Papers by Jessica Lara-Carrasco
Sleep, 2010
To assess whether dysfunctional autonomic regulation during REM sleep as indexed by heart rate va... more To assess whether dysfunctional autonomic regulation during REM sleep as indexed by heart rate variability (HRV) is a pathophysiological factor in frequent nightmares (NMs). design: Monitoring with polysomnography (PSG) and electrocardiography (ECG) for 3 consecutive nights: Night 1 (N1), adaptation night; N2, administration of partial REM sleep deprivation; N3, recovery night. Differences between NM and control (CTL) groups assessed for ECG measures drawn from wakefulness, REM sleep, and Stage 2 sleep on both N1 and N3. setting: Hospital-based sleep laboratory Participants: Sixteen subjects with frequent NMs (≥ 1 NM/week; mean age = 26.1 ± 8.7 years) but no other medical or psychiatric disorders and 11 healthy comparison subjects (< 1 NM/month; mean age = 27.1±5.6 years). results: NM and CTL groups differed on 2 REM sleep measures only on N1; the NM group had longer REM latencies and REM/NREM cycle durations than did the CTL group. No differences were found on time domain and absolute frequency domain ECG measures for either N1 or N3. However, altered HRV for the NM group was suggested by significantly higher LFnu, lower HFnu, and higher LF/HF ratio than for the CTL group. conclusions: Results are consistent with a higher than normal sympathetic drive among NM subjects which is unmasked by high REM sleep propensity. Results also support a growing literature linking anxiety disorders of several types (panic disorder, posttraumatic stress disorder (PTSD), generalized anxiety disorder) to altered HR variability.
doi: 10.3389/fpsyg.2013.00551 Maternal representations in the dreams of pregnant women: a prospec... more doi: 10.3389/fpsyg.2013.00551 Maternal representations in the dreams of pregnant women: a prospective comparative study
According to many perinatal health care professionals, dreams are more frequent and disturbed dur... more According to many perinatal health care professionals, dreams are more frequent and disturbed during pregnancy. Some suggest that in being more vivid, realistic and impactful than during any other period of life, pregnancy dreams might increase women’s awareness to their intrapsychic world and therefore facilitate the resolution of past relational issues. Other clinicians suggest that dreams during pregnancy might help women to integrate their maternal role through the elaboration of various mental representations, such as the future mother-baby relationship. While these notions have been frequently mentioned in the clinical literature, empirical evidence is lacking. The first objective of this thesis was to provide a better description of changes occurring in the dreams of the third trimester (≥26 weeks) of a first pregnancy, using measures of dream recall, dysphoric dreams prevalence, and dream content. Our results show—for the first time—that when pregnant women’s dreams are pros...
Abstract 1. A satisfactory explanation of nightmares remains elusive. Theorists since Freud have ... more Abstract 1. A satisfactory explanation of nightmares remains elusive. Theorists since Freud have speculated on mechanisms that produce nightmares, but no single, widely accepted explanation has emerged (see Nielsen &amp;amp;amp;amp; Levin, 2007b; Levin &amp;amp;amp;amp; Nielsen, 2007). This continuing uncertainty stems, in part, from the fact that nightmares, like dreams more generally, are expressions of human emotional memory--which itself is a complex and intransigent phenomenon. The inner workings of emotional memory have yet to be ...
Sleep Medicine, 2013
Introduction Sleep disturbances during pregnancy affect delivery outcomes, including shorter preg... more Introduction Sleep disturbances during pregnancy affect delivery outcomes, including shorter pregnancies and longer labour (Okun, 2009). Studies also reveal associations between recall of negative dreams and shorter labour (Mancuso et al., 2008; Winget and Kapp, 1972). However, prospective longitudinal studies assessing the value of pregnancy dreams in predicting delivery outcomes are lacking. Whether dream measures constitute better predictors of delivery outcomes than do sleep measures also remains to be determined. This 2-stage longitudinal study assessed whether prospective dream measures during pregnancy (Time-1; T1) predict delivery outcomes (Time-2; T2) controlling for pregnancy, sleep and psychosocial risk factors. Materials and methods Fifty-two 3rd trimester pregnant women ( M = 29.78 ± 3.62 wks of gestation) aged 18–37 years ( M = 28.48 ± 4.06 yrs) and not planning to undergo caesarean sections were followed-up post-delivery. At T1, pregnant women completed demographic and psychological questionnaires and a 14-day home log to assess sleep/dream characteristics. Gestational length and labour duration were assessed at T2. Deliveries occurred at 36–42 weeks of gestation ( M = 39.29 ± 1.46); labour lasted 1–40 h ( M = 13.62 ± 8.99). Four women had unplanned caesareans; their labour duration did not differ from women who delivered vaginally ( M = 13.40 ± 9.28 vs. 16.25 ± 0.03; p = 0.60). Two sets of hierarchical multiple regression analyses were run to predict delivery outcomes from pregnancy dream variables (#dreams, positive–negative dreams ratio, dream clarity, dream impact), controlling for sleep (duration, quality, bedtime/rise time, night awakenings), demographic (age, employment status, family income, education) and psychosocial (mood/concerns, stress, history of emotional problems) characteristics. All demographic variables, prenatal psychosocial factors and sleep variables associated with outcomes at p Results More negative dreams during pregnancy predicted shorter gestation (Beta = −0.61, p = 0.00002); no adjustment was required. Controlling for age, education, stress and sleep duration, later bedtime/rise time predicted longer labour (Beta = 0.28, p = 0.04). Conclusion The study provides new evidence that pregnant women who report more negative dreams are at greater risk for shorter pregnancies. Results are also consistent with the possibility that chronotype mediates relationships between sleep and labour duration. Acknowledgement Research was supported by the Canadian Institutes of Health Research.
Neurobiology of learning and memory, Jan 5, 2014
Memory consolidation is associated with sleep physiology but the contribution of specific sleep s... more Memory consolidation is associated with sleep physiology but the contribution of specific sleep stages remains controversial. To clarify the contribution of REM sleep, participants were administered two REM sleep-sensitive tasks to determine if associated changes occurred only in REM sleep. Twenty-two participants (7 men) were administered the Corsi Block Tapping and Tower of Hanoi tasks prior to and again after a night of sleep. Task improvers and non-improvers were compared for sleep structure, sleep spindles, and dream recall. Control participants (N=15) completed the tasks twice during the day without intervening sleep. Overnight Corsi Block improvement was associated with more REM sleep whereas Tower of Hanoi improvement was associated with more N2 sleep. Corsi Block improvement correlated positively with %REM sleep and Tower of Hanoi improvement with %N2 sleep. Post-hoc analyses suggest Tower of Hanoi effects-but not Corsi Block effects-are due to trait differences. Sleep spin...
Sleep, 2005
Sleep onset (SO) is cognitively and physiologically similar to rapid eye movement (REM) sleep, su... more Sleep onset (SO) is cognitively and physiologically similar to rapid eye movement (REM) sleep, supporting the notion that REM sleep-related processes are 'covertly' active at this time. The objective was to determine if SO mentation is sensitive to REM sleep deprivation. Two-group cross-sectional design; sleep recordings for 3 nights. Standard sleep laboratory with 24-channel polysomnography recording. Fourteen female, 13 male healthy volunteers (18-41 yrs, mean=24.8 +/- 6.07). On Night 2, half were and half were not partially REM sleep-deprived (REMD), recalled REM mentation, and rated it for dream-like quality (DLQ), sleepiness, and sensory attributes. On Night 3, all were awakened from SO substages 4 and 5 for mentation reports and further ratings. REMD measures were derived from scored sleep tracings. REMD produced increases in DLQ for both REM and SO reports (P < .05); DLQ scores were higher for REM than for SO mentation (P < .001). Covarying sleepiness preserved ...
Sleep Medicine, 2011
awakenings in every spectral frequency studied, in relation to the group and presence or absence ... more awakenings in every spectral frequency studied, in relation to the group and presence or absence of recall. The various spectral bands evolved according to an underlying rhythm, which is attenuated in the presence of dream recall; this was more evident in Normal subjects. Verbal activities were negatively correlated with high frequency bands in C3, T5 and P3 electrodes in controls. Conclusion: Differences between recall and no recall were detected. The spectral frequency bands powers were attenuated with dream recall. A cyclic variation in spectral power was detected in association with recall. Verbal activities correlated with high frequencies in left centro-temporoparietal areas.
Sleep Medicine, 2010
Objectives: To examine whether disrupted regulation of REM sleep propensity is implicated in nigh... more Objectives: To examine whether disrupted regulation of REM sleep propensity is implicated in nightmare (NM) pathophysiology. Background: Heightened REM propensity induced by REM sleep deprivation is belied by increases in REM %, REM density and the dreamlike quality of dream mentation during post-deprivation recovery sleep. Compromised regulation of REM sleep propensity may be a contributing factor in the pathophysiology of frequent NMs. Methods: A preliminary study of 14 subjects with frequent NMs (P1 NM/week; 27.6 ± 9.9 years) and 11 healthy control subjects (<1 NM/month; 24.3 ± 5.3 years) was undertaken. Subjects completed home sleep/dream logs and underwent three nights of polysomnographic recording with REM sleep deprivation on night 2. Group differences were assessed for a battery of REM sleep and dream measures on nights 1 and 3. Results: Several measures, including #skipped early-night REM periods, REM latency, REM/NREM cycle length, early/late REM density, REM rebound, late-night REM% and dream vividness, suggested that REM sleep propensity was abnormally low for the frequent NM group throughout the 3-day study. Conclusions: Findings raise the possibility that REM anomalies recorded from NM sufferers sleeping in the laboratory environment reflect a disruption of one or more endogenous regulators of REM sleep propensity.
Sleep Medicine, 2014
Objective: The majority of women develop sleep impairments during pregnancy, but alterations in d... more Objective: The majority of women develop sleep impairments during pregnancy, but alterations in dream experiences remain poorly understood. This study aimed to assess prospectively and comparatively the recall of dreaming and of disturbed dreaming in late pregnancy. Methods: Fifty-seven nulliparous, third-trimester pregnant women (mean age ± SD, 28.7 ± 4.06 years) and 59 non-pregnant controls (mean age ± SD, 26.8 ± 4.21 years) completed demographics and psychological questionnaires. A 14-day prospective home log assessed sleep and dream characteristics and the Sleep Disorders Questionnaire measured retrospective dream and disturbed dream recall. Results: Even though pregnant and non-pregnant women showed similar prospective dream recall (P = 0.47), pregnant women reported prospectively more bad dreams (P = 0.004). More pregnant women (21%) than non-pregnant women (7%) reported a nightmare incidence exceeding moderately severe pathology (>1/week) (P = 0.03). Pregnant women also reported overall lower sleep quality (P = 0.007) and more night awakenings (P = 0.003). Higher prospective recall of bad dreams (r = À0.40, P = 0.002) and nightmares (r = À0.32, P = 0.001) both correlated with lower sleep quality in pregnant women. Conclusions: Late pregnancy is a period of markedly increased dysphoric dream imagery that may be a major contributor to impaired sleep at this time. Further polysomnographic assessments of pregnant women are needed to clarify relationships between sleep and disturbed dream production in this population.
Journal of Sleep Research, 2009
Rapid eye movement (REM) sleep and dreaming may be implicated in cross-night adaptation to emotio... more Rapid eye movement (REM) sleep and dreaming may be implicated in cross-night adaptation to emotionally negative events. To evaluate the impact of REM sleep deprivation (REMD) and the presence of dream emotions on a possible emotional adaptation (EA) function, 35 healthy subjects randomly assigned to REMD (n = 17; mean age 26.4 ± 4.3 years) and control (n = 18; mean age 23.7 ± 4.4 years) groups underwent a partial REMD and control nights in the laboratory, respectively. In the evening preceding and morning following REMD, subjects rated neutral and negative pictures on scales of valence and arousal and EA scores were calculated. Subjects also rated dream emotions using the same scales and a 10-item emotions list. REMD was relatively successful in decreasing REM% on the experimental night, although a mean split procedure was applied to better differentiate subjects high and low in REM%. High and low groups differed -but in a direction contrary to expectations. Subjects high in REMD% showed greater adaptation to negative pictures on arousal ratings than did those low in REMD% (P < 0.05), even after statistically controlling sleep efficiency and awakening times. Subjects above the median on EA valence had less intense overall dream negativity (P < 0.005) and dream sadness (P < 0.004) than subjects below the median. A correlation between the emotional intensities of the morning dream and the morning picture ratings supports a possible emotional carry-over effect. REM sleep may enhance morning reactivity to negative emotional stimuli. Further, REM sleep and dreaming may be implicated in different dimensions of cross-night adaptation to negative emotions. k e y w o r d s dreaming, emotional adaptation, emotion-induction task, rapid eye movement sleep, standardized picture stimuli, valence/arousal of emotions Correspondence: Tore A. Nielsen,
Frontiers in Psychology, 2013
Dreams are thought to respond to self-and socially-relevant situations that evoke strong emotions... more Dreams are thought to respond to self-and socially-relevant situations that evoke strong emotions and require rapid adaptation. First pregnancy is such a situation during which maternal mental representations (MMR) of the unborn baby, the self and significant others undergo remodeling. Some studies suggest that dreams during pregnancy contain more MMR and are more dysphoric, but such studies contain important methodological flaws. We assessed whether dreamed MMR, like waking MMR, change from the 7th month of pregnancy to birth, and whether pregnancy-related themes and nonpregnancy characteristics are also transformed. Sixty non-pregnant and 59 pregnant women (37 early and 22 late 3rd trimester) completed demographic and psychological questionnaires and 14-day home dream logs. Dream reports were blindly rated according to four dream categories: (1) Dreamed MMR, (2) Quality of baby/child representations, (3) Pregnancy-related themes, (4) Non-pregnancy characteristics. Controlling for age, relationship and employment status, education level and state anxiety, women in both pregnant groups reported more dreams depicting themselves as a mother or with babies/children than did non-pregnant women (all p = 0.006). Baby/child representations were less specific in the late 3rd than in the early 3rd trimester (p = 0.005) and than in non-pregnant women (p = 0.01). Pregnant groups also had more pregnancy, childbirth and fetus themes (all p = 0.01). Childbirth content was higher in late than in early 3rd trimester (p = 0.01). Pregnant groups had more morbid elements than did the non-pregnant group (all p < 0.05). Dreaming during pregnancy appears to reflect daytime processes of remodeling MMR of the woman as a mother and of her unborn baby, and parallels a decline in the quality of baby/child representations in the last stage of pregnancy. More frequent morbid content in late pregnancy suggests that the psychological challenges of pregnancy are reflected in a generally more dysphoric emotional tone in dream content.
Early Child Development and Care, 2011
Sleep fragmentation in infancy can burden a family by disrupting the sleep of all its members. Ho... more Sleep fragmentation in infancy can burden a family by disrupting the sleep of all its members. However, there has been no longitudinal prospective investigation of the determinants of infant sleep fragmentation. We undertook such an investigation. New mothers (N = 106) completed questionnaires and were administered structured telephone interviews at three, six and 12 weeks postpartum. Pre-and postnatal maternal adjustment and sleep-related parental practices were evaluated as potential predictors of infants' sleep fragmentation. Risk factors for infants sleeping less than six consecutive hours per night at 12 weeks were found to be mother's depressed mood (OR = 1.55, p < .01), breastfeeding (OR = 6.40, p < .01) and room sharing (OR = 2.91, p < .05). The mother's depressed mood and breastfeeding were also related to poor sleep consolidation when the latter was assessed as a continuous outcome (p < .01). This study identifies factors to target in sleep-focused interventions in families where the child's sleep has become a problem.
1. A satisfactory explanation of nightmares remains elusive. Theorists since Freud have speculate... more 1. A satisfactory explanation of nightmares remains elusive. Theorists since Freud have speculated on mechanisms that produce nightmares, but no single, widely accepted explanation has emerged (see Nielsen & Levin, 2007b; Levin & Nielsen, 2007). This continuing uncertainty stems, in part, from the fact that nightmares, like dreams more generally, are expressions of human emotional memory--which itself is a complex and intransigent phenomenon. The inner workings of emotional memory have yet to be ...
Sleep, 2010
study Objectives: To assess whether dysfunctional autonomic regulation during REM sleep as indexe... more study Objectives: To assess whether dysfunctional autonomic regulation during REM sleep as indexed by heart rate variability (HRV) is a pathophysiological factor in frequent nightmares (NMs). design: Monitoring with polysomnography (PSG) and electrocardiography (ECG) for 3 consecutive nights: Night 1 (N1), adaptation night; N2, administration of partial REM sleep deprivation; N3, recovery night. Differences between NM and control (CTL) groups assessed for ECG measures drawn from wakefulness, REM sleep, and Stage 2 sleep on both N1 and N3. setting: Hospital-based sleep laboratory Participants: Sixteen subjects with frequent NMs ( ≥ 1 NM/week; mean age = 26.1 ± 8.7 years) but no other medical or psychiatric disorders and 11 healthy comparison subjects ( < 1 NM/month; mean age = 27.1±5.6 years). results: NM and CTL groups differed on 2 REM sleep measures only on N1; the NM group had longer REM latencies and REM/NREM cycle durations than did the CTL group. No differences were found on time domain and absolute frequency domain ECG measures for either N1 or N3. However, altered HRV for the NM group was suggested by significantly higher LFnu, lower HFnu, and higher LF/HF ratio than for the CTL group. conclusions: Results are consistent with a higher than normal sympathetic drive among NM subjects which is unmasked by high REM sleep propensity. Results also support a growing literature linking anxiety disorders of several types (panic disorder, posttraumatic stress disorder (PTSD), generalized anxiety disorder) to altered HR variability.
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Papers by Jessica Lara-Carrasco