Sleep features in Tourette's syndrome, neuroacanthocytosis and Huntington's chorea

Sleep Disorders in Patients with Choreic Syndromes

PURPOSE OF REVIEW

Patients with different types of choreic syndromes, specially those with Huntington's (HD) and Wilson's (WD) diseases, report frequent sleep complaints. This review focuses on the main findings of studies addressing the sleep features in these diseases, and other less frequent causes of chorea associated with sleep disorders, including a new syndrome described in the last decade associated with IgLON5 antibodies.

RECENT FINDINGS

Patients with HD and WD showed a bad quality of sleep and high frequency of insomnia and excessive daytime somnolence. WD patients also showed high scores on a specific scale for rapid eye movement sleep behavior disorders. HD and WD share decreased sleep efficiency and increased REM sleep latencies, percentage of sleep stage N1, and wake after sleep onset (WASO) among their polysomnographic features. Patients with HD and WD showed a high prevalence of different sleep disorders. Patients with other causes of chorea, including neuroacanthocytosis, parasomnia with sleep breathing disorder associated with antibodies to IgLON5, Sydenham's chorea, and choreic syndromes associated to certain genetic mutations show sleep disorders as well.

Sleep Disturbance in Tourette's Disorder: Potential Underlying Mechanisms

Purpose of review

Sleep disturbance is common in TD. However, our understanding of the pathophysiological mechanisms involved is preliminary. This review summarizes findings from neuroimaging, genetic, and animal studies to elucidate potential underlying mechanisms of sleep disruption in TD.

Recent findings

Preliminary neuroimaging research indicates increased activity in the premotor cortex, and decreased activity in the prefrontal cortex is associated with NREM sleep in TD. Striatal dopamine exhibits a circadian rhythm; and is influenced by the suprachiasmatic nucleus via multiple molecular mechanisms. Conversely, dopamine receptors regulate circadian function and striatal expression of circadian genes. The association of TD with restless legs syndrome and periodic limb movements indicates shared pathophysiology, including iron deficiency, and variants in the BTDB9 gene. A mutations in the L-Histidine Decarboxylase gene in TD, suggests the involvement of the histaminergic system, implicated in arousal, in TD.

Summary

These biological markers have implications for application of novel, targeted interventions, including noninvasive neuromodulation, iron supplementation, histamine receptor antagonists, and circadian-based therapies for tic symptoms and/or sleep and circadian rhythms in TD.

Sleep Disorders and Circadian Disruption in Huntington's Disease

Sleep and circadian alterations are common in patients with Huntington's disease (HD). Understanding the pathophysiology of these alterations and their association with disease progression and morbidity can guide HD management. We provide a narrative review of the clinical and basic-science studies centered on sleep and circadian function on HD. Sleep/wake disturbances among HD patients share many similarities with other neurodegenerative diseases. Overall, HD patients and animal models of the disease present with sleep changes early in the clinical course of the disease, including difficulties with sleep initiation and maintenance leading to decreased sleep efficiency, and progressive deterioration of normal sleep architecture. Despite this, sleep alterations remain frequently under-reported by patients and under-recognized by health professionals. The degree of sleep and circadian alterations has not consistently shown to be CAG dose-dependent. Evidence based treatment recommendations are insufficient due to lack of well-designed intervention trials. Approaches aimed at improving circadian entrainment, such as including light therapy, and time-restricted feeding have demonstrated a potential to delay symptom progression in some basic HD investigations. Larger study cohorts, comprehensive assessment of sleep and circadian function, and reproducibility of findings are needed in future in order to better understand sleep and circadian function in HD and to develop effective treatments.

Sleep Dysfunction in Movement Disorders: a Window to the Disease Biology

PURPOSE OF REVIEW

To comprehensively summarize the sleep pathologies associated with movement disorders, focusing on neurodegenerative diseases.

RECENT FINDINGS

Mounting evidence has further implicated both sleep and circadian disruption in the pathophysiology of many movement disorders. In particular, recent data illuminate the mechanisms by which poor sleep quality and circadian dysfunction can exacerbate neurodegeneration. In addition, anti-IgLON5 disease is a recently described autoimmune disease with various symptoms that can feature prominent sleep disruption and parasomnia. Many movement disorders are associated with sleep and circadian rhythm disruption. Motor symptoms can cause sleep fragmentation, resulting in insomnia and excessive daytime sleepiness. Many neurodegenerative movement disorders involve brainstem pathology in regions close to or affecting nuclei that regulate sleep and wake. Further, commonly used movement medications may exacerbate sleep concerns. Providers should screen for and address these sleep symptoms to improve function and quality of life for patients and caregivers.

Sleep Disorders and Sleep Problems in Patients With Tourette Syndrome and Other Tic Disorders: Current Perspectives

Sleep disorders seem to be a frequent complaint of patients diagnosed with Tourette syndrome (TS) or chronic or persistent tic disorders (CTD or PTD). In this review, we expanded a previously used search using 4 well-known databases up to February 15, 2022, looking for the coexistence of global and/or specific sleep disorders and polysomnographic studies performed on patients with TS/CTD/PTD. The references of interest in the topic were selected by hand. Sleep disorders in general, insomnia, different arousal disorders, the persistence of tics during sleep, excessive daytime sleepiness, and periodic limb movements during sleep (PLMS) were very frequent in patients with TS, most of them being more frequent in patients with comorbid Attention Deficit Hyperactivity Disorder. The most frequent results from polysomnographic studies were decreased sleep efficiency and increased sleep onset latency. Many of these findings could be related to medication used for the treatment of tics and comorbid disorders.

Circadian rhythms in neurodegenerative disorders

Endogenous biological clocks, orchestrated by the suprachiasmatic nucleus, time the circadian rhythms that synchronize physiological and behavioural functions in humans. The circadian system influences most physiological processes, including sleep, alertness and cognitive performance. Disruption of circadian homeostasis has deleterious effects on human health. Neurodegenerative disorders involve a wide range of symptoms, many of which exhibit diurnal variations in frequency and intensity. These disorders also disrupt circadian homeostasis, which in turn has negative effects on symptoms and quality of life. Emerging evidence points to a bidirectional relationship between circadian homeostasis and neurodegeneration, suggesting that circadian function might have an important role in the progression of neurodegenerative disorders. Therefore, the circadian system has become an attractive target for research and clinical care innovations. Studying circadian disruption in neurodegenerative disorders could expand our understanding of the pathophysiology of neurodegeneration and facilitate the development of novel, circadian-based interventions for these disabling disorders. In this Review, we discuss the alterations to the circadian system that occur in movement (Parkinson disease and Huntington disease) and cognitive (Alzheimer disease and frontotemporal dementia) neurodegenerative disorders and provide directions for future investigations in this field.

Dissociation of tic generation from tic expression during the sleep-wake cycle

Motor tics, the hallmark of Tourette syndrome (TS), are modulated by different behavioral and environmental factors. A major modulating factor is the sleep-wake cycle in which tics are attenuated to a large extent during sleep. This study demonstrates a similar reduction in tic expression during sleep in an animal model of chronic tic disorders and investigates the underlying neural mechanism. We recorded the neuronal activity during spontaneous sleep-wake cycles throughout continuous GABA_A antagonist infusion into the striatum. Analysis of video streams and concurrent kinematic assessments indicated tic reduction during sleep in both frequency and intensity. Extracellular recordings in the striatum revealed a state-dependent dissociation between motor tic expression and their macro-level neural correlates ("LFP spikes") during the sleep-wake cycle. Local field potential (LFP) spikes, which are highly correlated with tic expression during wakefulness, persisted during tic-free sleep and did not change their properties despite the reduced behavioral expression. Local, micro-level, activity near the infusion site was time-locked to the LFP spikes during wakefulness, but this locking decreased significantly during sleep. These results suggest that whereas LFP spikes encode motor tic generation and feasibility, the behavioral expression of tics requires local striatal neural activity entrained to the LFP spikes, leading to the propagation of the activity to downstream targets and consequently their motor expression. These findings point to a possible mechanism for the modulation of tic expression in patients with TS during sleep and potentially during other behavioral states.

Sleep disorders in tourette syndrome

Sleep disorders are very common in patients diagnosed with Tourette syndrome (TS). The present review focuses on sleep disorders and the results of polysomnographic studies performed in patients with TS. We made a search using the PubMed, Embase, MedLine, and Web of Science Databases, from 1966 until November 14, 2019, crossing the search term "Tourette syndrome" with "sleep", "sleep disorders", "sleep disturbances", and "polysomnography", and with each of the specific sleep disorders listed according to the International Classification of the Sleep Disorders-Third Edition. Then we identified the references of interest for the topic. Insomnia, excessive daytime sleepiness, disorders of arousal (sleepwalking, sleeptalking, sleep terrors, and enuresis), the persistence of tics during sleep, and presence of periodic limb movements during sleep (PLMS) were very frequent in patients with TS. These disturbances were more frequent in children and in patients with comorbid Attention Deficit Hyperactivity Disorder. Decreased sleep efficiency, decreased percentage of delta sleep, increased nocturnal awakenings and increased PLMS were the most consistent findings in the polysomnographic studies.

Sleep and Sleep Disorders in Tourette Syndrome: What is Known and What is Still Unknown

Background:

Most of the patients with Tourette Syndrome (TS) present additional comorbidities. Attention Deficit Hyperactivity Disorder (ADHD) and Obsessive-Compulsive Disorder (OCD) are the most common. Sleep Disorder has been suggested also as common comorbidity.

Objective:

To review the literature on sleep characteristics and sleep disorder in patients with Tourette Syndrome (TS), with emphasis on the contribution of specific co-morbidities to the severity of impaired sleep and life quality of the patients.

Results:

In general, sleep problems are not frequent at the age when tics appear which are estimated to affect about 10 % of these children. In severe cases, tics appear in all sleep stages. In a large study, the prevalence of sleep problems was 17.8% but was 12 % in “TS-only” (9.4% in children and 7.5 in adults) compared to 22% in children and 18% in adults with TS+ADHD. Unfortunately, in most of the studies, the characteristics of these “sleep problems” are not defined. In spite of the scarcity of data, the two main sleep disorders in TS patients are insomnia and parasomnias. Although much more data is needed, many TS subjects are sleep deprived (which exacerbate the tics) and may suffer from excessive daytime sleepiness, which negatively affects normal functioning.

Conclusions:

Although the literature is not conclusive, children and adolescents with TS appear to suffer more from sleep disturbances and sleep disorders than age-matched controls. Not all patients have tics during sleep, but in severe cases, tics may appear in all sleep stages. It is clear that when patients present both TS and ADHD, (a very common condition), the sleep difficulties are related mainly to ADHD. Much more research is warranted in all aspects of sleep and sleep disorders in TS.

Sleep Disorders in Huntington's Disease

Huntington's chorea (Huntington's disease, HD) is a genetic disorder caused by autosomal dominant mutation, leading to progressive neurodegenerative changes in the central nervous system. Involuntary movements such as chorea occur typically in HD patients, accompanied by progressive cognitive and psychiatric disturbances. Other common symptoms of HD are circadian and sleep abnormalities, which are observed from the earliest stages of the disease or even before the occurrence of clinical symptoms. The most common sleep problems reported by HD patients include insomnia, difficulties in falling asleep, frequent nocturnal awakenings, and excessive daytime sleepiness. Also, specific changes in sleep architecture have been identified in HD. In this paper, we review studies on sleep and circadian rhythm disorders in HD. We outline findings concerning sleep patterns and disturbances of circadian rhythms in HD patients, as well as the role of psychiatric disorders and motor disorders in HD patients' sleep problems. We also discuss problems related to the different methods of diagnosing sleep disorders in HD. Furthermore, the adverse effects of medication used for the treatment of core HD symptoms as one of the sources of sleep disturbances in HD are emphasized. In conclusion, the diversity and complexity of the determinants of sleep and circadian rhythm disorders in HD are highlighted. Finally, the relevance of effective treatment to improve patients' functioning and quality of life as well as the potential relief of their cognitive and emotional symptoms is addressed.

Non-motor symptoms in Huntington's disease: a comparative study with Parkinson's disease

BACKGROUND/AIMS

The presence of non-motor symptoms in Huntington's disease (HD) has not been systematically assessed so far. Our objective was to know their prevalence and to compare it with a cohort of patients with Parkinson's disease (PD).

MATERIALS AND METHODS

Participants were consecutively recruited from our outpatient clinic. They were assessed through the motor part of the Unified Huntington's Disease Rating Scale, the motor part of the Unified Parkinson's Disease Rating Scale, the total functional capacity scale and the PD non-motor symptoms questionnaire.

RESULTS

We enrolled 123 participants: 53 HD, 45 PD and 25 healthy controls (HC). Non-motor symptoms were significantly more prevalent in HD patients than in HC. The most frequent non-motor symptoms in HD, involving more than 50% of patients, were attentional deficits, apathy, dysphagia, memory complaints, depression falls, insomnia and urinary urgency. The total score of non-motor symptoms correlated with disease duration, total functional capacity and disease stage. HD scored significantly higher than PD in 11 items (dysphagia, constipation, bowel incontinence, faecal tenesmus, weight loss, memory, apathy, attention, falls, nightmares, delusions) and in four domains (cognitive, hallucinations and delusions, digestive and cardiovascular). PD did not score significantly higher than HD in any domain.

CONCLUSIONS

HD patients have a high prevalence of non-motor symptoms, which is even higher than in PD, and correlates with disease progression.

Chronic Paroxetine Treatment Prevents the Emergence of Abnormal Electroencephalogram Oscillations in Huntington's Disease Mice

Disturbance of rapid eye movement (REM) sleep appears early in both patients with Huntington's disease (HD) and mouse models of HD. Selective serotonin reuptake inhibitors are widely prescribed for patients with HD, and are also known to suppress REM sleep in healthy subjects. To test whether selective serotonin reuptake inhibitors can correct abnormal REM sleep and sleep-dependent brain oscillations in HD mice, we treated wild-type and symptomatic R6/2 mice acutely with vehicle and paroxetine (5, 10, and 20 mg/kg). In addition, we treated a group of R6/2 mice chronically with vehicle or paroxetine (20 mg/kg/day) for 8 weeks, with treatment starting before the onset of overt motor symptoms. During and after treatment, we recorded electroencephalogram/electromyogram from the mice. We found that both acute and chronic paroxetine treatment normalized REM sleep in R6/2 mice. However, only chronic paroxetine treatment prevented the emergence of abnormal low-gamma (25-45 Hz) electroencephalogram oscillations in R6/2 mice, an effect that persisted for at least 2 weeks after treatment stopped. Chronic paroxetine treatment also normalized REM sleep theta rhythm in R6/2 mice, but, interestingly, this effect was restricted to the treatment period. By contrast, acute paroxetine treatment slowed REM sleep theta rhythm in WT mice but had no effect on abnormal theta or low-gamma oscillations in R6/2 mice. Our data show that paroxetine treatment, when initiated before the onset of symptoms, corrects both REM sleep disturbances and abnormal brain oscillations, suggesting a possible mechanistic link between early disruption of REM sleep and the subsequent abnormal brain activity in HD mice.

A single dose of hypnotic corrects sleep and EEG abnormalities in symptomatic Huntington's disease mice

Sleep and electroencephalogram abnormalities are prominent early features of Huntington's disease (HD) that typically appear before the onset of characteristic motor symptoms. The changes in sleep and electroencephalogram seen in HD patients are largely recapitulated in mouse models of HD such as transgenic R6/2 lines. To test whether or not drugs with hypnotic properties can correct the sleep and electroencephalogram abnormalities seen in HD mice, we treated male wild-type (WT; N = 7) and R6/2 mice (N = 9) acutely with intraperitoneal injections of vehicle, zolpidem (5, 10 or 20 mg/kg) or amitriptyline (5, 10 or 20 mg/kg), and then monitored their sleep-wake behavior. In R6/2 mice, both zolpidem and amitriptyline suppressed the abnormally high REM sleep amount and electroencephalographic gamma (30-46 Hz) oscillations in a dose-dependent manner. Amitriptyline's effect on sleep was similar in both genotypes, whereas zolpidem showed significant genotype differences. Zolpidem exerted a strong hypnotic effect in WT mice by increasing electroencephalographic delta power, doubling the mean bout duration and the total amount of non-rapid eye movement sleep. However, no such effect was seen in R6/2 mice. Our study demonstrates that the pathophysiological changes seen in sleep and electroencephalogram are not 'hard-wired' in HD brain and can be reversed even at late stages of the disease. The diminished hypnotic effect of zolpidem suggests that the GABAergic control of sleep-wake states is impaired in HD mice. A better understanding of the neurochemical basis underlying these abnormalities should lead to more effective and rational therapies for HD.

Therapeutic strategies for circadian rhythm and sleep disturbances in Huntington disease

Aside from the well-known motor, cognitive and psychiatric signs and symptoms, Huntington disease (HD) is also frequently complicated by circadian rhythm and sleep disturbances. Despite the observation that these disturbances often precede motor onset and have a high prevalence, no studies are available in HD patients which assess potential treatments. In this review, we will briefly outline the nature of circadian rhythm and sleep disturbances in HD and subsequently focus on potential treatments based on findings in other neurodegenerative diseases with similarities to HD, such as Parkinson and Alzheimer disease. The most promising treatment options to date for circadian rhythm and sleep disruption in HD include melatonin (agonists) and bright light therapy, although further corroboration in clinical trials is warranted.

Early-onset sleep defects in Drosophila models of Huntington's disease reflect alterations of PKA/CREB signaling

Huntington's disease (HD) is a progressive neurological disorder whose non-motor symptoms include sleep disturbances. Whether sleep and activity abnormalities are primary molecular disruptions of mutant Huntingtin (mutHtt) expression or result from neurodegeneration is unclear. Here, we report Drosophila models of HD exhibit sleep and activity disruptions very early in adulthood, as soon as sleep patterns have developed. Pan-neuronal expression of full-length or N-terminally truncated mutHtt recapitulates sleep phenotypes of HD patients: impaired sleep initiation, fragmented and diminished sleep, and nighttime hyperactivity. Sleep deprivation of HD model flies results in exacerbated sleep deficits, indicating that homeostatic regulation of sleep is impaired. Elevated PKA/CREB activity in healthy flies produces patterns of sleep and activity similar to those in our HD models. We were curious whether aberrations in PKA/CREB signaling were responsible for our early-onset sleep/activity phenotypes. Decreasing signaling through the cAMP/PKA pathway suppresses mutHtt-induced developmental lethality. Genetically reducing PKA abolishes sleep/activity deficits in HD model flies, restores the homeostatic response and extends median lifespan. In vivo reporters, however, show dCREB2 activity is unchanged, or decreased when sleep/activity patterns are abnormal, suggesting dissociation of PKA and dCREB2 occurs early in pathogenesis. Collectively, our data suggest that sleep defects may reflect a primary pathological process in HD, and that measurements of sleep and cAMP/PKA could be prodromal indicators of disease, and serve as therapeutic targets for intervention.

Sleep Physiology Alterations Precede Plethoric Phenotypic Changes in R6/1 Huntington's Disease Mice

In hereditary neurodegenerative Huntington’s disease (HD), there exists a growing consideration that sleep and circadian dysregulations may be important symptoms. It is not known, however, whether sleep abnormalities contribute to other behavioral deficits in HD patients and mouse models. To determine the precise chronology for sleep physiology alterations and other sensory, motor, psychiatric and cognitive symptoms of HD, the same R6/1 HD transgenics and their wild-type littermates were recorded monthly for sleep electroencephalogram (EEG) together with a wide range of behavioral tests according to a longitudinal plan. We found an early and progressive deterioration of both sleep architecture and EEG brain rhythms in R6/1 mice, which are correlated timely with their spatial working memory impairments. Sleep fragmentation and memory impairments were accompanied by the loss of delta (1-4Hz) power in the transgenic mice, the magnitude of which increased with age and disease progression. These precocious sleep and cognitive impairments were followed by deficits in social behavior, sensory and motor abilities. Our data confirm the existence and importance of sleep physiology alterations in the widely used R6/1 mouse line and highlight their precedence over other plethoric phenotypic changes. The brainwave abnormalities, may represent a novel biomarker and point to innovative therapeutic interventions against HD.

REM Sleep Behaviour Disorder in a Child with Tourette's Syndrome

Purpose:

To describe an association of Tourette's syndrome with rapid eye movement sleep behaviour disorder (RBD) in a prepubescent boy.

Methods:

A four year longitudinal single-case study.

Results:

The co-existence of Tourette's syndrome and RBD was confirmed after polysomnographic studies using the standard criteria. The authors propose possible overlap in the pathophysiological mechanisms underlying the two disorders.

'The clocks that time us'--circadian rhythms in neurodegenerative disorders

Circadian rhythms are physiological and behavioural cycles generated by an endogenous biological clock, the suprachiasmatic nucleus. The circadian system influences the majority of physiological processes, including sleep-wake homeostasis. Impaired sleep and alertness are common symptoms of neurodegenerative disorders, and circadian dysfunction might exacerbate the disease process. The pathophysiology of sleep-wake disturbances in these disorders remains largely unknown, and is presumably multifactorial. Circadian rhythm dysfunction is often observed in patients with Alzheimer disease, in whom it has a major impact on quality of life and represents one of the most important factors leading to institutionalization of patients. Similarly, sleep and circadian problems represent common nonmotor features of Parkinson disease and Huntington disease. Clinical studies and experiments in animal models of neurodegenerative disorders have revealed the progressive nature of circadian dysfunction throughout the course of neurodegeneration, and suggest strategies for the restoration of circadian rhythmicity involving behavioural and pharmacological interventions that target the sleep-wake cycle. In this Review, we discuss the role of the circadian system in the regulation of the sleep-wake cycle, and outline the implications of disrupted circadian timekeeping in neurodegenerative diseases.

Inter-expert and intra-expert reliability in sleep spindle scoring

OBJECTIVES

To measure the inter-expert and intra-expert agreement in sleep spindle scoring, and to quantify how many experts are needed to build a reliable dataset of sleep spindle scorings.

METHODS

The EEG dataset was comprised of 400 randomly selected 115s segments of stage 2 sleep from 110 sleeping subjects in the general population (57±8, range: 42-72 years). To assess expert agreement, a total of 24 Registered Polysomnographic Technologists (RPSGTs) scored spindles in a subset of the EEG dataset at a single electrode location (C3-M2). Intra-expert and inter-expert agreements were calculated as F1-scores, Cohen's kappa (κ), and intra-class correlation coefficient (ICC).

RESULTS

We found an average intra-expert F1-score agreement of 72±7% (κ: 0.66±0.07). The average inter-expert agreement was 61±6% (κ: 0.52±0.07). Amplitude and frequency of discrete spindles were calculated with higher reliability than the estimation of spindle duration. Reliability of sleep spindle scoring can be improved by using qualitative confidence scores, rather than a dichotomous yes/no scoring system.

CONCLUSIONS

We estimate that 2-3 experts are needed to build a spindle scoring dataset with 'substantial' reliability (κ: 0.61-0.8), and 4 or more experts are needed to build a dataset with 'almost perfect' reliability (κ: 0.81-1).

SIGNIFICANCE

Spindle scoring is a critical part of sleep staging, and spindles are believed to play an important role in development, aging, and diseases of the nervous system.

Progressive sleep and electroencephalogram changes in mice carrying the Huntington's disease mutation

Sleep disturbances in Huntington's disease may be deleterious to the cognitive performance, affective behaviour, and general well-being of patients, but a comprehensive description of the progression of changes in sleep and electroencephalogram in Huntington's disease has never been conducted. Here we studied sleep and electroencephalogram disturbances in a transgenic mouse model of Huntington's disease (R6/2 mice). We implanted 10 R6/2 mice and five wild-type littermates with electromyography electrodes, frontofrontal and frontoparietal electroencephalogram electrodes and then recorded sleep/wake behaviour at presymptomatic, symptomatic and late stages of the disease. In addition to sleep-wake scoring, we performed a spectral analysis of the sleep electroencephalogram. We found that sleep and electroencephalogram were already significantly disrupted in R6/2 mice at 9 weeks of age (presymptomatic stage). By the time they were symptomatic, R6/2 mice were unable to maintain long periods of wakefulness and had an increased propensity for rapid eye movement sleep. In addition, the peak frequency of theta rhythm was shifted progressively from 7 Hz to 6 Hz during rapid eye movement sleep, whereas slow wave activity decreased gradually during non-rapid eye movement sleep. Finally, as the disease progressed, an abnormal electroencephalogram gamma activity (30-40 Hz) emerged in R6/2 mice irrespective of sleep states. This is reminiscent of the increased gamma power described in schizophrenic patients during sleep and events of psychosis. Gaining a better understanding of sleep and electroencephalogram changes in patients with Huntington's disease should be a priority, since it will enable clinicians to initiate appropriate investigations and to instigate treatments that could dramatically improve patients' quality of life.

Circadian and sleep disorder in Huntington's disease

Huntington's disease is a progressive neurological disorder that starts insidiously with motor, cognitive or psychiatric disturbance, and progresses through a distressing range of symptoms to end with a devastating loss of function, both motor and executive. There is a growing awareness that, in addition to cognitive and psychiatric symptoms, there are other important non-motor symptoms in HD, including sleep and circadian abnormalities. It is not clear if sleep-wake changes are caused directly by HD gene-related pathology, or if they are simply a consequence of having a neurodegenerative disease. From a patient point of view, the answer is irrelevant, since sleep and circadian disturbances are deleterious to good daily living, even in neurologically normal people. The assumption should be that, at the very least, sleep and/or circadian disturbance in HD patients will contribute to their symptoms. At worst, they may contribute to the progressive decline in HD. Here I review the state of our understanding of sleep and circadian abnormalities in HD. I also outline a set of simple rules that can be followed to improve the chances of a good night's sleep, since preventing any 'preventable' symptoms is the a logical first step in treating disease. The long-term impact of sleep disruption in HD is unknown. There have been no large-scale systematic studies of in sleep in HD. Furthermore, there has never been a study of the efficacy of pharmaceuticals that are typically used to treat sleep deficits in HD patients. Thus treatment of sleep disturbance in HD is necessarily empirical. A better understanding of the relationship between sleep/circadian abnormalities and HD pathology is needed, if treatment of this aspect of HD is to be optimized.

Asymptomatic sleep abnormalities are a common early feature in patients with Huntington's disease

Huntington's disease (HD) is a fatal neurodegenerative disease characterized by motor, cognitive, and psychiatric disturbance. In this article, we used polysomnography, actigraphy and a variety of validated questionnaires to ascertain the extent to which sleep changes are identifiable and measurable in mild stage HD, and importantly, to see whether patients are negatively impacted by the changes in their sleep. We found significant differences in sleep architecture and sleep efficiency in patients compared with controls using polysomnography. However, patient scores on the Functional Outcomes of Sleep Questionnaire, Medical Outcomes of Sleep Scale, and Epworth Sleepiness Scale were not significantly different to controls. These results suggest that although marked changes in sleep architecture are present in early HD and can be detected using polysomnography, patients do not necessarily recognize or report these abnormalities.

Neuroacanthocytosis

The term "neuroacanthocytosis" describes a heterogeneous group of molecularly-defined disorders which result in progressive neurodegeneration, predominantly of the basal ganglia, and erythrocyte acanthocytosis. The clinical presentation of neuroacanthocytosis syndromes typically involves chorea and dystonia, but a range of other movement disorders may be seen. Psychiatric and cognitive symptoms may be prominent. There can be considerable phenotypic overlap; however, features of inheritance, age of onset, neuroimaging and laboratory findings, in addition to the spectrum of central and peripheral neurological abnormalities and extraneuronal involvement, can help to distinguish the specific syndromes. The two core neuroacanthocytosis syndromes, in which acanthocytosis is a typical, although not invariable finding, are autosomal recessive chorea-acanthocytosis and X-linked McLeod syndrome. Acanthocytes are found in a smaller proportion of patients with Huntington's disease-like 2 and pantothenate kinase-associated neurodegeneration. Additionally, acanthocytosis has been reported in a few patients with other neurological disorders. The causative genes do not appear to be linked by a specific function or pathway, although abnormalities of membrane processing may be implicated. The connection between the erythrocyte membrane abnormality, which results in the characteristic "thorny" protrusions, the vulnerability of the basal ganglia, and the respective genetic mutations, is obscure.

Identifying sleep disturbances in Huntington's disease using a simple disease-focused questionnaire

Sleep disturbances have been shown to affect patients with various neurological diseases, including Huntington’s disease (HD). We therefore aimed to develop a sleep questionnaire that could be used by clinicians to help identify sleep disturbances in patients with the disease.

Design

A detailed questionnaire was used that was modelled on recent sleep questionnaires used for Parkinson’s disease patients, and developed after consultation with sleep specialists. This questionnaire contained 45 questions that focused on different sleep-related issues such as duration, quality of sleep, abnormal nocturnal behaviour and quality of life.

Setting

Questionnaires were either completed in the home environment or in clinic.

Participants

66 patients, 38 carers and 60 non-carers were recruited.

Measurements & Results

Various sleep-related difficulties were identified in a significantly greater proportion of HD patients compared to control subjects, with both quality and quantity of sleep being affected.

Conclusions

Disturbed sleep in HD may contribute towards the deterioration of the patient’s ability to do activities of daily living and have a significantly deleterious effect on the quality of life of both patients and carers. This simple questionnaire should aid the clinician by providing subjective insight into the patient’s sleep patterns that could enable more effective, individual-specific treatment to be instigated and ultimately improve quality of life.

Sleep and circadian rhythm alterations correlate with depression and cognitive impairment in Huntington's disease

OBJECTIVE

Sleep disturbances are a prominent feature of Huntington's disease (HD) and can substantially impair patients' quality of life. However, sleep complaints and their association with other symptoms and signs of HD have not yet been assessed in large groups of patients or premanifest mutation carriers. Therefore, we aimed to delineate the nature of subjective sleep disturbances and identify important correlates of sleep impairment in HD patients and premanifest mutation carriers.

SUBJECTS & METHODS

Using standardized questionnaires (including Epworth's Sleepiness Scale, Pittsburgh Sleep Quality Index, SCOPA-SLEEP, and Beck's Depression Inventory), daytime sleepiness, night-time sleep, and depressed mood were assessed in 63 HD patients, 21 premanifest mutation carriers and 84 controls.

RESULTS

Night-time sleep impairment was significantly more prevalent in HD patients compared with controls (58.1% vs. 34.9%, p = 0.012), but daytime sleepiness was not (12.7% vs. 7.9%, p = 0.560). Depression was the only independent correlate of night-time sleep impairment in HD patients, accounting for 10% of the variance. Compared with controls, both sleep onset latency and wake-up time were significantly delayed in HD patients. Moreover, in HD patients, later wake-up time was significantly associated with cognitive score (r = -0.43), total functional capacity (r = -0.54) and depressive symptoms (r = +0.47). In general, the degree of sleep (phase) changes in premanifest mutation carriers lay in between those of HD patients and controls.

CONCLUSIONS

HD is primarily accompanied by night-time sleep disturbances and a delayed sleep phase, which are associated with depression and lower cognitive as well as functional performance.

Increased numbers of motor activity peaks during light cycle are associated with reductions in adrenergic alpha(2)-receptor levels in a transgenic Huntington's disease rat model

Huntington's disease (HD) is a neurodegenerative disorder caused by a CAG repeat expansion in the HD gene. Besides psychiatric, motor and cognitive symptoms, HD patients suffer from sleep disturbances. In order to screen a rat model transgenic for HD (tgHD rats) for sleep-wake cycle dysregulation, we monitored their circadian activity peaks in the present study. TgHD rats of both sexes showed hyperactivity during the dark cycle and more frequent light cycle activity peaks indicative for a disturbed sleep-wake cycle. Focusing on males at the age of 4 and 14 months, analyses of receptor levels in the hypothalamus and the basal forebrain revealed that 5-HT(2A)- and adrenergic alpha(2)-receptor densities in these regions were significantly altered in tgHD rats compared to their wild-type littermates. Adrenergic receptor densities correlated negatively with the light cycle hyperactivity peaks at later stages of the disease in male tgHD rats. Furthermore, reduced leptin levels, a feature associated with circadian misalignment, were present. Our study demonstrates that the male tgHD rat is a suitable model to investigate HD associated sleep alterations. Further studies are warranted to elucidate the role of adrenergic- and 5-HT(2A)-receptors as therapeutic targets for dysregulation of the circadian activity in HD.

The current clinical management of Huntington's disease

Huntington's disease is a neurodegenerative condition, characterized by movement disorders, cognitive decline, and psychiatric disturbance. We review the pharmacological management of the various movement disorders associated with the disease, the cognitive decline and the commonly encountered behavioral disturbances. We discuss the nonclassical features of the disease, important in the management of these patients. Nonpharmacological support including genetic counseling and therapy and the importance of palliative care are also addressed. Finally, experimental approaches that may soon impact upon clinical practice are discussed.

Huntington's disease. Part 1: essential background and management

Huntington's disease is a neurodegenerative disorder that manifests in motor, cognitive and behavioural symptoms, gradually progressing over a number of years, if not decades. The complexity and unpredictability of the disease poses challenges for health-and social-care professionals. This article provides an essential background to the understanding and management of care for people with Huntington's disease, presenting a discussion of the main stages to highlight the symptoms and challenges associated with the disease. The article then moves on to discuss potential management and therapy issues identifying some key considerations in the treatment of the disease. Finally, the combined role of the multidisciplinary team is highlighted in providing health and social care to people with Huntington's disease as it progresses and increasing professional support is required.

Hypothalamic dysfunction and neuroendocrine and metabolic alterations in Huntington's disease: clinical consequences and therapeutic implications

Huntington's disease (HD) is a hereditary neurodegenerative disorder characterized by cognitive, psychiatric, behavioural and motor disturbances. Although the course of HD is also frequently complicated by unintended weight loss, sleep disturbances and autonomic nervous system dysfunction, the aetiology of these signs and symptoms remains largely unknown. In recent years, many novel findings from both animal and human studies have emerged that indicate considerable hypothalamic, endocrine and metabolic alterations in HD. However, a comprehensive overview of these findings is lacking and their precise clinical significance is far from clear. Therefore, in this review we attempt to put these recent developments in the field into perspective by integrating them with previous findings in a comprehensible manner, and by discussing their clinical relevance, with a special focus on body weight, sleep and autonomic functions in HD, which will also allow for the identification of future lines of research in this area.

Pharmacological imposition of sleep slows cognitive decline and reverses dysregulation of circadian gene expression in a transgenic mouse model of Huntington's disease

Transgenic R6/2 mice carrying the Huntington's disease (HD) mutation show disrupted circadian rhythms that worsen as the disease progresses. By 15 weeks of age, their abnormal circadian behavior mirrors that seen in HD patients and is accompanied by dysregulated clock gene expression in the circadian pacemaker, the suprachiasmatic nucleus (SCN). We found, however, that the electrophysiological output of the SCN assayed in vitro was normal. Furthermore, the endogenous rhythm of circadian gene expression, monitored in vitro by luciferase imaging of organotypical SCN slices removed from mice with disintegrated behavioral rhythms, was also normal. We concluded that abnormal behavioral and molecular circadian rhythms observed in R6/2 mice in vivo arise from dysfunction of brain circuitry afferent to the SCN, rather than from a primary deficiency within the pacemaker itself. Because circadian sleep disruption is deleterious to cognitive function, and cognitive decline is pronounced in R6/2 mice, we tested whether circadian and cognitive disturbances could be reversed by using a sedative drug to impose a daily cycle of sleep in R6/2 mice. Daily treatment with Alprazolam reversed the dysregulated expression of Per2 and also Prok2, an output factor of the SCN that controls behavioral rhythms. It also markedly improved cognitive performance of R6/2 mice in a two-choice visual discrimination task. Together, our data show for the first time that treatments aimed at restoring circadian rhythms may not only slow the cognitive decline that is such a devastating feature of HD but may also improve other circadian gene-regulated functions that are impaired in this disease.

Developments in neuroacanthocytosis: Expanding the spectrum of choreatic syndromes

As with other neurodegenerative disorders, research into the group of diseases known under the umbrella term of "neuroacanthocytosis" has greatly benefited from the identification of causative genes. The distinct and unifying aspect of these disorders is the presence of thorny deformations of circulating erythrocytes. This may be due to abnormal properties of red cell membranes, which could lead to insights into mechanisms of neurodegeneration. Research approaches in this field, in addition to examining functions and protein interactions of the affected proteins with particular respect to neurons, have also drawn upon the expertise of hematologists and red cell membrane biologists. In this article, recent developments in the field are presented.

Hypothalamic-endocrine aspects in Huntington's disease

Huntington's disease (HD) is a hereditary and fatal disorder caused by an expanded CAG triplet repeat in the HD gene, resulting in a mutant form of the protein huntingtin. Wild-type and mutant huntingtin are expressed in most tissues of the body but the normal function of huntingtin is not fully known. In HD, the neuropathology is characterized by intranuclear and cytoplasmic inclusions of huntingtin aggregates, and cell death primarily in striatum and cerebral cortex. However, hypothalamic atrophy occurs at early stages of HD with loss of orexin- and somatostatin-containing cell populations. Several symptoms of HD such as sleep disturbances, alterations in circadian rhythm, and weight loss may be due to hypothalamic dysfunction. Endocrine changes including increased cortisol levels, reduced testosterone levels and increased prevalence of diabetes are found in HD patients. In HD mice, alterations in the hypothalamic-pituitary-adrenal axis occurs as well as pancreatic beta-cell and adipocyte dysfunction. Increasing evidence points towards important pathology of the hypothalamus and the endocrine system in HD. As many neuroendocrine factors are secreted into the cerebrospinal fluid, blood and urine, it is possible that their levels may reflect the disease state in the central nervous system. Investigating neuroendocrine changes in HD opens up the possibility of finding biomarkers to evaluate future therapies for HD, as well as of identifying novel targets for therapeutic interventions.

Periodic limb movements and other movement disorders in sleep: neuropsychiatric dimensions

Movement disorders such as Parkinson's disease and Tourette's syndrome, primarily manifest during wakefulness, intrude into sleep. There are some disorders, however, such as periodic limb movements in sleep, restless legs syndrome, paroxysmal nocturnal dystonia, bruxism, and somnambulism, which occur primarily during sleep. The diagnosis and management of these disorders pose a challenge to neuropsychiatric practice, not only because they may be difficult to distinguish from other neuropsychiatric disorders, but also because psychiatric disorders are often co-morbid with them. Study of these disorders is necessary for an understanding of the interaction of sleep and movement, and how disturbance in one may affect the other.

Tourette syndrome and chronic tics in a sample of children and adolescents

Forty-eight subjects with Tourette syndrome (M 36, F 12; mean age 11.2 years) and 48 with chronic tic disorder (M 33, F 15; mean age 12.1 years) were recruited in order to study the vertical transmission within families of a vulnerability to tic disorders or to other psychiatric disorders, the role of adverse pre- and perinatal events, and the presence of comorbid psychiatric conditions. As control group, 30 matched, psychiatrically unaffected subjects (M 20, F 10; mean age 10.8 years) were chosen. Screening measures included detailed anamnestic data, focused on family history of tics and other psychiatric disorders, prenatal events and birth. Subjects and parents were also questioned about psychiatric comorbidity. Group differences were compared using Fisher Test. Subjects with Tourette syndrome and those with chronic tic were similar to each other and different from controls in family history of tic disorders, pre- and perinatal events, and some comorbid psychiatric disorders (attention deficit hyperactivity disorder, sleep problems, and mood disorders). Tourette syndrome and chronic tic group were different in family history of obsessive-compulsive disorder and in comorbidity for obsessive-compulsive disorder and other anxiety disorders. Tourette syndrome and obsessive-compulsive disorder were significantly associated in this sample. These findings seem to indicate that Tourette syndrome and chronic tic disorder are part of the same disease entity, with Tourette syndrome being a more severe and complex form of tic disorder.

Disintegration of the sleep-wake cycle and circadian timing in Huntington's disease

Sleep disturbances in neurological disorders have a devastating impact on patient and carer alike. However, their pathological origin is unknown. Here we show that patients with Huntington's disease (HD) have disrupted night-day activity patterns. This disruption was mirrored in a transgenic model of HD (R6/2 mice) in which daytime activity increased and nocturnal activity fell, eventually leading to the complete disintegration of circadian behavior. The behavioral disturbance was accompanied by marked disruption of expression of the circadian clock genes mPer2 and mBmal1 in the suprachiasmatic nuclei (SCN), the principal circadian pacemaker in the brain. The circadian peak of expression of mPer2 was prematurely truncated, and the mRNA levels of mBmal1 were attenuated and failed to exhibit a significant circadian oscillation. Circadian cycles of gene expression in the motor cortex and striatum, markers of behavioral activation in wild-type mice, were also suppressed in the R6/2 mice, providing a neural correlate of the disturbed activity cycles. Increased daytime activity was also associated with reduced SCN expression of prokineticin 2, a transcriptional target of mBmal1 encoding a neuropeptide that normally suppresses daytime activity in nocturnal mammals. Together, these molecular abnormalities could explain the pathophysiological changes in circadian behavior. We propose that circadian sleep disturbances are an important pathological feature of HD, that they arise from pathology within the SCN molecular oscillation, and that their treatment will bring appreciable benefits to HD patients.

The use of the Actiwatch–Neurologica® system to objectively assess the involuntary movements and sleep–wake activity in patients with mild–moderate Huntington’s disease

Huntington's disease (HD) is a neurodegenerative disorder characterised by cognitive, psychiatric and motor abnormalities including a range of involuntary movements. Currently, assessment of these movements involves the use of subjective rating scales such as the Unified Huntington's Disease Rating Scales (UHDRS) for bradykinesia and maximal dystonia and chorea, without any objective measures. As new therapies emerge, it is critical that an objective means of evaluating these abnormal movements is developed and we have investigated the use of a wrist-worn activity monitor, the Actiwatch-Neurologica, to determine whether these movements can be measured. In addition, this activity monitor and subjective reports were used to objectively measure the degree of sleep disruption in these same HD patients. Eight patients with mild-moderate HD and 8 age- and sex-matched control subjects wore the monitor for a period of 48 hours and recorded in a diary whether they were asleep or awake for each hour over the 2-day period. Assessment of various movement parameters revealed that HD patients exhibited significantly greater total and maximum activity levels and spent longer performing high acceleration movements while they were awake compared with controls. During sleep, patients not only showed significantly more activity and spent more time making high acceleration movements, but they also made significantly more movements than control subjects. These results demonstrate that the Actiwatch-Neurologica activity monitor can be used to objectively assess movements in HD patients during periods of high activity as well as during sleep.

Long-term effects of striatal lesions on c-Fos immunoreactivity in the pedunculopontine nucleus

The basal ganglia are a group of subcortical nuclei classically thought to be involved in the control of movement, and they have reciprocal connections with the cortex, thalamus and structures in the brainstem. Recent findings suggest that the basal ganglia interact with structures involved in the control of the sleep-waking cycle. The pedunculopontine tegmental nucleus (PPN) maintains a close relationship with the basal ganglia and is intimately involved in the regulation of wakefulness and REM sleep. This study evaluated changes in activity of PPN neurons following striatal kainic acid-induced lesions. Rats were injected in the anterodorsal striatum with either kainic acid or vehicle and allowed to recover for 7 or 30 days. The results showed an increase in the number of c-Fos+ cells in the PPN 30 days but not 7 days after the striatal lesion, when motor hyperactivity was no longer detected. In addition, we found a significant correlation between the ventricular brain ratio, as an indicator of lesion size, and the number of c-Fos+ cells in the PPN. Furthermore, the spatial distribution of cell types suggested that most c-Fos+ cells in the PPN were not cholinergic. These results provide new insights into the functional relationship between the basal ganglia and the PPN and suggest that the striatum, through its indirect influence on the PPN, may contribute to the regulation of wakefulness and cortical activation.

Dyskinesias and associated psychiatric disorders following streptococcal infections

BACKGROUND

The classical extrapyramidal movement disorder following beta haemolytic streptococcus (BHS) infection is Sydenham's chorea (SC). Recently, other post-streptococcal movement disorders have been described, including motor tics and dystonia. Associated emotional and behavioural alteration is characteristic.

AIMS

To describe experience of post-streptococcal dyskinesias and associated co-morbid psychiatric features presenting to a tertiary referral centre 1999-2002.

METHODS

In all patients, dyskinetic movement disorders followed BHS pharyngeal infection. BHS infection was defined by pharyngeal culture of the organism, or paired streptococcal serology. Movement disorders were classified according to international criteria, and validated by experienced child neurologists. Psychiatric complications were defined using ICD-10 criteria using a validated psychiatric interview.

RESULTS

In the 40 patients, the following dyskinetic movement disorders were present: chorea (n = 20), motor tics (n = 16), dystonia (n = 5), tremor (n = 3), stereotypies (n = 2), opsoclonus (n = 2), and myoclonus (n = 1). Sixty five per cent of the chorea patients were female, whereas 69% of the tic patients were male. ICD-10 psychiatric diagnoses were made in 62.5%. Using the same psychiatric instrument, only 8.9% of UK children would be expected to have an ICD-10 psychiatric diagnosis. Emotional disorders occurred in 47.5%, including obsessive-compulsive disorder (27.5%), generalised anxiety (25%), and depressive episode (17.5%). Additional psychiatric morbidity included conduct disorders (27.5%) and hyperkinetic disorders (15%). Psychiatric, movement, and post-streptococcal autoimmune disorders were commonly observed in family members. At a mean follow up of 2.7 years, 72.5% had continuing movement and psychiatric disorders.

CONCLUSION

Post-streptococcal dyskinesias occur with significant and disabling psychiatric co-morbidity and are potential autoimmune models of common "idiopathic" movement and psychiatric disorders in children. Multiple factors may be involved in disease expression including genetic predisposition, developmental status, and the patient's sex.

Disturbed sleep in children with Tourette syndrome: a polysomnographic study

OBJECTIVE

To evaluate objective data on sleep quantity/quality and motor activity during night sleep in children with Tourette syndrome (TS).

METHOD

Polysomnography of 17 unmedicated TS children (ages: 7;11-15;5, mean: 11;10 years) without comorbid attention-deficit hyperactivity disorder (ADHD) was compared with 16 age-, sex- and IQ-matched healthy controls. Sleep analyses according to the procedure of Rechtschaffen and Kales were supplemented by counting epochs with short arousal-related movements (<or=15 s), thus allowing to calculate correlations between motor activity and sleep parameters.

RESULTS

Children with TS demonstrated changes in sleep parameters, including longer sleep period time, longer sleep latency, reduced sleep efficiency, and prolonged wakefulness after sleep onset. Their sleep profiles showed significantly more time awake and less sleep stage II. However, REM sleep variables, slow-wave sleep, and number of sleep stage changes were unaffected. Movement time was similar in both groups, but epochs with short arousal-related movements were increased in TS. Further analyses showed no significant correlations between sleep parameters and nighttime nontic movements, level of psychopathology or tic severity during daytime. Periodic limb movements during sleep (PLMS) were only seen in one TS patient (low PLMS index of 7.8/h).

CONCLUSIONS

Children with TS have disturbed sleep quality with increased arousal phenomena, which both may be intrinsic to the disorder and might trigger tics and other behavioral problems during daytime. This indicates the need for sleep evaluation in patients with TS.

Schlafstörungen bei kinder- und jugendpsychiatrischen Erkrankungen

Zusammenfassung: Schlafstörungen als Symptom zahlreicher kinder- und jugendpsychiatrischer Störungsbilder komplizieren häufig den Verlauf und die Behandlung der Grunderkrankung. Organische Störungen wie die Narkolepsie oder das Kleine-Levin-Syndrom können zu differentialdiagnostischen Schwierigkeiten und Fehleinschätzungen führen. Unklar ist, ob spezifische Veränderungen der Schlafarchitektur bereits im Kindes- und Jugendalter bestehen und damit als biologischer Trait-Marker für psychiatrische Erkrankungen zu verstehen sind. Während für das Erwachsenenalter die Bedeutung von Schlafstörungen vor allem für die Entwicklung späterer depressiver Störungen belegt werden konnte, ist derzeit offen, ob es sich bei persistierenden Schlafstörungen im Kindesalter um Vulnerabilitätsmarker für psychiatrische Erkrankungen handelt. In der vorliegenden Literaturübersicht sollen Wechselwirkungen zwischen Schlafstörung und psychischer Störung aufgezeigt und die Bedeutung der Berücksichtigung von Schlafstörungen für Diagnostik und Therapie kinder- und jugendpsychiatrischer Störungsbilder unterstrichen werden.

Behavioral and morphological comparison of two nonhuman primate models of Huntington's disease

OBJECTIVE

Huntington's disease is a progressive neurodegenerative disease characterized by movement disorder, cognitive deterioration, and selective striatal degeneration. No effective treatment exists, and thus stable primate models could aid in the development of novel therapies.

METHODS

Two primate models of Huntington's disease were analyzed: bilateral stereotactic intrastriatal injections of quinolinic acid (QA), and daily systemic intramuscular administration of 3-nitropropionic acid (3-NP) for up to 8 weeks in male Cebus apella monkeys. The animals' behavior was evaluated before, during, and 3 months after administration of the neurotoxin. Magnetic resonance imaging scans of the brain were obtained before and after treatment.

RESULTS

Frontal cognitive function as evaluated by object retrieval-detour task test demonstrated a marked deterioration in successful responses, with an increase in barrier reaches in both groups. No significant change in performance of fine motor tasks was observed. QA-treated animals displayed hyperactivity at night. Animals in both groups demonstrated abnormal posture, and the 3-NP-treated group showed spontaneous and apomorphine-induced dystonia and dyskinesia. The QA-treated group displayed large areas of increased signal on T2-weighted images in the caudate and putamen bilaterally. Treatment with 3-NP resulted in smaller lesions. Immunohistochemistry and morphometric analyses revealed that both groups had lesions in the striatum. A large area of neuronal loss with glial sparing was observed in the QA-treated group, including the caudate and putamen bilaterally. The 3-NP-treated group displayed smaller lesions restricted to the dorsolateral putamen.

CONCLUSION

These results suggest that both QA and 3-NP induce behavioral and morphological features that resemble the juvenile and akinetic-rigid variants of Huntington's disease, with the group with 3-NP-induced lesions displaying smaller lesions and spontaneous dyskinesia.

Sleep and brain lesions: a critical review of the literature and additional new cases

We present a comprehensive review of sleep studies performed in patients with brain lesions complemented by 16 additional personal selected cases and by discussion of the corresponding animal data. The reader is cautioned about the risk of establishing an erroneous correlation between abnormal sleep and a given disorder due to the important inter and intra variability of sleep parameters among individuals. Salient points are stressed: the high frequency of post-stroke sleep breathing disorders is becoming increasingly recognised and may, in the near future, change the way this condition is managed. Meso-diencephalic bilateral infarcts induce a variable degree of damage to both waking and non-REM sleep networks producing and abnormal waking and sometimes a stage 1 hypersomnia reduced by modafinil or bromocriptine, which can be considered as a syndrome of cathecholaminergic deficiency. Central pontine lesions induce REM and non-REM sleep insomnia with bilateral lateral gaze paralysis. Bulbar stroke leads to frequent sleep breathing disorders. Polysomnography can help define the extent of involvement of various degenerative diseases. Fragmented sleep in Parkinson's disease may be preceded by REM sleep behavioural disorders. Multiple system atrophies are characterised by important sleep disorganization. Sleep waking disorganization and a specific ocular REM pattern are often seen in supra-nuclear ophtalmoplegia. In Alzheimer patients, sleep perturbations parallel the mental deterioration and are possibly related to cholinergic deficiency. Fronto-temporal dementia may be associated with an important decrease in REM sleep. Few narcoleptic syndromes are reported to be associated with a tumour of the third ventricle or a multiple sclerosis or to follow a brain trauma; all these cases raise the question whether this is a simple coincidence, a revelation of a latent narcolepsy or, as in non-DR16/DQ5 patients, a genuine symptomatic narcolepsy. Trypanosomiasis and the abnormal prion protein precociously after sleep patterns. Polysomnography is a precious tool for evaluating brain function provided it is realised under optimal conditions in stable patients and interpreted with caution. Several unpublished cases are presented: one case of pseudohypersomnia due to a bilateral thalamic infarct and corrected by modafinil, four probable late-onset autosomal recessive cerebellar ataxias without sleep pattern anomalies, six cases of fronto-temporal dementia with strong reduction in total sleep time and REMS percentage on the first polysomnographic night, one case of periodic hypersomnia associated with a Rathke's cleft cyst and four cases of suspected symptomatic narcolepsy with a DR16-DQ5 haplotype, three of which were post-traumatic without MRI anomalies, and one associated with multiple sclerosis exhibiting pontine hyper signals on MRI.