Biomedical subjects

Michael H Silber

Publications and source records attributed to Michael H Silber.

24 records · Page 2Linked to original sources

PubMed2002

Current management of sleep disturbances in dementia.

The management of sleep disturbances in patients with dementia is a complicated and enormously important clinical and societal problem. In this review, we present one approach to the diagnosis and management of such sleep disturbances. Most disturbances can be categorized into four primary symptoms: insomnia, hypersomnia, excessive nocturnal motor activity, and hallucinations or behavioral problems. We describe how each symptom may relate to the dementing illnesses themselves, which primary sleep disorders may be at play, which medications employed for dementia may impact on the symptom, the role of depression in that symptom, and how circadian dysrhythmias can underlie that symptom. Although few well-designed studies have been conducted, we present management strategies for several sleep disturbances based on the literature and our clinical experience. Considering the impact on patient and caregiver quality of life, and the potential for delaying institutionalization with appropriate therapy, further research is clearly warranted to optimize the diagnosis and management of sleep disturbances in the cognitively impaired elderly population.

Aged↗

PubMed2002

Diagnosing narcolepsy: validity and reliability of new diagnostic criteria.

BACKGROUND AND PURPOSE: No gold standard currently exists for the diagnosis of narcolepsy. Conventional diagnostic criteria are unwieldy and arbitrary. Clearly defined criteria for case selection are needed to compare the results of different studies. METHODS: We developed new clinical and neurophysiologic criteria for narcolepsy using four categories, based on the degree of diagnostic certainty. Category A is Definite Narcolepsy, Category B is Probable Narcolepsy (Laboratory Supported; two subgroups B1 and B2) and Category C is Probable Narcolepsy (Clinical). We assessed the charts of 69 new or established patients with narcolepsy seen consecutively in the Mayo Sleep Disorders Center and classified them according to our system. The human leucocyte antigen (HLA) DQB1*0602 status was determined for each patient as an indirect measure of validity. Two investigators independently assessed 30 charts to assess interrater reliability. We assessed additional 337 charts of patients with other hypersomnolence states to assess the specificity of our definitions. RESULTS: Seventy-four percent were positive for HLA DQB1*0602 (including 85% of those with cataplexy). Only 33% of those without cataplexy were HLA DQB1*0602 positive. The two investigators agreed on the classification of 29/30 patients (0.97 reliability). None of the 337 additional patients fulfilled criteria for narcolepsy, and specifically not for cataplexy. CONCLUSIONS: We conclude that our new research diagnostic criteria for narcolepsy possess high interrater reliability and appear valid descriptors of the syndrome, based on HLA typing. They may be useful in providing consistent criteria to compare different research studies.

Journal Article↗

PubMed2002

Amnestic sleep-related eating disorder associated with zolpidem.

OBJECTIVE: To describe the association of amnestic nocturnal eating behavior with use of zolpidem for insomnia. BACKGROUND: Sleep-related eating disorder is increasingly recognized in relationship to other diagnosable sleep disorders. Many of these disorders, like restless legs syndrome (RLS), give rise to complaints of insomnia. Zolpidem is the most commonly prescribed drug for insomnia complaints, and although it has sometimes been associated with side effects of transient amnesia and sleep walking, an association with sleep-related eating has not been previously emphasized. METHODS: Consecutive case series of five patients who were using zolpidem and evaluated with nocturnal eating behaviors. RESULTS: We evaluated five patients over 11 months with problematic amnestic nocturnal eating associated with zolpidem used for complaints of insomnia. All five patients had RLS, three had obstructive sleep apnea syndrome, two had sleep walking, and one had psychophysiologic insomnia. With discontinuation of zolpidem and effective treatment of their sleep disorders, nocturnal eating resolved. CONCLUSIONS: Zolpidem, at least in patients with underlying sleep disorders that cause frequent arousals, may cause or augment sleep-related eating behavior. This report demonstrates the importance of arriving at a specific diagnosis for insomnia complaints, and alerts the sleep practitioner to this unusual side effect of zolpidem.

Journal Article↗

PubMed2002

Hypocretin (orexin) and melatonin values in a narcoleptic-like sleep disorder after pinealectomy.

Narcolepsy secondary to other neurologic processes has been recently associated with hypocretin (orexin) deficiency. We present a patient who developed a narcoleptic-like sleep disorder after receiving treatment for a choroid plexus carcinoma of the pineal gland. She underwent a pinealectomy, chemotherapy, and radiation treatment. The primary features of this condition were excessive daytime sleepiness, sleep paralysis and hypnagogic hallucinations. Increased percentage of rapid eye movement (REM) sleep and sleep onset REM periods were seen during the multiple sleep latency test. Circadian rhythmicity was preserved for melatonin and cortisol. She was negative for human leukocyte antigen DQB1*0602 and had a detectable cerebrospinal fluid hypocretin level (518 pg/ml). We emphasize that the narcoleptic-like disorder likely resulted from the surgical intervention or radiation therapy. Her symptoms are caused by an unknown mechanism unrelated to hypocretin depletion which merits more research.

Journal Article↗

PubMed2002

Dementia with Lewy bodies may present as dementia and REM sleep behavior disorder without parkinsonism or hallucinations.

Rapid eye movement (REM) sleep behavior disorder (RBD) is a sleep disturbance that commonly occurs in Dementia with Lewy bodies (DLB). Retrospective examination of DLB course has shown that RBD and cognitive decline may precede the onset of parkinsonism and visual hallucinations. Therefore, some patients with DLB may initially present with dementia and RBD, but would not meet current formal criteria for probable DLB at that time. The purpose of this study is to determine whether patients with dementia and RBD, who do not have parkinsonism or visual hallucinations, have cognitive profiles that can be distinguished from autopsy-confirmed definite AD, but not from clinically probable DLB. If so, this would support the hypothesis that the presence of RBD and dementia, as the only presenting symptoms, reflects the early manifestation of DLB. Results show that early dementia in probable DLB and dementia with RBD are neuropsychologically indistinguishable. Both groups differ from definite AD of a similar early stage with significantly worse visual perceptual organization, sequencing and letter fluency but significantly better confrontation naming and verbal memory. In addition, follow-up data from a subset of patients with dementia and RBD reveal the subsequent development of parkinsonism or hallucinations 1 to 6 years later. Results indicate that the presentation of dementia and RBD is suggestive of underlying Lewy body disease and not Alzheimer's disease. This provides further evidence in support of including RBD as one of the core diagnostic features of DLB.

Aged↗

PubMedDate not supplied

Neurophysiologic studies in Morvan syndrome.

This study was conducted to clarify the clinical and neurophysiologic characteristics of patients with Morvan syndrome, and to compare and contrast this syndrome with other forms of autoimmune encephalitis. A retrospective chart review of the clinical features and neurophysiologic studies of two cases of Morvan syndrome seen at the Mayo Clinic was performed. Neurophysiologic studies included polysomnography, comprehensive autonomic testing, MRI, positron emission tomography, EEG, and single-photon emission computed tomography. In two cases of Morvan syndrome, the clinical features, electrophysiologic findings, and immunologic studies (high levels of voltage-gated potassium channel antibodies) were consistent with previously reported findings. Several novel observations were made. Autonomic testing demonstrated peripheral autonomic neuropathy in addition to autonomic hyperactivity. Polysomnography showed complete absence of sleep. Neuroimaging study findings were largely normal. Morvan syndrome is an autoimmune disorder affecting both the peripheral and central nervous system. Neurophysiologic studies demonstrate hyperexcitability of peripheral nerves, autonomic dysfunction, and severe insomnia. The absence of abnormalities on imaging studies suggests that central nervous system symptoms are related to functional rather than structural disruption of neural networks.

Adult↗