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Biomedical subjects

F Lue

Publications and source records attributed to F Lue.

10 recordsLinked to original sources
PubMed1996

The effects of bright light treatment on the symptoms of fibromyalgia.

OBJECTIVE: To investigate the effects of bright light treatment on the symptoms of pain, mood, and sleep in patients with fibromyalgia (FM) reporting seasonality of symptoms on the Seasonal Pattern Assessment Questionnaire (SPAQ). METHODS: A randomized 10 week crossover study compared the effects of 4 weeks of "visible electromagnetic fields" (EMF) (light condition; mean 4750 lux, SD 2337 lux) to 4 weeks of "nonvisible EMF" (no light condition) in 14 patients with FM having a minimum SPAQ score of 11. The light visor system (Bio-Brite) was fitted with an opaque filter for the "nonvisible EMF" control condition. RESULTS: No significant differences were found between treatment conditions on tenderness measured with dolorimetry, self-ratings of sleep, pain, mood, and global measures. Mood was not related to pain or sleep. There was significant reduction in depression scores and subjective pain, but increased tenderness and nocturnal awakenings related to time. CONCLUSION: The were no significant differences between the light and no light conditions on pain, mood, or sleep in patients with FM reporting seasonality of symptoms. No relationship was found between mood and the symptoms of FM (i.e., pain, sleep, and fatigue).

Adult↗
PubMed1995

The reliability of visual scoring of alpha EEG activity during sleep.

The reliability of visual scoring of alpha electroencephalogram activity in nonrapid eye movement sleep was evaluated. Three trained scorers independently, on two occasions, assessed one record from each of 10 patients. In addition to standard sleep staging of the records, alpha activity was scored using three methods: a) while the record was being scored, an assessment of alpha activity during the preceding stage was made at each stage change; b) after the record was scored a single global rating of alpha was made; and c) each 20-second epoch of the record was rated on the amount of alpha present. Relative and absolute generalizability coefficients in excess of 0.810 and 0.698, respectively, were obtained. However, the results also indicated that careful attention to methodological factors is critical in ensuring satisfactory standards of reliability.

Alpha Rhythm↗
PubMed1994

Canine model of obstructive sleep apnea: model description and preliminary application.

This report describes a canine model of obstructive sleep apnea (OSA) developed in our laboratory and the results of its preliminary short-term application. Healthy adult dogs were prepared with a tracheostomy and with implanted electroencephalographic and nuchal electromyographic recording electrodes. A silent occlusion valve was attached to the outer end of the endotracheal tube. The electroencephalogram and electromyogram were monitored continuously by a computer that determined sleep-wake state using software developed in our laboratory. At a predetermined time (e.g., 12 s) after each sleep onset, a signal was transmitted from the computer to the valve controller, resulting in airway occlusion. When the dog aroused from sleep, the occlusion was released. These events therefore mimic those that occur in human OSA. Successful operation of the model was confirmed during 5-day continuous trials in two dogs. During the trials, the dogs became increasingly somnolent both by behavioral observation and objective measurement. The frequency of occlusions increased, and measures of apnea severity, including apnea duration and end-apneic arterial oxygen saturation, worsened. We conclude that this experimental model of repeated airway occlusion during sleep provides a potentially powerful tool for investigating the sequelae of OSA.

Airway Obstruction↗
PubMed1986

Role of diffuse airway obstruction in the hypercapnia of obstructive sleep apnea.

The mechanisms responsible for the development of chronic hypercapnia in patients with obstructive sleep apnea (OSA) are not well defined. Therefore, we tested the hypothesis that diffuse airway obstruction may be involved by studying 50 patients with a well-documented OSA syndrome. Seven patients had daytime hypercapnia with a mean PaCO2 of 51 +/- 2 (SEM) mm Hg, compared to a PaCO2 of 35 +/- 1 in the other 43 patients. There were no differences between the 2 groups in the number or duration of nocturnal obstructive events. In contrast, the hypercapnic patients were significantly heavier than the normocapnic patients (body weight, 189 +/- 11 versus 148 +/- 6% of ideal; p less than 0.005) and had evidence of diffuse airway obstruction, as indicated by an increased residual volume and a reduction in all expiratory flow rates. When the hypercapnic patients were compared with a weight-matched group of 9 normocapnic patients (body weight, 196 +/- 8% of ideal), there were still no differences in nocturnal obstructive events, but the differences in tests of airway mechanics persisted. Multiple regression analysis of PaCO2 against several anthropometric, respiratory physiologic, and polysomnographic variables revealed that only 2 variables (expiratory reserve volume and FEV1/FVC), both of which are influenced by airway mechanics, were significantly correlated with PaCO2 (multiple r = 0.78; p = 0.0001). The findings suggest that OSA alone does not produce daytime hypercapnia even in obese patients, and that the presence of diffuse airway obstruction is an important predisposing factor to the development of chronic CO2 retention in such patients.

Adult↗
PubMed1985

Physiological determinants of nocturnal arterial oxygenation in patients with obstructive sleep apnea.

Among patients with similar degrees of obstructive sleep apnea (OSA) there is considerable variability in the degree of associated nocturnal hypoxemia. The factors responsible for this variability have not been clearly defined. Therefore we studied 44 patients with OSA to identify the physiological determinants of nocturnal arterial O2 saturation (SaO2). All patients underwent pulmonary function testing, arterial blood gas analysis, and overnight polysomnography. Mean nocturnal SaO2 ranged from 96 to 66% and apnea-hypopnea index from 11 to 128 per hour of sleep. Several anthropometric, respiratory physiological, and polysomnographic variables that could be expected to influence nocturnal SaO2 were entered into a stepwise multiple linear regression analysis, with mean nocturnal SaO2 as the dependent variable. Three variables [awake supine arterial PO2 (PaO2), expiratory reserve volume, and percentage of sleep time spent in apnea] were found to correlate strongly with mean nocturnal SaO2 (multiple R, 0.854; P less than 0.0001) and accounted for 73% of its variability among patients. Body weight, other lung volumes, and airflow rates influenced awake PaO2 and expiratory reserve volume but had no independent influence on nocturnal SaO2. In a further group of 15 patients with OSA a high correlation was obtained between measured nocturnal SaO2 and that predicted by the model (r = 0.87; P less than 0.001). We conclude that derangements of pulmonary mechanics and awake PaO2 (generally attributable to obesity and diffuse airway obstruction) are of major importance in establishing the severity of nocturnal hypoxemia in patients with OSA.

Adult↗
PubMed1985

Role of daytime hypoxemia in the pathogenesis of right heart failure in the obstructive sleep apnea syndrome.

Although right heart failure is a recognized complication of obstructive sleep apnea, the incidence and pathogenesis of this complication have not been established. We therefore studied 50 consecutive patients with obstructive sleep apnea to determine the incidence of right heart failure and the factors involved in its development. Six patients (12%) were found to have right heart failure. There were no differences in the number of apneas between those with right heart failure (mean +/- SE, 30 +/- 10 per h sleep) and those without right heart failure (33 +/- 4 per h sleep). In contrast, mean nocturnal oxygen saturation was lower in patients with right heart failure (76 +/- 3%) than in those without right heart failure (90 +/- 1%; p less than 0.001). Furthermore, patients with right heart failure also had a substantially lower awake arterial PO2 (52 +/- 4 mmHg versus 75 +/- 2 mmHg; p less than 0.001) and a higher PCO2 (51 +/- 2 mmHg versus 36 +/- 1 mmHg; p less than 0.001) than those without right heart failure. Severe nocturnal hypoxemia in the absence of diurnal hypoxemia was not associated with right heart failure. Daytime hypoxemia in the patients with right heart failure was associated with a higher residual volume (p less than 0.001) and lower forced expiratory volume in one second (p less than 0.001) than in the patients without right heart failure. The findings suggest that sustained hypoxemia and/or hypercapnia over a 24-h period is a necessary prerequisite for the development of right heart failure in patients with obstructive sleep apnea, and that diffuse airway obstruction plays a major role in causing such hypoxemia.

Circadian Rhythm↗
PubMed1978

A spectral method for removing eye movement artifacts from the EEG.

A frequency-domain technique for compensating for eye artifacts in mid-line scalp EEG when power spectra are to be calculated is reported. It has been tested in 12 subjects during voluntary and random eye movements. The method which involves calculating the ratio of EEG and EOG spectra adequately controls for low-frequency components in the EEG due to eye artifacts and allows recovery of the dominant peaks in the scalp EEG spectrum.

Electroencephalography↗
PubMed1978

EEG frequency patterns associated with hallucinations in schizophrenia and "creativity" in normals.

This study attempts to define EEG power spectral patterns associated with hallucinatory behaviors in schizophrenia. Six unmedicated schizophrenics with Schneiderian criteria were interviewed and their tongue potentials were monitored and recorded on FM tape. Eye movements and tongue potentials were monitored and segments with artifacts were not used. Consecutive 4-sec intervals of EEG were analyzed in the frequency domain using fast Fourier transorm methods and serial power spectra plots obtained. The intrusiveness of the hallucinatory experience may be similar to the sudden internal experience of perceptual resolution in a creative task. Six normal controls were similarly monitored and analyzed while responding to tests of "creativity." In the 4-sec interval prior to reports of hallucinatory experiences, a frequency pattern of predominatly delta and theta power was found in 71.7% of the EEG segments. In the control group, 78.1% of the EEG segments preceding a creative response demonstrated a similar low frequency pattern which also differed significantly from the base line EEG frequency pattern.

Adult↗