Perturbations of the strict periodicity of the glottal vibrations are relevant features of the voice quality of normophonic and dysphonic speakers. Vocal perturbations in healthy speakers are assigned different names according to the range of the typical perturbation frequencies. The objective of the presentation is to model jitter and flutter, which are in the > 20Hz and 10Hz – 20Hz range respectively, via a simulation of the fluctuations of the tension of the thyro-arytenoid muscle and compare simulated perturbations to jitter and flutter observed in vowels sustained by normophonic speakers. Perturbations of the strict periodicity of the glottal vibrations are relevant features of the voice quality of normophonic and dysphonic speakers. Vocal perturbations in healthy speakers are assigned different names according to the range of the typical perturbation frequencies. The objective of the presentation is to model jitter and flutter, which are in the > 20Hz and 10Hz – 20Hz range respectively, via a simulation of the fluctuations of the tension of the thyro-arytenoid muscle and compare simulated perturbations to jitter and flutter observed in vowels sustained by normophonic speakers.