Overview of sleep & sleep disorders.

Sleep is defined on the basis of behavioural and physiological criteria dividing it into two states: non rapid eye movement (NREM) sleep which is subdivided into three stages (N1, N2, N3); and rapid eye movement (REM) sleep characterized by rapid eye movements, muscle atonia and desynchronized EEG. Circadian rhythm of sleep-wakefulness is controlled by the master clock located in the suprachiasmatic nuclei of the hypothalamus. The neuroanatomical substrates of the NREM sleep are located principally in the ventrolateral preoptic nucleus of the hypothalamus and those of REM sleep are located in pons. A variety of significant physiological changes occur in all body systems and organs during sleep as a result of functional alterations in the autonomic and somatic nervous systems. The international classification of sleep disorders (ICSD, ed 2) lists eight categories of sleep disorders along with appendix A and appendix B. The four major sleep complaints include excessive daytime sleepiness, insomnia, abnormal movements or behaviour during sleep and inability to sleep at the desired time. The most important step in assessing a patient with a sleep complaint is obtaining a detailed history including family and previous histories, medical, psychiatric, neurological, drug, alcohol and substance abuse disorders. Some important laboratory tests for investigating sleep disorders consist of an overnight polysomnography, multiple sleep latency and maintenance of wakefulness tests as well as actigraphy. General physicians should have a basic knowledge of the salient clinical features of common sleep disorders, such as insomnia, obstructive sleep apnoea syndrome, narcolepsy-cataplexy syndrome, circadian rhythm sleep disorders (e.g., jet leg, shift work disorder, etc.) and parasomnias (e.g., partial arousal disorders, REM behaviour disorder, etc.) and these are briefly described in this chapter. The principle of treatment of sleep disorders is first to find cause of the sleep disturbance and vigorously treat the co-morbid conditions causing the sleep disturbance. If a satisfactory treatment is not available for the primary condition or does not resolve the problem, the treatment should be directed at the specific sleep disturbance. Most sleep disorders, once diagnosed, can be managed with limited consultations. The treatment of primary sleep disorders, however, is best handled by a sleep specialist. An overview of sleep and sleep disorders viz., Basic science; international classification and approach; and phenomenology of common sleep disorders are presented.

World Association of Sleep Medicine (WASM) 2016 standards for recording and scoring leg movements in polysomnograms developed by a joint task force from the International and the European Restless Legs Syndrome Study Groups (IRLSSG and EURLSSG).

This report presents the results of the work by a joint task force of the International and European Restless Legs Syndrome Study Groups and World Association of Sleep Medicine that revised and updated the current standards for recording and scoring leg movements (LM) in polysomnographic recordings (PSG). First, the background of the decisions made and the explanations of the new rules are reported and then specific standard rules are presented for recording, detecting, scoring and reporting LM activity in PSG. Each standard rule has been classified with a level of evidence. At the end of the paper, Appendix 1 provides algorithms to aid implementation of these new standards in software tools. There are two main changes introduced by these new rules: 1) Candidate LM (CLM), are any monolateral LM 0.5-10 s long or bilateral LM 0.5-15 s long; 2) periodic LM (PLM) are now defined by runs of at least four consecutive CLM with an intermovement interval ≥10 and ≤ 90 s without any CLM preceded by an interval <10 s interrupting the PLM series. There are also new options defining CLM associated with respiratory events. The PLM rate may now first be determined for all CLM not excluding any related to respiration (providing a consistent number across studies regardless of the rules used to define association with respiration) and, subsequently, the PLM rate should also be calculated without considering the respiratory related events. Finally, special considerations for pediatric studies are provided. The expert visual scoringof LM has only been altered by the new standards to require accepting all LM > 0.5 s regardless of duration, otherwise the technician scores the LM as for the old standards. There is a new criterion for the morphology of LM that applies only to computerized LM detection to better match expert visual detection. Available automatic scoring programs will incorporate all the new rules so that the new standards should reduce technician burden for scoring PLMS.

Proximal vs distal slowing of nerve conduction in chronic renal failure treated by long-term hemodialysis.

An F-wave conduction study was performed to determine proximal vs distal slowing of motor nerve conduction in the lower extremities in nine patients with chronic renal failure who were undergoing-long-term hemodialysis and in 11 normal control subjects. The values of the F-wave ratio and the difference between the longest and shortest F-wave latencies were significantly longer than the control values in five patients, implying predominant affection of the proximal peroneal nerve segments. In the remaining patients, the proximal and distal peroneal nerve segments were equally affected. The distal motor nerve conduction velocities of the posterior tibial nerves were also reduced, while the values for the median and ulnar nerves were generally within the normal range. It is important to study multiple F-wave characteristics, in addition to the conventional nerve conduction, for complete assessment of peripheral nerve function in these patients.

Electrophysiological study of hemiplegia. Motor nerve conduction velocity, brachial plexus latency, and electromyography.

Motor nerve conduction velocities of the ulnar and common peroneal but not the median nerves were substantially reduced in the affected limbs in a series of hemiplegic patients. Slowing of conduction velocity of the common peroneal nerve was related to the reduction of skin temperature in the hemiplegic limbs. Brachial plexus latencies to biceps and deltoid muscles were longer in the affected than in the unaffected sides in five of 12 hemiplegic patients. Electromyograms (EMGs) of limb muscles showed absence of spontaneous activity in 83% of patients. Spontaneous EMG activities in 12 of the 13 patients were related to an associated subclinical neuropathy or plexopathy in the involved limbs. Entrapment andtraction causing subclinical or clinical neuropathy or radiculopathy may be present in some hemiplegic patients.

Autonomic dysfunction and sleep apnea in olivopontocerebellar degeneration.

We studied ten men with olivopontocerebellar degeneration. Our findings of the autonomic deficits as manifested by orthostatic hypotension, impaired Valsalva's response, abnormal findings on cold pressor and mental arithmetic tests, and plasma renin and norepinephrine abnormalities in some patients with olivopontocerebellar degeneration suggested a defective central control of the sympathetic nervous system. Five patients had sleep apnea. Autonomic dysfunction and sleep apnea in olivopontocerebellar degeneration may result from degenerative lesions in the cerebellum and the brain stem.

Pure motor hemiplegia due to pyramidal infarction.

A 77-year-old man suddenly developed left hemiplegia without sensory impairment, visual or speech difficulties, loss of consciousness, or ataxia. He died one month later of pulmonary embolism, and a cystic infarction in the right medullary pyramid was the only lesion in the corticospinal system.

Localized myokymia caused by peripheral nerve injury.

One year after a gunshot wound in the popliteal fossa, a 30-year-old man began to experience cramps and myokymia in the left gastrocnemius muscle. Myokymia was characterized by vermicular fibrillary movements localized to the gastrocnemius muscle and accompanied by plantarflexion and dorsiflexion of the toes. Neurologic examination, nerve conduction velocities, electromyograms, and muscle biopsy findings showed affection of left common peroneal and posterior tibial nerves. The myokymia disappeared during sleep, spinal anesthesia, and treatment with carbamazepine.

Pure motor hemiplegia due to cerebral cortical infarction.

Although pure motor hemiplegia has not been reported after cerebral cortical infarction, occasional exceptions may occur. We provide three such examples. Necropsy study confirmed the site of lesion in one patient, and laboratory results (EEG and computerized axial tomography) suggested cortical involvement in the other two patients.

Hemiplegic amyotrophy. Muscle and motor point biopsy study.

Thirty hemiplegic patients had simple muscle atrophy with reduced mean muscle cross sectional areas (predominantly type II fiber atrophy) and complex, multiple, or enlarged subneural apparatuses, many of which resembled subhuman endplates. Ultrastructural observations in a few patients revealed nonspecific responses of damage to sarcolemma and myofibrils. There was no correlation between structural changes and alteration of tone, sensory impairment, or site of lesion. We propose that hemiplegic amyotrophy results from a combination of disuse, loss of central "trophic" influence, and transsynaptic degeneration.

"Alpha-like" rhythms in electroencephalograms in coma after cariac arrest.

Electroencephalograms (EEGs) of 12 comatose patients showed "alpha-like" rhythms after cardiac arrest. Four patients revealed a stage II sleep pattern and two patients showed signs of reactivity in their EEGs. One patient recovered with minimal impairment of memory, one patient lived for 3 months, and 10 died 3 ot 30 days after cardiac arrest. Examination of the brain demonstrated the usual anoxic lesions in three patients and "respirator brain" in one. In three patients with ventral pontine syndrome, a somewhat similar EEG pattern, but with distinct differences in topography and reactivity, was observed. In order to recognize alpha-like rhythms in comatose patients after cardiac arrest, EEGs should be recorded daily for several days.

Diagnosis and treatment of sleep disorders caused by co-morbid disease.

Sleep disorders, both insomnia and hypersomnia, are commonly associated with various co-morbid conditions, including general medical and neurologic disorders, psychiatric illnesses, and secondary or symptomatic restless legs syndrome/periodic limb movements in sleep. Diagnosis of the co-morbidity is the first step in treatment, followed by an assessment of the sleep disturbance. This begins with a complete history and physical examination, followed by laboratory testing such as polysomnography, multiple sleep latency testing, and actigraphy. The treatment of sleep disorders caused by co-morbid conditions is discussed under seven categories, including the use of general measures (e.g., sleep hygiene, encouraging patients to develop good sleep habits, medication), treatment of the co-morbid condition, treatment of insomnia, treatment of excessive daytime somnolence, treatment of parasomnias, treatment of sleep-wake schedule disorders, and treatment of secondary or symptomatic restless legs syndrome.

Phasic tongue movements in human rapid eye-movement sleep.

Polygraphic recordings demonstrated complex tongue movements as unusual phasic phenomena during rapid-eye-movement (REM) sleep in patients with narcolepsy, sleep apnea syndrome, or posterior fossa lesions, and in normal controls. These tongue movements may counteract posterior displacement of the tongue to prevent obstructive sleep apnea, which may otherwise occur in REM sleep because of genioglossal hypotonia. Hypotonia affected not only the genioglossus but also other muscles innervated by pontomedullary neurons during non-REM-sleep-related apnea in patients with sleep apnea syndrome.

Posttraumatic delayed sleep phase syndrome.

Circadian rhythm sleep disorders may occur after traumatic brain injury. We describe a 48-year-old man who presented with sleep onset insomnia and cognitive dysfunction after a car accident. A diagnosis of delayed sleep phase syndrome (DSPS) was confirmed by sleep logs and actigraphy, which revealed sleep onset in the early morning hours and awakening around noon.

Thalamic neuroaxonal dystrophy and dementia in Hodgkin's disease.

The brain of a patient with Hodgkin's disease and dementia showed numerous dystrophic axons in the thalamus. In absence of lymphomatous cellular infiltration, necrosis, hemorrhage, demyelination, neuronal loss, or infection by opportunistic organisms, the axonal dystrophy in this patient appeared to be directly related to the Hodgkin's disease itself. Moreover, dementia as a nonmetastatic complication of Hodgkin's disease may have been the result of the thalamic axonal dystrophy.

Propriospinal myoclonus: a neurophysiologic analysis.

We are reporting a neurophysiologic analysis of two patients presenting with thoracoabdominal spontaneous muscle jerks. Polymyographic recordings showed myoclonic bursts with onset in the upper rectus abdominis or lower intercostal muscles followed by rostral propagation to the upper intercostal and caudal propagation to the abdominal muscles by slowly conducting pathways. Jerk-locked back-averaging did not show time-locked cortical or premovement potentials. Peroneal somatosensory evoked response, C-reflex, and intercostal nerve conduction were normal. These findings suggest a generator for the myoclonus in the midthoracic region of the spinal cord with up and down propagation by slowly conducting pathways, such as propriospinal fibers. This type of spinal myoclonus may thus be termed "propriospinal myoclonus," as suggested by Brown et al.

A physiologic and pharmacologic study in anticholinergic-responsive essential myoclonus.

We report the physiologic and pharmacologic analysis in two women, aged 18 and 17 years, with essential myoclonus. Both responded to benztropine mesylate and had been functioning normally. The physiologic analysis suggested ballistic movement overflow and audiogenic stimulus-sensitive myoclonus. The pharmacologic study showed a direct and mutual antagonism of physostigmine and anticholinergic agent on myoclonus, implying cholinergic hyperactivity in the pathophysiology of myoclonus.

Heat-sensitive myotonia in proximal myotonic myopathy.

Two siblings with proximal myotonic myopathy (PROMM), a hereditary disorder, had predominantly proximal weakness, pain, and gait impairment aggravated by warm temperatures. EMG of the deltoid showed sparse abnormal spontaneous activity at room temperature and with cooling. Warming induced frequent myotonic discharges and fibrillations. Profuse myotonia recorded at room temperature in the first dorsal interosseous abated following cooling. Repetitive stimulation did not reveal a decrement recording from distal muscles, but recording from the deltoid, in the one patient tested, revealed a significant decrement that did not improve with edrophonium. Myopathic motor units were recorded only in distal musculature. The myotonia of PROMM is provoked by heat and diminished by cold and may have a different physiologic basis than traditional myotonic syndromes.

Seizures in progressive supranuclear palsy.

Among 62 patients with progressive supranuclear palsy (PSP) seen over a 9-year period, we encountered seven who had seizure phenomena. We suggest that PSP patients have seizures more frequently than has been appreciated.

Viruslike particles in granulomatous angiitis of the central nervous system.

Neuropathologic examination of the brain of a 67-year-old woman with a 5-month history of progressive multiple neurologic deficits showed granulomatous angiitis of the small parenchymal and leptomeningeal blood vessels of the brain and spinal cord. Electron microscopy of formalin-fixed brain disclosed intranuclear viruslike particles resembling herpesvirus. Although definitive proof cannot be established without further virologic tests, this previously unreported finding suggests that some cases of granulomatous angiitis of the central nervous system may result from viral infection.

Glutamate dehydrogenase deficiency in patients with olivopontocerebellar atrophy.

Deficiency of glutamate dehydrogenase appears to be associated with a chronic progressive degenerative disorder manifesting parkinsonian extrapyramidal features, ataxia, supranuclear oculomotor dysfunction, a peripheral neuropathy and, in some cases, amyotrophy. The clinical features resemble those of the Dejerine-Thomas type of olivopontocerebellar atrophy. The data suggest autosomal dominant inheritance with low penetrance. Measurement of leukocyte glutamate dehydrogenase should be routinely performed in the evaluation of newly diagnosed or atypical cases of parkinsonism.