Chest
Volume 119, Issue 1, January 2001, Pages 45-52
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Clinical Investigations
SLEEP
Daytime Sleepiness and EEG Spectral Analysis in Apneic Patients Before and After Treatment With Continuous Positive Airway Pressure

https://doi.org/10.1378/chest.119.1.45Get rights and content

Background:

Obstructive sleep apnea syndrome (OSAS) ischaracterized by recurrent apneas during sleep, resulting in repetitivehypoxemic episodes and interruptions of the normal sleep pattern. Aprevious study showed EEG slowing (ie, a higher ratio ofdelta + theta frequencies to alpha + beta frequencies on EEG)during rapid eye movement (REM) sleep and wakefulness in untreated OSASpatients.

Study and objectives:

To determine whether, EEG slowing is reversible with continuous positive air pressure (CPAP)treatment and to verify whether the persistence of excessive daytimesleepiness (EDS) is correlated with residual slowing of the EEG.

Patients:

Ten healthy subjects (9 men and 1 woman) and 14patients with moderate-to-severe OSAS (13 men and 1 woman) were studiedbefore and after 6 months of treatment with CPAP.

Results:

Untreated OSAS patients showed EEG slowing infrontal and central cortical regions during both wakefulness andduring REM sleep compared to healthy control subjects. This EEG slowingwas found to be independent of time spent with arterial oxygensaturation < 90%, severity of OSAS, or mean sleep latency asdetermined by the multiple sleep latency test. CPAP treatment was foundto correct the EEG slowing for both REM sleep and wakefulness. Daytimesleepiness also greatly improved with treatment, but some degree ofsomnolence remained.

Conclusion:

CPAP treatment wasfound to correct the EEG slowing that was observed in untreated OSASpatients. Persistent EDS may be related to persistent obesity after, CPAP treatment.

Section snippets

Subjects

Fourteen subjects (13 men and 1 woman; age range, 34 to 58years; mean age [± SD], 45.0 ± 6.4 years) withmoderate-to-severe OSAS were studied before and after 6 to 9 months oftreatment with CPAP. Inclusion criteria were the presence of anapnea-hypopnea index (AHI) > 10 events per hour of sleep and aminimum arterial oxygen saturation(Sao2) level < 80%. Tenhealthy subjects (nine men and one woman; age range, 36 to 55 years; mean age, 44.2 ± 6.1 years) served as a control group. The healthysubjects

Respiratory and Polysomnographic Variables

Untreated OSAS patients were statistically different from controlsubjects for body mass index (BMI) and all sleep-related respiratoryvariables (ie, minimal, Sao2 value, time spent at< 90% of oxygen saturation, and AHI) (Table 1).

Between-group differences also were found for polysomnographicvariables (Table 2). Apneic patients hadlower percentages of slow-wave sleep and REM sleep and had lower REMsleep efficiency (ie, time spent in REM sleep over theentire duration of the REM sleep period). They

Discussion

To our knowledge, this is the first time that q, EEGs have beenperformed during REM sleep and wakefulness in OSAS patients before andafter treatment with CPAP.

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  • Cited by (0)

    Supported by the Fonds de la Recherche en Santé du Québecand the Medical Research Council of Canada.

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