Sleep deprivation detected by voice analysis.

Sleep deprivation has an ever-increasing impact on individuals and societies. Yet, to date, there is no quick and objective test for sleep deprivation. Here, we used automated acoustic analyses of the voice to detect sleep deprivation. Building on current machine-learning approaches, we focused on interpretability by introducing two novel ideas: the use of a fully generic auditory representation as input feature space, combined with an interpretation technique based on reverse correlation. The auditory representation consisted of a spectro-temporal modulation analysis derived from neurophysiology. The interpretation method aimed to reveal the regions of the auditory representation that supported the classifiers' decisions. Results showed that generic auditory features could be used to detect sleep deprivation successfully, with an accuracy comparable to state-of-the-art speech features. Furthermore, the interpretation revealed two distinct effects of sleep deprivation on the voice: changes in slow temporal modulations related to prosody and changes in spectral features related to voice quality. Importantly, the relative balance of the two effects varied widely across individuals, even though the amount of sleep deprivation was controlled, thus confirming the need to characterize sleep deprivation at the individual level. Moreover, while the prosody factor correlated with subjective sleepiness reports, the voice quality factor did not, consistent with the presence of both explicit and implicit consequences of sleep deprivation. Overall, the findings show that individual effects of sleep deprivation may be observed in vocal biomarkers. Future investigations correlating such markers with objective physiological measures of sleep deprivation could enable "sleep stethoscopes" for the cost-effective diagnosis of the individual effects of sleep deprivation.

Immune disruptions and night shift work in hospital healthcare professionals: The intricate effects of social jet-lag and sleep debt.

Objectives: We aimed to examine the effects of circadian and sleep rhythm disruptions on immune biomarkers among hospital healthcare professionals working night shifts and rotating day shifts. Methods: Hospital nurses working either as permanent night shifters (n=95) or as day shifters rotating between morning and afternoon shifts (n=96) kept a daily diary on their sleep and work schedules over a full working week. Blood samples were collected at the beginning and end of the last shift during the week, and participants were categorized into three groups based on work shift: morning shift (39 day shifters sampled at 7:00 and 14:00), afternoon shift (57 day shifters sampled at 14:00 and 21:00), and night shift (95 night shifters sampled at 21:00 and 7:00). Circulating blood counts in immune cells, interleukin-6 and C-reactive protein concentrations as well as total sleep time per 24 hours during work days (TST24w) and free days (TST24f), sleep debt (TST24f - TST24w) and social jet-lag (a behavioral proxy of circadian misalignment) were assessed. Results: Compared with day shifters, night shifters had shorter sleep duration (TST24w=5.4 ± 1.4h), greater sleep debt (3.2 ± 1.4 h) and social jet-lag (6.7 ± 2.4 h). Variations of immune biomarkers concentrations were consistent with the expected diurnal variations among day shifters (i.e., low level in the morning, increase during the day, peak value in the evening). By contrast, in night shifters, blood concentrations of total lymphocytes, T-helper cells, cytotoxic T-cells, memory B-cells and interleukin-6 were lower at 21:00, increased during the night, and reached higher values at 7:00. Multivariate analyses ruled out significant impact of TST24w, sleep debt, and social jet-lag on immune biomarkers concentrations among day shifters. In contrast, among night shifters, multivariate analyses indicated a combined effect of total sleep time (TST24w), sleep debt and social jet-lag for total lymphocytes and T-helper cells but only a social jet-lag effect for interleukin-6 and a single total sleep time effect for neutrophil and B-Cells. Conclusions: Altogether, our results point to intricate response patterns of immune rhythms to circadian misalignment and sleep debt in night shifters. Specifically, these altered pattern expressions of immune cells may increase vulnerability to infections and reduce vaccination efficiency in night workers.

"You look sleepy " The impact of sleep restriction on skin parameters and facial appearance of 24 women.

BACKGROUND: Total sleep deprivation has a visible impact on subjective facial appearance. However, there is a lack of knowledge on how moderate sleep restriction objectively impairs skin quality and facial aspect. METHODS: Twenty-four healthy good-sleeping women, aged 30-55, volunteered for this study on the impact of sleep restriction (SR) on their facial skin. SR was limited to 3 h per night for 2 consecutive nights. We assessed the following parameters at the same time of day, before and after SR: sebumetry (Sebumeter SM 815), hydration (Corneometer CM 825), trans-epidermal water loss (Tewameter TM 210), biomechanical properties (Cutometer MPA 580), pH (PH-meter 900), desquamation quantification (D-Squameter and microscopy), and image analysis (ColorFace - Newtone Technologies). We also obtained skin samples (swab) for malondialdehyde quantification (MDA). RESULTS: We observed that some skin parameters are significantly associated with SR in both the morning and afternoon, including: lower hydration (p < 0.001), increased trans-epidermal water loss (PIE) (p < 0.001), and decreased extensibility (Uf; p = 0.015) and viscosity (Uv; p < 0.001) of the skin. The average pH increased from 4.8 (±0.2) to 4.9 ± 0.4; p < 0.001. For face photography, brightness and saturation also significantly decreased with SR in mornings and afternoons (p < 0.001 for all tests). Finally, we observed a significant decrease in isolated corneocytes after desquamation associated with SR (p < 0.001 for all tests). SR was also associated with significantly increased MDA levels (p < 0.001 for all tests). CONCLUSIONS: Two nights of SR significantly altered the skin and facial appearances in our test group of typically good-sleeping women.

Sleep and Prospective Memory: A Retrospective Study in Different Clinical Populations.

Prospective memory (PM) is essential in everyday life because it concerns the ability to remember to perform an intended action in the future. This ability could be influenced by poor sleep quality, the role of which, however, is still being debated. To examine the role of sleep quality in PM in depth, we decided to perform a retrospective naturalistic study examining different clinical populations with a primary sleep disorder or comorbid low sleep quality. If sleep is important for PM function, we could expect poor sleep to affect PM performance tasks both directly and indirectly. We examined a total of 3600 nights, recorded using actigraphy in participants belonging to the following groups: primary insomnia (731 nights); narcolepsy type 1 (1069 nights); attention deficit hyperactivity disorder (152 nights in children and 239 in adults); severe obesity (232 nights); essential hypertension (226 nights); menopause (143 nights); healthy controls (808 nights). In a naturalistic activity-based PM task, each participant originally wore an actigraph around the non-dominant wrist and was requested to push the event-marker button at two specific times of day: bedtime (activity 1) and get-up time (activity 2). Each clinical group showed significantly lower sleep quality in comparison to the control group. However, only narcolepsy type 1 patients presented a significantly impaired PM performance at get-up time, remembering to push the event-marker button around half the time compared not only to healthy controls but also to the other clinical groups. Overall, the present results seem to point to sleep quality having no effect on the efficiency of a naturalistic activity-based PM task. Moreover, the data indicated that narcolepsy type 1 patients may show a disease-specific cognitive deficit of PM.

A study on the optimal length of actigraphic recording in narcolepsy type 1.

OBJECTIVE: The aim of the present study was to assess the optimal length of actigraphic recordings in patients with narcolepsy type 1. METHODS: A secondary analysis was carried out with the previously collected data in eleven patients with narcolepsy type 1. Ten of the 11 patients were medicated at the time of actigraphic recording. Each patient originally wore an Actiwatch AW64 actigraph for at least 28 consecutive days. Overall, the patients were analyzed for 308 nights. RESULTS: No significant differences were observed between the mean values of the 7-day and 14-day analyzed sets for the parameters sleep efficiency, fragmentation index, sleep onset latency, wake after sleep onset, and total sleep time. CONCLUSIONS: Our data suggest that 7 days of actigraphic recording could be sufficient for these patients. SIGNIFICANCE: Our results for the optimal length of actigraphic recording could be useful for both physicians and patients.

Daytime Exposure to Blue-Enriched Light Counters the Effects of Sleep Restriction on Cortisol, Testosterone, Alpha-Amylase and Executive Processes.

Sleep debt is becoming a better acknowledged cause of physiological stress and neurobehavioral deficits with major public-health concerns. We investigated whether exposure to blue light during daytime could be an efficient countermeasure to limit sleep restriction's impact on relevant behavioral (stress, sleepiness, sustained attention, and memory performance) and physiological (saliva cortisol, testosterone, and alpha-amylase) markers. Our semi-ecological, crossover, randomized design included 17 young men that underwent two sleep-restricted nights (3 h each) followed or not by blue light exposure (30-min-long sessions at 100 lux repeated four times throughout the day). Behavioral and physiological measurements were performed in the lab but outside these periods the participants kept following their usual routine. After sleep restriction, morning cortisol and testosterone, and afternoon alpha-amylase levels decreased. In parallel, subjective ratings of stress and sleepiness increased while performance on the sustained attention and memory tasks deteriorated. In contrast, after periods of blue light exposure, all these parameters were largely restored to baseline levels, despite an identical sleep restriction procedure, although this restorative effect was reduced for the memory task. Our findings suggest that even short exposure to blue light could trigger persistent beneficial effects throughout the day and could be potentially efficient in real-life settings.

Using actigraphy to assess sleep and wake rhythms of narcolepsy type 1 patients: a comparison with primary insomniacs and healthy controls.

OBJECTIVE/BACKGROUND: It has been shown that actigraphy may have a discriminant function (DS) for the diagnosis of narcolepsy type 1 patients (NT1), based on a combination of nighttime and daytime parameters. Here, we aimed to test those findings using another actigraph model with a different clinical sample as control (ie, primary insomniacs, PI), carrying out a secondary analysis of previously collected data. PATIENTS/METHODS: The study sample consisted of 13 NT1 (nine females; mean age 39.38 ± 11.48), 13 PI (nine females; mean age 38.69 ± 10.72) and 13 Healthy Controls (HC) (nine females; mean age 38 ± 10.77). Participants wore the Actiwatch AW64 (Cambridge Neurotechnology Ltd, Cambridge, UK) around the non-dominant wrist for seven consecutive days. RESULTS: Significant differences between groups were observed with a higher number of episodes of wakefulness (wake bouts, WB) in PI than HC, a higher fragmentation index (FI) in NT1 than HC and PI, a higher duration of the longest nap (LNAP) in NT1 than HC and PI and higher DS in PI and NT1 than HC. A new DS (NDS), with LNAP and FI as independent variables, was proposed; which was higher in NT1 than HC and PI. CONCLUSIONS: The present study confirms that actigraphy discriminates NT1 from HC. However, considering PI, a new discriminant function NDS which takes into account LNAP and FI is better for this actigraph model.

[Sleep, an issue for nurses and patients]. / Le sommeil, un enjeu pour les soignants et les patients.

A three-day training programme on sleep in hospitals was created in 2008 on the initiative of the national association for the continuing training of hospital staff, in collaboration with the French ministry of health. 448 nurses have been trained thanks to a participative programme integrating new, interactive pedagogical tools.

[Objective improvement of sleep disorders in the elderly by a health education program]. / Les troubles du sommeil peuvent être objectivement améliorés chez les seniors par un programme personnalisé d'éducation à la santé

INTRODUCTION: The prevalence of sleep disorders increases with age and reaches 20 to 40% of those older than 60 years. We set up a health education program to help the elderly to improve their sleep. It includes a preliminary 9-day evaluation with a sleep diary and wrist actigraph, a day of group cognitive behavioral therapy, and a follow-up assessment, again with sleep diary and actigraph. METHODS: Of the 26 study participants (9 men and 17 women, mean age: 68+/-1 years), 14 had insomnia with night awakenings of 1 hour or longer or a sleep latency of 30 minutes or longer or both (group 1). The other 12 (group 2) also complained of insufficient sleep. RESULTS: In the weeks following cognitive behavioral therapy, group 1 improved their total sleep time by an average of 24 to 33 minutes, with reduced night-time awakenings and sleep latency and no change in their time spent in bed. Those in group 2 also increased their total sleep time by 18 to 47 minutes, by spending more time in bed and maintaining a sleep efficiency close to 88%. CONCLUSION: This study showed that cognitive behavioral therapy coupled with individual sleep evaluation improves sleep duration in elderly people who complain of insufficient sleep. These beneficial effects were accompanied by positive assessments of both subjective sleep quality and morning energy.

Posterior triangular thalamic neurons convey nociceptive messages to the secondary somatosensory and insular cortices in the rat.

This study investigated the responses of posterior triangular (PoT) thalamic neurons to tactile and noxious calibrated stimuli in anesthetized rats. We report here that 41% of PoT units responded to cutaneous stimulation, in most cases, by increasing strongly their firing. Forty-five percent of the responding units were nociceptive specific (NS), 19% were nociceptive nonspecific (NNS), and 36% were tactile. The NS units responded only to frankly noxious stimuli applied to relatively large receptive fields (several parts of the body). They encoded nociceptive temperatures chiefly in 46-50 degrees C ranges. The NNS units resembled NS units but also responded to innocuous stimuli. Tactile units responded chiefly to repeated innocuous stimuli applied to very small receptive fields (one to two fingers or vibrissae). A representative sample of PoT somatosensory neurons, characterized first by their response to innocuous and noxious cutaneous stimuli, were filled with juxtacellular injection of biotin-dextran that made it possible to label adequately the soma, the dendrites, and the entire axon of PoT neurons. We observed that the axons of NS neurons terminated only in secondary somatosensory (S2) cortex, whereas the axons of NNS and tactile neurons projected chiefly to the insular cortex and the amygdala. In conclusion, our results demonstrate a spinal-PoT-S2/insular cortices nociceptive pathway that conveys nociceptive messages arising from lamina I and spinal neurons of deep laminas. Furthermore, our results demonstrate for the first time that projections of PoT neurons are correlated to their physiological properties.

A comparative reappraisal of projections from the superficial laminae of the dorsal horn in the rat: the forebrain.

Projections to the forebrain from lamina I of spinal and trigeminal dorsal horn were labeled anterogradely with Phaseolus vulgaris-leucoagglutinin (PHA-L) and/or tetramethylrhodamine-dextran (RHO-D) injected microiontophoretically. Injections restricted to superficial laminae (I/II) of dorsal horn were used primarily. For comparison, injections were also made in deep cervical laminae. Spinal and trigeminal lamina I neurons project extensively to restricted portions of the ventral posterolateral and posteromedial (VPL/VPM), and the posterior group (Po) thalamic nuclei. Lamina I also projects to the triangular posterior (PoT) and the ventral posterior parvicellular (VPPC) thalamic nuclei but only very slightly to the extrathalamic forebrain. Furthermore, the lateral spinal (LS) nucleus, and to a lesser extent lamina I, project to the mediodorsal thalamic nucleus. In contrast to lamina I, deep spinal laminae project primarily to the central lateral thalamic nucleus (CL) and only weakly to the remaining thalamus, except for a medium projection to the PoT. Furthermore, the deep laminae project substantially to the globus pallidus and the substantia innominata and more weakly to the amygdala and the hypothalamus. Double-labeling experiments reveal that spinal and trigeminal lamina I project densely to distinct and restricted portions of VPL/VPM, Po, and VPPC thalamic nuclei, whereas projections to the PoT appeared to be convergent. In conclusion, these experiments indicate very different patterns of projection for lamina I versus deep laminae (III-X). Lamina I projects strongly onto relay thalamic nuclei and thus would have a primary role in sensory discriminative aspects of pain. The deep laminae project densely to the CL and more diffusely to other forebrain targets, suggesting roles in motor and alertness components of pain.

Dendritic domains of nociceptive-responsive parabrachial neurons match terminal fields of lamina I neurons in the rat.

This study investigates, in the anesthetized rat, the dendritic extent of parabrachial (PB) neurons whose nociceptive response to noxious stimuli has been previously recorded with an extracellular micropipette. The PB neurons were then injected with biocytin through the recording micropipette, via a juxtacellular technique. The dendritic arborization of individual PB neurons was carefully compared with the projections of medullary (trigeminal) and spinal lamina I neurons. The latter projections were labeled in separate animals that received injections of Phaseolus vulgaris-leucoagglutinin restricted to the superficial layers of spinal or medullary dorsal horn. We report here that: 1) PB neurons excited chiefly by noxious stimulation of the face have their dendritic tree located primarily within the field of lamina I trigeminal projections, i.e., in the caudal portion of PB area, around the external medial and the caudal part of the external lateral subnuclei; and 2) PB neurons excited chiefly by noxious stimulation of the paw or the tail have their dendritic tree located primarily within the field of lamina I spinal projections, i.e., in PB mid-extent, around the borderline between the external lateral and both the lateral crescent and the superior lateral subnuclei. Our results suggest the presence of an extensive excitatory axodendritic link between lamina I projections and PB nociceptive neurons around the lateral crescent and the external medial subnuclei. These findings strengthen the possibility of involvement of a subgroup of PB neurons in nociceptive processes.

Pain pathways and parabrachial circuits in the rat.

This review presents a schematic attempt to classify the major pain pathways, based on the results of recent studies in our laboratory, with a special emphasis on the parabrachial system. Our view is based on results from experiments in the rat, using very small iontophoretic injections of anterograde tracers. As illustrated in this report, we have found a very dramatic difference between ascending projections originating from deep laminae compared with those arising from lamina I of the dorsal horn. We propose three main pain systems and discuss their functional-anatomical relationships. The first system is centred on the projection from deep laminae to three caudal reticular areas - the lateral reticular nucleus (LRN), the subnucleus reticularis dorsalis (SRD) and the gigantocellular lateral paragigantocellular reticular nuclei (NGc) - and the parabrachial internal lateral subnucleus (PBil). The second system is centred on the projection from lamina I to the ventral posterolateral nucleus (VPL), the ventral posteromedial (VPM), the posterior nuclear group (Po) and triangular posterior nucleus (PoT) of the thalamus. The third system is centred on the projection from lamina I to the lateral parabrachial area. We also present the four main projections from the latter area to the extended amygdala, the hypothalamus, the periaqueductal grey matter (PAG), and the ventrolateral medulla (VLM), and their involvement in emotional and autonomic (homeostatic) aspects of pain.