Published accounts of RBD have dwelt almost exclusively on adults with this disorder. However, the admittedly limited literature about younger patients serves to emphasize the importance of knowing that the condition can occur in children and adolescents.
It also raises further challenges about its recognition, underlying pathology and pathophysiology, and also appropriate treatment strategies in young patients, although much of what has already been outlined previously mainly about adults with RBD applies (or might well apply) at an earlier age.
That said, the published accounts of RBD in children and adolescents require close scrutiny. The patients described consist of a miscellany of ages and associated conditions. In addition, they are best separated into those reported to have both clinical and PSG features of RBD (the ‘clinical’ group) and others described as having ‘subclinical’ RBD in the sense that, at the time of assessment, they displayed only the PSG features of loss of REM atonia.
Inevitably, assessing the clinical aspects (especially subjective reports of dream content) can pose problems in children with impaired ability to communicate because they are young or limited in other ways. In such circumstances reliance has to be placed on inferences from the child’s behaviour at the time of the dreaming episode.
Treatment is either not mentioned in some reports or given at unspecified dosages; neither is the patient’s sex always stated. Considering that some associated disorders need treatment in their own right, further reports would be improved by a discussion of wider aspects of care.
As implied earlier, it cannot be assumed that the subclinical group will necessarily develop clinical RBD eventually. One of the drawbacks of the present literature is the very little long-term follow-up information it contains. This also makes it difficult to know how many of the young ‘idiopathic’ cases eventually declared some underlying definitive disorder, including the types described in many adults with RBD.
The first report of this type concerned an 8-year-old female with an infiltrating tumour of the pons.13 In addition to cerebellar and other neurological signs, she exhibited agitated periods at night and mouth movements, as well as sleep talking and laughter accompanied by bursts of REM sleep. PSG findings demonstrated loss of REM atonia.
A few years later, a 10-year-old female was described who developed severe sleep disturbance after the removal of a midline cerebellar astrocytoma.14 Her complex sleep disturbance included excessive restlessness (including smooth and jerky movements, complicated stereotyped behaviours such as hand waving, reaching out or fumbling movements and body turning), falling out of bed (often during a dream), and an increase in vivid dreaming. The movements tended to begin about 2 hours after onset of sleep, becoming more pronounced afterwards. PSG findings showed intermittent loss of REM atonia accompanying some of these behaviours and frequent aperiodic limb movements in both REM and non-REM sleep. Interestingly, the female’s healthy 8-year-old brother showed similar aperiodic movements during both types of sleep but no comparable clinical sleep disturbance.
Shortly afterwards, a brief report was published about an 18-month-old male with hereditary quivering chin syndrome or hereditary essential chin myoclonus (a dominantly inherited condition, thought to involve dysfunction of the pontine reticular formation), frequent tongue-biting during sleep, prolonged screaming, crying, and stiffness at night without alteration of consciousness, and periods of restlessness and ‘disorganized behaviour’, followed by awakenings.15 Prolonged electroencephalographic (EEG) monitoring revealed no evidence of seizure activity, but PSG findings demonstrated a loss of REM atonia associated with vigorous body movements. Clonazepam is said to have improved the child’s sleep disturbance but not the tongue-biting.
The same group then described yet another case of this rare condition of hereditary quivering chin syndrome.16 This male, almost 2 years old, had severely lacerated his tongue repeatedly but was also described by his parents as having ‘violent jerking, agitated crawling, and loud vocalizations’ during sleep. PSG recordings showed a loss of REM atonia. Complex behaviour, including crawling and vocalizations, occurred during REM sleep. Again, the recordings provided no evidence of epilepsy. In this case, 0.5mg of clonazepam suppressed both the abnormal behaviour and the tongue-biting.
The brainstem location of the lesions (or the putative location in the last two cases) is in keeping with the site of the nuclei particularly implicated in the pathophysiology of RBD.3 Different mechanisms (as yet ill-defined) must be involved in the remaining cases.
A 16-year-old male was diagnosed as having narcolepsy (primarily a disorder of REM sleep) in view of daytime hypersomnolence and multiple sleep latency test results characteristic of this condition.17 Nocturnal PSG findings included excessive electromyographic (EMG) twitching during REM sleep. During one REM period during the multiple sleep latency test, the patient threw his arms up in front of his face and, on waking up, said that he had been having an ‘action packed dream’. The limited EEG coverage during the multiple sleep latency tests showed no evidence of epileptic activity. The combined clinical features and PSG findings were considered to be compatible with RBD.
In a further report about narcolepsy, of 10 patients meeting strict criteria for this condition and also for RBD, three were aged 12, 17, and 19 years.18 All three were males. Chance association between the two disorders was considered statistically unlikely. The report does not make a clear distinction between the adults and other patients in the series. General reference is made to the RBD behaviours including running, wrestling or clawing movements in sleep (sometimes causing injury), kicking, elbowing, arm waving, or talking and arguing during sleep. These and other behaviours were thought to represent dream enactments. It was felt that treatment of the cataplexy component of the narcolepsy syndrome with clomipramine could have induced or promoted RBD in three patients. Treatment of the RBD was not reported.
A recent report19 described two females aged 7 and 9 years in whom narcolepsy of recent onset was diagnosed on the basis of detailed assessment, apparently accompanied by RBD. In other respects, both children were neurologically normal. The two conditions seem to have developed at about the same time. Long-term follow-up information was not available at the time of reporting.
Nightmares and restless sleep with frequent nocturnal awakenings were described in the 7-year-old female, together with PSG features of loss of REM atonia, sometimes accompanied by sleep talking and ‘complex movements’. In addition, arousals from deep non-REM sleep with disorientation were observed. A diagnosis of parasomnia overlap disorder was made and treatment with modafinil (150mg) and clonazepam (0.5mg in the evening) was introduced, the effect of which was not stated.
The 9-year-old female was reported to have had restless nocturnal sleep with ‘harmful’ behaviour, aggressively attacking her sister and kicking and striking the wall, together with sleep talking. Again, PSG findings compatible with RBD were found, associated with ‘gross extremity movements’. At the time of reporting, her narcolepsy symptoms were partly controlled with a combination of modafinil (200mg) and sodium oxybate (2g), and the RBD was being treated with an evening dose of clonazepam (0.5mg).
RBD has been linked with juvenile Parkinson’s disease.20 A 16-year-old female began to show signs of idiopathic Parkinson’s disease and also excessive daytime sleepiness, which on investigation was considered to be somehow related to her parkinsonism rather than other causes such as narcolepsy. Regularly, her behaviour at night was disturbed. She would talk in her sleep and flail her limbs as if enacting a dream, in the process frequently striking nearby objects and injuring herself. On waking she described vivid movement-laden dreams. PSG findings demonstrated EMG findings compatible with RBD. To a smaller extent, the same type of EMG findings were seen in the patient’s healthy monozygotic twin.
A particularly intriguing report described RBD in children with autism21– nowadays clearly established as a neurodevelopmental disorder. Eleven children with autism diagnosed by the DSM-IV22 were investigated for disrupted sleep with frequent awakenings. With a certain amount of difficulty because of the children’s mental state, limited PSG recordings were obtained. Five of the children (overall ages 3–9y, and including three males) were reported to show both clinical and PSG signs of RBD.
Their nighttime disturbances included repeated waking up in very distressed, ‘dream-like’ or agitated and violent states. One child was said to move, twitch, jerk her limbs, look round and sit up and cry for several minutes without appearing fully awake before falling asleep again. Another wandered about the house still asleep. There is no mention of seizure activity in any of the recordings. The other six children out of the 11 showed none of the PSG features of RBD.
Four of the five children in whom RBD was diagnosed (or thought probable) began to sleep well after treatment with 0.25 to 0.5mg clonazepam. This treatment made the remaining child agitated and restless, but his sleep problems resolved with carbamazepine.
There seemed to be no relationship between the presence or absence of RBD in this series and whether or not the children’s development had regressed. However, as various medical conditions can underlie autism, long-term follow-up might reveal the presence of such a condition, especially in those with PSG signs of RBD, on the grounds that such signs indicate some type of pathophysiology.
An account of five cases of childhood RBD23 included one child with ‘documented narcolepsy’ (details not provided). This series of children (ages and sexes not specified) were all investigated because of unusual sleep-related violent or injurious behaviours or vigorous body movements (including running in circles as if trying to escape, screaming, or thrashing about in bed) associated with frightening dream reports. PSG recordings revealed excessive muscle tone, frequent gross body movements, and increased phasic EMG activity during REM sleep. Clonazepam (0.25mg at bedtime) led to a complete resolution of the nighttime disturbances.
The authors of that report stopped short of saying that the children’s condition was the same as adult RBD, but the correspondence between the two seems to be close. Apart from the case associated with narcolepsy, their condition could be categorized as idiopathic, subject to revision in the light of possible further developments.
The same can be said of another patient who first began to act out his dreams of riding a motorbike at the age of 14 years (Stores G, unpublished data). In subsequent years his frequent dream enactment took an increasingly violent form, in keeping with the content of his dreams. However, he did not come to medical attention until the age of 30 years when he not only injured himself when dreaming that he was fighting off a bedroom intruder but also hurt his girlfriend while protecting her from a similar threat. An additional concern was that he might harm their new baby with whom they shared their bedroom.
Although wayward earlier in life, he had been well-adjusted, responsible, and otherwise healthy in recent times. Investigations included PSG recordings which showed the characteristic features of RBD together with periodic limb movements. Clonazepam (0.25mg at bedtime) stopped the nighttime episodes promptly without any ill effects. Five years later, and 21 years after the apparent onset of his RBD, he remained physically and psychiatrically well.
Loss of REM atonia, unaccompanied by convincing clinical signs of RBD, have been reported in young patients in association with various conditions. Uncertainty about the nature of several of these cases arises from insufficiently detailed reporting and lack of information about subsequent developments.
There is an outline account of 19 patients who met PSG, but not clinical, criteria for RBD.24 The pathological categories in which they were placed included non-REM parasomnias, narcolepsy, and olivopontocerebellar degeneration, in each of which some children and adolescents were mentioned but their details were not provided. The other categories that contained only adults were obstructive sleep apnoea and fluoxetine treatment for major depression.
According to another report, an otherwise healthy female began to have daytime sleep attacks at the age of almost 5 years followed a few months later by other problems including frequent nightmares and restless sleep.25 PSG findings are said to have revealed ‘REM-related motor disturbances at night’. Later she developed classical cataplexy, and narcolepsy was diagnosed. Because of the lack of detail in the descriptions of both the clinical features and the PSG findings in this case, at best it can also be placed in the subclinical RBD category.
Similar diagnostic difficulties are encountered in a preliminary report of a series of 16 patients with Tourette syndrome, age range 6 to 65 years, said to have RBD.26 Again, insufficient information is provided in a report of a 4-year-old male and a 5-year-old female with posttraumatic stress disorder, contentiously thought by some to be basically a disorder of REM sleep,27 and REM sleep motor abnormalities.28
More detailed accounts, focusing on early developmental aspects of brainstem neurophysiology rather than claims to have demonstrated RBD features, have described REM abnormalities of an RBD type in children with West syndrome, associated with many forms of neurological disorders,29 and in others with group A xeroderma pigmentosum, a serious skin condition that is, however, also characterized by cortical and subcortical neuronal degeneration.30