Table 2. Self-assessed and acoustic voice indicators of the teachers from a public school, according to the groups and intervention periods. Salvador, BA, Northeastern Brazil, 2013.

Indicator	Vocal warm-up					Breathing training
	Before		After		p	Before		After		p
	Average	SD	Average	SD		Average	SD	Average	SD
VHI (%)	21.78	17.44	13.04	14.18	0.007*	20.44	13.70	13.82	10.86	0.001*
F0 (Hz)	196.21	34.47	186.25	31.53	0.049*	191.87	43.35	185.71	33.70	0.345
Jitter (%)	0.14	0.11	0.10	0.05	0.323	0.19	0.14	0.45	0.94	0.171
Shimmer (%)	2.90	0.85	3.10	0.97	0.296	2.77	0.94	4.19	2.60	0.022*
Noise (dB)	0.69	0.50	0.68	0.50	0.776	0.72	0.46	0.72	0.44	0.451
GNE (dB)	0.89	0.12	0.92	0.06	0.959	0.88	0.11	0.88	0.11	0.477

VHI: Voice Handicap Index (Índice de Desvantagem Vocal); F₀: Fundamental frequency; GNE: Glottal to Noise Excitation ratio

* Wilcoxon’s signed-rank test.