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Biomedical subjects

R D Chervin

Publications and source records attributed to R D Chervin.

At least 19 recordsLinked to original sources
PubMed2000

The pathology of REM sleep behavior disorder with comorbid Lewy body dementia.

A patient with REM sleep behavior disorder who subsequently developed probable Lewy body dementia is now reported to have a definite pathologic diagnosis of Lewy body dementia. Examination of brain revealed Lewy bodies as well as marked neuronal loss in brainstem monoaminergic nuclei-particularly locus coeruleus and substantia nigra-that inhibit cholinergic neurons in the pedunculopontine nucleus mediating atonia during REM sleep.

Aged↗
PubMed2000

Decreased striatal dopaminergic innervation in REM sleep behavior disorder.

REM sleep behavior disorder (RBD) is a possible herald of neurodegenerative disorders with parkinsonism. The authors determined the density of striatal dopaminergic terminals with [11C]dihydrotetrabenazine PET in six elderly subjects with chronic idiopathic RBD and 19 age-appropriate controls. In subjects with RBD, there were significant reductions in striatal [11C]dihydrotetrabenazine binding, particularly in the posterior putamen.

Aged↗
PubMed2000

Sleep disordered breathing in patients with cluster headache.

OBJECTIVE: To study subjects with active or inactive cluster headache (CH) for occult sleep disordered breathing (SDB). BACKGROUND: CH frequently occurs during sleep. The authors previously found that symptoms of SDB predicted reported occurrence of CH in the first half of the night, which suggested that CH could be triggered in some cases by unrecognized SDB. METHODS: The authors performed polysomnography in 25 adults (22 men) with CH. Subjects were not selected for any sleep-related complaint. In addition to standard measures, studies included monitoring of end-tidal carbon dioxide (n = 22), and esophageal pressure (n = 20). RESULTS: The rate of apneas and hypopneas per hour of sleep was >5 in 20 subjects (80%; 95% CI, 64% to 96%), minimum oxygen saturation was <90% in 10 subjects, maximum negative esophageal pressure ranged from -13 to -65 cm H2O, and maximum end-tidal carbon dioxide was > or =50 mm Hg in eight subjects. The eight subjects with active (versus inactive) CH at the time of study had higher maximum end-tidal carbon dioxide levels (50 +/- 3 versus 44 +/- 5 mm Hg; p = 0.0007). More severe oxygen desaturation was associated with reports that CH typically occurred in the first half of the nocturnal sleep period (p = 0.008). CONCLUSIONS: SDB occurred in the majority of patients with CH. Evaluation of a patient with CH should include consideration that SDB may be present.

Adult↗
PubMed2000

Parkinsonism after correction of hyponatremia with radiological central pontine myelinolysis and changes in the basal ganglia.

Parkinsonism has been rarely described following central pontine and extrapontine myelinolysis. We report a case of parkinsonism developing following rapid correction of hyponatremia with radiological evidence of central pontine myelinolysis and changes in the basal ganglia. A 56-year-old man developed drooling and bilateral hand tremors 3 weeks after correction of hyponatremia from 103 to 125 mmol/L over 14 h. He had a prominent 6 Hz resting tremor which worsened with action and mild cogwheel rigidity. Magnetic resonance imaging (MRI) showed changes consistent with central pontine myelinolysis and increased signal on T1-weighted images in the putamen bilaterally. His tremor responded well to L-dopa therapy. There have been several other cases of parkinsonism developing after central pontine/extrapontine myelinolysis. Increased signal in the basal ganglia on T1-weighted images has been described in another case of central pontine myelinolysis imaged about the same time after sodium correction as our case.

Antiparkinson Agents↗
PubMed2000

Sleep onset REM periods during multiple sleep latency tests in patients evaluated for sleep apnea.

Although 2 or more sleep onset rapid eye movement (REM) periods (2omSOREMPs) on a Multiple Sleep Latency Test (MSLT) raise the possibility of narcolepsy, patients with obstructive sleep apnea (OSA) also can have 2omSOREMPs, which may then cause diagnostic uncertainty. To explore what features among OSA patients predict 2omSOREMPs on an MSLT that follows nocturnal polysomnography, we reviewed data from 1,145 consecutively studied patients suspected or confirmed to have OSA rather than narcolepsy. Overall, 4.7% of the subjects had 2omSOREMPs. Variables that were independently predictive of 2omSOREMPs in logistic regression models included male gender (OR = 4.4, 95% CI = 1.9 to 12.7), a 5-min decrease in the MSLT-derived mean sleep latency (OR = 1.9, 95% CI = 1.3 to 2.8), a 90-min decrease in nocturnal latency to REM sleep (OR = 1.6, 95% CI = 1.1 to 2.5), and a 15-unit decrease in minimal recorded oxygen saturation (OR = 1.6, 95% CI = 1.3 to 2.0). We conclude that among patients suspected or confirmed to have OSA, one or more of these four variables-male sex, sleepiness, nocturnal REM sleep latency, and extent of oxygen desaturation-could reflect neurophysiological mechanisms responsible for 2omSOREMPs. Consideration of these variables, and especially gender, may be useful in clinical practice when 2omSOREMPs are found unexpectedly.

Adolescent↗
PubMed2000

Sleepiness, fatigue, tiredness, and lack of energy in obstructive sleep apnea.

STUDY OBJECTIVES: Sleepiness is a key symptom in obstructive sleep apnea syndrome (OSAS) and can be objectively assessed with a multiple sleep latency test (MSLT). We studied the terms that patients prefer to describe their symptoms-sleepiness, fatigue, tiredness, or lack of energy-and how these terms relate to objective findings. DESIGN: Observational. SETTING: University-based sleep laboratory. PATIENTS: Consecutive OSAS patients referred for diagnostic polysomnography and an MSLT. METHODS: Data were obtained from sleep studies and questionnaires. RESULTS: Subjects included 117 men and 73 women, with a mean (+/- SD) age of 49 +/- 13 years, an apnea and hypopnea rate of 32 +/- 28/h of sleep, and an MSLT mean sleep latency of 7 +/- 5 min. Subjects more frequently reported problems with fatigue, tiredness, and lack of energy than sleepiness (57%, 61%, and 62% vs 47%). When required to select the one most significant symptom, more patients chose lack of energy (about 40%) than any other problem, including sleepiness (about 22%). Objective measures of sleepiness and apnea severity showed little or no association with any symptom, but female gender showed significant associations with each. CONCLUSIONS: Complaints of fatigue, tiredness, or lack of energy may be as important as that of sleepiness to OSAS patients, among whom women appear to have all such complaints more frequently than men. The diagnosis of OSAS should not be excluded based only on a person's tendency to emphasize fatigue, tiredness, or lack of energy more than sleepiness.

Circadian Rhythm↗
PubMed1999

Cost-utility of three approaches to the diagnosis of sleep apnea: polysomnography, home testing, and empirical therapy.

BACKGROUND: Obstructive sleep apnea syndrome (OSAS) is usually diagnosed with overnight polysomnography in a sleep laboratory. Home sleep studies can be performed at lower cost, but results are somewhat less reliable. Bedside diagnosis of OSAS without any testing has also been discussed. OBJECTIVE: To model the costs and utility of laboratory polysomnography, home study, and no testing during the 5 years after initial evaluation for OSAS. DESIGN: Cost-utility analysis. DATA SOURCES: Published data. TARGET POPULATION: Hypothetical cohort of persons suspected of having OSAS. TIME HORIZON: The 5 years after initial evaluation for OSAS. PERSPECTIVE: Societal. INTERVENTION: Nasal continuous positive airway pressure when OSAS was diagnosed. MEASUREMENTS: Quality of life, survival and charges (as proxies for costs) for each diagnostic method. RESULTS OF BASE-CASE ANALYSIS: Under almost all modeled conditions, polysomnography provided maximal quality-adjusted life-years in the 5 years after the initial diagnostic evaluation. The incremental charges for polysomnography over home study or no testing were about $13,400 and $9200, respectively, per quality-adjusted life-year gained during this period. RESULTS OF SENSITIVITY ANALYSIS: Results were sensitive to the utility of treatment in the absence of OSAS. CONCLUSIONS: The cost-utility of polysomnography instead of home study or no testing in the diagnosis of OSAS compares favorably with that of other procedures for which society judges the added utility per dollar spent to be worthwhile. More precise determination of certain key variables in this model should be a goal of future research.

Cost-Benefit Analysis↗
PubMed1999

The Epworth Sleepiness Scale may not reflect objective measures of sleepiness or sleep apnea.

OBJECTIVE: To assess the validity of the Epworth Sleepiness Scale score (ES) as a measure of sleepiness among patients suspected or confirmed to have obstructive sleep apnea syndrome. BACKGROUND: The ES is used with increasing frequency as a measure of excessive daytime sleepiness in part because several studies suggested that the ES correlates with mean sleep latency (MSL) on the Multiple Sleep Latency Test and with severity of sleep apnea among patients with that disorder. However, associations identified between the ES and other measures were not strong or consistent. METHODS: The authors used regression models and retrospective data from a relatively large series of 237 patients to restudy how ES relates to MSL, to a simple self-rating of problem sleepiness (available for 141 patients), and to two polysomnographic measures of sleep apnea severity: the number of apneas or hypopneas per hour of sleep and the minimum recorded oxygen saturation. RESULTS: The ES had a statistically significant association with self-rated problem sleepiness but not with MSL or measures of sleep apnea severity. Male gender, adjusted for potential confounding variables, had considerably more influence on the ES than did MSL or measures of sleep apnea severity. CONCLUSIONS: Our data suggest that the subjectively derived ES cannot be used as a surrogate for the objectively determined MSL.

Adult↗
PubMed1998

Characteristics of apneas and hypopneas during sleep and relation to excessive daytime sleepiness.

STUDY OBJECTIVES: One of the most important symptoms in patients evaluated for possible obstructive sleep apnea syndrome is excessive daytime sleepiness, but the measures of apnea severity and of sleepiness used most commonly have not generally shown strong associations. We explored whether information recorded during standard polysomnography, other than the overall rate of apneas and hypopneas per hour of sleep (AHI), might help explain the measured severity of sleepiness. DESIGN: Observational SETTING: A clinical sleep laboratory in a university hospital PATIENTS: N = 1,146 patients evaluated for suspected sleep-disordered breathing with nocturnal polysomnograms and multiple sleep latency tests. RESULTS: The AHI during supine sleep (recorded in a subgroup of n = 169 subjects), the rate of apneas (n = 1,146), and the rate of obstructive apneas (n = 1,146) were particularly useful in explaining variation in measured levels sleepiness; rates of hypopneas and central apneas were less useful (n = 1,146). In addition, the minimum recorded oxygen saturation (n = 1,097) was as important as the AHI to the level of sleepiness. CONCLUSIONS: In an attempt to explain excessive daytime sleepiness among patients evaluated for sleep-disordered breathing, additional insight is provided by observation of supine sleep during polysomnography, by emphasis on apneas rather than hypopneas, by emphasis on obstructive rather than central events, and by consideration of the minimum oxygen saturation.

Adult↗
PubMed1998

The relation between multiple sleep latency test findings and the frequency of apneic events in REM and non-REM sleep.

STUDY OBJECTIVES: A recent study of 34 patients with mild obstructive sleep apnea syndrome (OSAS) suggested that the number of apneas and hypopneas per hour of sleep (apnea/hypopnea index [AHI]) may show a stronger correlation with sleepiness, as measured by the Multiple Sleep Latency Test (MSLT), when calculated for rapid eye movement (REM) sleep alone (AHIR) as opposed to the entire night. We sought to reexamine this possibility in a larger group of similar patients and in patients who had a wider range of OSAS severity. DESIGN: Retrospective and observational. SETTING: A large, accredited, academic sleep disorders center where a database of sleep study results is maintained. PATIENTS: We studied 1,146 persons who had polysomnography and MSLTs for clinical indications. RESULTS: In linear regression models, the AHI explained 11.0% of the variance in MSLT results, AHIN (AHI during non-REM sleep) explained 10.8%, and AHIR explained only 6.0% (p < or = 0.0001 for each). Among subjects with AHI < 10, the AHI explained 3.1% of the variance (p=0.0012), the AHIN 2.3% (p=0.0049), and the AHIR 0.2% (p=0.40). Among all subjects, the ratio AHIR/AHIN had no influence on the overall relationship between AHI and sleepiness (p=0.23). CONCLUSIONS: We conclude that apneic events during REM and non-REM sleep probably contribute equally to sleepiness as measured by the MSLT.

Adult↗
PubMed1997

Comparison of the results of the Epworth Sleepiness Scale and the Multiple Sleep Latency Test.

The Epworth Sleepiness Scale (ESS), which asks patients to estimate the likelihood that they would doze off or fall asleep in sedentary situations, has been proposed to be a quick, inexpensive way to assess sleepiness. We analyzed relations among ESS scores, mean sleep latencies on the Multiple Sleep Latency Test (MSLT), and subjective assessments of severity of sleepiness in 60 patients (34 women) with suspected excessive daytime sleepiness. Mean scores were 14.2 +/- 5.9 on the ESS and 8.3 +/- 5.2 minutes on the MSLT. ESS scores correlated negatively, but not strongly, with MSLT scores (rho = -0.37, p = 0.0042) and ESS scores of 14 and above predicted a low mean sleep latency on the MSLT. The ESS score correlated with the degree to which patients complained of sleepiness and may be useful as an otherwise elusive link between patients' complaints and their objective findings on MSLT.

Adolescent↗
PubMed1997

Symptoms of sleep disorders, inattention, and hyperactivity in children.

Children with sleep disorders are often inattentive or hyperactive, and some carry a diagnosis of attention deficit/hyperactivity disorder (ADHD) until their sleep disorder is detected. However, the potential behavioral impact of undiagnosed sleep disorders is not known. We sought to determine whether children with higher levels of inattention and hyperactivity more frequently have symptoms of sleep-related breathing disorders (SRBDs) or periodic limb movement disorder (PLMD). We surveyed parents of 2-18-year-old patients at a child psychiatry clinic (n = 70) and a general pediatrics clinic (n = 73) to assess the children's behavior, snoring, complaints of restless legs at night, and daytime sleepiness. A validated pediatric sleep questionnaire provided the explanatory variables, and a scale for inattention and hyperactivity, derived from the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV), provided the dependent variable. Habitual snoring was more frequent (33%) among children who carried a diagnosis of ADHD than among the other children at the psychiatry or general pediatric clinics (11 and 9%, respectively, chi-square test, p = 0.01). Snoring scores, derived from six snoring- and SRBD-related question items, were associated with higher levels of inattention and hyperactivity. The complaint of restless legs and a composite score for daytime sleepiness showed some evidence, though less consistent, of an association with inattention and hyperactivity. The association of snoring with inattention and hyperactivity suggests that SRBDs and perhaps other sleep disorders could be a cause of inattention and hyperactivity in some children. If a causal effect is present, our data suggest that 81% of habitually snoring children who have ADHD--25% of all children with ADHD--could have their ADHD eliminated if their habitual snoring and any associated SRBD were effectively treated.

Adolescent↗
PubMed1997

Compliance with nasal CPAP can be improved by simple interventions.

Effectiveness of continuous positive airway pressure (CPAP) as a treatment of obstructive sleep apnea can be limited by poor compliance, but little is known about how to improve compliance. We performed a randomized, controlled clinical trial among 33 subjects of two interventions to improve compliance. One group of subjects received weekly phone calls to uncover any problems and encourage use, another received written information about sleep apnea and the importance of regular CPAP use, and a third served as control subjects. We found that intervention improved CPAP compliance (p = 0.059) and that the effect was particularly strong when intervention occurred during the first month of CPAP treatment (p = 0.004). Although the sample size did not allow definitive investigation of other explanatory variables, subjects with lower levels of education or those with relatives who used CPAP may have benefited from intervention more than other subjects. We conclude that simple, inexpensive efforts to improve compliance with CPAP can be effective, especially when applied at the start of CPAP treatment, but optimal intervention may vary with certain patient characteristics.

Adult↗
PubMed1997

Diaphragm pacing for respiratory insufficiency.

Diaphragm pacing (DP) by electrical stimulation of the phrenic nerve offers important advantages to a highly select group of patients with respiratory paralysis. The patient wears an external radiofrequency (RF) transmitter over an implanted receiver, and a stimulating current is induced without the need for any transcutaneous wires. We review the conditions and requirements of patients who may benefit most from DP. We outline the preoperative evaluation and procedures for surgical implantation. We discuss the risk of diaphragmatic fatigue posed by initiation of DP and the use of gradual conditioning to limit this problem. Other problems encountered by patients in the course of DP can be minimized by well-instructed home caregivers and by systematic medical follow-up. Although a few patients derive considerable benefit from DP, many patients with respiratory paralysis are better treated by less invasive means such as nasal bilevel positive airway pressure or intermittent positive pressure ventilation, which we also review.

Contraindications↗