-Giganti F, Hayes
MJ Cioni G, Salzarulo P Yawning frequency
and distribution in preterm and near term
infants assessed throughout 24-h recordings
Infant Behav & Development
2007;30(4):641-647
-Giganti F,
Ziello ME Contagious and spontaneous yawning
in autistic and typically developing children
CPL 2009
-Giganti
F, Zilli I. The daily time course of
contagious and spontaneous yawning among humans.
J Ethol 2011;29(2):215-216
-Giganti
F, Toselli M, Ramat S. Developmental trends
in a social behaviour: contagious yawning in the
elderly. Giornale di Psicologia dello Sviluppo.
2012;101:111-117
-Zilli I,
Giganti F, Uga V. Yawning and subjective
sleepiness in the ederly. J Sleep Res
2008;17:3003-308
Yawning is related to sleep/wake transitions
and time of day, probably reflecting the time
course of sleepiness. As aging modifies
sleep-wake and sleepiness rhythms, we suppose
that yawning frequency and its time course vary
as a function of age.
Thirteen aged healthy subjects (77.15 +/-
4.09 years) and 12 young adults (24.41 +/- 3.31
years) were instructed to keep their habitual
sleep schedules for three consecutive work-days,
during which they were required to signal every
yawning occurrence and to evaluate hourly their
sleepiness level.
Results showed that aged subjects yawn less
frequently than young adults, particularly
during morning and mid-afternoon hours. The time
course of yawning was different between the two
age groups: aged subjects showed earlier morning
peak and evening rise compared with young
adults; in addition, aged subjects showed two
minor peaks in-between. Differences as a
function of age in the time course of yawning
were associated with differences in the time
course of sleepiness. The only exception
pertained to the early morning yawning peak,
which was close to the awakening but it was not
associated with high sleepiness in aged
subjects.
Our study discloses that aging modifies
yawning frequency and its time course.
Furthermore, as in the elderly yawning after the
awakening is not associated with high sleepiness
level as in young adult, we put forward that
sleepiness level and the proximity of sleep/wake
transitions could separately affect
yawning.
Discussion
Overall yawning frequency is reduced in aged
subjects compared with their younger
counterparts, supporting the previous report by
Walusinski
(2006).....
It is noteworthy that the reduction of
yawning frequency in aged subjects is not spread
throughout wakefulness: aged subjects yawn less
frequently than young adults during the morning
and in the mid-afternoon. This result could be
explained by the age-related shift towards
morningness, previously highlighted (for review,
Monk and Kupfer, 2007) and replicated in the
present study. In fact, a recent research
(Zilli et
al., 2007) emphasized that morning-types yawn
less frequently than evening-types particularly
during daytime....
Although both elderly and young subjects
yawn more frequently early in the morning and
late in the evening, aged subjects show earlier
morning peak and evening rise compared with the
young adults, according to the earlier sleep
times. In addition, aged subjects exhibit two
minor yawning peaks, which occur early in the
afternoon and early in the evening.
Several factors such as boredom (Provine
and Hamernik, 1986) and the view of yawning
individuals (Provine, 1986, 1989) also modify
yawning frequency. Thus, it could be argued that
differences with age in daily-life could
interfere with yawning production. However, we
recruited old subjects amongst healthy and
independent persons who live on their own and
participate to social activities in order to
make as slight as possible the disparity between
young and elderly individuals. Hence, it is
tenable that age per se could reliably account
for differences in yawning frequency and its
time course.
Our results show that the time course of
sleepiness varies as a function of age in
agreement with previous findings (Carrier et
al., 1997; Monk et al., 1996; Munch et al.,
2005). Moreover, the time course of sleepiness
across wakefulness is related to the time course
of yawning in both age groups. This finding is
consistent with the association between yawning
and sleepiness emphasized by previous researches
(Guggisberg
et al., 2007; Provine et al., 1987; Zilli et
al., 2007) and it underscores that this link is
evident even in the elderly.
As we hypothesized, changes as a function of
age in the time course of yawning are associated
with changes in the time course of sleepiness.
The lower sleepiness levels reported by the aged
subjects during morning hours could account for
the reduction of yawning frequency observed in
this part of the day. It is also noticeable that
the two additional yawning peaks, detected in
the midst of wakefulness period in the elderly,
approximately correspond to sleepiness rises.
Furthermore, the advanced evening rise in
yawning frequency showed by aged subjects
matched up with the advanced sleepiness
increase.
Concerning the relationship between yawning
and sleep episode, both aged and young subjects
show an increase of yawning frequency before
sleep and a decrease after the awakening, with
yawns peaking in the hour preceding sleep onset
and in the hour following sleep
termination.
However, aged subjects yawn less frequently
than young adults from the second hour following
the awakening. In other words, young adults
progressively reduce yawning frequency after the
end of sleep, whereas aged subjects show a
steeper reduction and yawns become virtually
absent shortly after the awakening. Given the
link between yawning and stretching after the
awakening previously evidenced in the young
adult (Provine et al., 1987), it would have been
interesting to verify this association in the
elderly; unfortunately, our procedure missed to
collect information about stretching.
It is remarkable that the rise of yawning
before sleep parallels the increase of
sleepiness in both age groups, whereas yawning
peak after the awakening is not associated with
high sleepiness level in the aged subjects. This
discrepancy suggests that the time course of
subjective sleepiness by itself could not give
an explanation for all of the yawning frequency
oscillations: the relationship between yawning
frequency and the proximity of wake&endash;sleep
and sleep&endash;wake transitions should also be
taken into account. It seems reasonable to
suppose that sleepiness level and sleep episode
proximity could separately affect yawning, even
though further researches including
sleep&endash; wake rhythm manipulation and
sleepiness objective measurement are necessary
to clarify their respective role.
-Giganti F, Hayes
MJ Cioni G, Salzarulo P Yawning frequency
and distribution in preterm and near term
infants assessed throughout 24-h recordings
Infant Behav & Development
2007;30(4):641-647
