Restless legs syndrome: diagnostic criteria, special considerations, and epidemiology. A report from the restless legs syndrome diagnosis and epidemiology workshop at the National Institutes of Health.

A large International Restless Legs Syndrome (RLS) Study Group has been formed. As its first task, the group has taken upon itself the role of definig the clinical features of the RLS. As minimal criteria for diagnosis, the group proposes the following four features: (a) desire to move the extremities, often associated with paresthesias/dysesthesias; (b) motor restlessness; (c) worsening of symptoms at rest with at least temporary relief by activity, and (d) worsening of symptoms in the evening or night. Other features commonly seen in RLS include sleep disturbance, periodic limb movements in sleep and similar involuntary movements while awake, a normal neurological examination in the idiopathic from, a tendency for the symptoms to be worse in middle to older age, and, in some cases, a family history suggestive of an autosomal dominant mode of inheritance.

Toward a better definition of the restless legs syndrome

Use of sleep hygiene in the treatment of insomnia.

Several theories claim that dreaming is a random by-product of REM sleep physiology and that it does not serve any natural function. Phenomenal dream content, however, is not as disorganized as such views imply. The form and content of dreams is not random but organized and selective: during dreaming, the brain constructs a complex model of the world in which certain types of elements, when compared to waking life, are underrepresented whereas others are over represented. Furthermore, dream content is consistently and powerfully modulated by certain types of waking experiences. On the basis of this evidence, I put forward the hypothesis that the biological function of dreaming is to simulate threatening events, and to rehearse threat perception and threat avoidance. To evaluate this hypothesis, we need to consider the original evolutionary context of dreaming and the possible traces it has left in the dream content of the present human population. In the ancestral environment human life was short and full of threats. Any behavioral advantage in dealing with highly dangerous events would have increased the probability of reproductive success. A dream-production mechanism that tends to select threatening waking events and simulate them over and over again in various combinations would have been valuable for the development and maintenance of threat-avoidance skills. Empirical evidence from normative dream content, children's dreams, recurrent dreams, nightmares, post traumatic dreams, and the dreams of hunter-gatherers indicates that our dream-production mechanisms are in fact specialized in the simulation of threatening events, and thus provides support to the threat simulation hypothesis of the function of dreaming.

https://www.unil.ch/files/live/sites/ln/files/shared/Revonsuo_1.pdf

The reinterpretation of dreams: An evolutionary hypothesis of the function of dreaming

Difficulties initiating or maintaining sleep are frequently encountered in patients with schizophrenia. Disturbed sleep can be found in 30–80% of schizophrenic patients, depending on the degree of psychotic symptomatology. Measured by polysomnography, reduced sleep efficiency and total sleep time, as well as increased sleep latency, are found in most patients with schizophrenia and appear to be an important part of the pathophysiology of this disorder. Some studies also reported alterations of stage 2 sleep, slow-wave sleep (SWS) and rapid eye movement (REM) sleep variables, i.e. reduced REM latency and REM density. A number of sleep parameters, such as the amount of SWS and the REM latency, are significantly correlated to clinical variables, including severity of illness, positive symptoms, negative symptoms, outcome, neurocognitive impairment and brain structure. Concerning specific sleep disorders, there is some evidence that schizophrenic patients carry a higher risk of experiencing a sleep-related breathing disorder, especially those demonstrating the known risk factors, including being overweight but also long-term use of antipsychotics. However, it is still unclear whether periodic leg movements in sleep or restless legs syndrome (RLS) are found with a higher or lower prevalence in schizophrenic patients than in healthy controls. There are no consistent effects of first-generation antipsychotics on measuresof sleep continuity and sleep structure, including the percentage of sleep stages or sleep and REM latency in healthy controls. In contrast to first-generation antipsychotics, the studied atypical antipsychotics (clozapine, olanzapine, quetiapine, risperidone, ziprasidone and paliperidone) demonstrate a relatively consistent effect on measures of sleep continuity, with an increase in either total sleep time (TST) or sleep efficiency, and individually varying effects on other sleep parameters, such as an increase in REM latency observed for olanzapine, quetiapine and ziprasidone, and an increase in SWS documented for olanzapine and ziprasidone in healthy subjects. The treatment of schizophrenic patients with first-generation antipsychotics is consistently associated with an increase in TST and sleep efficiency, and mostly an increase in REM latency, whereas the influence on specific sleep stages is more variable. On the other hand, withdrawal of such treatment is followed by a change in sleep structure mainly in the opposite direction, indicating a deterioration of sleep quality. On the background of the rather inconsistent effects of first-generation antipsychotics observed in healthy subjects, it appears possible that the high-potency drugs exert their effects on sleep in schizophrenic patients, for the most part, in an indirect way by suppressing stressful psychotic symptomatology. In contrast, the available data concerning second-generation antipsychotics (clozapine, olanzapine, risperidone and paliperidone) demonstrate a relatively consistent effect on measures of sleep continuity in patients and healthy subjects, with an increase in TST and sleep efficiency or a decrease in wakefulness. Additionally, clozapine and olanzapine demonstrate comparable influences on other sleep variables, such as SWS or REM density, in controls and schizophrenic patients. Possibly, the effects of second-generation antipsychotics observed on sleep in healthy subjects and schizophrenic patients might involve the action of these drugs on symptomatology, such as depression, cognitive impairment, and negative and positive symptoms. Specific sleep disorders, such as RLS, sleep-related breathing disorders, night-eating syndrome, somnambulism and rhythm disorders have been described as possible adverse effects of antipsychotics and should be considered in the differential diagnosis of disturbed or unrestful sleep in this population.

Sleep disturbances in patients with schizophrenia : impact and effect of antipsychotics.

Fluoxetine-induced sleep disturbance in depressed patients

Thyroid evaluation is frequently performed in patients with sleep apnea because of a suspected causal relationship between hypothyroidism and obstructive sleep apnea (OSA). The aim of this study was to determine the actual prevalence of hypothyroidism in patients referred for polysomnography and evaluate whether its rate was higher in patients with OSA than those without OSA. Ultrasensitive thyroid stimulating hormone (TSH) was performed on 255 of 279 consecutive patients referred for polysomnography from the neurology service of a large HMO. Hypothyroidism was detected in 1.6% (4/243) of all patients, 1.5% (3/194) of patients referred to evaluate OSA, and 2.0% of patients referred to evaluate the presence of periodic leg movement disorder (PLMD)/narcolepsy/parasomnia. There was no significant difference in rates of hypothyroidism in patients with documented OSA (2.9%, 3/103) compared to those without OSA (0.7%, 1/135). Two of the four patients with elevated TSHs had previously documented hypothyroidism and were on thyroxine replacement. Rates of hyperthyroidism were as high or higher than those of hypothyroidism in all groups. We conclude that thyroid screening does not appear to be appropriate for patients with suspected, or confirmed, OSA in the absence of signs or symptoms consistent with hypothyroidism or unless they are in a high risk group (women over the age of 60).

/pdf/are-thyroid-function-tests-necessary-in-patients-with-13qz1uhdyt.pdf

Are thyroid function tests necessary in patients with suspected sleep apnea

The purpose of this study was to evaluate passive body heating (PBH) as a treatment for insomnia in older adults. Polysomnographic recordings of older adults routinely show an increase in sleep fragmentation and a substantial decrease in slow-wave sleep (SWS) consistent with complaints of "lighter" more disturbed sleep. An increase in body temperature in young adults early in the evening by way of PBH has been shown to produce an increase in SWS in the early part of the sleep period. In a crossover design, nine female insomniacs (aged 60-72 yr) participated in two consecutive nights of PBH, involving hot (40-40.5 degrees C) and luke-warm (37.5-38.5 degrees C) baths 1.5 hours before bedtime. Significant improvement in sleep continuity and a trend toward an increase in SWS occurred after hot baths. Results of subjective measures showed that subjects experienced significantly "deeper" and more restful sleep after hot baths. In addition, hot baths resulted in a significant delay of temperature nadir in comparison to baseline nights.

Effects of passive body heating on the sleep of older female insomniacs

Reversal of sleep disturbances in cocaine- and heroin-dependent men during chronic buprenorphine treatment

To investigate nocturnal leg movement activity and other polysomnographic features in patients with neuroleptic-induced akathisia (NIA), all-night polysomnography was performed in nine patients with NIA and compared with nine healthy individuals and eight unmedicated patients with depression. Patients with NIA displayed a pattern of leg movement activity during sleep similar to healthy individuals and depressed patients. In addition, eight of nine patients with NIA exhibited 10- to 40-second bursts of increased leg muscle tone before sleep onset. Although the significance of this finding is unclear, it is possible that it may be a pathophysiological correlate of NIA.

Steven L. Cunningham

Papers

Fluoxetine-induced sleep disturbance in depressed patients

Are thyroid function tests necessary in patients with suspected sleep apnea

Effects of passive body heating on the sleep of older female insomniacs

Reversal of sleep disturbances in cocaine- and heroin-dependent men during chronic buprenorphine treatment

Polysomnographic characteristics of neuroleptic-induced akathisia.