Leppänen 2009.

Methods	Randomised controlled trial
Participants	60 female teachers in Finland
Interventions	1) Direct and indirect voice training: Voice Hygiene Lecture and Voice Massage (TM) 2) Indirect voice training: Voice Hygiene Lecture only
Outcomes	1) No subjective outcomes 2) Perceptual evaluation by 3 speech trainers, fundamental frequency (F0), equivalent sound level (Leq), alpha‐ratio, jitter and shimmer
Notes	It is unclear if the sample used in this study overlaps with that used in Ilomäki 2008 and/or Laukkanen 2009