Sleepwalking violence: a sleep disorder, a legal dilemma, and a psychological challenge

Sleep disorders and criminal behavior

Behaviors that would otherwise be considered criminal acts, but occur in the context of a sleep disorder, pose challenges to the traditional application of legal principles of criminal responsibility. Determining the degree to which consciousness is present during such behaviors becomes a necessary step in assigning criminal culpability. Historically, legal defense theories of unconsciousness, automatism, and insanity have been raised to negate culpability for parasomnia related behaviors. Accordingly, proper assessment of sleep disorders in the context of criminal charges becomes critical in assisting the functions of the justice system. This article reviews principles related to the legal tradition, expert assessment, and elements of expert testimony related to criminal behaviors and sleep disorders.

The parasomnia defense in sleep-related homicide: A systematic review and a critical analysis of the medical literature

This review critically analyzes the forensic application of the Parasomnia Defense in homicidal incidents, drawing from medical literature on disorders of arousal (DOA) and rapid-eye-movement sleep behavior disorder (RBD). A systematic search of PubMed, Scopus, Embase, and Cochrane databases was conducted until October 16, 2022. We screened English-language articles in peer-reviewed journals discussing murders committed during sleep with a Parasomnia Defense. We followed PRISMA guidelines, extracting event details, diagnosis methods, factors influencing the acts, perpetrator behavior, timing, motives, concealment, mental experiences, victim demographics, and court verdicts. Three sleep experts evaluated each case. We selected ten homicides, four attempted homicides, and one homicide/attempted homicide that met inclusion/exclusion criteria. Most cases were suspected DOA as unanimously confirmed by experts. RBD cases were absent. Among aggressors, a minority reported dream-like experiences. Victims were primarily female family members killed in or near the bed by hands and/or with sharp objects. Objective sleep data and important crime scene details were often missing. Verdicts were ununiform. Homicides during DOA episodes, though rare, are documented, validating the Parasomnia Defense's use in forensics. RBD-related fatal aggression seems very uncommon. However, cases often lack diagnostic clarity. We propose updated guidelines to enhance future reporting and understanding of such incidents.

Challenges in diagnosing NREM parasomnias: Implications for future diagnostic classifications

NREM parasomnias are frequent and potentially disabling sleep disorders characterized by recurrent abnormal behaviors emerging from NREM sleep. Recently, several studies provided more detailed clinical and polysomnographic characterization of NREM parasomnia which may enhance the diagnostic process. Several revisions of the diagnostic criteria have been proposed in the classification of sleep disorders, the latest being ICSD-3-TR in 2023 with no changes on NREM parasomnias since ICSD-3 published in 2014. We performed an extensive literature review to assess the evidence on the procedure of its diagnosis. We dissected the inconsistencies and shortcomings in the ICSD-3-TR to propose a revision of the current diagnostic criteria. We highlighted the limits of several clinical criteria which should rather be supportive features than mandatory criteria. Infrared cameras with video-recordings with are promising tools to precisely characterize home episodes. Sensitive and specific polysomnographic markers of NREM parasomnias have been identified and should be considered in future revisions. We also suggest the use of diagnostic specifiers (clinical subtypes, clinical significance, levels of severity, age effect, levels of certainty) to define homogeneous subgroups of patients for therapeutic intervention and research purposes. In conclusion, we advocate for significant changes in the current diagnostic criteria of NREM parasomnias for future classification.

Fearful arousals in sleep terrors and sleep-related hypermotor epileptic seizures may involve the salience network and the acute stress response of Cannon and Selye

We consider the disorders of arousal and sleep-related hypermotor epilepsy as genetic twin-conditions, one without, one with epilepsy. They share an augmented arousal-activity during NREM sleep with sleep-wake dissociations, culminating in sleep terrors and sleep-related hypermotor seizures with similar symptoms. The known mutations underlying the two spectra are different, but there are multifold population-genetic-, family- and even individual (the two conditions occurring in the same person) overlaps supporting common genetic roots. In the episodes of disorders of arousal, the anterior cingulate, anterior insular and pre-frontal cortices (shown to be involved in fear- and emotion processing) are activated within a sleeping brain. These regions overlap with the seizure-onset zones of successfully operated sleep-related hypermotor seizures, and notably, belong to the salience network being consistent with its hubs. The arousal-relatedness and the similar fearful confusion occurring in sleep terrors and hypermotor seizures, make them alike acute stress-responses emerging from sleep; triggered by false alarms. The activation of the anterior cingulate, prefrontal and insular regions in the episodes of both conditions, can easily mobilize the hypothalamo-pituitary-adrenal axis (preparing fight-flight responses in wakefulness); through its direct pathways to and from the salience network. This hypothesis has never been studied.

Violent and Complex Behaviors and Non-Restorative Sleep Are the Main Features of Disorders of Arousal in Adulthood: Real Picture or a More Severe Phenotype?

Disorders of arousal (DoA) are NREM parasomnias characterized by motor and emotional behaviors emerging from incomplete arousals from deep sleep. DoA are largely present in pediatric populations, a period during which they are labeled as self-limited manifestations. However, an extensive literature has shown that DoA can persist in adulthood, with different characteristics from childhood DoA. Adult DoA patients usually report excessive daily sleepiness, sleep-related violence during DoA episodes or potentially harmful behaviors, which are rare in childhood. The semeiological features of DoA episodes in adulthood may complicate differential diagnoses with other motor manifestations during sleep, in particular sleep-related hypermotor epilepsy. However, it cannot be excluded that adults with DoA attending sleep centers constitute a more severe phenotype, thus not being representative of adult DoA in the general population. Video-polysomnographic studies of DoA document a spectrum of motor patterns of different complexities, the simplest of which may often go unnoticed. Despite the different complexities of the episodes, neurophysiologic studies showed the co-existence of deep sleep and wakefulness during DoA episodes or even before their onset. These aspects make DoA an ideal model to investigate the mechanisms regulating local sleep, sleep arousal and cognitive functions including spatial and temporal orientation, attention or memory.

Self-reported developmental changes in the frequency and characteristics of somnambulistic and sleep terror episodes in chronic sleepwalkers

BACKGROUND

Far from being benign, somnambulistic episodes can be frequent and/or severe and potentially injurious. Episodes may also be accompanied by sleep mentation with variable degrees of retrograde amnesia. The present study investigated how somnambulistic episodes unfold from childhood through adulthood, a topic that remains understudied.

METHODS

Adult sleepwalkers with a diagnosis of primary somnambulism and a childhood onset of the disorder (n = 113) were assessed for changes in frequency of their episodes, recall of episode-related sleep mentation and aggressive episodes during childhood, adolescence and adulthood. In addition, sleepwalkers (n = 52) with childhood-onset of sleep terrors were assessed for developmental changes in sleep terror frequency.

RESULTS

Results indicate that the frequency of somnambulistic episodes remains unchanged during childhood and adolescence before increasing during adulthood. An opposite trend was observed for sleep terrors. The frequency of aggressive somnambulistic episodes and of sleep mentation associated with somnambulism increased from childhood to adolescence and into adulthood. By contrast, the recall of sleep mentation associated with sleep terrors did not change over time. Additionally, a higher frequency of aggressive somnambulistic episodes predicted a higher frequency of sleep mentation associated with somnambulism. These patterns were similar across men and women.

CONCLUSION

Our study demonstrates that in chronic sleepwalkers, sleep mentation associated with somnambulistic episodes increases with age while episodes worsen in frequency and severity from childhood to adulthood. These findings add to the limited literature in the field and provide valuable insights into how key clinical characteristics of somnambulism evolve across the lifespan.

Sleep-Related Hypermotor Epilepsy vs Disorders of Arousal in Adults: A Step-Wise Approach to Diagnosis

Disorders of arousal (DoA) and sleep-related hypermotor epilepsy (SHE) are sleep-related events characterized by complex, often bizarre, and violent behaviors. DoA are involuntary motor manifestations of various complexities occurring during incomplete awakening from non-rapid eye movement sleep. SHE is a focal epilepsy characterized by stereotyped hyperkinetic or/and asymmetric tonic/dystonic seizures usually arising from non-rapid eye movement sleep. Even if many aspects regarding DoA and SHE have been clarified, the differential diagnosis remains challenging, because DoA and SHE share some semiologic features and genetic background. The clinical history, collected from the patient and his/her witness, represents the first and common milestone in the diagnosis. Validated questionnaires constitute suitable screening tools that could guide further analysis. The worldwide availability of homemade video recordings has increased the possibility of adding more objective information to the clinical history alone. The confirmed diagnosis relies on video-polysomnographic recording although it requires time, economic resources, and specific skills for the analysis. In this review we propose a simple diagnostic algorithm for the differential diagnosis between DoA and SHE in adults, based on the most updated knowledge, from the simpler tool to the most specific and tailored one.

The Arousal Disorders Questionnaire: a new and effective screening tool for confusional arousals, Sleepwalking and Sleep Terrors in epilepsy and sleep disorders units

BACKGROUND

Arousal Disorders (DoA) include Confusional Arousals, Sleepwalking and Sleep Terrors. DoA diagnosis is mainly clinical but no validated questionnaires exist for DoA screening according to the criteria of the International Classification of Sleep Disorders, Third Edition. Recently our group proposed the Arousal Disorders Questionnaire (ADQ) as a new diagnostic tool for DoA diagnosis. The objective of this study was to evaluate the diagnostic accuracy of the ADQ in a sleep and epilepsy center.

METHODS

One interviewer blinded to clinical and video-polysomnographic (VPSG) data administered the ADQ to 150 patients consecutively admitted to our Sleep and Epilepsy Centers for a follow-up visit. The final diagnosis, according to VPSG recordings of at least one major episode, classified patients either with DoA (DoA group) or with other sleep-related motor behaviors confounding for DoA (nDoA group).

RESULTS

47 patients (31%) composed the DoA group; 56 patients with REM sleep behavior disorder, 39 with sleep-hypermotor epilepsy, six with night eating syndrome, and two with drug-induced DoA composed the nDoA group. The ADQ had a sensitivity of 72% (95% CI: 60-82) and a specificity of 96% (95% CI: 89-98) for DoA diagnosis; excluding the items regarding consciousness and episode recall, sensitivity was 83% (95% CI: 71-90) and specificity 93% (95% CI: 86-97).

CONCLUSIONS

The ADQ showed good accuracy in screening patients with DoA in a sleep and epilepsy center setting. Diagnostic criteria related to cognition and episode recall reduced ADQ sensitivity, therefore a better definition of these criteria is required, especially in adults.

Disorders of Arousal in adults: new diagnostic tools for clinical practice

Disorders of Arousal  (DOA) are mental and motor behaviors arising from NREM sleep. They comprise a spectrum of manifestations of increasing intensity from confusional arousals to sleep terrors to sleepwalking.

Although DOA in childhood are usually harmless, in adulthood they are often associated with injurious or violent behaviors to the patient or others. Driving motor vehicles, suspected suicide, and even homicide or attempted homicide have been described during sleepwalking in adults. Furthermore, adult DOA need to be differentiated from other sleep disorders such as Sleep-related Hypermotor Epilepsy or REM Sleep Behavior Disorder.

Although many aspects of DOA have been clarified in the last two decades there is still a lack of objective and quantitative diagnostic criteria for DOA.

Recent advances in EEG analysis and in the semiological characterization of DOA motor patterns have provided a better definition of DOA diagnosis.

Our article focuses on the DOA diagnostic process describing accurately the newest DOA clinical, EEG and video-polysomnographic tools in order to aid clinicians in DOA assessment.

Sexsomnia: sleep sex research and its legal implications

"Sleep sex," also known as sexsomnia, is a sleep disorder characterized by sexual behaviors committed while asleep. There has recently been increased interest in sexsomnia due to controversies arising in legal trials that have been widely publicized in the social and public media. This article attempts to marshal the current information about sexsomnia from the forensic literature and provides an overview of sexsomnia including common features, precipitating factors, prevalence rates, diagnostic procedures, and treatment. As sexsomnia represents a condition in which sexual acts are committed without awareness or intention, this paper also reviews the development of sexsomnia as a legal defense and summarizes Canadian case law on the topic. It provides an overview of the hurdles presented to defense attorneys attempting to utilize the defense and examines popular public notions surrounding the legitimacy of sexsomnia and the possibility of malingering. We conclude that sexsomnia is a legitimate sleep disorder for which case law now exists to support its use in legal defenses based on automatism. The question of whether it is an example of "sane" or "insane" automatism remains to be determined by the courts. Regardless of whether or not sexsomnia is determined to be a mental disorder by the courts, it is now a recognized and well-described sleep disorder that can be safely treated and managed by knowledgeable clinicians.

Sleep-related violence and sexual behavior in sleep: a systematic review of medical-legal case reports

OBJECTIVE

To review systematically medical-legal cases of sleep-related violence (SRV) and sexual behavior in sleep (SBS).

SEARCH METHODS

We searched Pubmed and PsychINFO (from 1980 to 2012) with pre-specified terms. We also searched reference lists of relevant articles.

SELECTION CRITERIA

Case reports in which a sleep disorder was purported as the defense during a criminal trial and in which information about the forensic evaluation of the defendant was provided.

DATA EXTRACTION AND ANALYSIS

Information about legal issues, defendant and victim characteristics, circumstantial factors, and forensic evaluation was extracted from each case. A qualitative-comparative assessment of cases was performed.

RESULTS

Eighteen cases (9 SRV and 9 SBS) were included. The charge was murder or attempted murder in all SRV cases, while in SBS cases the charge ranged from sexual touching to rape. The defense was based on sleepwalking in 11 of 18 cases. The trial outcome was in favor of the defendant in 14 of 18 cases. Defendants were relatively young males in all cases. Victims were usually adult relatives of the defendants in SRV cases and unrelated young girls or adolescents in SBS cases. In most cases the criminal events occurred 1-2 hours after the defendant's sleep onset, and both proximity and other potential triggering factors were reported. The forensic evaluations widely differed from case to case.

CONCLUSION

SRV and SBS medical-legal cases did not show apparent differences, except for the severity of the charges and the victim characteristics. An international multidisciplinary consensus for the forensic evaluation of SRV and SBS should be developed as an urgent priority.

Opportunities, threats and limitations of neuroscience data in forensic psychiatric evaluation

PURPOSE OF REVIEW

In the last decade, a number of studies have been published to shed light on the interaction between neuroscience and the law, notably on the introduction of neuroscience data in forensic psychiatric evaluation (FPE). Even if there is a growing consensus on the relevance of neuroscience in clinical practice, the role of neuroscience in FPE is still controversial.

RECENT FINDINGS

The use of neuroscience data in FPE can support the detection of psychopathological disabilities (e.g. deficit of self-control, aggressiveness) that may be involved in criminal action. Traumatic brain injury-related clinical disorders that may lead to misconduct have a relevant role in the debate. Traditionally, literature refers also to rare and weird cases in which brain tumours, infections and morphological abnormalities were supposed to be significantly associated with disorders leading to criminal action.

SUMMARY

After reviewing recent literature from both legal and neuroscientific perspectives, we consider a broader range of clinical conditions (e.g. disorders of consciousness in sleepwalking, dopamine replacement therapy in Parkinson's disease, misattributions of self in delusional experience) that may have implications in legal settings. Obviously, it would be possible to consider also different clinical conditions. We conclude by suggesting further experimental and theoretical analysis.

Defending sleepwalkers with science and an illustrative case

OBJECTIVE

To test whether laboratory-based research differentiating sleepwalkers (SW) from controls (C) can be applied in an uncontrolled forensic case as evidence the alleged crime was committed during an arousal from sleep in which the mind is not fully conscious due to a SW disorder.

METHODS

A PSG study recorded 8 months after the defendant was charged was analyzed independently by spectral analysis. Slow wave activity (SWA) and cyclic alternating pattern (CAP) rates were computed. Clinical interviews and police records were reviewed for data re: the defendant's sleep prior to the event and use of drugs, alcohol, and stimulants.

RESULTS

The SWA distribution was abnormally low and flat, significantly lower than published controls; in the first NREM cycle, CAP rate 55 was above normal. Two weeks of prior sleep deprivation was confirmed from interviews and defendant's observed daytime sleepiness. Caffeine intake the day before the event was calculated at 826 mg over 14 hours. Snoring and a mild breathing disorder were present in the PSG.

CONCLUSION

Testimony based on spectral analysis of PSG recorded following an alleged criminal event supported a SW explanation for the non-rational behaviors charged. The defendant was acquitted of all charges and has been successfully treated.

Somnambulism: clinical aspects and pathophysiological hypotheses

Somnambulism, or sleepwalking, can give rise to a wide range of adverse consequences and is one of the leading causes of sleep-related injury. Accurate diagnosis is crucial for proper management and imperative in an ever-increasing number of medicolegal cases implicating sleep-related violence. Unfortunately, several widely held views of sleepwalking are characterised by key misconceptions, and some established diagnostic criteria are inconsistent with research findings. The traditional idea of somnambulism as a disorder of arousal might be too restrictive and a comprehensive view should include the idea of simultaneous interplay between states of sleep and wakefulness. Abnormal sleep physiology, state dissociation, and genetic factors might explain the pathophysiology of the disorder.

Auditory arousal responses and thresholds during REM and NREM sleep of sleepwalkers and controls

BACKGROUND

It has been suggested that sleepwalkers are more difficult to awaken from sleep than are controls. However, no quantified comparisons have been made between these two populations. The main goal of this study was to assess arousal responsiveness via the presentation of auditory stimuli (AS) in sleepwalkers and controls during normal sleep and recovery sleep following sleep deprivation.

METHODS

Ten adult sleepwalkers and 10 age-matched control subjects were investigated. After a screening night, participants were presented with AS during slow-wave sleep (SWS), REM, and stage 2 sleep either during normal sleep or daytime recovery sleep following 25 h of sleep deprivation. The AS conditions were then reversed one week later.

RESULTS

When compared to controls sleepwalkers necessitated a significantly higher mean AS intensity (in dB) to induce awakenings and arousal responses during REM sleep whereas the two groups' mean values did not differ significantly during SWS and stage 2 sleep. Moreover, when compared to controls sleepwalkers had a significantly lower mean percentage of AS that induced arousal responses during REM sleep while the opposite pattern of results was found during SWS.

CONCLUSIONS

The data indicate that sleepwalkers have a higher auditory awakening threshold than controls, but only for REM sleep. These findings may reflect a compensatory mechanism of the homeostatic process underlying sleep regulation during sleepwalkers' REM sleep in reaction to their difficulties maintaining consolidated periods of NREM sleep.

Sleepwalking through history: medicine, arts, and courts of law

Somnambulism, or sleepwalking, has always been of interest to theologians, writers, philosophers, physicians, and others fascinated by unusual behaviors. This parasomnia, which was defined less precisely in the past than it is today, has long been featured in medical dissertations and books of medicine. Further, Shakespeare, Bellini, and Brown, among others, incorporated it into their plays, operas, and novels. Because some somnambulists turned violent and committed other acts detrimental to society, sleepwalking also demanded attention from legal systems, and guidelines were set for whether somnambulists could be held responsible for their actions. This historical review focuses on these developments pertaining to somnambulism through the seventeenth, eighteenth, and nineteenth centuries.

Sleepwalking, a possible side effect of antipsychotic medication

Two case examples and a review of the sleep literature illustrate the potential of antipsychotic medication to trigger sleepwalking episodes in the context of schizophrenia. Causative hypotheses are briefly reviewed, as well as risk factors, differential diagnosis, and management. Sleepwalking may contribute to delusions, aggression, and accidental suicide. It is important to investigate sleep disorders in schizophrenia. They are not rare and may contribute to behavior that increases the stigma and isolation of individuals with schizophrenia.

Prevalence of different parasomnias in the general population

OBJECTIVE

To estimate lifetime and current prevalence (defined as having experienced the specific parasomnia at least once during the last 3 months) of different parasomnias in the general population. In addition, to study the relationship between the different parasomnias and gender, depressive mood, and symptoms of sleep apnea, insomnia and restless legs, as well as estimating the prevalence of having multiple parasomnias.

METHODS

Population based cross-sectional study. One thousand randomly selected adults (51% female), 18years and above, participated in a telephone interview in Norway.

RESULTS

Lifetime prevalence of the different parasomnias varied from about 4% to 67%. For sleep walking lifetime prevalence was 22.4% and current prevalence 1.7%. For the other parasomnias, lifetime and current prevalence were as follows: sleep talking 66.8% and 17.7%, confusional arousal 18.5% and 6.9%, sleep terror 10.4% and 2.7%, injured yourself during sleep 4.3% and 0.9%, injured somebody else during sleep 3.8% and 0.4%, sexual acts during sleep 7.1% and 2.7%, nightmare 66.2% and 19.4%, dream enactment 15.0% and 5.0%, sleep related groaning 31.3% and 13.5%, and sleep-related eating 4.5% and 2.2%. Depressive mood was associated with confusional arousal, sleep terror, sleep-related injury, and nightmare. There were few associations between the parasomnias and gender and symptoms of sleep apnea, insomnia, and restless legs, respectively. About 12% reported having five or more parasomnias.

CONCLUSIONS

This is one of few population based studies investigating the prevalence of parasomnias. Several parasomnias were highly prevalent in the general population. The data need to be interpreted with caution due to methodological issues, i.e., low response rate and single questions.

Analysis of slow-wave activity and slow-wave oscillations prior to somnambulism

STUDY OBJECTIVIES: several studies have investigated slow wave sleep EEG parameters, including slow-wave activity (SWA) in relation to somnambulism, but results have been both inconsistent and contradictory. The first goal of the present study was to conduct a quantitative analysis of sleepwalkers' sleep EEG by studying fluctuations in spectral power for delta (1-4 Hz) and slow delta (0.5-1 Hz) before the onset of somnambulistic episodes. A secondary aim was to detect slow-wave oscillations to examine changes in their amplitude and density prior to behavioral episodes.

PARTICIPANTS

twenty-two adult sleepwalkers were investigated polysomnographically following 25 h of sleep deprivation.

RESULTS

analysis of patients' sleep EEG over the 200 sec prior to the episodes' onset revealed that the episodes were not preceded by a gradual increase in spectral power for either delta or slow delta over frontal, central, or parietal leads. However, time course comparisons revealed significant changes in the density of slow-wave oscillations as well as in very slow oscillations with significant increases occurring during the final 20 sec immediately preceding episode onset.

CONCLUSIONS

the specificity of these sleep EEG parameters for the occurrence and diagnosis of NREM parasomnias remains to be determined.

Prevalence of sleepwalking in an adult population

BACKGROUND

Sleepwalking consists of a series of behavioral activities that occur during sleep. These activities may be simple, complex or aggressive in nature. They include motor activities, confusion, and amnesia for the events. Sleepwalking is a disorder of arousal from non-rapid eye movement (NREM) sleep. In children, episodes of sleepwalking are rarely violent; in adults, however, sleepwalking might include violence, which could endanger the patient or others and might precipitate legal issues. There is inadequate information on the prevalence and demographic correlates of sleepwalking in Nigeria.

OBJECTIVES

One objective of this study was to determine the lifetime prevalence rate of sleepwalking in an adult population in Ile-Ife, in Southwestern Nigeria. Another objective was to determine the age and sex distribution of sleepwalking among those who have experienced it at least once in their lifetime.

MATERIALS AND METHODS

A random sample of 228 healthy individuals aged 18-60 years was obtained and the members were asked to fill out a survey form about lifetime prevalence rate of sleepwalking.

RESULTS

The overall lifetime prevalence rate of sleepwalking was 7% (16 of 228 participants). It was 10.4% in males and 3.5% in females, but the difference was not statistically significant (p=0.07).

CONCLUSION

This study has shown that sleepwalking is common in the population. In view of the psychological effects of sleepwalking and the potential physical and legal problems associated with it, adequate efforts should be made for early detection and prompt management of the condition.

Prevalence of Sleepwalking in an Adult Population

BACKGROUND

Sleepwalking consists of a series of behavioral activities that occur during sleep. These activities may be simple, complex or aggressive in nature. They include motor activities, confusion, and amnesia for the events. Sleepwalking is a disorder of arousal from non-rapid eye movement (NREM) sleep. In children, episodes of sleepwalking are rarely violent; in adults, however, sleepwalking might include violence, which could endanger the patient or others and might precipitate legal issues. There is inadequate information on the prevalence and demographic correlates of sleepwalking in Nigeria.

OBJECTIVES

One objective of this study was to determine the lifetime prevalence rate of sleepwalking in an adult population in Ile-Ife, in Southwestern Nigeria. Another objective was to determine the age and sex distribution of sleepwalking among those who have experienced it at least once in their lifetime.

MATERIALS AND METHODS

A random sample of 228 healthy individuals aged 18-60 years was obtained and the members were asked to fill out a survey form about lifetime prevalence rate of sleepwalking.

RESULTS

The overall lifetime prevalence rate of sleepwalking was 7% (16 of 228 participants). It was 10.4% in males and 3.5% in females, but the difference was not statistically significant (p = 0.07).

CONCLUSION

This study has shown that sleepwalking is common in the population. In view of the psychological effects of sleepwalking and the potential physical and legal problems associated with it, adequate efforts should be made for early detection and prompt management of the condition.

Sleep violence

Violence during sleep is more common than is usually thought and has characteristic clinical features. These reflect the altered cerebral activity during sleep as well as the specific pathophysiology of the underlying sleep disorder. There are often forensic as well as clinical implications of violence during sleep which need careful assessment.

Complex dream-enacting behavior in sleepwalking

OBJECTIVE

Currently, dream-enacting behaviors are viewed as occurring typically in association with a REM-sleep behavior disorder. In some cases, dream-like mentation is found also in non-REM parasomnia.

METHODS

We report a case of complex and dramatic sleepwalking behavior in a 26-year-old adult male who tied his 4-month-old daughter to the clothesline in the attic of his house.

RESULTS

The explanation of this seemingly senseless behavior, which was related to psychosocial stressors, was found in a detailed dream-like mentation that was reported by the patient. At the same time, an organic factor, namely, a worsening of the patient's asthma, was identified as the cause of an increased fragmentation of sleep.

CONCLUSIONS

In some cases of non-REM parasomnia, detailed dream-like mentation may act as a bridge between psychosocial stressors and the specific parasomnic behavior.

Polysomnographic diagnosis of sleepwalking: effects of sleep deprivation

OBJECTIVE

Somnambulism affects up to 4% of adults and constitutes one of the leading causes of sleep-related violence and self-injury. Diagnosing somnambulism with objective instruments is often difficult because episodes rarely occur in the laboratory. Because sleep deprivation can precipitate sleepwalking, we aimed to determine the effects of 25 hours of sleep deprivation on the frequency and complexity of somnambulistic episodes recorded in the laboratory.

METHODS

Thirty consecutive sleepwalkers were evaluated prospectively by video-polysomnography for one baseline night and during recovery sleep after 25 hours of sleep deprivation. Ten sleepwalkers with a concomitant sleep disturbance were investigated with the same protocol.

RESULTS

Sleepwalkers experienced a significant increase in the mean frequency of somnambulistic episodes during postdeprivation recovery sleep. Postsleep deprivation also resulted in a significantly greater proportion of patients experiencing more complex forms of somnambulism. Sleep deprivation was similarly effective in 9 of the 10 patients presenting with a comorbid sleep disturbance. Combining data from all 40 patients shows that whereas 32 episodes were recorded from 20 sleepwalkers (50%) at baseline, recovery sleep resulted in 92 episodes being recorded from 36 patients (90%).

INTERPRETATION

The findings support the view that sleepwalkers suffer from a dysfunction of the mechanisms responsible for sustaining stable slow-wave sleep and suggest that these patients are particularly vulnerable to increased homeostatic sleep pressure. Strong evidence is provided that 25 hours of sleep deprivation can be a valuable tool that facilitates the polysomnographically based diagnosis of somnambulism in predisposed patients.

Sexual behaviour in sleep: an internet survey

The objective of the study was to provide further information related to newly described parasomnia variant, Sexual Behaviour in Sleep (SBS, sexsomnia). Previous studies dealt with selected population, typically middle-aged males, featuring extensive medico-legal exposure. At the same time, an anecdotal evidence suggested higher involvement of younger population, and skew towards balance between genders comparable to those seen in other non-Rapid Eye Movement (NREM) sleep parasomnias. The epidemiological information regarding this condition is still virtually non-existent. In order to sample this difficult-to-reach population, a 28-item Internet survey was posted on the sexsomnia reference site and the link was also sent to prospective respondents (mostly registered visitors to this site). The respondents were able to complete the survey anonymously, which resulted in a need for the screening of bogus and duplicate results. At the end, a total of 219 validated responses were collected and analysed. The results showed greater representation of females (31% of the total number), and wider age distribution (mean age of 30.4 years). The respondents typically reported multiple sexsomnia episodes, in most cases precipitated by body contact, stress and fatigue. Relatively small number of respondents reported involvement of legal authorities (8.6% of males and 3% of females) and participation of minors in their sexsomnia (6% of the total sample). In spite of known limitations of such surveys, the study provided much needed insight into this complex nocturnal behaviour. It confirmed the anecdotal evidence about the gender and age distribution, and provided information on some key features, such as precipitating factors, type of behaviour, medication use, personal medical history and medico-legal aspects.

Disorders of arousal from sleep and violent behavior: the role of physical contact and proximity

STUDY OBJECTIVES

To review medical and legal case reports to determine how many appear to support the belief that violence against other individuals that occurs during Disorders of Arousal - sleepwalking, confusional arousal, and sleep terrors - is triggered by direct physical contact or close proximity to that individual and does not occur randomly or spontaneously.

DESIGN

Historical review of case reports in the medical and legal literature.

MEASUREMENTS AND RESULTS

A total of 32 cases drawn from medical and legal literature were reviewed. Each case contained a record of violence associated with Disorders of Arousal; in each, details of the violent behavior were available. Violent behaviors associated with provocations and/or close proximity were found to be present in 100% of confusional arousal patients and 81% of sleep terror patients. Violent behaviors were associated with provocation or close proximity in 40%-90% of sleepwalking cases, depending on whether the legal verdict and other factors were taken into account. Often the provocation was quite minor and the response greatly exaggerated. The specific manner in which the violence was triggered differed among sleepwalking, confusional arousals, and sleep terrors.

CONCLUSIONS

In the cases reviewed, violent behavior directed against other individuals associated with Disorders of Arousal most frequently appeared to follow direct provocation by, or close proximity to, another individual. Sleepwalkers most often did not seek out victims, but rather the victims sought out or encountered the sleepwalker. These conclusions are tempered by several limitations: the selection of cases was not random and may not represent an accurate sample of violent behaviors associated with Disorders of Arousal. Also, final verdicts by juries in reported legal cases should not be confused with scientific proof of the presence or absence of sleepwalking. The pathophysiology of Disorders of Arousal with and without violent behavior could be associated with normally occurring deactivation of the frontal lobes during slow wave sleep (SWS) connected via atypically active thalamocortical pathways to the limbic areas. It is not known if the violent sleepwalker, confusional arousal patient, or sleep terror patient differs from other patients with these disorders. The conclusions of this case series await confirmation by the results of future sleep laboratory based studies.

Parasomnias

Parasomnias are undesirable behaviors that arise from sleep but are not fully under voluntary control. Parasomnias are grouped broadly according to whether they arise from non-rapid eye movement (NREM) or rapid eye movement (REM) sleep. NREM parasomnias are disorders of arousal that occur along a continuum of behavioral, affective, and autonomic activation. REM-related parasomnias include REM sleep behavior disorder, sleep paralysis, and nightmare disorder. Parasomnias can often be managed successfully using behavioral and pharmacologic therapies.

Somnambulistic sexual behaviour (sexsomnia)

Somnambulism or sleepwalking is a viable defence on the basis of automatism. The behaviours that occur during sleepwalking can be highly complex and include sexual behaviour of all types. Somnambulistic sexual behaviour (also called sexsomnia, sleep sex) is considered a variant of sleepwalking disorder as the overwhelming majority of people with Sexsomnia have a history of parasomnia and a family history of sleepwalking. Sexual behaviour during a sleep automatism can vary from explicit sexual vocalisations, to violent masturbation, to complex sexual acts including anal, oral and vaginal penetration. A recent case in England is reported where the defendant was acquitted on 3 charges of rape on the basis of automatism due to somnambulistic sexual behaviour.