Distinctive polysomnographic traits in nocturnal frontal lobe epilepsy

Purpose: To describe the polysomnographic features and distribution of epileptic motor events, in relation to conventional sleep measures and cyclic alternating pattern (CAP) parameters, in 40 untreated patients with nocturnal frontal lobe epilepsy (NFLE). Methods: We analyzed the basal polysomnographic recordings of 40 patients (20 male and 20 female; mean age: 31 ± 10 years) with a diagnosis of nocturnal frontal lobe epilepsy. Conventional sleep measures and CAP parameters were assessed. Polysomnographic recordings were subdivided in sleep cycles. The distribution of the epileptic motor events (including minor motor events, paroxysmal arousals, tonic‐dystonic, or hyperkinetic seizures and epileptic nocturnal wandering) was analyzed throughout: total sleep time, non–rapid eye movement (NREM) and REM sleep, light sleep (S1 + S2), slow wave sleep (SWS), each sleep cycle, CAP or non‐CAP sleep, phase A and phase B of CAP. Only clear epileptic motor events supported by video–polysomnographic evidence were taken into consideration. Polysomnographic findings of patients with NFLE were compared with those of 24 age‐ and gender‐balanced healthy subjects without sleep complaints. Key Findings: Compared to controls, patients with NFLE showed a significant increase in wake after sleep onset, SWS duration, and REM latency, whereas REM sleep duration was significantly lower in NFLE patients. The patients with NFLE showed a significant increase of CAP time, CAP rate (72% vs. 32% in control group), CAP cycles, and mean duration of a CAP sequence. These findings were associated with a significant enhancement of all subtypes of the A phases of CAP (mainly subtype A1). A total of 139 epileptic motor events supported by video‐polysomnographic evidence were counted: 98% of all seizures occurred in NREM sleep and 72% of NREM seizures emerged from SWS, the latter being particularly collected in the first sleep cycles and decreasing in frequency together with the progressive decline of deep sleep. Ninety percent of total NREM seizures occurred during a CAP sequence, and CAP‐related seizures occurred in association with a phase A. Significance: Significant polysomnographic alterations seem to emerge in patients with NFLE (increased REM latency, epileptic fragmentation of SWS, and increase of CAP rate). The analysis of seizure distribution showed that most epileptic events occurred in SWS, with predominance in the first sleep cycle and decreasing in frequency together with the homeostatic decline of SWS across the night. Within the NREM sleep, CAP is a manifestation of unstable sleep and represents a powerful predisposing condition for the occurrence of nocturnal motor seizures, which arise in concomitance with a phase A.     

Concurrent occurrence of rapid eye movement with spindle burst during nocturnal sleep in mentally retarded children

Concurrence of REM and sleep spindle in 45 mentally retarded children (from 4 months to 8 years of age) was studied throughout nocturnal sleep, and the following results were obtained. (1) Twenty-five cases showed a single or burst of REMs during stage NREM with sleep spindles. (2) Twenty-nine cases showed sleep spindles at the beginning or toward the end of stage REM sleep. (3) No significant difference in DQ was found between the subjects with and without REMs during stage NREM sleep. The former subjects, however, had more normal clinical EEGs than the latter. (4) No significant difference in DQ or clinical EEG classification was revealed between the subjects with REMs during stage NREM sleep and those with spindles during stage REM sleep. (5) It was concluded that the concurrence of REM and sleep spindle during stage NREM is a useful sign for early diagnosis of mental retardation.     

Sleep polygraphy in Angelman syndrome.

OBJECTIVE: Sleep disturbances are frequent in Angelman syndrome (AS); however, beside the few studies which have investigated sleep disorders in AS by means of questionnaires, to our knowledge, no systematic polysomnographic recordings have been carried out in AS patients. The present study represents the first attempt to study sleep patterns of AS by polysomnography, to evaluate the influences of sleep on the paroxysmal electroencephalogram (EEG) patterns of AS and to assess the eventual age-related changes of sleep architecture and of sleep EEG abnormalities in children and adolescents with AS. METHODS: Fifteen children with AS (7 males and 8 females, mean age 7.2 years, range 3-16 years), attending the Sleep Center of the Department of Child Neurology and Psychiatry of the University of Rome 'La Sapienza' and the Sleep Research Centre of the Oasi Institute (IRCCS) of Troina were included and subdivided into two subgroups by age: subgroup 1, aged 3-5 years, and subgroup 2, aged 9-17 years. Two control groups of age-matched normal subjects were also included: one aged less than 8 years and another aged more than 8 years; additionally, two other groups of age-matched children with epilepsy and mental retardation of different origin, one aged less and one aged more than 9 years were taken into consideration. The statistical comparison between the sleep parameters obtained from the patients and those from the other groups was carried out by means of the non-parametric Kruskal-Wallis ANOVA and the Mann-Whitney U test. RESULTS: The most frequent EEG abnormality found in AS patients appeared to be the 2-3 c/s poorly defined spike/waves complexes. This pattern was influenced by sleep stages; the duration of the runs showed an increasing length with sleep deepening from sleep stage 1 to slow-wave sleep (SWS). Moreover, the 2-3 c/s bursts activity present in sleep stage 2 showed a slowing to 1-2 c/s during SWS. Regarding sleep architecture, in subjects with AS aged <8 year there was a significant reduction in sleep efficiency as compared to normal controls, while the percentage and duration of REM sleep was significantly lower and the percentage of SWS was significantly higher. REM sleep time was reduced in AS subjects aged >8 years than in normal controls. The comparison between AS groups and mental retardation with epilepsy groups did not show significant differences. CONCLUSIONS: Similarly to other types of genetically determined mental retardation syndromes, also subjects with AS seems to show important abnormalities of their sleep polysomnographic patterns. SIGNIFICANCE: This is the first study which reports, in detail, these abnormalities and opens a new path for further insight into the knowledge of additional sleep-related disturbances which are reported in sleep questionnaires by the caregivers of AS subjects.     

Sleep in children with autistic spectrum disorder: a questionnaire and polysomnographic study

OBJECTIVE: To evaluate sleep in children with autistic spectrum disorder (ASD) by means of sleep questionnaires and polysomnography; moreover, to analyze their cyclic alternating pattern (CAP). METHODS: Thirty-one patients with ASD (28 males, 3 females, aged 3.7-19 years) and age-matched normal controls were included. ASD children were evaluated by a standard sleep questionnaire that consisted of 45 items in a Likert-type scale covering several areas of sleep disorders and by overnight polysomnography in the sleep laboratory after one adaptation night. RESULTS: The questionnaire results showed that parents of ASD children reported a high prevalence of disorders of initiating and maintaining sleep, enuresis, repetitive behavior when falling asleep, and daytime sleepiness. Polysomnographically, ASD children showed reduced time in bed, total sleep time, sleep period time and rapid eye movement (REM) latency. ASD subjects had a CAP rate during slow-wave sleep (SWS) lower than normal controls, together with a lower percentage of A1 subtypes. CONCLUSIONS: ASD children questionnaires showed a higher percentage of disorders of initiating and maintaining sleep than normal controls; this was not completely confirmed by sleep staging. CAP measures showed subtle alterations of NREM sleep which could be detected with an appropriate methodology of analysis. The reduction of A1 subtypes during SWS might play a role in the impairment of cognitive functioning in these subjects.     

Aberrant neural function during emotion attribution in female subjects with fragile X syndrome

ObjectiveFragile X (FraX) syndrome is caused by mutations of the FraX mental retardation-1 gene—a gene responsible for producing FraX mental retardation protein. The neurocognitive phenotype associated with FraX in female subjects includes increased risk for emotional disorders including social anxiety, depression, and attention deficit. Here, the authors investigated the neurobiological systems underlying emotion attribution in female subjects with FraX syndrome.MethodWhile undergoing functional magnetic resonance imaging, 10 high-functioning female subjects with FraX syndrome and 10 typically developing (TD) female subjects were presented with photographs of happy, sad, and neutral faces and instructed to determine the facial emotion.ResultsNo significant group differences were found for the recognition of happy faces, although the FraX group showed a trend toward a significant difference for the recognition of sad faces and significantly poorer recognition of neutral faces. Controlling for between-group differences in IQ and performance accuracy, the TD group had greater activation than the FraX group in the anterior cingulate cortex (ACC) for neutral faces compared with scrambled faces and the caudate for sad faces compared with scrambled faces (but not for sad faces compared with neutral faces). In the FraX group, FraX mental retardation protein levels positively correlated with activation in the dorsal ACC for neutral, happy, and sad faces when independently compared with scrambled faces. Significantly greater negative correlation between IQ and insula activation for neutral faces relative to scrambled faces was observed in the FraX group compared with the TD group. Significantly greater positive correlation between IQ and ACC activation for neutral faces relative to scrambled faces was observed in the TD group compared with the FraX group.ConclusionsAlthough emotion recognition is generally spared in FraX syndrome, the emotion circuit (i.e., ACC, caudate, insula) that modulates emotional responses to facial stimuli may be disrupted. J. Am. Acad. Child Adolesc. Psychiatry, 2008;47(12):1443-1454.     

Sleep cycling alternating pattern (CAP) expression is associated with hypersomnia and GH secretory pattern in Prader-Willi syndrome

BACKGROUND AND PURPOSE: Hypersomnia, sleep-disordered breathing and narcoleptic traits such as rapid eye movement (REM) sleep onset periods (SOREMPs) have been reported in Prader-Willi syndrome (PWS). In a group of young adult patients with genetically confirmed PWS we evaluated sleep and breathing polysomnographically, including cycling alternating pattern (CAP), and we analyzed the potential interacting role of sleep variables, sleep-related breathing abnormalities, hypersomnia, severity of illness variables and growth hormone (GH) secretory pattern. PATIENTS AND METHODS: Eleven males and 7 females (mean age: 27.5+/-5.5 years) were submitted to a full night of complete polysomnography and the multiple sleep latency test (MSLT). GH secretory pattern was evaluated by a standard GH-releasing hormone plus arginine test. Sixteen non-obese healthy subjects without sleep disturbances were recruited as controls. RESULTS: Compared to controls PWS patients showed reduced mean MSLT score (P<0.001), reduced mean latency of sleep (P=0.03), increased REM sleep periods (P=0.01), and increased mean CAP rate/non-rapid eye movement (NREM) (P<0.001). Only four PWS patients had apnea/hypopnea index (AHI)>or=10. Conversely, significant nocturnal oxygen desaturation was frequent (83% of patients) and independent from apneas or hypopneas. In the PWS group, CAP rate/NREM showed a significant negative correlation with MSLT score (P=0.02) independently from arousals, respiratory disturbance variables, severity of illness measured by Holm's score or body mass index (BMI). PWS patients with CAP expression characterized by higher proportion of A1 subtypes presented less severe GH deficiency (P=0.01). CONCLUSIONS: Our study suggests a relationship between hypersomnia and CAP rate, and between CAP expression and GH secretory pattern in PWS, possibly reflecting underlying central dysfunctions.     

Reduced NREM sleep instability in benign childhood epilepsy with centro-temporal spikes

ObjectiveTo analyze sleep architecture and NREM sleep instability by means of the cyclic alternating pattern (CAP) in children with benign epilepsy with rolandic spikes (BERS).MethodsTen children with BERS, drug free at the time of the study and 10 age-matched normal controls were included in this study. Sleep was visually scored for sleep architecture and CAP using standard criteria.ResultsSleep architecture in BERS showed only few significant differences vs. controls with a reduction of total sleep time, sleep efficiency, and REM sleep percentage. CAP analysis revealed several significant differences: reduced total CAP rate, mainly in sleep stage 2, and reduced EEG slow oscillations and arousals during stages N1 and N2.ConclusionsSleep architecture is not importantly affected in BERS but CAP analysis reveals a decrease of NREM instability, mainly in sleep stage 2. Since there is a spindle-related spike activation in BERS, we speculate that the decrease of CAP and of EEG slow oscillations and arousals might be linked with the inhibitory action of spindling activity and spikes on arousals.SignificanceCAP analysis discloses sleep structure abnormalities in children with BERS not shown by the classical sleep scoring. Spike activity and CAP A1 subtypes seem to be mutually exclusive probably because centro-temporal spikes disturb the physiological synchronization mechanisms needed for the generation of slow-wave components of CAP.     

Sleep in Lennox-Gastaut syndrome: the role of the cyclic alternating pattern (CAP) in the gate control of clinical seizures and generalized polyspikes

Non-rapid eye movement (NREM) sleep contains periods of arousal instability (cyclic alternating pattern or CAP) and periods of arousal stability (non-CAP). During CAP, arousal oscillates between higher (phase A) and lower (phase B) levels of activation. We evaluated the relationship between CAP and the occurrence of epileptic events, i.e. clinical seizures and generalized interictal discharges, during sleep in 10 patients with Lennox-Gastaut syndrome (LGS). The macro- and microstructure of sleep of 10 attended overnight polysomnograms were analyzed. Compared with 10 age- and gender-matched controls, patients with LGS had significantly less stage 2 and REM sleep and higher amounts of CAP rate (68% vs. 33%; P<0.0001). The number of generalized polyspike bursts per hour of sleep was highest in slow wave sleep (226.5+/-57.6) and lowest in REM sleep (3.9+/-1.5). The polyspike burst frequency was significantly greater (P<0.017) during CAP (213.2+/-60.1) than during non-CAP (100.3+/-40), and within CAP, generalized polyspikes occurred more often (P=0.005) during phase A (461.1+/-127.2) than during phase B (6.1+/-1.9). The total amount of generalized polyspike bursts identified in NREM sleep correlated positively both with the number of A phases containing at least one generalized polyspike (P=0.005) and with the mean number of polyspikes within each of these A phases (P<0.0001). Nocturnal clinical seizures occurred in 8 of the 10 patients and showed a similar trend. We conclude from our results that CAP modulates the occurrence of both clinical seizures and generalized epileptic discharges in LGS by means of a gate-control mechanism: an independent spike generator is inhibited in phase B and non-CAP and bursts with its intrinsic activity in phase A.     

NREM sleep instability changes following rapid maxillary expansion in children with obstructive apnea sleep syndrome

ObjectiveTo evaluate NREM sleep microstructure in children with obstructive sleep apnea syndrome (OSAS) before and after one year of rapid maxillary expander (RME) treatment by means of the cyclic alternating pattern (CAP).MethodsNine children with OSAS aged 4–8 years (6 males, mean age 6.4 ± 1.97 years) and age-matched normal controls were included. All subjects underwent an overnight polysomnography in the sleep laboratory after one adaptation night, as a baseline evaluation; children with OSAS were recorded again after one year of RME treatment.ResultsAfter one year of treatment the OSAS group showed a longer duration of time in bed and sleep period time, a reduction in number of stage shifts compared to baseline recordings, and the apnea–hypopnea index decreased significantly. At baseline, the OSAS group had a higher CAP rate during slow-wave sleep and an increased A2 index compared to normal controls. After one year of RME application, children with OSAS showed an increase in CAP rate associated with an increase of A1 index during slow-wave sleep.ConclusionsRME treatment almost normalized sleep architecture and improved sleep respiratory disturbances; however, sleep microstructure and respiratory parameters did not completely recover. The persistence of increased CAP rate in slow-wave sleep associated with an increase of A1 index might reflect a partial failure of orthodontic treatment. On the other hand, the rebound of A1 subtypes might be an indirect sign of an attempt to normalize sleep that has been disturbed by the respiratory events.     

Overnight polygraphic study of Lennox-Gastaut syndrome

Nine children with Lennox-Gastaut syndrome, aged 2-14 years, were studied by overnight polygraphy for one night. Percentage of sleep period time (SPT) for stage rapid eye movement (REM) and REM density during REM sleep decreased in Lennox-Gastaut syndrome as compared with control. Alpha rhythm was seen in only 3 cases and sleep spindles in only 6 cases. The effect of sleep-wake or REM-non-REM (NREM) sleep rhythm on the rate of generalized epileptiform discharges varied with the individual. Ictal discharges with or without clinical tonic seizures observed in 5 children appeared during NREM sleep and awakening in the morning, and in 2 of these cases they also occurred frequently during the NREM sleep of the first sleep cycle. Subclinical ictal discharges were also seen during REM sleep in the early morning in one case who was 2 years old. The Lennox-Gastaut syndrome is assumed to involved a considerable degree of brain stem dysfunction.     

Cyclic alternating pattern (CAP) alterations in narcolepsy

BACKGROUND AND PURPOSE: Narcolepsy is a sleep disorder with clinical symptoms attributed to a reduced activation of the arousal system. Cyclic alternating pattern (CAP) is the expression of rhythmic arousability during non-rapid eye movement (NREM) sleep. CAP parameters, arousals and conventional sleep measures were studied in narcoleptic patients with cataplexy. PATIENTS AND METHODS: Data were collected from all-night polysomnographic (PSG) recordings and the multiple sleep latency test (MSLT) on the intervening day of 25 drug-naive patients (10 males and 15 females; mean age: 34+/-16 years) after adaptation and exclusion of other sleep disorders. A group of 25 age- and gender-matched normal sleepers were selected as controls. Each PSG recording was subdivided into sleep cycles. Analysis of CAP included classification of A phases into subtypes A1, A2, and A3. RESULTS: There was an increase in sleep period time mainly due to an increased wake time after sleep onset. REM latency was sharply reduced. The percentage of NREM sleep was slightly reduced and the balance between light sleep (S1+S2) and deep sleep (S3+S4) showed a curtailment of the former, while deep sleep was slightly increased. Excluding sleep cycles with sleep onset REM periods (SOREMPs), the duration of ordered sleep cycles was not different between narcoleptics and controls. The two groups showed similar values of arousal index, while CAP time, CAP rate, number of CAP cycles and of phase A subtypes (in particular subtypes A1) were significantly reduced in narcoleptic patients. CONCLUSIONS: The reduced periods of CAP in narcoleptic NREM sleep could be the electroencephalographic (EEG) expression of a generally reduced arousability or an increased strength of sleep-promoting forces in the balance between sleep and arousal systems. This can explain some of the clinical correlates of the disorder, i.e. excessive sleepiness, short sleep latency and impaired attentive performances, even without any sign of arousal-induced sleep fragmentation.     

Sleep in children with autistic spectrum disorder: A questionnaire and polysomnographic study

ObjectiveTo evaluate sleep in children with autistic spectrum disorder (ASD) by means of sleep questionnaires and polysomnography; moreover, to analyze their cyclic alternating pattern (CAP).MethodsThirty-one patients with ASD (28 males, 3 females, aged 3.7–19 years) and age-matched normal controls were included. ASD children were evaluated by a standard sleep questionnaire that consisted of 45 items in a Likert-type scale covering several areas of sleep disorders and by overnight polysomnography in the sleep laboratory after one adaptation night.ResultsThe questionnaire results showed that parents of ASD children reported a high prevalence of disorders of initiating and maintaining sleep, enuresis, repetitive behavior when falling asleep, and daytime sleepiness. Polysomnographically, ASD children showed reduced time in bed, total sleep time, sleep period time and rapid eye movement (REM) latency. ASD subjects had a CAP rate during slow-wave sleep (SWS) lower than normal controls, together with a lower percentage of A1 subtypes.ConclusionsASD children questionnaires showed a higher percentage of disorders of initiating and maintaining sleep than normal controls; this was not completely confirmed by sleep staging. CAP measures showed subtle alterations of NREM sleep which could be detected with an appropriate methodology of analysis. The reduction of A1 subtypes during SWS might play a role in the impairment of cognitive functioning in these subjects.     

Non-REM sleep instability in patients with major depressive disorder: subjective improvement and improvement of non-REM sleep instability with treatment (Agomelatine)

OBJECTIVE: To assess the importance of non-rapid eye movement (NREM) sleep disturbance in major depressive disorder (MDD) patients using cyclic alternating pattern (CAP) analysis, and to determine the usefulness of CAP analysis in evaluating treatment effect. METHODS: Baseline sleep-staging data and CAP analysis of NREM sleep was compared in 15 MDD patients (Hamilton depression scale score>20) and normal controls. Longitudinal evaluation of sleep changes using similar analysis during a treatment trial was also performed. ANALYSIS: A single-blinded researcher scored and analyzed the sleep of MDD and age-matched normal controls at baseline and during a treatment trial using the international scoring system as well as CAP analysis. RESULTS: MDD patients had evidence of disturbed sleep with both analyses, but CAP analysis revealed more important changes in NREM sleep of MDD patients at baseline than did conventional sleep staging. There was a significant decrease in CAP rate, time, and cycle and disturbances of phase A subtype of CAP. NREM abnormalities, observed by CAP analysis, during the treatment trial paralleled subjective responses. Analysis of subtype A phase of CAP demonstrated better sleep improvement. CONCLUSION: CAP analysis demonstrated the presence of more important NREM sleep disturbances in MDD patients than did conventional sleep staging, suggesting the involvement of slow wave sleep (SWS) in the sleep impairment of MDD patients. Improvement of NREM sleep paralleled subjective mood improvement and preceded REM sleep improvement. CAP analysis allowed objective investigation of the effect of treatment on sleep disturbances.     

Sleep in the Down syndrome

Polysomnographic recordings were obtained for 10 Down syndrome (DS) children (6 males and 4 females, 9 months to 7 years old) and 16 age-matched normal controls. The present study was conducted to study the sleep characteristics of DS patients of this age group. The percentage of each sleep stage, rapid eye movements (REMs)/min, time intervals between REMs(I)/min, times of awakening in the middle of sleep, body movements (BMs) and twitch movements (TMs) were studied. I/min was divided into three frequencies: I less than 1 sec, l less than or equal to I less than 2 sec and I greater than or equal to 2 sec. Two of the 10 patients showed an increase in the percentage of REM sleep. In the group aged 1 to 5 years old, the REMs/min and I/min (I less than 1 sec) values were higher than those in normal controls (p less than 0.05). Many times of awakening in the middle of sleep (greater than or equal to 5 times and/or greater than or equal to 60 min) were observed in 4 cases. The frequency of BMs in total sleep was higher than that in controls (p less than 0.01). Five of the 10 cases showed an abnormal pattern as to the frequency of BMs during each sleep stage. The frequency of TMs was less than that in controls (total sleep and stage 1, p less than 0.05; stage REM, p less than 0.01). Seven of 9 cases showed an abnormal pattern as to the frequency of TMs during each sleep stage.(ABSTRACT TRUNCATED AT 250 WORDS)     

Phonotactic patterns in the speech of children with Down syndrome

Phonotactic patterns of seven 11-15-year-old Kannada speaking children with Down syndrome (DS), mental age matched children with mental retardation (MR) without DS and six 4-5-year-old typically developing (TD) children were investigated. Conversational speech analyses and target analyses of conversational speech were carried out in all three groups of participants. Imitated speech samples from both groups of children with disorders were also analysed with respect to phonotactic patterns. Both conversational and imitated speech analyses revealed that children with DS showed a higher percentage of occurrences of simpler phonotactic patterns than the later acquired complex ones. Target analyses revealed certain similarities in all three groups indicating that while persons with Down syndrome attempted certain complex phonotactic shapes, errors such as consonant deletions, syllable deletions and cluster reductions led to the use of simpler phonotactic patterns. Based on these analyses, the study explores the possible presence of Childhood Apraxia of Speech (CAS) in children with DS and stresses the importance of assessing phonotactic deficits in these children.     

The cyclic alternating pattern sequences in the dynamic organization of sleep

The cyclic alternating pattern (CAP) is a physiological component of normal NREM sleep, functionally correlated with long-lasting arousal oscillations. This EEG periodic activity, organized in sequences of two or more decasecond cycles, is detectable also in coma and in other neurologic disorders, appearing as a general modality of arousal organization. Within NREM sleep, the fluctuations of CAP alternate with sustained homogeneous EEG patterns, characterized by a greater stability of arousal and called non-CAP (NCAP). In 20 sleep records of 10 healthy young adults we analysed the chronological relationship between CAP and 3 fundamental states of arousal: wakefulness, NREM sleep, REM sleep. Sleep onset and sleep recoveries after nocturnal awakenings were closely linked to CAP sequences, indicating a functional linkage between cyclic fluctuations of arousal and the beginning of any sleep behavioural state. On the basis of their temporal relationship with CAP sequences, the waking to sleep and the waking transitions appeared a symmetrical events in the organization of arousal, whereas the NREM to REM transitions and the REM to NREM transitions occurred as asymmetrical events. Moreover, almost 50% of all NREM stage changes were accompanied by CAP sequences. The EEG and dynamic features of CAP sequences show morphological and behavioural analogies with some phasic phenomena (i.e., phase d'activation transitoire or micro-arousals) and EEG patterns reported in the literature (e.g., tracé alternant; phase transitionnelles; tracé intermittent). Our data suggest a functional correlation between the control mechanisms of CAP and the organization of sleep.     

Nocturnal dipping of heart rate is impaired in children with Down syndrome and sleep disordered breathing

BackgroundChildren with Down syndrome (DS) are at increased risk for sleep disordered breathing (SDB), which can have adverse effects on the cardiovascular system. In adults with SDB, nocturnal dipping of heart rate (HR) and blood pressure (BP) is reduced, and this is associated with an increased risk of future cardiovascular events. We aimed to compare nocturnal dipping of HR and pulse transit time (PTT) (a surrogate inverse measure of BP change) in children with DS and SDB to those of typically developing (TD) children with and without SDB.Methods19 children with DS (3–18 years) were age and sex matched with 19 TD children without SDB (TD-) and with 19 TD children with matched severity of SDB (TD+). Nocturnal dipping was assessed as the percentage change in HR and PTT from wake before sleep onset to total sleep, N2, N3 and REM sleep across the night and to the first cycle of sleep.ResultsChildren with DS exhibited reduced nocturnal dipping of HR during total sleep, N2, N3 and REM sleep and increased PTT (reduced BP dipping) in N2 sleep. Fewer children with DS exhibited a greater than 10% fall in HR between wake and N2 or REM sleep compared to TD+ children.ConclusionsOur findings demonstrate significantly reduced nocturnal dipping of HR in children with DS compared to TD children matched for SDB severity, suggesting SDB has a greater cardiovascular effect in these children. Further studies are required to fully understand the mechanisms involved and to assess if treatment of SDB improves nocturnal dipping.     

Phonotactic patterns in the speech of children with Down syndrome

Phonotactic patterns of seven 11–15‐year‐old Kannada speaking children with Down syndrome (DS), mental age matched children with mental retardation (MR) without DS and six 4–5‐year‐old typically developing (TD) children were investigated. Conversational speech analyses and target analyses of conversational speech were carried out in all three groups of participants. Imitated speech samples from both groups of children with disorders were also analysed with respect to phonotactic patterns. Both conversational and imitated speech analyses revealed that children with DS showed a higher percentage of occurrences of simpler phonotactic patterns than the later acquired complex ones. Target analyses revealed certain similarities in all three groups indicating that while persons with Down syndrome attempted certain complex phonotactic shapes, errors such as consonant deletions, syllable deletions and cluster reductions led to the use of simpler phonotactic patterns. Based on these analyses, the study explores the possible presence of Childhood Apraxia of Speech (CAS) in children with DS and stresses the importance of assessing phonotactic deficits in these children.     

Polysomnographic assessment of sleep disturbances in children with developmental disabilities and seizures

The aim of this study was to assess the presence of sleep breathing disorder and periodic leg movements during sleep (PLMS), and to evaluate NREM sleep instability in a group of children with mental retardation (MR) and epilepsy. Eleven subjects with MR and epilepsy (6 males, age range 9–17 years) were recruited for this study. A control group was formed by 11 age-matched normal children. Three children with MR and epilepsy showed an apnea–hypopnea index > 5, two of them had also a PLMS index > 5. Another subject had only a PLMS index > 5. Children with MR showed many sleep architecture differences compared to controls. They also showed higher cyclic alternating pattern (CAP) rate, increased A1 index, long and less numerous CAP sequences than controls. A detailed investigation and treatment of sleep disorders in children affected by MR and epilepsy may have a positive impact on seizure control.     

Polysomnographic phenotypes in developmental disabilities.

People with developmental disabilities express a number of unique behavioral patterns that have both phylogenetic and ontogenetic origins. Researchers have identified distinct behavioral phenotypes among developmental disabilities expressed as language development, cognitive profiles, adaptive behavior, and self-injury/aggression. In this article, we discuss evidence for the presence of polysomnographic phenotypes in developmental disabilities. Researchers using behavioral and/or electrophysiological measures have identified differences in sleep architecture among people with autism, Down syndrome, and fragile X syndrome. In general, the greater the level of mental retardation, the less time spent in rapid eye movement sleep. The presence of autism or Down syndrome is associated with fewer and briefer bouts of rapid eye movement sleep, and total sleep time. Autism is also associated with greater levels of undifferentiated sleep. These findings for autism and Down syndrome contrast with fragile X syndrome whose sleep architecture anomalies appear to be a function of mental retardation level.