Patricia Franco - Academia.edu (original) (raw)

Papers by Patricia Franco

Research paper thumbnail of Reduced Arousals Following Obstructive Apneas in Infants Sleeping Prone

Pediatric Research, 2001

A decreased arousability and an increased risk for sudden infant death syndrome (SIDS) have been ... more A decreased arousability and an increased risk for sudden infant death syndrome (SIDS) have been shown in infants sleeping prone. Obstructive apnea, a known risk factor for SIDS, is less often terminated by an arousal reaction in infants than in adults. The effect of body position on the arousal reaction to spontaneous respiratory events had not been previously studied in infants. The aim of our study was to see if body position has an influence on the frequency and delay of the arousal reaction to obstructive apnea. All obstructive events recorded during two successive nights in 20 infants sleeping one night prone and one night supine were studied. During the supine recording 153 obstructive events were detected, and 217 were detected during the prone session. Prone sleep was not associated with an increased frequency of obstructive apneas. Total sleep time was 382 min (range, 283-456) supine and 423 min (range, 325-521) prone (p ϭ 0.003). Obstructive events duration was 6.5 s (range, 3-21.5) when sleeping supine and 8 s (range, 3.5-30.5) when prone (p ϭ 0.002). Behavioral arousal were found in 57.5% of obstructive events recorded supine and in 31.3% of those seen prone (p Ͻ 0.001). Arousal occurred after 8 s (range, 0 -21) from the start of the obstructions when supine and 10.5 s (range, 3.5-23.5) when prone (p ϭ 0.001). Sighs were found in 34% of supine obstructive events and in 44.7% of those prone (p ϭ 0.040). A reaction, i.e. arousal or sigh, was found in 91.5% of supine events and 76% of those prone (p Ͻ 0.001). We conclude that when sleeping supine, infants arouse to obstructive events more often and after shorter delay than when prone. (Pediatr Res 49: 402-406, 2001) Abbreviations SIDS, sudden infant death syndrome NREM, nonrapid eye movements REM, rapid eye movements RR, interval between two R waves ABSTRACT 402

Research paper thumbnail of Association between sleep apnea and reactive astrocytes in brainstems of victims of SIDS and in control infants

Forensic Science International, 2002

Among 27,000 infants studied prospectively to characterize their sleep-wake behavior, 38 infants ... more Among 27,000 infants studied prospectively to characterize their sleep-wake behavior, 38 infants died under 6 months of age; 27 infants died from sudden infant death syndrome (SIDS), 5 from congenital cardiac abnormalities, 2 from infected pulmonary dysplasia, 2 from septic shock with multi-organ failure, 1 with a prolonged seizure, and another with prolonged neonatal hypoxemia. The frequency and duration of sleep apneas recorded some 3-12 weeks prior to the infants' death were analyzed. Brainstem material was retrospectively collected from these 33 infants and studied in an attempt to elucidate the relationship between sleep apnea and hypoxic gliosis. The findings were compared between the SIDS victims and the control infants. Brainstem materials were immunohistochemically studied for quantitization of reactive astrocytes using an anti-glial fibrillary acidic protein (GFAP) antibody. The pathological materials were collected within 24h of death. This study focuses on the association between respiratory characteristics and pathology. Physiological and pathological data in the arousal pathway of the brainstem were linked for each infant and variant-covariant analyses were carried out using physiological data as dependent variables and pathological data and categorical data to evaluate the association with SIDS or non-SIDS as independent variables. The study failed to statistically support an association between hypoxic loads, reflected by the GFAP-positive reactive astrocytes in brainstems, the classification of being SIDS or non-SIDS infants, and the characteristics of sleep apnea.

Research paper thumbnail of Pacifier use modifies infant's cardiac autonomic controls during sleep

Early Human Development, 2004

Objective: The risk for sudden infant death (SIDS) was postulated to decrease with the use of a p... more Objective: The risk for sudden infant death (SIDS) was postulated to decrease with the use of a pacifier and by conditions increasing parasympathetic tonus during sleep. We evaluated the influence of a pacifier on cardiac autonomic controls in healthy infants. Study design: Thirty-four healthy infants were studied polygraphically during one night: 17 infants regularly used a pacifier during sleep and 17 never used a pacifier. Thumb users or occasional pacifier users were not included in the study. The infants were recorded at a median age of 10 weeks (range 6 -18 weeks). Autonomic nervous system (ANS) was evaluated by spectral analysis of the heart rate (HR). The high frequency component of HR spectral analysis reflected parasympathetic tonus and the low frequency on high frequency ratio corresponded to the sympathovagal balance. Results: Most infants (63.6%) lost their pacifier within 30 min of falling asleep. Sucking periods were associated with increases in cardiac sympathovagal balance. During non-sucking periods, in both REM and NREM sleep, infants using a pacifier were characterized by lower sympathetic activity and higher parasympathetic tonus compared with non-pacifier users. Conclusions: The use of pacifiers modifies cardiac autonomic controls during both sucking and non-sucking sleep periods. Non-nutritive sucking could regulate autonomic control in infants. These findings could be relevant to mechanisms implicated in the occurrence of sudden infant deaths during sleep.

Research paper thumbnail of Arousal deficiency theory in sudden infant death syndrome with reference to neuronal plasticity

Sleep Medicine, 2002

Objective: Among 27,000 infants studied prospectively to characterize their sleep-wake behavior, ... more Objective: Among 27,000 infants studied prospectively to characterize their sleep-wake behavior, 38 infants died under 6 months of age (including 26 infant victims of sudden infant death syndrome (SIDS), five with congenital cardiac abnormalities, two from infected pulmonary dysplasia, two from septic shock with multi-organ failure, one with a prolonged seizure, one from prolonged neonatal hypoxemia and one from meningitis and brain infarction).

Research paper thumbnail of Polysomnographic study of the autonomic nervous system in potential victims of sudden infant death syndrome

Clinical Autonomic Research, 1998

To determine the influence of sleep stages and night-time distribution on cardiac autonomic activ... more To determine the influence of sleep stages and night-time distribution on cardiac autonomic activity, the polysomnographic recordings of 18 victims of sudden infant death syndrome (SIDS) and of 36 control infants were studied. Autoregressive spectral analyses of heart rate (HR), using both short-term and whole-night methods, were evaluated as a function of sleep stages. The two main peaks of normalized LF and HF were computed during the night and the sympathovagal balance (LF/HF) was determined. In both NREM and REM sleep, SIDS infants were characterized by significantly lower normalized HF powers and higher LF/HF ratios. This finding was observed in both short-term and whole-night HR spectral analyses. In addition, SIDS victims were characterized by the presence of a high desynchronized peak of sympathetic tonus in the late hours of the night, a finding not seen in the control subjects. This report adds further indirect evidence for a possible sleep-related impairment of autonomic controls in some infants who died of SIDS.

Research paper thumbnail of Effects of body position on sleep and arousal characteristics in infants

Early Human Development, 2002

The prone sleeping position has been identified in world-wide epidemiological studies as a major ... more The prone sleeping position has been identified in world-wide epidemiological studies as a major risk factor for sudden infant death syndrome (SIDS). Public awareness campaigns throughout the western world have led to an over 50% reduction in postneonatal mortality and frequency of SIDS. This reduction in mortality has been mainly attributed to the avoidance of the prone sleep position. Various mechanisms have been postulated to explain the increased risk of SIDS associated with prone sleeping, among these, impairment of arousal from sleep. This paper reviews the effects of prone sleeping on infant sleep architecture, arousability from sleep and cardiorespiratory controls. Sleeping in the prone position has been shown to increase the amount of time spent sleeping, particularly time spent in quiet sleep (QS). Sleeping prone has also been demonstrated to be associated with a reduced responsiveness to a variety of arousal stimuli. Such impairment of arousal has been demonstrated to be associated with changes in control of autonomic cardiac function. During arousal, heart rate, blood pressure and breathing movements increase, while gross body movements occur to avoid the stimulus. Any impairment in arousability from sleep such as could occur when infants sleep in the prone position, could possibly contribute to the final pathway to SIDS. D

Research paper thumbnail of Influences of maternal cigarette smoking on infant arousability

Early Human Development, 2004

Since the reduction in the incidence of the prone sleeping position, maternal cigarette smoking h... more Since the reduction in the incidence of the prone sleeping position, maternal cigarette smoking has become the strongest modifiable risk factor for Sudden Infant Death Syndrome (SIDS). This risk is dose dependent. Various mechanisms have been postulated to explain the increased risk of SIDS associated with maternal smoking, among these, impairment of arousal from sleep. This paper reviews the effects of maternal smoking on infant arousability from sleep, cardiorespiratory controls and sleep architecture.

Research paper thumbnail of From physiology to pathology: arousal deficiency theory in sudden infant death syndrome (SIDS)—with reference to apoptosis and neuronal plasticity

Forensic Science International, 2002

Among 27,000 infants studied prospectively to characterize their sleep-wake behavior, 38 infants ... more Among 27,000 infants studied prospectively to characterize their sleep-wake behavior, 38 infants died under 6 months of age (including 26 infant victims of sudden infant death syndrome (SIDS), 5 with congenital cardiac abnormalities, 2 from infected pulmonary dysplasia, 2 from septic shock with multi-organ failure, 1 with a prolonged seizure, 1 from prolonged neonatal hypoxemia, 1 from meningitis and brain infarction). The frequency and duration of sleep apneas recorded some 3-12 weeks before the infants' death were analyzed. Brainstem material from these 38 infants was studied in an attempt to elucidate the relationship between sleep apnea and neuronal pathological changes in the arousal pathway. Immunohistochemical analyses included the evaluation of growth-associated phosphoprotein 43 (GAP43) as a marker for synaptic plasticity. The terminal-deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) method was used to identify apoptosis. The positive pathological reactions were quantitatively analyzed. The pathological and physiological data were linked for each infant. Akaike Information Criterion (AIC) statistics was calculated to elucidate the relationship between the physiological and the pathological data in the SIDS victims. The findings illustrated the possibility of an organic fragility within the arousal pathway, particularly in the midbrain periaqueductal gray matter, which is associated with the "visceral alerting response". This autonomic response occurs within an acetylcholine afferent system and pedunculopontine tegmental nucleus (PPTN). The finding is, in future SIDS infants, associated with repetitive sleep apnea.

Research paper thumbnail of Decreased Arousals in Infants Who Sleep With the Face Covered by Bedclothes

Objective. The risk of becoming a victim of sudden infant death syndrome is increased in infants ... more Objective. The risk of becoming a victim of sudden infant death syndrome is increased in infants who sleep with their face under bedding items. The present study was designed to evaluate auditory arousal thresholds of infants who sleep with their face covered by bedclothes.

Research paper thumbnail of Auditory arousal thresholds are higher when infants sleep in the prone position

Journal of Pediatrics, 1998

Research paper thumbnail of Sudden infant deaths: arousal as a survival mechanism

Sleep Medicine, 2002

The mechanisms responsible for sudden infant death syndrome (SIDS) are still largely unknown. To ... more The mechanisms responsible for sudden infant death syndrome (SIDS) are still largely unknown. To explain what factors contribute to the deaths, we suggest a model: the '3 S model for SIDS' that includes 'sicknesses', 'stages of development' and 'surroundings': (1) 'sicknesses' refers to infectious diseases or other medical condition.

Research paper thumbnail of Prenatal exposure to cigarette smoking is associated with a decrease in arousal in infants

Journal of Pediatrics, 1999

Objective: Sudden infant death syndrome has been related to both exposure to prenatal cigarette s... more Objective: Sudden infant death syndrome has been related to both exposure to prenatal cigarette smoke and impaired arousability from sleep. We evaluated whether healthy infants born to mothers who smoked during pregnancy had higher auditory arousal thresholds than those born to mothers who did not smoke and whether the effects of smoking occurred before birth.

Research paper thumbnail of Normal Sleep Architecture in Infants and Children

Journal of Clinical Neurophysiology, 1996

Because the collection of normative sleep data in the pediatric age group largely depends on tech... more Because the collection of normative sleep data in the pediatric age group largely depends on technical issues, this article discusses various aspects of sleep recordings in infants and children. Polygraphic monitoring of sleep and waking behavior contributes to a better description of maturational stages in children, from the prenatal period to the end of adolescence. This article reviews the general characteristics of normal children's sleep and the environmental factors that influence these maturational processes. The use of polygraphic recordings to identify neurological deficits and to predict behavioral and neurological outcome in infants and children, however, does not hold great promise. The importance of polysomnographic evaluation is admitted for some major clinical conditions, such as risks for abnormal breathing or narcoleptic attacks.

Research paper thumbnail of Sudden infant deaths: stress, arousal and SIDS

Early Human Development, 2003

The prevalence of the Sudden Infant Death Syndrome (SIDS) has dropped in most countries following... more The prevalence of the Sudden Infant Death Syndrome (SIDS) has dropped in most countries following the development of education campaigns on the avoidance of preventable risk factors for SIDS. These include factors in the infant's micro environment, such as prenatal passive smoking, administration of sedative drugs, prone sleep, high ambient temperature or sleeping with the face covered. Sleep laboratory studies have shown that these risk conditions contribute to the development of respiratory and autonomic disorders and reduce the child's arousability. The opposite effects were seen when studying factors protective from SIDS, such as breastfeeding or the use of a pacifier. In victims of SIDS, similar breathing, autonomic and arousal characteristics were recorded days or weeks before their death. It is concluded that in some infants, already immature control mechanisms can be aggravated by environmental factors. D

Research paper thumbnail of Cardiac autonomic characteristics in infants sleeping with their head covered by bedclothes

Journal of Sleep Research, 2003

The risk of Sudden Infant Death Syndrome is increased in infants sleeping with their head covered... more The risk of Sudden Infant Death Syndrome is increased in infants sleeping with their head covered by bedding items. This study was designed to evaluate cardiac autonomic nervous controls in infants sleeping with the head covered by bedclothes. Sixteen healthy infants with a median age of 12 weeks (range 9–13 weeks) were recorded polygraphically for one night. While they slept in their usual supine position, a bedsheet was placed over their head for about 45 min. All infants were challenged with the head covered and with the head free during both rapid eye movement (REM) and non-rapid eye movement (NREM) sleep. Sleep, breathing and heart rate (HR) characteristics were recorded simultaneously, together with rectal and pericephalic temperatures. In both head-free and head-covered conditions, autoregressive spectral analysis of HR was evaluated as a function of sleep stages. During the head-covered periods, parasympathetic tonus decreased and sympathetic activity increased in both REM and NREM sleep. Compared with the head-free periods, the head-covered sleep periods were characterized by greater rectal (P = 0.012) and pericephalic temperatures (P = 0.002). Covering the infant's head with a bedsheet was associated with significant changes in autonomic balance. The finding could be related to an elevation in temperatures within the infant's microenvironment.

Research paper thumbnail of The influence of a pacifier on infants' arousals from sleep

Journal of Pediatrics, 2000

Objective: The risk of sudden infant death during sleep was postulated to decrease with the use o... more Objective: The risk of sudden infant death during sleep was postulated to decrease with the use of a pacifier and by conditions facilitating arousals from sleep. We evaluated the influence of a pacifier on arousal from sleep in healthy infants.

Research paper thumbnail of Influence of Swaddling on Sleep and Arousal Characteristics of Healthy Infants

Objective. Swaddling is an old infant care practice. It was reported to favor sleep and to reduce... more Objective. Swaddling is an old infant care practice. It was reported to favor sleep and to reduce crying among irritable infants. There are few data on the physiologic effects of swaddling on infants' sleep-wake characteristics. This study was conducted to evaluate whether swaddling influences infants' arousal thresholds for environmental auditory stress.

Research paper thumbnail of Decreased Arousals in Infants Who Sleep With the Face Covered by Bedclothes

Pediatrics, 2002

Objective. The risk of becoming a victim of sudden infant death syndrome is increased in infants ... more Objective. The risk of becoming a victim of sudden infant death syndrome is increased in infants who sleep with their face under bedding items. The present study was designed to evaluate auditory arousal thresholds of infants who sleep with their face covered by bedclothes.

Research paper thumbnail of Clinical problems in relation to apparent life-threatening events in infants

Research paper thumbnail of Incomplete Arousal Processes in Infants Who Were Victims of Sudden Death

Infants who became victims of sudden infant death syndrome (SIDS) aroused less from sleep than co... more Infants who became victims of sudden infant death syndrome (SIDS) aroused less from sleep than control infants. This study was conducted to determine the characteristics of arousal from sleep of infants who eventually died of SIDS. Sixteen infants were monitored some days or weeks before they died of SIDS. Their polygraphic sleep recordings were compared with those of matched control infants. Arousals were scored as subcortical activation (incomplete arousals) or cortical arousal (complete arousals). Cortical arousals were significantly less frequent in the victims who would succumb to SIDS in the future than in the control infants during both REM and non-REM sleep (p ϭ 0.039). The frequency (p ϭ 0.017) and duration (p ϭ 0.005) of subcortical activation were significantly greater in the infants who died of SIDS than in the control infants during REM sleep. Compared with the control infants, the infants who later died of SIDS had more frequent subcortical activation in the first part of the night, between 9:00 P.M. and 12:00 A.M. (p ϭ 0.038), and fewer cortical arousals during the latter part of the night, between 3:00 and 6:00 A.M. (p ϭ 0.011). The present data are suggestive of incomplete arousal processes in infants who eventually died at a time they were presumed to have been asleep.

Research paper thumbnail of Reduced Arousals Following Obstructive Apneas in Infants Sleeping Prone

Pediatric Research, 2001

A decreased arousability and an increased risk for sudden infant death syndrome (SIDS) have been ... more A decreased arousability and an increased risk for sudden infant death syndrome (SIDS) have been shown in infants sleeping prone. Obstructive apnea, a known risk factor for SIDS, is less often terminated by an arousal reaction in infants than in adults. The effect of body position on the arousal reaction to spontaneous respiratory events had not been previously studied in infants. The aim of our study was to see if body position has an influence on the frequency and delay of the arousal reaction to obstructive apnea. All obstructive events recorded during two successive nights in 20 infants sleeping one night prone and one night supine were studied. During the supine recording 153 obstructive events were detected, and 217 were detected during the prone session. Prone sleep was not associated with an increased frequency of obstructive apneas. Total sleep time was 382 min (range, 283-456) supine and 423 min (range, 325-521) prone (p ϭ 0.003). Obstructive events duration was 6.5 s (range, 3-21.5) when sleeping supine and 8 s (range, 3.5-30.5) when prone (p ϭ 0.002). Behavioral arousal were found in 57.5% of obstructive events recorded supine and in 31.3% of those seen prone (p Ͻ 0.001). Arousal occurred after 8 s (range, 0 -21) from the start of the obstructions when supine and 10.5 s (range, 3.5-23.5) when prone (p ϭ 0.001). Sighs were found in 34% of supine obstructive events and in 44.7% of those prone (p ϭ 0.040). A reaction, i.e. arousal or sigh, was found in 91.5% of supine events and 76% of those prone (p Ͻ 0.001). We conclude that when sleeping supine, infants arouse to obstructive events more often and after shorter delay than when prone. (Pediatr Res 49: 402-406, 2001) Abbreviations SIDS, sudden infant death syndrome NREM, nonrapid eye movements REM, rapid eye movements RR, interval between two R waves ABSTRACT 402

Research paper thumbnail of Association between sleep apnea and reactive astrocytes in brainstems of victims of SIDS and in control infants

Forensic Science International, 2002

Among 27,000 infants studied prospectively to characterize their sleep-wake behavior, 38 infants ... more Among 27,000 infants studied prospectively to characterize their sleep-wake behavior, 38 infants died under 6 months of age; 27 infants died from sudden infant death syndrome (SIDS), 5 from congenital cardiac abnormalities, 2 from infected pulmonary dysplasia, 2 from septic shock with multi-organ failure, 1 with a prolonged seizure, and another with prolonged neonatal hypoxemia. The frequency and duration of sleep apneas recorded some 3-12 weeks prior to the infants' death were analyzed. Brainstem material was retrospectively collected from these 33 infants and studied in an attempt to elucidate the relationship between sleep apnea and hypoxic gliosis. The findings were compared between the SIDS victims and the control infants. Brainstem materials were immunohistochemically studied for quantitization of reactive astrocytes using an anti-glial fibrillary acidic protein (GFAP) antibody. The pathological materials were collected within 24h of death. This study focuses on the association between respiratory characteristics and pathology. Physiological and pathological data in the arousal pathway of the brainstem were linked for each infant and variant-covariant analyses were carried out using physiological data as dependent variables and pathological data and categorical data to evaluate the association with SIDS or non-SIDS as independent variables. The study failed to statistically support an association between hypoxic loads, reflected by the GFAP-positive reactive astrocytes in brainstems, the classification of being SIDS or non-SIDS infants, and the characteristics of sleep apnea.

Research paper thumbnail of Pacifier use modifies infant's cardiac autonomic controls during sleep

Early Human Development, 2004

Objective: The risk for sudden infant death (SIDS) was postulated to decrease with the use of a p... more Objective: The risk for sudden infant death (SIDS) was postulated to decrease with the use of a pacifier and by conditions increasing parasympathetic tonus during sleep. We evaluated the influence of a pacifier on cardiac autonomic controls in healthy infants. Study design: Thirty-four healthy infants were studied polygraphically during one night: 17 infants regularly used a pacifier during sleep and 17 never used a pacifier. Thumb users or occasional pacifier users were not included in the study. The infants were recorded at a median age of 10 weeks (range 6 -18 weeks). Autonomic nervous system (ANS) was evaluated by spectral analysis of the heart rate (HR). The high frequency component of HR spectral analysis reflected parasympathetic tonus and the low frequency on high frequency ratio corresponded to the sympathovagal balance. Results: Most infants (63.6%) lost their pacifier within 30 min of falling asleep. Sucking periods were associated with increases in cardiac sympathovagal balance. During non-sucking periods, in both REM and NREM sleep, infants using a pacifier were characterized by lower sympathetic activity and higher parasympathetic tonus compared with non-pacifier users. Conclusions: The use of pacifiers modifies cardiac autonomic controls during both sucking and non-sucking sleep periods. Non-nutritive sucking could regulate autonomic control in infants. These findings could be relevant to mechanisms implicated in the occurrence of sudden infant deaths during sleep.

Research paper thumbnail of Arousal deficiency theory in sudden infant death syndrome with reference to neuronal plasticity

Sleep Medicine, 2002

Objective: Among 27,000 infants studied prospectively to characterize their sleep-wake behavior, ... more Objective: Among 27,000 infants studied prospectively to characterize their sleep-wake behavior, 38 infants died under 6 months of age (including 26 infant victims of sudden infant death syndrome (SIDS), five with congenital cardiac abnormalities, two from infected pulmonary dysplasia, two from septic shock with multi-organ failure, one with a prolonged seizure, one from prolonged neonatal hypoxemia and one from meningitis and brain infarction).

Research paper thumbnail of Polysomnographic study of the autonomic nervous system in potential victims of sudden infant death syndrome

Clinical Autonomic Research, 1998

To determine the influence of sleep stages and night-time distribution on cardiac autonomic activ... more To determine the influence of sleep stages and night-time distribution on cardiac autonomic activity, the polysomnographic recordings of 18 victims of sudden infant death syndrome (SIDS) and of 36 control infants were studied. Autoregressive spectral analyses of heart rate (HR), using both short-term and whole-night methods, were evaluated as a function of sleep stages. The two main peaks of normalized LF and HF were computed during the night and the sympathovagal balance (LF/HF) was determined. In both NREM and REM sleep, SIDS infants were characterized by significantly lower normalized HF powers and higher LF/HF ratios. This finding was observed in both short-term and whole-night HR spectral analyses. In addition, SIDS victims were characterized by the presence of a high desynchronized peak of sympathetic tonus in the late hours of the night, a finding not seen in the control subjects. This report adds further indirect evidence for a possible sleep-related impairment of autonomic controls in some infants who died of SIDS.

Research paper thumbnail of Effects of body position on sleep and arousal characteristics in infants

Early Human Development, 2002

The prone sleeping position has been identified in world-wide epidemiological studies as a major ... more The prone sleeping position has been identified in world-wide epidemiological studies as a major risk factor for sudden infant death syndrome (SIDS). Public awareness campaigns throughout the western world have led to an over 50% reduction in postneonatal mortality and frequency of SIDS. This reduction in mortality has been mainly attributed to the avoidance of the prone sleep position. Various mechanisms have been postulated to explain the increased risk of SIDS associated with prone sleeping, among these, impairment of arousal from sleep. This paper reviews the effects of prone sleeping on infant sleep architecture, arousability from sleep and cardiorespiratory controls. Sleeping in the prone position has been shown to increase the amount of time spent sleeping, particularly time spent in quiet sleep (QS). Sleeping prone has also been demonstrated to be associated with a reduced responsiveness to a variety of arousal stimuli. Such impairment of arousal has been demonstrated to be associated with changes in control of autonomic cardiac function. During arousal, heart rate, blood pressure and breathing movements increase, while gross body movements occur to avoid the stimulus. Any impairment in arousability from sleep such as could occur when infants sleep in the prone position, could possibly contribute to the final pathway to SIDS. D

Research paper thumbnail of Influences of maternal cigarette smoking on infant arousability

Early Human Development, 2004

Since the reduction in the incidence of the prone sleeping position, maternal cigarette smoking h... more Since the reduction in the incidence of the prone sleeping position, maternal cigarette smoking has become the strongest modifiable risk factor for Sudden Infant Death Syndrome (SIDS). This risk is dose dependent. Various mechanisms have been postulated to explain the increased risk of SIDS associated with maternal smoking, among these, impairment of arousal from sleep. This paper reviews the effects of maternal smoking on infant arousability from sleep, cardiorespiratory controls and sleep architecture.

Research paper thumbnail of From physiology to pathology: arousal deficiency theory in sudden infant death syndrome (SIDS)—with reference to apoptosis and neuronal plasticity

Forensic Science International, 2002

Among 27,000 infants studied prospectively to characterize their sleep-wake behavior, 38 infants ... more Among 27,000 infants studied prospectively to characterize their sleep-wake behavior, 38 infants died under 6 months of age (including 26 infant victims of sudden infant death syndrome (SIDS), 5 with congenital cardiac abnormalities, 2 from infected pulmonary dysplasia, 2 from septic shock with multi-organ failure, 1 with a prolonged seizure, 1 from prolonged neonatal hypoxemia, 1 from meningitis and brain infarction). The frequency and duration of sleep apneas recorded some 3-12 weeks before the infants' death were analyzed. Brainstem material from these 38 infants was studied in an attempt to elucidate the relationship between sleep apnea and neuronal pathological changes in the arousal pathway. Immunohistochemical analyses included the evaluation of growth-associated phosphoprotein 43 (GAP43) as a marker for synaptic plasticity. The terminal-deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) method was used to identify apoptosis. The positive pathological reactions were quantitatively analyzed. The pathological and physiological data were linked for each infant. Akaike Information Criterion (AIC) statistics was calculated to elucidate the relationship between the physiological and the pathological data in the SIDS victims. The findings illustrated the possibility of an organic fragility within the arousal pathway, particularly in the midbrain periaqueductal gray matter, which is associated with the "visceral alerting response". This autonomic response occurs within an acetylcholine afferent system and pedunculopontine tegmental nucleus (PPTN). The finding is, in future SIDS infants, associated with repetitive sleep apnea.

Research paper thumbnail of Decreased Arousals in Infants Who Sleep With the Face Covered by Bedclothes

Objective. The risk of becoming a victim of sudden infant death syndrome is increased in infants ... more Objective. The risk of becoming a victim of sudden infant death syndrome is increased in infants who sleep with their face under bedding items. The present study was designed to evaluate auditory arousal thresholds of infants who sleep with their face covered by bedclothes.

Research paper thumbnail of Auditory arousal thresholds are higher when infants sleep in the prone position

Journal of Pediatrics, 1998

Research paper thumbnail of Sudden infant deaths: arousal as a survival mechanism

Sleep Medicine, 2002

The mechanisms responsible for sudden infant death syndrome (SIDS) are still largely unknown. To ... more The mechanisms responsible for sudden infant death syndrome (SIDS) are still largely unknown. To explain what factors contribute to the deaths, we suggest a model: the '3 S model for SIDS' that includes 'sicknesses', 'stages of development' and 'surroundings': (1) 'sicknesses' refers to infectious diseases or other medical condition.

Research paper thumbnail of Prenatal exposure to cigarette smoking is associated with a decrease in arousal in infants

Journal of Pediatrics, 1999

Objective: Sudden infant death syndrome has been related to both exposure to prenatal cigarette s... more Objective: Sudden infant death syndrome has been related to both exposure to prenatal cigarette smoke and impaired arousability from sleep. We evaluated whether healthy infants born to mothers who smoked during pregnancy had higher auditory arousal thresholds than those born to mothers who did not smoke and whether the effects of smoking occurred before birth.

Research paper thumbnail of Normal Sleep Architecture in Infants and Children

Journal of Clinical Neurophysiology, 1996

Because the collection of normative sleep data in the pediatric age group largely depends on tech... more Because the collection of normative sleep data in the pediatric age group largely depends on technical issues, this article discusses various aspects of sleep recordings in infants and children. Polygraphic monitoring of sleep and waking behavior contributes to a better description of maturational stages in children, from the prenatal period to the end of adolescence. This article reviews the general characteristics of normal children's sleep and the environmental factors that influence these maturational processes. The use of polygraphic recordings to identify neurological deficits and to predict behavioral and neurological outcome in infants and children, however, does not hold great promise. The importance of polysomnographic evaluation is admitted for some major clinical conditions, such as risks for abnormal breathing or narcoleptic attacks.

Research paper thumbnail of Sudden infant deaths: stress, arousal and SIDS

Early Human Development, 2003

The prevalence of the Sudden Infant Death Syndrome (SIDS) has dropped in most countries following... more The prevalence of the Sudden Infant Death Syndrome (SIDS) has dropped in most countries following the development of education campaigns on the avoidance of preventable risk factors for SIDS. These include factors in the infant's micro environment, such as prenatal passive smoking, administration of sedative drugs, prone sleep, high ambient temperature or sleeping with the face covered. Sleep laboratory studies have shown that these risk conditions contribute to the development of respiratory and autonomic disorders and reduce the child's arousability. The opposite effects were seen when studying factors protective from SIDS, such as breastfeeding or the use of a pacifier. In victims of SIDS, similar breathing, autonomic and arousal characteristics were recorded days or weeks before their death. It is concluded that in some infants, already immature control mechanisms can be aggravated by environmental factors. D

Research paper thumbnail of Cardiac autonomic characteristics in infants sleeping with their head covered by bedclothes

Journal of Sleep Research, 2003

The risk of Sudden Infant Death Syndrome is increased in infants sleeping with their head covered... more The risk of Sudden Infant Death Syndrome is increased in infants sleeping with their head covered by bedding items. This study was designed to evaluate cardiac autonomic nervous controls in infants sleeping with the head covered by bedclothes. Sixteen healthy infants with a median age of 12 weeks (range 9–13 weeks) were recorded polygraphically for one night. While they slept in their usual supine position, a bedsheet was placed over their head for about 45 min. All infants were challenged with the head covered and with the head free during both rapid eye movement (REM) and non-rapid eye movement (NREM) sleep. Sleep, breathing and heart rate (HR) characteristics were recorded simultaneously, together with rectal and pericephalic temperatures. In both head-free and head-covered conditions, autoregressive spectral analysis of HR was evaluated as a function of sleep stages. During the head-covered periods, parasympathetic tonus decreased and sympathetic activity increased in both REM and NREM sleep. Compared with the head-free periods, the head-covered sleep periods were characterized by greater rectal (P = 0.012) and pericephalic temperatures (P = 0.002). Covering the infant's head with a bedsheet was associated with significant changes in autonomic balance. The finding could be related to an elevation in temperatures within the infant's microenvironment.

Research paper thumbnail of The influence of a pacifier on infants' arousals from sleep

Journal of Pediatrics, 2000

Objective: The risk of sudden infant death during sleep was postulated to decrease with the use o... more Objective: The risk of sudden infant death during sleep was postulated to decrease with the use of a pacifier and by conditions facilitating arousals from sleep. We evaluated the influence of a pacifier on arousal from sleep in healthy infants.

Research paper thumbnail of Influence of Swaddling on Sleep and Arousal Characteristics of Healthy Infants

Objective. Swaddling is an old infant care practice. It was reported to favor sleep and to reduce... more Objective. Swaddling is an old infant care practice. It was reported to favor sleep and to reduce crying among irritable infants. There are few data on the physiologic effects of swaddling on infants' sleep-wake characteristics. This study was conducted to evaluate whether swaddling influences infants' arousal thresholds for environmental auditory stress.

Research paper thumbnail of Decreased Arousals in Infants Who Sleep With the Face Covered by Bedclothes

Pediatrics, 2002

Objective. The risk of becoming a victim of sudden infant death syndrome is increased in infants ... more Objective. The risk of becoming a victim of sudden infant death syndrome is increased in infants who sleep with their face under bedding items. The present study was designed to evaluate auditory arousal thresholds of infants who sleep with their face covered by bedclothes.

Research paper thumbnail of Clinical problems in relation to apparent life-threatening events in infants

Research paper thumbnail of Incomplete Arousal Processes in Infants Who Were Victims of Sudden Death

Infants who became victims of sudden infant death syndrome (SIDS) aroused less from sleep than co... more Infants who became victims of sudden infant death syndrome (SIDS) aroused less from sleep than control infants. This study was conducted to determine the characteristics of arousal from sleep of infants who eventually died of SIDS. Sixteen infants were monitored some days or weeks before they died of SIDS. Their polygraphic sleep recordings were compared with those of matched control infants. Arousals were scored as subcortical activation (incomplete arousals) or cortical arousal (complete arousals). Cortical arousals were significantly less frequent in the victims who would succumb to SIDS in the future than in the control infants during both REM and non-REM sleep (p ϭ 0.039). The frequency (p ϭ 0.017) and duration (p ϭ 0.005) of subcortical activation were significantly greater in the infants who died of SIDS than in the control infants during REM sleep. Compared with the control infants, the infants who later died of SIDS had more frequent subcortical activation in the first part of the night, between 9:00 P.M. and 12:00 A.M. (p ϭ 0.038), and fewer cortical arousals during the latter part of the night, between 3:00 and 6:00 A.M. (p ϭ 0.011). The present data are suggestive of incomplete arousal processes in infants who eventually died at a time they were presumed to have been asleep.