Does more sleep matter? Differential effects of NREM- and REM-dominant sleep on sleepiness and vigilance.

We investigated effects of NREM and REM predominant sleep periods on sleepiness and psychomotor performances measured with visual analog scales and the psychomotor vigilance task, respectively. After one week of stable sleep-wake rhythms, 18 healthy sleepers slept 3hours of early sleep and 3hours of late sleep, under polysomnographic control, spaced by two hours of sustained wakefulness between sleep periods in a within subjects split-night, sleep interruption protocol. Power spectra analysis was applied for sleep EEG recordings and sleep phase-relative power proportions were computed for six different frequency bands (delta, theta, alpha, sigma, beta and gamma). Both sleep periods presented with similar sleep duration and efficiency. As expected, phasic NREM and REM predominances were obtained for early and late sleep conditions, respectively. Albeit revealing additive effects of total sleep duration, our results showed a systematic discrepancy between psychomotor performances and sleepiness levels. In addition, sleepiness remained stable throughout sustained wakefulness during both conditions, whereas psychomotor performances even decreased after the second sleep period. Disregarding exchanges for frequency bands in NREM or stability in REM, correlations between outcome measures and EEG power proportions further evidenced directional divergence with respect to sleepiness and psychomotor performances, respectively. Showing that the functional correlation pattern changed with respect to early and late sleep condition, the relationships between EEG power and subjective or behavioral outcomes might however essentially be related to total sleep duration rather than to the phasic predominance of REM or NREM sleep.

Noche Partida: Utilidad y tolerancia comparada con titulación de CPAP en noche completa / Split night. Usefulness and tolerance compared with full-night CPAP titration

Introducción: El tratamiento de elección en el síndrome de apneas/hipopneas obstructivas del sueño (SAHOS) es el empleo de la presión continua positiva sobre la vía aérea (CPAP). La presión eficaz que corrige los eventos respiratorios debe ser determinada en forma individual en cada paciente independientemente del método utilizado. Se ha planteado que la polisomnografia noche partida (PSGNP) podría no ser adecuada para evaluar la gravedad de la enfermedad y los pacientes tendrían una menor adherencia al equipo de CPAP. Objetivo: Se plantea corroborar la utilidad de la realización de la PSGNP. Materiales y métodos: Se evaluaron los pacientes con SAHOS severo. Se dividieron en dos grupos, aquellos que realizaron PSGNP y polisomnografia noche completa (PSGNC). Se evalúo el éxito o fracaso de la titulación a la CPAP y se compararon ambos grupos por edad, sexo, índice de masa corporal (IMC), circunferencia de cuello, escala de Epworth, índice de perturbación respiratoria (IPR), saturación basal y mínima. Resultados: Se evaluaron 314 pacientes. Se realizó PSGNP a 216 pacientes (68.8%) y PSGNC a 98. La titulación fue eficaz y bien tolerada en 159 (73.6%) de los pacientes que realizaron PSGNP. En el grupo de PSGNC, en 73 se realizó un segundo estudio para titulación y 25 no concurrieron. En este grupo, la titulación fue eficaz en 64 (87.7%) p = 0.013. A los pacientes que fracasaron en la PSGNP se los citó a un nuevo estudio de PSGNC, de estos concurrieron 42 (73.7%) y lograron titular en forma eficaz a 31 (73.8%). Utilizando la modalidad PSGNP se logró titular a 190 (88%) de los pacientes vs 64 (65.3%) del grupo PSGNC (p < 0.0001). Conclusión: La PSGNP ha demostrado ser eficaz y bien tolerada en la mayoría de los pacientes resolviendo en una sola noche el diagnóstico y tratamiento.

Introduction: The treatment of choice for obstructive sleep apnea / hypopnea syndrome (OSAHS) is the use of continuous positive airway pressure (CPAP). Effective pressure correcting respiratory events must be determined individually for each patient regardless of the method used. It has been suggested that the split-night polysomnography (SNPSN) may not be appropriate to assess the severity of the disease and patients may have a lower adherence to CPAP. Objetives: To evaluate the utility SNPSG study performance. Materials and Methods: Patients with severe OSAHS were evaluated. They were divided into two groups, SNPSG and full night polysomnography (FNPSG). The success or failure of the CPAP titration was evaluated and both groups were compared by age, sex, body mass index (BMI), neck circumference, Epworth scale, respiratory perturbation index (PRI), basal and lowest saturation. Results: 314 patients were evaluated. SNPSG was conducted on 216 patients (68.8%) and FNPSG on 98 patients. Titration was effective and well tolerated in 159 (73.6%) of the patients undergoing PSGSN. In the group of FNPSG, a second study of titration was performed on 73 patients and 25 were absent. In this group titration was effective in 64 (87.7%) p = 0.013. Patients who failed SNPSG took part in a new FNPSG study, of whom 42 (73.7 %) attended achieving effective pressure in 31 (73.8%). SNPSG mode achieved effective titration at 190 (88%) patients vs 64 (65.3%) from FNPSG group (p < 0.0001). Conclusion: SNPSG has proven to be effective and well tolerated by most patients solving diagnosis and treatment in a single night.