. 2015 Jun;58(3):638–652. doi: 10.1044/2015_JSLHR-S-13-0270

Table 2.

Template for experimental procedures

Condition	Activity	Duration (min)
Baseline	Participant performs normal, tidal breathing, no phonation	5
Eupnea	Participant breathes room air	5 (approx.)
Eupnea	Phonation task	5 (approx.)
Rest	Rest	15
Hypocapnia	Participant breathes room air metered from an H-cylinder starting at 2× the participant's resting respiratory rate	5 (approx.)
Hypocapnia	Phonation task	5 (approx.)
Rest	Rest	15
Hypercapnia	Participant breathes CO₂-enriched air metered from an H-cylinder	5 (approx.)
Hypercapnia	Phonation task	5 (approx.)
Rest	Rest	15

Note. The order of breathing conditions was counterbalanced and randomized across participants.