Cristiano Violani

Sleep habits and circadian preference in Italian children and adolescents

Sleep habits and circadian preference (morningness/eveningness, M/E) have been extensively analyzed in adolescents and young adults, while few studies were conducted on children and early adolescents. Aim of the present study was to investigate the developmental changes of circadian preference and to analyze its relationship with sleep habits, sleep problems and circadian preference in a large sample by means of a school‐based survey. One thousand seventy‐three participants (50.8% boys and 49.2% girls; mean age = 10.6; range = 8–14 years), recruited from four schools randomly extracted within the district of Rome, completed a modified version of School Sleep Habits Survey developed by Carskadon et al. The questionnaire included items about sleep habits during schooldays and weekends; a Sleepiness Scale; a Sleep–Wake Problems Behaviour Scale; a Morningness/Eveningness scale. The results show a consistent age‐related change in sleep habits, particularly in the weekends. The difference in sleep duration between schooldays and weekends increases linearly with age. No gender difference was observed in morningness/eveningness, while a significant linear increase in evening preference was found with increasing ages. M/E total scores correlated significantly with both self‐reported sleep/wake problems and daytime sleepiness indicating a higher prevalence of sleep complaints in evening‐type subjects. Overall, the present results support the existence of consistent age‐related changes in sleep habits and M/E dimension in the 8‐ to 14‐year age range.

Sleep and migraine: an actigraphic study.

The aim of the study was to evaluate sleep of children with migraine during the interictal period and the modifications of sleep which precede, are concomitant with, or follow migraine attacks. Eighteen patients with migraine without aura were compared with a group of 17 healthy age-matched children. Sleep parameters were monitored for two full weeks by means of actigraphs and self-report diaries. Headache diaries were also filled out in order to evaluate the occurrence and the characteristics of migraine attacks. Fifty-seven attacks were recorded during the monitoring period. During the interictal period, sleep parameters of children suffering from migraine did not differ from those of controls; only sleep onset latency was slightly prolonged in the migraine group. Timing of the attack affected nocturnal motor activity which presented the lowest values on the night preceding the attack, indicating a decrease in cortical activation during sleep preceding migraine attacks. Further studies should clarify if the observed reduction in nocturnal motor activity close to the attack is related to neurotransmitter imbalance.

Electrodermal responses in patients with unilateral brain damage

Skin conductance responses (SCR) to emotional and to nonemotional stimuli were measured in 16 right and 16 left unilateral brain-damaged patients. Replicating findings by Morrow, Vrtunski, Kim and Boller (1981), those patients with a lesion in the left hemisphere showed higher SCRs to emotional than to nonemotional stimuli while those with a right lesion showed no difference between them. This pattern of results remained when variance in performance on a Facial Expression Recognition task was partialled out, suggesting that the absence of differentiated arousal in right-brain-damaged patients is unrelated to their impairment in perceptual analysis.

Assessing vigilance through a brief pencil and paper letter cancellation task (LCT): effects of one night of sleep deprivation and of the time of day

Behavioural effects of the lack of sleep in normal subjects have been investigated mostly by experimenter-paced choice reaction times in prolonged stimulus detection tasks. However, length and procedure complexity of these tasks limit their use in research on larger numbers of subjects. The aim of the present study was to assess the effectiveness of a brief subject-paced pencil and paper performance task, i.e. letter cancellation task (LCT) in revealing the effects of one night of sleep deprivation. In addition, the authors evaluated sleep loss and time of day effects on six Visual Analogue Scales (VAS) measuring subjective activation-deactivation. Results show that a LCT is sensitive in revealing the effects of time of day and of 24 h of sleep deprivation. Effects of sleep deprivation were also revealed by VAS data. Sleepiness, tiredness and energy scales on the VAS were also affected by time of day. Despite the sensitivity of both the LCT and VAS, there was little correspondence between performance and subjective measures.

Psychophysiological reactivity to sleep-related emotional stimuli in primary insomnia.

The present study examined psychophysiological reactivity to emotional stimuli related and non-related to sleep in people with primary insomnia (PPI) and in good sleepers (GS). Twenty-one PPI and 18 GS were presented with five blocks of neutral, negative, positive, sleep-related negative and sleep-related positive pictures. During the presentation of the pictures, facial electromyography (EMG) of the corrugator and the zygomatic muscles, heart rate (HR) and cardiac vagal tone (CVT) were recorded. Subjective ratings of the stimuli were also collected. We found that only PPI exhibited greater inhibition of the corrugator activity in response to sleep-related positive stimuli compared to the other blocks of stimuli. Furthermore, PPI rated the sleep-related negative stimuli as more unpleasant and arousing and showed higher CVT in response to all stimuli as compared to GS. Results were interpreted as indicating that PPI exhibit craving for sleep-related positive stimuli, and also hyper-arousability in response to sleep-related negative stimuli, as compared to GS. Our results suggest that psychological treatment of insomnia could benefit by the inclusion of strategies dealing with emotional processes linked with sleep processes.

Variations in sleep mentation as a function of time of night

Mentation reports collected from sleep onset, Stage 2 and REM Stage awakenings, in the first part and in the second part of the night were analyzed both with systematic psycholinguistic and global measures. Results confirm the relationship between activation and the length of sleep mentation report shown by Antrobus. Length of the report increases with sleep time, but time does not modulate qualitative inter-stage differences. By partialling out the length of the report, many inter-stage differences disappeared; however significant differences remain in the global measure of bizarreness and in the psycholinguistic measure of visual imagery. These results cannot be explained entirely by differences in attention and memory and point to more basic differences in mental activity.

Insomnia Disorder is Associated with Increased Amygdala Reactivity to Insomnia-Related Stimuli

STUDY OBJECTIVES Alterations in emotional reactivity may play a key role in the pathophysiology of insomnia disorder (ID). However, only few supporting experimental data are currently available. We evaluated in a hypothesis-driven design whether patients with ID present altered amygdale responses to emotional stimuli related and unrelated to the experience of insomnia and, because of chronic hyperarousal, less habituation of amygdala responses. DESIGN Case-control study. SETTING Departments of Psychiatry and Psychotherapy and of Radiology of the University of Freiburg Medical Center. PARTICIPANTS There were 22 patients with ID (15 females; 7 males; age 40.7 ± 12.6 y) and 38 healthy good sleepers (HGS, 21 females; 17 males; age 39.6 ± 8.9 y). INTERVENTIONS N/A. MEASUREMENTS AND RESULTS In a functional magnetic resonance imaging session, five different blocks of pictures with varying emotional arousal, valence, and content (insomnia-relatedness) were presented. Pictures were presented twice to test for habituation processes. Results showed that patients with ID, compared to HGS, presented heightened amygdala responses to insomnia-related stimuli. Moreover, habituation of amygdale responses was observed only in HGS, but not in patients with ID who showed a mixed pattern of amygdala responses to the second presentation of the stimuli. CONCLUSIONS The results provide evidence for an insomnia-related emotional bias in patients with ID. Cognitive behavior treatment for ID could benefit from strategies dealing with the emotional charge associated with the disorder. Further studies should clarify the role of ID with respect to habituation of amygdala responses.

P300 amplitude in subjects with primary insomnia is modulated by their sleep quality

OBJECTIVE The hyperarousal hypothesis is evaluated while controlling the influence of the quality of sleep in the night preceding the evaluation. METHOD Eleven primary insomniacs and 11 healthy age matched controls participated to the study. Participants filled in 2 weeks of sleep logs and self-monitored their subjective tension the evening before and the morning after each night. Afterwards, subjects were called in to the Lab for a recording session of the P300 ERP (oddball paradigm) once after a night of bad sleep quality (N-) and once after a night of good sleep quality (N+). RESULTS The main result of the present study indicated that the P300 amplitude at Fz in insomniacs resulted higher following a N- and lower following a N+ with respect to controls. CONCLUSIONS This result suggests that cortical hyperarousal in primary insomniacs is not a stable individual characteristic, but is associated with the poor quality of their nocturnal sleep.

Rapid eye movements density as a measure of sleep need: REM density decreases linearly with the reduction of prior sleep duration

In the recovery nights from total and partial sleep deprivation there is a reduction of oculomotor activity during paradoxical sleep as compared to baseline nights. Aims of the present within-subjects study are to contribute in understanding the nature of the relationship between REM density and sleep need and to evaluate whether an inverse relationship exists between REM density and slow wave sleep (SWS) amount. Six healthy subjects were studied for 7 consecutive weeks with standard polysomnographic recordings. Variations in REM density were assessed in the recovery nights following a gradual sleep restriction, obtained by postponing the sleep onset time while maintaining the final awakening time constant. Results indicate that sleep curtailment decreases REM density in the ensuing recovery nights; the decrease is linearly related to the amount of sleep curtailment. The decrease in REM density parallels an increase in SWS, while no corresponding variation was found neither in the duration of paradoxical sleep nor in the latency of any other sleep stage. These results suggest that REM density could be used as a measure of sleep need.

Brain Function and Effects of Shift Work: Implications for Clinical Neuropharmacology

Night or shift work is to a relevant extent unavoidable, suits a growing preference for flexibility and is predicted to spread. However, a significant percentage of shift workers report discomfort or health problems and they often (15–20% of cases) move to different occupations. Apart from social implications, the issue has medical and scientific relevance, with evidence suggesting that the circadian rhythm phases are neither equivalent nor interchangeable with respect to function and performance. Shift work may affect the gastrointestinal and cardiovascular functions, alter the hormonal and sleepiness cycles, favor sleep disturbances of medical relevance, interfere with behavior and social life and increase the risk of accidents (e.g. road accidents). The implications for clinical (neuro)pharmacology are relevant and, in several instances, critical. Shift work can interfere with mechanisms regulating drug kinetics in peripheral compartments and action at selective brain sites, either directly or through effects on the gastrointestinal/hormonal cycles. In this paper, the relevant literature is reviewed and original data on the effects of shift work are reported. Basic and clinical research should take into account the possible effects on drug action of an active life and working schedule in inappropriate phases of the circadian cycles and the risk of inadequate drug dosing or inexpected abnormal action in subjects under long-term or chronic treatment. A scientific approach, action by the scientific community involved in pharmacological research and monitoring by the regulating agencies are advisable. Regulation may help reduce the medical and social impact and improve quality of life.