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Biomedical subjects

R D Chervin

Publications and source records attributed to R D Chervin.

At least 37 records · Page 2Linked to original sources
PubMed2000

Timing patterns of cluster headaches and association with symptoms of obstructive sleep apnea.

Cluster headaches (CH) frequently recur at the same point in the circadian cycle, often during sleep. They may, in some cases, represent a susceptible individual's response to hypoxemia or other physiological changes induced by obstructive sleep apnea (OSA). If and when this mechanism exists, timing of CH close to the onset of sleep-and therefore OSA-might be expected. We questioned 36 subjects with CH about the times at which their CH usually occurred and about several symptoms known to be predictive of OSA, including habitual snoring, loud snoring, observed apneas and excessive daytime sleepiness. We then used logistic regression to determine whether occurrence of CH in each of six time periods was associated with OSA symptoms. The 23 subjects (64%) who reported CH in the first half of a typical night's sleep also tended to report headaches during the midday/afternoon period. Symptoms of OSA, and in particular habitual snoring, were predictive of both first-half-of-the-night and midday/afternoon CH (p<.05). Thirty-one subjects (86%) reported that their CH were sleep-related, usually occurring during any part of the night or on awakening, but symptoms of OSA were not predictive of this timing pattern. In short, several OSA symptoms showed an association with CH occurrence in the first half of the night but not with sleep-related CH in general. These findings suggest that in some patients, physiological consequences of OSA may trigger CH during the first few hours of sleep and thereby influence the timing of subsequent daytime headaches.

Adult↗
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↗
PubMed1997

Effects of esophageal pressure monitoring on sleep architecture.

Esophageal pressure (Pes) monitoring can be performed during polysomnography with a thin, water-filled catheter connected to a transducer. The resulting quantitative assessment of respiratory effort aids in the diagnosis of sleep-related breathing disorders, but little is known about the potential effect of the procedure on sleep architecture. We monitored Pes during polysomnography in 155 patients and compared their sleep architecture with that of 155 matched patients who slept without esophageal catheters. Cases were matched for age, sex, and severity of respiratory disturbance during sleep. Esophageal manometry was associated with small but statistically significant (p < 0.05) decrements in total recording time, total sleep time, sleep efficiency, percent Stage 2 sleep, and percent rapid-eye-movement (REM) sleep, and with increases in latency to REM sleep, latency to persistent sleep, and percent Stage 3/4 sleep. The differences were of such small magnitude that their clinical significance is doubtful. The number of awakenings per hour of sleep, latency to sleep onset, and percent Stage 1 sleep were no different when esophageal manometry was used. We conclude that the effects of monitoring Pes on sleep architecture are minimal, and that the decision of whether or not to use the technique can be based to a large extent on whether quantitative information about respiratory effort will be useful.

Adolescent↗
PubMed1997

Probable diffuse Lewy body disease presenting as REM sleep behavior disorder.

Rapid eye movement sleep behavior disorder may herald several neurodegenerative disorders associated with parkinsonism, including Parkinson's disease. A 72-year-old man with a 17-year history of rapid eye movement sleep behavior disorder confirmed by polysomnography developed a progressive dementia that met operational clinical criteria for diffuse Lewy body disease. The differential diagnosis of progressive neurodegenerative disorders heralding as rapid eye movement sleep behavior disorder should now include diffuse Lewy body disease.

Aged↗
PubMed1997

Value of the multiple sleep latency test (MSLT) for the diagnosis of narcolepsy.

Since its introduction, the multiple sleep latency test (MSLT) has played a major role in the diagnosis of narcolepsy. We assessed its diagnostic value in a series of 2,083 subjects of whom 170 (8.2%) were diagnosed with narcolepsy. The sensitivity of the combination of two or more sleep onset rapid eye movement (REM) periods (SOREMPs) with a mean sleep latency of < 5 minutes on an initial MSLT was 70% with a specificity of 97%, but 30% of all subjects with this combination of findings did not have narcolepsy. In some narcoleptics who had more than one MSLT, the proportion of naps with SOREMPs varied substantially from the initial MSLT to the follow-up test. The highest specificity (99.2%) and positive predictive value (PPV) (87%) for MSLT findings was obtained with the criteria of three or more SOREMPs combined with a mean sleep latency of < 5 minutes, but the sensitivity of this combination was only 46%. The combination of a SOREMP with a sleep latency < 10 minutes on polysomnography yielded a specificity (98.9%) and PPV (73%) almost equal to those obtained from combinations of MSLT findings, but the sensitivity was much lower. Our results suggest that the MSLT cannot be used in isolation to confirm or exclude narcolepsy, is indicated only in selected patients with excessive daytime sleepiness, and is most valuable when interpreted in conjunction with clinical findings.

Adolescent↗
PubMed1996

Obstructive sleep apnea and related disorders.

OSAS, a common cause of disrupted sleep and EDS, result from repetitive closure of the upper airway during sleep. It probably represents the most severe syndrome related to obstruction of the upper airway; less severe forms include UARS, a syndrome characterized by the need for increased effort to breath but no prominent apneas or hypopneas, and primary snoring. Initial clues to the presence of OSAS and related disorders are derived from the history and include loud snoring, EDS or insomnia, and witnessed apneas. Some patients, especially women, may complain mostly of tiredness or fatigue, and children may present with behavioral abnormalities. Obesity, a large neck circumference, and a crowded oropharynx are common on physical examination. Nonobese patients, in particular, often have retrognathia, a high-arched narrow palate, macroglossia, enlarged tonsils, temporomandibular joint abnormalities, or chronic nasal obstruction. The clinical suspicion of obstructed nocturnal breathing is confirmed by overnight polysomnography, and an MSLT may be used to assess sleepiness. Esophageal manometry during polysomnography facilitates diagnosis of UARS. Treatment most commonly consists of nasal CPAP or BPAP, although problems with compliance make surgical treatment preferable in some cases. Although UPPP eliminates sleep apnea only in a minority of patients, combining UPPP with maxillofacial procedures appears to improve outcomes. Other treatments such as the use of dental appliances or medications, weight loss, and positional therapy may be useful as adjunctive therapy for moderate to severe OSAS or as primary treatments for UARS or mild OSAS.

Adult↗
PubMed1996

Overestimation of sleep latency by patients with suspected hypersomnolence.

The latency to sleep onset has been reported to be overestimated by chronic insomniacs. Observing that some patients evaluated for suspected hypersomnolence complain of insomnia and others fail to report that they are sleepy, we wondered whether overestimation of sleep latency could be occurring in these subjects as well. Since polysomnography (PSG) only provides one sleep onset with which to assess a patient's estimation, we investigated the use of the multiple sleep latency test (MSLT) for this purpose. Among 147 patients who had an MSLT, 137 of whom had a preceding PSG, overestimation of sleep latency occurred on 78% and 74% of the respective tests. The magnitude of overestimation averaged 3 minutes and 27 minutes, respectively, and was not dependent on diagnosis. Subjects who had reported a history of difficulty falling asleep, compared to those who did not, tended to show equivalent objective sleep latencies, longer subjective nocturnal sleep latencies and less overall accuracy in their estimates. Those who denied having a problem with excessive daytime sleepiness (EDS) showed objective sleep latencies nearly identical to those who complained of EDS but had only a trend toward higher overestimation on the MSLT. Overestimation of sleep latency is therefore more readily part of an explanation for why hypersomnolent patients sometimes complain of insomnia than it is for failure to recognize EDS. The MSLT as well as nocturnal recordings can provide data with which to assess overestimation of sleep latency.

Adult↗
PubMed1996

Sleep apnea in patients with transient ischemic attack and stroke: a prospective study of 59 patients.

Although sleep apnea (SA) appears to be a cardiovascular risk factor, little is known about its frequency in patients with transient ischemic attack (TIA) and stroke. We prospectively studied 59 subjects (26 women and 33 men; mean age, 62 years) with stroke (n = 36) or TIA (n = 23) with the use of a standard protocol that included assessment of snoring and daytime sleepiness (Epworth Sleepiness Score [ESS]), a validated SA score (Sleep Disorders Questionnaire [SDQ-SA]), and a severity of stroke score (Scandinavian Stroke Scale [SSS]). SA was considered clinically probable (P-SA) when habitual snoring was associated with an ESS of > 10 or when SDQ-SA score was > or = 32 in women and > or = 36 in men. Polysomnography (PSG) was obtained in 36 subjects (group 1) a mean of 12 days after TIA or stroke. In 23 subjects (group 2), PSG was not available (n = 11), refused (n = 10), or inadequate (n = 2). Clinical and PSG data were compared with those obtained in 19 age- and gender-matched control subjects. Groups 1 and 2 were similar in mean age (61 versus 64 years), type of event (36% versus 44% TIA), reported habitual snoring (58% versus 52%), and P-SA (58% versus 50%). PSG showed SA (Apnea-Hypopnea Index [AHI], > or = 10) in 25 of 36 subjects (69%). The proportion of subjects with SA was similar in the TIA and stroke groups (69% versus 70%) and was well above the frequency found in our control group (15%). An AHI of > or = 20 and a minimal oxygen saturation of < 85% were each found in 20 of 36 subjects (55%). Gender and age did not correlate with severity of SA. Subjects with habitual snoring, P-SA, or severe stroke (SSS of < 30) had a significantly higher AHI (p < 0.05). The sensitivity of P-SA for SA was 64%, and the specificity was 67%. We conclude that SA has a high frequency in patients in the acute phase of TIA and stroke and SA cannot be predicted reliably on clinical grounds alone but is more likely in patients with habitual snoring, abnormal SDQ-SA, or severe stroke.

Adult↗
PubMed1995

Correlates of sleep latency on the multiple sleep latency test in a clinical population.

The multiple sleep latency test (MSLT) is commonly used as an objective measure of sleepiness. We retrospectively correlated MSLT scores from 147 patients with other information relating to sleepiness, namely demographic information, data from nocturnal polysomnograms (PSGs), and subjective assessments. The only variable that showed a valid and statistically significant correlation with the MSLT score was sleep latency on the PSG. The results were largely similar within subgroups focusing on (1) individuals with the ability to fall asleep on every nap, (2) subjects with abnormally short MSLT scores, (3) nap attempts that were successful, and (4) patients with particular diagnoses. We conclude that the mean sleep latency on the MSLT, in a clinical population, does not correlate well with a number of variables expected to influence sleepiness. While the validated utility of the MSLT in separating patients from normals or in identifying narcolepsy is not disputed, the accuracy of the MSLT as a measure of sleepiness appears to be limited.

Adult↗