak EMG burst amplitude, and total number of EMG trill bursts. From each rat and call type, 14–20 calls were analyzed. N indicates the number of rats and the total number of calls; NA, not applicable. No statistical test was performed for upward calls because data from only one rat were available.