Fiorenza Giganti

Yawning in morning and evening types

Yawning occurs more frequently in the early morning and in the late evening, close to sleep onset and after the awakening, and it might be linked to sleep propensity. We aimed to study yawning and its temporal distribution in morning and evening subjects who display different sleep-wake and sleepiness rhythms. Sixteen healthy young adults (8 evening-types and 8 morning-types, matched for age and gender) have been selected and instructed to keep their habitual sleep schedules and to signal every yawning occurrence for three consecutive days. Results show that evening-types yawn more frequently than morning-types, particularly during morning hours. Yawning frequency decreases across daytime in evening-types reaching its lowest level in the early evening and increases thereafter. Instead, in morning-types, yawning frequency remains quite low during daytime and increases in the evening. Moreover, both morning and evening types show a progressive increase of yawning frequency in the hours preceding sleep onset, whereas they differ after the awakening. Evening-types show a higher yawning frequency that remains quite stable in the hours following the awakening, while morning-types display a decline in yawning frequency. Our findings show that the temporal distribution of yawning frequency differs between chronotypes, supporting the hypothesis that differences in sleep-wake rhythm affect yawning, which could represent a behavioural sign of sleep propensity.

Yawning and subjective sleepiness in the elderly

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.

Body movements during night sleep and their relationship with sleep stages are further modified in very old subjects

The night sleep of 12 healthy subjects aged 76-98 was polygraphically investigated in order to analyse body movements and their association with sleep stages at very old age; this group was compared with 11 healthy old subjects aged 61-75 years. In very old subjects sleep is less punctuated by body movements and the association of body movements with each sleep stage is further modified compared to less old subjects. Short-lasting movements emerge indifferently from stage 1, stage 2 and REM sleep, but are significantly less frequent in SWS. Furthermore, in very old subjects the probability of awakening after body movements is higher than in old subjects, suggesting that sleep is more vulnerable to the occurrence of body movements than at previous ages. The difficulty in the elderly to maintain a stable state expresses the inability to sustain and coordinate stable physiological activities characteristic of the old age. In addition, the presence of numerous awakenings, not preceded by movements, supports the hypothesis that the awakening in the very old people may be a sudden event, as should be confirmed by the study of other behavioural and physiological activities preceding awakening.

Spontaneous awakenings from sleep in the first year of life.

Spontaneous awakenings from nocturnal sleep were studied in a sample of 48 healthy infants (M = 26, F = 22), in four age groups (1 to 7 weeks, 8 to 15 weeks, 17 to 22 weeks, 25 to 54 weeks). Consistent with previous data, the number of awakenings is reported less frequently at later ages, owing to a lower frequency of awakenings out of REM sleep. Like young adults, infants in all age groups awake more often from REM than from quiet sleep (QS); this is particularly evident in the first 6 months of life, less so in the second. The duration of the bouts of wakefulness following awakenings remains stable with age. Awakenings out of QS are followed by longer periods of wakefulness than those out of REM sleep, although in older infants the duration is considerably reduced. Night sleep first shows a decrease in the number of awakenings out of REM sleep and then continues after the sixth month of life with the shortening of the wakefulness after awakenings out of QS. In the two younger groups, the distribution of the awakenings shows two main peaks and one main peak differently located during the night; a polymodal pattern appears in group 3, and is even more evident in group 4. It should be stressed that several changes as a function of age occur in the second 6 months of life, indicating this as a period of intense developmental change in sleep-wake rhythms.

Body movements during night sleep in healthy elderly subjects and their relationships with sleep stages.

In order to enlighten the profile of body movements during sleep at old age, the night sleep of twelve elderly subjects was polygraphically investigated; seven young healthy subjects were the control group. Significantly less body movements during sleep were found in the elderly compared to young subjects, meaning that the decrease in the number of body movements observed from infancy to childhood up to adulthood also continues at later ages. Differently from young adult, whose sleep body movements mainly occur in stage REM, no specific sleep state and/or stage was preferentially associated with the occurrence of body movements in the elderly. These data may point to an age-related modification in the interaction between motor cortex control and subcortical circuits. Furthermore, when body movements occur in elderly individuals, they are significantly more often followed in the next 60 s by a sleep stage change or by a spontaneous behavioural awakening. This might reflect a peculiar inability of elderly subjects to sustain stable states, and could also suggest that body movements may act as a co-factor in a process, comprising other physiological changes, leading to state shifts.

Activity patterns assessed throughout 24-hour recordings in preterm and near term infants.

The motility of 10 low-risk infants, aged between 34 and 40 weeks of postmenstrual age, has been continuously recorded for 24 h. Four codes were distinguished: code 1 (absence of motility or occasional occurrence of startles), code 2 (presence of small general or isolated body movements, startles, smiles, grimaces, and other facial activity), code 3 (forceful and prolonged general movements, startles, and stretches), code 4 (vigorous and abrupt general body movements accompanied by crying). Changes with age concern mainly the increase of the duration of code 1 (quiescence) episodes. Confrontation between day and night showed higher levels of motility during the night than during the day. The last weeks before term represent a time for increase in the ability to sustain a quiet behavior and to reorganize day-night motility distribution.

The daily time course of contagious and spontaneous yawning among humans

Yawning, besides being a spontaneous behavior, can also be evoked by observing others yawn. However, contagious yawning does not always occur, depending possibly on several factors, such as one’s propensity to spontaneously yawn and a heightened level of sleepiness. The aim of this study is to investigate in young adults whether contagious yawning frequency varies throughout the day, and if it is related to the daily time course of spontaneous yawning frequency and level of sleepiness. For the study, 22 subjects were instructed to log hourly, throughout wakefulness, the number of spontaneous yawns and sleepiness level. Subjects were required to continue this procedure for 3 consecutive days, after which they underwent five experimental sessions occurring at regular intervals throughout the same day. During each experimental session, subjects observed others yawn (stimulus condition) and smile (control condition). Our findings show that the contagious effect of yawning is always present throughout the daytime. Both contagious and spontaneous yawning peaked in the early morning and in the late evening, according to the sleepiness time course. However, the frequency of spontaneous yawns was remarkably lower than the frequency of contagious yawns around 19:00. This difference suggests that different mechanisms control spontaneous and contagious yawning.

Impact of Psychological Interventions on Reducing Anxiety, Fear and the Need for Sedation in Children Undergoing Magnetic Resonance Imaging

Children undergoing magnetic resonance imaging examination frequently experience anxiety and fear before and during the scanning. The aim of the present study was to assess: i) whether and to what extent psychological interventions might reduce anxiety and fear levels; ii) whether the intervention is related to a decrease in the need for sedation. The interventions consisted of three activities: a clown show, dog interaction and live music. The emotional status (anxiety and fear) of the children was evaluated before and after the activities through a rating scale questionnaire. The results showed that the activities had high effectiveness in reducing the level of anxiety and fear and decreased the need for sedation in the experimental group compared to the control group. This approach proved to be a positive patient experience, helping to alleviate children’s anxiety and fear, decreasing the need for sedation, and was cost-effective.

Sleep, sleepiness and yawning.

This chapter will discuss the relationship between yawning, sleep onset, awakening and sleepiness. Models concerning wake-sleep regulation will be discussed in relation to yawning. Yawning close to sleep, before and after, will be examined in several conditions and populations. Also, the time course of yawning and sleepiness assessed by subjective estimates will be described.

Daytime course of sleepiness in de novo Parkinson's disease patients.

Normal subjects show an increase of sleepiness in the morning, early afternoon and before sleep. In the advanced stages of Parkinsons disease (PD) the mean level of sleepiness is quite high, while with respect to healthy subjects it seems to be unchanged in the early stages. The aim of this study was to evaluate the time–course of the sleepiness level during the wakefulness period in untreated patients with early‐stage Parkinsons disease. Eighteen Parkinsons disease patients who had never been treated before with dopaminergic drugs (male = 9, female = 9, age: 68.39 ± 1.89, mean ± standard error) and 18 healthy subjects (male = 9, female = 9, age: 67.22 ± 1.98) were recruited for this study. All subjects underwent continuous actigraphic recording for three consecutive days, during which they also completed the Karolinska Sleepiness Scale (KSS) once an hour throughout wakefulness. Our results showed a higher level of sleepiness in the patients than the controls in the hours following awakening and in the early afternoon, specifically at 08:00 and 14:00 hours (08:00 hours, PD patients, KSS: 3 ± 0.3 versus healthy subjects, KSS: 2 ± 0.2, P < 0.05; 14:00 hours, PD patients, KSS: 4.4 ± 0.5 versus healthy subjects, KSS: 3 ± 0.3, P < 0.05). We suggest that some daytime hours are sensitive windows showing the first increase of sleepiness which will spread later to the whole daytime.