Matilde Valencia-Flores

Effect of Bariatric surgery on Obstructive sleep apnea and hypopnea syndrome, electrocardiogram, and pulmonary arterial pressure

Background: We evaluated the impact of surgically-induced weight loss on Obstructive Sleep Apnea/Hypopnea Syndrome (OSAHS), electrocardiographic changes, pulmonary arterial pressure and daytime sleepiness in morbidly obese patients. Methods: 16 women and 13 men (n=29) underwent bariatric surgery in a 3-year period. The following tests were performed before and 1 year after surgery: nocturnal polysomnography, daytime Multiple Sleep Latency Test (MSLT), and echocardiogram. Results: Mean age was 37.9±11 years (range 20-56). Preoperative body mass index was 56.5±12.3 kg/m2 and it was 39.2±8.5 kg/m2 at 13.7±6.6 months follow-up. Performed surgical procedures included: vertical banded gastroplasty in 6, Roux-en-Y gastric bypass in 12, and Distal Roux-en-Y gastric bypass in 11. Weight loss induced by surgery eliminated OSAHS in 46% of obese patients with an important improvement in oxygen saturation. Neck, thorax, waist and hip circumferences decreased significantly after surgical intervention but only neck circumference correlated significantly with the apnea/hypopnea index (Spearman rho=0.63, P <0.0001). Electrocardiographic abnormalities were present in 9 patients (31%) before surgery (sinus arrhythmia, ventricular arrhythmias, and sinus arrest). The number of electrocardiographic abnormalities decreased after surgery but new abnormalities appeared in some patients. Systolic pulmonary arterial pressure significantly decreased in the group of patients in whom OSAHS disappeared after surgery. Daytime sleepiness persisted after surgery in most patients. Conclusion: Bariatric surgery effectively reduces respiratory disturbances during sleep and improves pulmonary hypertension. Electro cardiographic abnormalities change after surgery. Daytime sleepiness appeared not to be related to respiratory disturbances during sleep.

Cognitive function in patients with sleep apnea after acute nocturnal nasal continuous positive airway pressure (CPAP) treatment: sleepiness and hypoxemia effects.

Patients with sleep apnea are typically hypersomnolent during the daytime and may demonstrate higher order cognitive dysfunction. A persistent problem in interpreting impaired neuropsychological test performance in such patients is whether the observed deficits can be explained wholly by impaired vigilance. We examined 37 sleep apnea patients prior to and immediately subsequent to successful sleep apnea treatment with nasal continuous positive airway pressure (CPAP). Patients were evaluated immediately after morning awakening in the sleep lab. A brief neuropsychological evaluation, was administered at that time. Following this, alertness was measured with a 30-min polysomnographically determined sleep latency test. Both test (approximately 50 min in duration) were performed once following a baseline (diagnostic) night in the sleep lab and once in the morning following a CPAP (therapeutic) night in the lab. Subgroup analyses indicted that while vigilance impairment can account for some of the decreased test performance seen in sleep apnea (auditory verbal learning) the effects of severe nocturnal hypoxemia appear to affect other function (sustained attention in repetitive arithmetic calculations) that were not easily modified by treatment. Thus, performance on the recall trial of the Rey Auditory Verbal Learning Test increased from pre-CPAP to post-CPAP for the increased alertness group but decreased significantly for the decreased alertness group. On the Wilkinson Addition Test, non-hypoxemic patients showed statistically significant improvement in problems correctly solved from pre-CPAP to post-CPAP, but the hypoxemic patients showed only a marginal increase. These results are compatible with other studies suggesting that patients having sleep apnea may incur deficits as a result of both decreased vigilance and hypoxemia, and that at least some of these deficits are immediately reversible.

Objective and subjective sleep disturbances in patients with systemic lupus erythematosus

OBJECTIVE To assess objective and subjective evidence of sleep disorders in patients with systemic lupus erythematosus (SLE) and to examine correlations between parameters of lupus activity, depression, and sleep disturbances. METHODS Fourteen SLE patients and 11 normal control subjects of similar age underwent all-night polysomnography on 3 consecutive nights. The patients and controls were also evaluated for daytime sleepiness by the Multiple Sleep Latency Test and completed a sleep disorders questionnaire and the Beck Depression Inventory. RESULTS The polysomnographic data showed that sleep in SLE patients was characterized by respiratory and movement disorders. These intrinsic primary sleep disorders are related to the symptom of restless, poor sleep at night. Lupus patients were more sleepy during the day, and their sleepiness was related to sleep fragmentation, with more arousals and stage transitions than the control group. Disease activity was associated with decreases in sleep efficiency and delta sleep and with increases in sleep fragmentation. Depression was not correlated with the activity of the disease. CONCLUSION There is an enhanced presence of sleep disorders in patients with SLE. The most frequent primary sleep disorders are respiratory and movement disorders.

The siesta culture concept is not supported by the sleep habits of urban Mexican students

Evidence in support for the concept of the so‐called ‘siesta culture’ is not well developed and has, to date, relied largely on qualitative anthropological data. Presumably such cultures are characterized by a strong tendency for daytime naps and daytime sleepiness, phenomena which may partially represent the effects of geographic, climatic or light conditions and/or cultural influences. In this study we surveyed the nocturnal sleep habits and daytime sleep tendencies of 577 Mexican college students residing in Mexico City (19°N latitude). Results indicated a number of parallels between the reported sleep habits of these students and those reported from other cultures at latitudes far to the north (North America, Europe), such as longer sleep at the weekends, an association between snoring and daytime sleepiness and a lack of relationship between nocturnal sleep duration and the reported tendency to nap. There was some suggestion that these Mexican students may actually nap less when compared to other college student populations. Taken together, these results call into question what is meant by the concept of a ‘siesta culture’, at least in this urban, educated, upper social economic scale (SES) population, and suggest that future studies in equatorial regions be undertaken to further appreciate the role of climate, photoperiod and/or culture in the tendency for humans to nap during the day.

Sleepiness, performance and mood state in a group of Mexican undergraduate students

The objective of this study was to compare the basic academic activities like reading comprehension and arithmetical operation solution, sleep habits and mood states in two groups of students with different levels of sleepiness. A total of 64 healthy undergraduate students enrolled in psychology courses at the Universidad Nacional Autónoma de México volunteered to participate in the study. The mean age was 20.3 ± 2.0 years (range 17 – 25). Students were asked to fill out a Spanish version of the Epworth Sleepiness Scale (ESS) and the Sleep Habits Questionnaire. Students also completed the Profile of Mood States (POMS) and the Beck Depression Inventory. Reading comprehension and mathematical skills are fundamental behaviors for academic performance. Students had to read a brief text and answer five questions related to its content. Mathematical skills were evaluated with five standardized mathematical problems with different degrees of difficulty. Students were also tested with the Rey Auditory Verbal Learning Test. Subjects were classified as sleepy and non-sleepy according with their ESS score (sleepy students score ⩾ 11 and non-sleepy ⩽ 5). There were no statistically significant differences in demographic characteristics between the sleepy and non-sleepy group. Data show that sleepiness can induce a decrease in basic academic behavior such as mathematical problem solution. Also, the presence of sleepiness was related with a greater negative mood state. These data support the need for a heightened awareness of the negative impact of sleepiness in academic performance of otherwise healthy college students.

Gender differences in sleep architecture in sleep apnoea syndrome

SUMMARY  This study compared sleep architecture in women and men with sleep apnoea syndrome. Women (n= 126) had longer sleep latencies, greater amounts of slow wave sleep, and fewer awakenings during the night than men (n= 181), despite no differences in age, RDI (Respiratory Disturbance Index) or oxygen saturation. In a subgroup of men and women treated with nasal CPAP, gender differences generally persisted. There was no difference in the complaint of daytime sleepiness between the groups, but the women reported more fatigue during the day than the men, as well as complaining about more sleep disturbance at night. We interpret these differences in terms of known gender differences in sleep architecture and sleep complaints.

Intermittent hypoxemia and sleep fragmentation: associations with daytime alertness in obese sleep apnea patients living at moderate altitude

BACKGROUND Although obstructive sleep apnea (OSA) has long been associated with daytime sleepiness, far less is known about its association with the ability to remain awake. The aim of this study was to examine the relative importance of inter-correlated measures of OSA severity (eg, various indices of oxygen saturation and sleep fragmentation) in the ability to stay alert as measured objectively by the Maintenance of Wakefulness Test (MWT), defined by a mean sleep latency of ≥12 min. METHODS Seventy-eight obese women and men of similar age and body mass index living at altitude (Mexico City) underwent standard polysomnography, MWT, and completed validated sleep-related questionnaires. RESULTS Men had more severe sleep apnea than women (p = 0.002) and were also less alert on MWT (p = 0.022). Logistic regression models indicated that measures of desaturation consistently predicted MWT-defined alertness, whereas varied measures of sleep fragmentation did not. Nearly a third of the variance (r(2) = 0.304) in MWT-defined alertness was accounted for by the number of desaturations per hour of sleep (p = 0.003), which is considerably higher than other studies have reported in different populations. CONCLUSION The ability to remain awake in obese patients is best accounted for by hypoxemia rather than sleep fragmentation. Whether the size of this effect reflects differences in the population under study (eg, extent of obesity, racial background, residence at moderate altitude) and/or is a function of the measurement of alertness with the MWT remains uncertain.

Behavioral and biochemical correlates of chronic administration of quipazine

In Experiment 1 groups of rats received single injections of 1, 3, 10, 20 or 40 mg/kg quipazine, and their total 24-hr food and water intake after a 24-hr deprivation period was recorded; there was a dose-related reduction of both food and water intake. In Experiment 2 a group of 15 rats received 5 mg/kg/day, SC quipazine during 29 days, and a control group received saline injections. During treatment, all animals were exposed to a 24-hr food and water deprivation schedule, alternated with 24 hr of free access. Food and water consumption was measured 2 and 24 hr after drug injection; regional 5-HT concentrations were determined at 1 and 13 treatment days by fluorometric assay. Beginning the first treatment day, food and water intake decreased, but by the 13th day the quipazine group had returned to normal ingestion levels. 5-HT concentrations were increased in cerebellum and cortex in acute conditions, but after 13 days they had decreased in cerebellar samples. In Experiment 3 we found that the effects of quipazine on food and water ingestion were recovered after 14 days of discontinuing chronic drug administration.

Sleep, Fatigue, Depression, and Pain in Mexican Women With Systemic Lupus Erythematosus: An Exploratory Study

] age = 39.3 [11.1] underwent nocturnal polysomnography (PSG) and daytime testing (Multiple Sleep Latency Test, [MSLT]) and were compared to healthy female age-matched controls. We employed validated instru-ments to assess disease activity, fatigue, and depressive symptoms. Results: SLE patients had lower sleep efficiency, greater number of awakenings, and greater time awake after sleep onset than controls. The majority (over 70%) of SLE patients were sleepy (mean MSLT 6.7 ± 3.9 minutes). Clinically sleep com-plaints scores were higher than the control group and they correlated with PSG total sleep time, time of oxygen desaturation, Apnea and Hypopnea Index (AHI), and Periodic Limb Movement Index (PLMI). Conclusion: Poor nocturnal sleep and daytime sleepiness are common in SLE patients. Sleepiness (MSLT) in SLE may be associated with total sleep time of oxygen desaturation and sleep fragmentation. Our study also confirmed previous findings that sleep apnea and periodic limb movements while you sleep (PLMS) are common sleep disorders in patients with SLE.

Sleep onset: scoring criteria in patients with sleep apnea syndrome.

It has been suggested that in patients with sleep apnea syndrome (SAS) modified scoring criteria may improve accuracy in the determination of sleep onset in the Multiple Sleep Latency Test (MSLT). Scoring in 30-sec epochs according to the standard criteria requires more than 50% of the epoch asleep to score sleep latency (SL). In patients with SAS, short apneas with arousals could prevent the accurate determination of SL. This study compared three time-duration epochs (5-sec, 10-sec, 30-sec) for scoring SL in patients with SAS. Sleep onset during a single sleep latency test, the morning subsequent to a nocturnal polysomnogram, was determined by the criterion of at least 50% of the epoch asleep. Neuropsychological evaluation was performed immediately after the single sleep latency test. There was no statistically significant difference in time to fall asleep as defined by 10-sec and 30-sec epochs, but SL defined by 5-sec epochs was significantly shorter than SL defined by 10-sec and 30-sec epochs. Wilkinson Addition Test correct score correlated better with SL as defined by 30-sec epochs. The results imply that the level of sleepiness measured by 30-sec epochs may be more useful to appreciate behavior and performance.