The purpose of this Study was to determine the variability in speaking
fundamental frequency (F-0) associated with sample type in two age gr
oups of normal male and female speakers and a group with vocal-fold pa
ralysis. Young and elderly normal control men and women produced a sus
tained vowel, read a passage, and spoke extemporaneously in the mornin
g, early afternoon, and late afternoon on three different days. The vo
cal-fold-paralysis group produced two voice samples at different times
on the same day, Two patterns of variability emerged in the normal gr
oups. Young men produced sustained phonation at a significantly lower
F-0 than their reading or extemporaneous samples. Young and older wome
n and older men produced sustained phonation with a higher F-0 than th
eir reading or extemporaneous samples, The eight subjects with unilate
ral vocal-fold paralysis (seven women, one man) produced samples with
a pattern similar to that of the older normal groups but with greater
differences between the sustained vowel and speech samples. The use of
different sample types resulted in variations in mean speaking F-0 in
the normal subjects as well as in the vocal-fold-paralysis group. Wit
hin-day sampling of all normal subjects resulted in approximately the
same variability as across-day sampling. In the vocal-fold-paralysis g
roup, within-day sampling resulted in greater variability of mean F-0
for vowels than for connected speech, following a pattern similar to t
he older normal control subjects and various speech materials for voic
e. In the groups examined in this study, variability in sample type (r
eading versus sustained phonation) was found to be greater than the va
riability associated with repeated sampling of the same sample type.