Table 2.

Acoustic measures

Speech tasks	Function assessed	Acoustic measures
Steady vowel /a/ phonation	Phonation	Mean F0 (Hz) F0 variation (SD, in Hz) Shimmer (%)—cycle-to-cycle F0 variation Jitter (%)—cycle-to-cycle intensity variation HNR (%)
Maximal phonation time of the vowel /a/	Aero-phonatory control	Longest duration (in seconds)
Oral diadochokinesia	Supralaryngeal articulatory control	Number of breath groups Proportion of breath groups (%) Articulatory rate (in syllables/second) Pause-to-sound ratio (%) Speech proportion ratio (%)
Reading aloud of text	Prosody	F0 range (Hz) Intensity (dB)

F0, fundamental frequency; HNR, harmonics-to-noise ratio.