Periodic limb movements in syringomyelia and syringobulbia

Periodic Limb Movements Syndrome in Patients With Cerebral Small Vessel Disease: Protocol for a Prospective Observational Study

Background: Cerebrovascular diseases are the leading cause of cognitive decline and dementia. Therefore, the investigation of the potential ways to slow down the disease progression is an important research field. Periodic limb movements in sleep (PLMS) are known to be associated with transient changes in heart rate and blood pressure. These changes might influence the course of cerebral small vessel disease (cSVD). Nevertheless, the clinical significance of PLMS, particularly its influence on cardiovascular diseases course, is still controversial and underinvestigated.

Methods/design: Patients from 60 to 75 years old diagnosed with cSVD will undergo nocturnal polysomnography. Subjects with apnea/hypopnea index under 5 will be enrolled. Sleep quality and daytime functioning will be assessed at baseline with self-reported questionnaires. Brain MRI and cognitive assessment will be performed at baseline and in the 2-year follow-up. Progression of cSVD markers and cognitive dysfunction will be compared between patients with PLMS index (PLMI) equal to or more than 15 movements per hour of sleep and controls (PLMI <15/h).

Discussion: The negative role of PLMS in cSVD progression and related cognitive decline is expected. We suppose that patients with PLMS tend to worsen in cognitive performance more rapidly than age-, gender-, and comorbidity-matched controls. We also expect them to have more rapid white matter hyperintensities and other cSVD marker progression. The limitations of the study protocol are the short follow-up period, the absence of a treatment group, and inability to make a conclusion about causality.

Propriospinal myoclonus: clinical reappraisal and review of literature

OBJECTIVE

Propriospinal myoclonus (PSM) is a rare disorder with repetitive, usually flexor arrhythmic brief jerks of the trunk, hips, and knees in a fixed pattern. It has a presumed generation in the spinal cord and diagnosis depends on characteristic features at polymyography. Recently, a historical paradigm shift took place as PSM has been reported to be a functional (or psychogenic) movement disorder (FMD) in most patients. This review aims to characterize the clinical features, etiology, electrophysiologic features, and treatment outcomes of PSM.

METHODS

Re-evaluation of all published PSM cases and systematic scoring of clinical and electrophysiologic characteristics in all published cases since 1991.

RESULTS

Of the 179 identified patients with PSM (55% male), the mean age at onset was 43 years (range 6-88 years). FMD was diagnosed in 104 (58%) cases. In 12 cases (26% of reported secondary cases, 7% of total cases), a structural spinal cord lesion was found. Clonazepam and botulinum toxin may be effective in reducing jerks.

CONCLUSIONS

FMD is more frequent than previously assumed. Structural lesions reported to underlie PSM are scarce. Based on our clinical experience and the reviewed literature, we recommend polymyography to assess recruitment variability combined with a Bereitschaftspotential recording in all cases.

A case of reversible restless legs syndrome (RLS) and sleep-related eating disorder relapse triggered by acute right leg herpes zoster infection: literature review of spinal cord and peripheral nervous system contributions to RLS

Restless legs syndrome (RLS) is thought to be due to abnormalities of iron metabolism in the central nervous system; however, occasional cases are associated with lesions of the spinal cord, spinal rootlets, and peripheral nervous system. This is a case report of RLS exacerbated by shingles with a review of the literature of extra-cerebral lesions or disorders causing or contributing to RLS.

Periodic leg movements in sleep and periodic limb movement disorder: prevalence, clinical significance and treatment

Periodic leg movements in sleep (PLMS) are a frequent finding in polysomnography. The prevalence of PLMS is estimated to be 4-11% in adults. In childhood, PLMS rarely occur although medical conditions like sleep apnea syndrome or neuropsychiatric disorders can lead to high rates of PLMS. In the elderly, PLMS are also common in subjects without sleep disturbances. In sleep studies, PLMS are found most frequently in restless legs syndrome (RLS) and often occur in narcolepsy, sleep apnea syndrome and REM sleep behavior disorder. Some patients with otherwise unexplained insomnia or hypersomnia reveal an elevated number of PLMS, a condition defined as periodic limb movement disorder (PLMD). PLMS were found also in various medical and neurological disorders that do not primarily affect sleep. A summary of these is presented. In sleep disorders related to dopaminergic dysfunction such as RLS, PLMS are considered to be a symptom of the disease. In other disorders like primary insomnia, the clinical relevance of PLMS is still being controversially discussed. Studies with findings both pro and contra are referred. To date, only a few studies have evaluated the efficacy of therapeutic substances in reducing PLMS in PLMD patients. Their results need to be confirmed in controlled randomized trials.

Unilateral periodic limb movement in sleep after supratentorial cerebral infarction

We report a patient with involuntary right leg movements during sleep, which developed after acute ischemic stroke in the corona radiata. Nocturnal polysomnography confirmed the diagnosis of periodic limb movement in sleep (PLMS). Although the pathogenesis of PLMS is still controversial, it has been proposed that the loss of cortical or subcortical inhibition resulting from the pyramidal tract lesion might cause PLMS. The present case provides evidence to support this hypothesis.

Graves' disease associated with spasmodic truncal flexion

A 40-year-old Chinese man was admitted with 1-2 Hz spasmodic truncal flexion resembling myoclonus. He was known to be thyrotoxic, and had defaulted antithyroid therapy. Clinical examination revealed truncal flexion from contraction of the rectus abdominis, with no involvement of limbs or face and no jerking in sleep. He was biochemically thyrotoxic. Treatment with clonazepam and propylthiouracil resulted in resolution of the myoclonic jerks within the next 3 weeks. He stopped taking clonazepam within the next 3 months with no recurrence of myoclonus. He remained well until he stopped taking his antithyroid medications 9 months later, when he developed spasmodic truncal jerking again. Biochemical tests confirmed that he was hyperthyroid at this time. These movements ceased within a month of compliance with antithyroid therapy, and he has been well since. MRI of the brain and thoracic spine were unremarkable. Thyrotoxicosis is known to cause chorea and tremors, and has rarely been described in association with myoclonus.

Unique form of propriospinal myoclonus as a possible complication of an enteropathogenic toxin

Propriospinal myoclonus is an uncommon form of spinal myoclonus propagated, presumably, by slowly conducting polysynaptic intraspinal pathways. Although most patients demonstrate no clear etiology, a variety of disorders have been linked to this abnormal movement, including trauma, multiple sclerosis, tumors, and infectious disorders such as herpes zoster, human immunodeficiency virus, and Lyme disease. We describe 2 young male patients from the same town in Northern Ontario, Canada, exposed to an outbreak of Escherichia coli O157:H7 from contaminated municipal water, who developed identical clinical and electrophysiological features suggestive of a rhythmic form of propriospinal myoclonus with activity alternating between abdominal and paraspinal muscles. A toxin-mediated microvascular thrombosis is proposed as a possible pathogenic mechanism underlying this novel association.

Motor pattern of periodic limb movements in sleep in idiopathic RLS patients

OBJECTIVE

Periodic limb movements in sleep (PLMS) are recurrent sleep-related movements that often occur in association with restless legs syndrome (RLS). The purpose of the present study was to examine the pathophysiology of PLMS in patients with idiopathic RLS.

METHODS

Ten patients with idiopathic RLS who were medication-free or who had withdrawn from medication at least 2 weeks prior to the study underwent an extensive neurophysiological investigation that included nocturnal video-polysomnographic recording (VPSG), EMG recording, and the Multiple Sleep Latency Test (MSLT). Sleep efficiency and PLMS index were calculated during VPSG.

RESULTS

All patients had an increased PLMS index, decreased sleep efficiency, and a pathological MSLT score. Leg muscles were the first to be activated, often with alternation of side, and no constant recruitment pattern could be found from one episode of PLMS to another, even in the same patient. No ordinate caudal or rostral spread of the EMG activity was observed.

CONCLUSIONS

The results suggest that there are different, independent, and unsynchronized generators for PLMS. The direct participation of the cerebral cortex in the origin of PLMS is unlikely, suggesting that abnormal spinal cord hyperexcitability may act as the primary cause of PLMS, triggered by unidentified sleep-related factors.