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Biomedical subjects

S S Mosko

Publications and source records attributed to S S Mosko.

At least 19 recordsLinked to original sources

Apnea and periodic breathing in bed-sharing and solitary sleeping infants.

Mother-infant bed sharing, compared with the solitary sleeping condition, has recently been associated with several physiological and behavioral effects. Because the physiological effects of bed sharing may also include respiratory changes, we compared the incidence of central and obstructive apneas and periodic breathing in bed-sharing and solitary sleeping infants. Twenty routinely bed-sharing mother-infant pairs and fifteen routinely solitary sleeping pairs slept for 3 nights in a sleep laboratory. After an initial adaptation night, each pair spent 1 night bed sharing and 1 night in solitary sleep in random order. Apnea and periodic breathing were scored from polysomnographic recordings. The frequency of central apnea was significantly increased on the bed-sharing night, compared with the solitary night, regardless of routine sleeping arrangement. There were significantly fewer obstructive apneas on the bed-sharing night than on the solitary night, but only in routinely solitary sleeping infants. In both groups, there was a significantly higher frequency of periodic breathing events on the bed-sharing night than on the solitary night. These findings demonstrate that the bed-sharing environment can have a significant impact on respiratory control in the infant. Evidence is also presented to suggest that routine bed sharing may result in subtle neurophysiological and/or developmental differences in infants.

Female↗

Bedsharing promotes breastfeeding.

OBJECTIVE: Because breastfeeding is thought to be protective against sudden infant death syndrome (SIDS), environmental or child care factors that promote breastfeeding might reduce infant vulnerability to SIDS. The effect of mother-infant bedsharing on nocturnal breastfeeding behavior was studied in 20 routinely bedsharing and 15 routinely solitary sleeping Latino mother-infant pairs when the infants were 3 to 4 months old. METHODOLOGY: All pairs were healthy and exclusively breastfeeding at night. The videotape portion of all-night laboratory polysomnographic studies was used for the analyses. For each pair, an adaptation night was followed by one night each of bedsharing and solitary sleeping. RESULTS: The most important finding is that when tested in their usual sleeping conditions, routinely bedsharing infants breastfed approximately three times longer during the night than infants who routinely slept separately: this reflected a two-fold increase in the number of breastfeeding episodes and 39% longer episodes. Breastfeeding was also facilitated on the bedsharing night relative to the solitary night within the routinely bedsharing group: the number and total duration of breastfeeding episodes were significantly larger on the bedsharing night. CONCLUSIONS: We suggest that, by increasing breastfeeding, bedsharing might be protective against SIDS, at least in some contexts. Furthermore, maternal reproductive physiology could be impacted because nursing frequency affects ovulation. This is the first study to directly measure nocturnal breastfeeding behavior in any cultural group.

Adult↗

Sleep and arousal, synchrony and independence, among mothers and infants sleeping apart and together (same bed): an experiment in evolutionary medicine.

Although solitary sleeping in infancy is a very recent custom, limited to Western industrialized societies, and most contemporary people practice parent-infant co-sleeping, virtually all laboratory research on sleep in human infants assumes that solitary infant sleep is the normal and desirable environment. We have used evolutionary and developmental data to challenge this view. We suggest that co-sleeping provides a sensory-rich environment which is the more appropriate environment in which to study infant sleep. In addition, two preliminary, in-laboratory, polygraphic investigations of mother-infant co-sleeping are reported in normal infants, within the peak age range for sudden infant death syndrome (SIDS). Five mother-infant pairs co-slept one night in the first study; in the second, three additional pairs slept separately for two nights and co-slept the third consecutive night. The results suggest that co-sleeping is associated with enhanced infant arousals and striking temporal overlap (synchronicity) in infant and maternal arousals, and that, possibly as a result, co-sleeping mothers and infants spend more time in the same sleep stage or awake condition. The implications of the hypothesis and preliminary results for research on the normal development of infant sleep and on SIDS are discussed.

Female↗

Morbidity cut-offs for sleep apnea and periodic leg movements in predicting subjective complaints in seniors.

Despite its widespread use, the validity of the 5/h morbidity cut-off for the Respiratory Disturbance Index (RDI) or the Movement Index (MI) in determining presence of sleep apnea (SA) or sleep-related periodic leg movements (PLMs), respectively, has not been determined for any aged population. One hundred community resident seniors 60 years of age or older underwent three consecutive nights of polysomnography and also completed conventional measures of subjective sleep-wake complaints (written sleep questionnaire, sleep log, sleep interview) and mood disturbances (Zung Self-Rating Depression and Anxiety Scales, Profile of Mood States, Beck Depression Inventory). Based on the 5/h cut-off, 34% had SA and 58% had PLMs. Despite this, the frequency of subjective sleep-wake and mood disturbance was low across methods of assessment. Groups formed by the 5/h cut-off for RDI or MI failed to differ significantly in responses on all subjective sleep-wake and mood measures. Higher cut-offs also were examined and proved weak or ineffective in predicting subjective sleep-wake and mood disturbance. Preliminary investigations suggested that alternative measures of severity of SA (means oxygen desaturation and means duration of apneas or hypopneas) may be better predictors of subjective disturbance than RDI in this population. These findings both (a) demonstrate that the polygraphically identified SA and PLMs which are widespread in seniors tend not to be manifested in self-reported sleep-wake or mood disturbance, and (b) illustrate the need for validated morbidity cut-offs for SA and PLMs.

Affect↗

Preliminary longitudinal assessment of sleep in the elderly.

This is a preliminary report of a longitudinal assessment of sleep architectural changes over time and rate of progression of sleep apnea (SA) and sleep-related periodic leg movements (PLMs) in the elderly. Multiple night polysomnograms were performed in 11 community resident seniors (8 women and 3 men, aged 60-72 years) and repeated 3 years (34-38 months) later. Subjects were selected who exhibited at most mild SA or PLMs at initial testing. The respiratory disturbance index (but not the movement index) showed a significant increase over 3 years. Sleep architecture did not change significantly except for an increase in frequency of stage changes that was not solely attributable to the increase in frequency of apneas/hypopneas. Together with other published longitudinal studies, these findings suggest that elderly individuals with at most mild SA or PLMs can expect no more than a mild increase in the frequency of apneas/hypopneas or PLMs over the course of a few years.

Aged↗

Sleep apnea and sleep-related periodic leg movements in community resident seniors.

The elderly have a high incidence of sleep complaints. A high incidence of sleep apnea (SA) and sleep-related periodic leg movements (PLMs) is also suspected. The relationship between the incidence and severity of SA and PLMs and sleep complaints has not, however, been determined in terms of symptomatology and physiologic abnormality. In a group of 46 community resident seniors (60 to 95 years old), the incidence of SA and PLMs was correlated with subjective sleep-wake complaints. Sixty-one percent of subjects had SA and/or PLMs. Apneas/hypopneas were associated with an average oxygen desaturation of less than 5% and an average change in heart rate of less than 10 beats per minute. While subjects with SA or PLMs had clear evidence of objective sleep disturbance, only one quarter of them admitted to any subjective sleep complaints or daytime sleepiness. Furthermore, severity of SA or PLMs failed to predict sleep-wake complaints, and vice versa. This study confirms that typically mild SA and PLMs are widespread in the elderly but tend not to be manifested in sleep-wake complaints and probably go untreated as a result. Further research is needed to determine any long-term medical significance.

Aged↗

Night-to-night variability in sleep apnea and sleep-related periodic leg movements in the elderly.

The amount of night-to-night variability in sleep apnea (SA) and sleep-related periodic leg movements (PLMs) is largely unknown but, despite this, clinical decisions are based on single-night studies in many clinical sleep laboratories. We examined variability in SA and PLMs over three nights in 46 community-resident seniors. No evidence was found for either a first-night effect or a directional trend across nights in either the Respiratory Disturbance Index (RDI) or the Movement Index (MI), despite a prominent first-night effect on pattern of sleep. Duration of apneas/hypopneas and degree of associated heart rate change and oxygen desaturation in subjects with SA and intermovement interval in subjects with PLMs also failed to show systematic change across nights. However, if a cut-off score of 5/h for RDI and MI was used, the classification recorded on the first night did differ from the classification given on at least one of the other nights in 43% of the subjects. The magnitude of fluctuation in RDI or MI from night to night was large enough in some subjects that, in a clinical situation, decisions based on one night would have been entirely different had the subject been studied on a different night. Night-to-night variability in RDI and MI within subjects also was associated with significant alterations in the sleep pattern. We conclude that caution should be taken in drawing conclusions from single-night studies, especially in individuals with relatively mild forms of SA and PLMs where nightly variations could easily place them above or below an arbitrary cut-off score.

Aged↗

Somatosensory and brainstem auditory evoked responses in sleep-related periodic leg movements.

The pathophysiological mechanisms of sleep-related periodic leg movements (sPLM) and restless legs syndrome are unknown. Evoked potentials have been demonstrated to be abnormal in a variety of episodic movement disorders. In the present study, mixed nerve somatosensory and brainstem auditory evoked responses were examined in patients with polysomnographically documented sPLM who also had restless legs. Normal lower extremity (posterior tibial nerve stimulation) and upper extremity (median nerve stimulation) somatosensory evoked responses were recorded in a group of 10 patients with documented sPLM. Brainstem auditory evoked responses also were normal. These findings do not provide any evidence for a primary afferent sensory disturbance and indirectly support a recently forwarded hypothesis that sPLM is a reflection of suppression of descending inhibitory influences on pyramidal tract function.

Adult↗

Nocturnal REM latency and sleep disturbance in narcolepsy.

A retrospective study of 92 narcoleptics was undertaken to investigate the significance of prolonged nocturnal REM latencies observed in approximately one in every five narcoleptics undergoing single all-night clinical polysomnograms in our laboratory. Clinical and laboratory findings were examined as a function of REM latency. Our findings emphasize a high incidence of other sleep disorders, particularly sleep-related periodic leg movements, in narcoleptics. Furthermore, sleep disturbance secondary to other sleep disorders, especially during the period of NREM sleep preceding the first REM episode, accounts in large part for prolonged REM latencies observed in some narcoleptics. This study also provides one of the most extensive compilations of clinical and laboratory findings in a large population of narcoleptics.

Adolescent↗

Middle latency auditory evoked potentials in sleep apneics during waking and as a function of arterial oxygen saturation during apneas.

In adults with obstructive sleep apnea middle latency auditory evoked responses were recorded as a function of apnea-related arterial oxygen desaturation both before sleep onset and during nocturnal sleep. In waking, wave Pa latency was normal in five of six subjects, and Pa amplitude was normal in all. During sleep apneas, wave Pa remained stable even during intervals of severe oxygen desaturation (e.g., 45-90% and 50-84% saturation in two subjects). Furthermore, wave Pa recorded immediately on awakening in the morning was unaltered compared with the response recorded just prior to sleep onset, despite a high frequency of nocturnal apneas in all subjects. These data indicate that repetitive nocturnal oxygen desaturation associated with severe obstructive sleep apnea syndrome has neither immediate nor cumulative measureable effects on the functioning of neurons that subserve the middle latency evoked response. These findings are discussed in relation to a possible cortical contribution to the middle latency response.

Adult↗

The 24-hour rhythm of core temperature in narcolepsy.

A circadian rhythm disturbance in narcolepsy has been postulated. To investigate this issue, the 24-h pattern of rectal temperature variation was monitored under entrained conditions in narcoleptics selected on the basis of documented sleep-onset REM episode(s). The 24-h temperature mesor of narcoleptics was elevated in comparison with control subjects. This is attributable to higher nocturnal temperatures, perhaps related to increased sleep disturbance. The actual recorded temperature minimum in narcoleptics appeared 1 h after sleep onset, independent of the occurrence of sleep-onset REM, compared with 4-5 h after sleep onset in control subjects. In contrast, the results of cosinor analyses indicated that the estimated temperature nadir is phase-advanced in those narcoleptics who exhibited sleep-onset REM during the 24-h temperature study compared with those without sleep-onset REM. An early nocturnal temperature minimum in narcolepsy is consistent with recent reports that the latency to the appearance of REM sleep in normals varies as a function of the phase of the circadian temperature rhythm when sleep onset occurs.

Adult↗

Sleep-stage-dependent Cheyne-Stokes respiration after cerebral infarct: a case study.

Polysomnographic studies of nocturnal sleep were performed on a 63-year-old women. Sleep-onset and sleep-maintenance insomnia dated back to a cerebral infarction at age 53, which resulted in bilateral cerebral injury. Two patterns of respiration were observed, and both were sleep-stage-dependent. Classic Cheyne-Stokes respiration predominated during slow-wave sleep and stages 1 and 2. REM sleep, in contrast, was associated almost exclusively with normal respiration. Recurrent brief arousals, temporally linked to the Cheyne-Stokes pattern of respiration, markedly disturbed sleep stages 1 and 2 and appeared related to the patient's subjective sleep complaints. During waking, REM, and NREM sleep, respiration is known to have different sensitivity to CNS and peripheral controls. The selective association of Cheyne-Stokes respiration with NREM sleep in this patient supports the view that anatomically separate CNS mechanisms regulate respiration in REM and NREM sleep.

Cerebral Infarction↗

Normal brain stem auditory evoked potentials recorded in sleep apneics during waking and as a function of arterial oxygen saturation during sleep.

Brain stem auditory evoked potentials (BAEPs) can be utilized as an index of neuronal dysfunction at the level of the brain stem. These waves are known to be independent of level of arousal. In the present study, BAEPs (waves I-V) to monaural click stimulation were recorded during daytime waking and as a function of arterial oxygen saturation during nocturnal sleep in 6 subjects with obstructive sleep apnea syndrome. Normal conduction times were recorded in all 6 subjects during daytime waking. In addition, BAEPs remained stable in every case during sleep-related apneas when averaged over intervals of arterial oxygen saturation as low as 45-70% in one subject. Our data indicate that (1) the repetitive oxygen desaturation experienced during sleep in apneics had neither acute nor chronic, measurable effects on neurons which subserve the BAEP, and (2) a brain stem abnormality involving the structures which subserve the BAEP does not underly obstructive sleep apnea.

Adolescent↗

Impaired sexual maturation associated with sleep apnea syndrome during puberty: a case study.

A 20-year-old hypogonadal man was discovered to have had obstructive sleep apnea syndrome--secondary to hypertrophied tonsils, adenoids, and uvula--spanning the years of puberty. All-night polysomnographic recordings and 24 hr measurements of plasma luteinizing hormone (LH) concentrations (sampling at 20 min intervals) were performed before and after combined tonsillectomy, adenoidectomy, and uvulectomy. Two weeks preoperatively, nocturnal sleep was markedly disturbed by 407 apneic episodes, and the patient was found to be hypogonadotropic. Daytime LH concentrations were in the low-normal range for an adult male, and concentrations fell dramatically during nocturnal sleep. This contrasts with both the sleep-related elevation of LH normally seen in puberty and the adult pattern, where no difference is observed in mean concentrations during waking and sleep. Two week and 6 month postoperative evaluations revealed complete alleviation of the sleep apnea syndrome and normalization of the 24 hr pattern of plasma LH, although LH values remained in the low-normal range. Plasma testosterone concentrations were in the low to low-normal range both pre- and postoperatively. No evidence of continued sexual development, beyond that achieved preoperatively, was observed 20 months after surgery, despite continued relief from apnea. These data suggest that sleep apnea during puberty may impair sexual development by preventing the sleep-related elevation in LH secretion normally observed during a critical period spanning puberty.

Adenoidectomy↗

Neonatal suprachiasmatic nucleus lesions: effects on the development of circadian rhythms in the rat.

Previous studies of the effects of suprachiasmatic nucleus (SCN) destruction and visual pathway transections in adult rodents have revealed the primary significance of the SCN and the retinohypothalamic (RH) projection in the generation and entrainment of circadian rhythms. In the present study we found that complete ablation of the SCN in 2-day-old rats, prior to its innervation by the RH projection, permanently eliminates circadian rhythms in spontaneous locomotor activity and drinking; activity and drinking appear randomly distributed over the light-dark cycle. In addition, females exhibit long periods of constant vaginal cornification and an absence of normal estrous cycles. These effects are independent of the animal's visual status; that is, they occur in blinded as well as sighted animals. Incomplete SCN lesions results in partial disruption of rhythmic functions such as damping of circadian rhythms in activity and/or drinking, irregular estrous cycling, and/or complete disruption of only one or two of these measures of rhythmicity. The absence of spared functions after early SCN destruction is consistent with the high degree of specificity for the SCN exhibited by developing RH fibers and further emphasizes the significance of the SCN in circadian rhythm generation. Neither morphological nor functional plasticity has been found following neonatal ablation of the SCN in the rat.

Animals↗

Neonatal ablation of the suprachiasmatic nucleus. Effects on the development of the pituitary-gonadal axis in the female rat.

Ablation of the suprachiasmatic nucleus (SCN) at 2 days of age, prior to the formation of the retinohypothalamic projection, produces a permanent state of constant vaginal estrus in the postpubertal female rat. Although such lesions do not alter the onset of puberty in sighted rats, they do compensate for the delay in vaginal opening induced by neonatal binding. The ovaries of sighted and blinded SCN-lesion rats are small and polyfollicular and the pituitaries of blinded SCN-lesion rats are abnormally large. Sampling of plasma in the morning and afternoon for up to 12 consecutive days in sighted SCN-lesion rats reveals continuously low luteinizing hormone levels. This constellation of endocrine alterations does not correlate with damage to any structures outside the SCN. Since the organization of the rodent estrous cycle is circadian, these results emphasize further the importance of the SCN in circadian rhythm generation. The necessity of an intact SCN for the development of normal, cyclic reproductive function implies that sparing or recovery of function does not occur.

Animals↗

Serotonergic afferents to the dorsal raphe nucleus: evdience from HRP and synaptosomal uptake studies.

Afferent connections of the serotonin (5-HT)-containing dorsal raphe nucleus were investigated in the rat utilizing the horseradish peroxidase (HRP) retrograde cell labeling technique. Small quantities (0.1-0.5 mul) of HRP solutions were infused into the dorsal raphe, and the brains were examined 19-72 h later for retrograde transport of the enzyme. Intrinsic connections within the dorsal raphe nucleus were revealed by this mapping technique, as was an input to the dorsal raphe from another serotonergic cell group, the median raphe nucleus. Little evidence was found for projections from other, more remote, brain sites. A serotonergic innervation of the dorsal raphe was also demonstrated by the presence of high affinity uptake of [3H]5-HT (Km=0.17 muM) into synaptosomal suspensions of the dorsal raphe nucleus. Synaptosomal uptake of [3H]5-HT was blocked by selective destruction of serotonergic axon terminals induced by the intraventricular injection of 200 mug of 5,7-dihydroxytryptamine following desipramine HCl pretreatment, but not by destruction of catecholaminergic axon terminals induced by intraventricularly injected 6-hydroxydopamine (2 X 250 mug). The uptake of [3H]-5-HT by synaptosomes of the dorsal raphe was comparable to that of striatal and hypothalamic synaptosomes, and markedly greater than that of synaptosomes from the cerebellum or nearby dorsal central gray or midbrain reticular formation, indicating the presence of a relatively dense serotonergic innervation. These data together indicate that neurons in the dorsal raphe nucleus receive a prominent serotonergic input that is derived, at least in part, from other neurons within the dorsal nucleus and from a neighboring raphe nucleus.

5,6-Dihydroxytryptamine↗