Síndrome de apnea/hipopnea obstructiva del sueño: ¿polisomnografía o poligrafía respiratoria? / Obstructive sleep apnea / hypopnea syndrome: polysomnography or polygraphy respiratory

La poligrafía respiratoria (PR) o estudio de sueño de nivel III permite evaluar a pacientes con sospecha de síndrome apnea/hipopnea obstructiva del sueño (SAHOS) en su casa o fuera del laboratorio de sueño (pacientes internados). Las señales mínimas que un polígrafo respiratorio debe registrar son flujo aéreo, movimientos toracoabdominales y saturación de oxígeno (SO2). A pesar de que esta tecnología está disponible desde hace más de 20 años, recientemente la comunidad médica la ha aceptado como una alternativa válida a la polisomnografía para el diagnóstico y manejo del SAHOS. Posiblemente intereses sectoriales de las sociedades médicas de sueño que nacieron con las señales electroencefalográficas, simple resistencia al cambio, característica de la naturaleza humana asociada a la insuficiente evidencia científica, fueron algunas de las razones que retrasaron la incorporación de la poligrafía respiratoria para el diagnóstico de los trastornos respiratorios del sueño. Afortunadamente, la poligrafía respiratoria ha llegado para quedarse definitivamente en la comunidad médica. Aún hoy, en nuestro medio hay todavía algunos prejuicios especialmente entre los defensores a ultranza de las señales neurobiológicas (neurólogos, neurofisiológicos) en aceptar esta modalidad diagnóstica. Los argumentos que esgrimen son varios, pero tres revisiones sistemáticas publicadas en el 20071-3 dan por tierra este deseo de mantener el "statu quo". Estas publicaciones han demostrado que la poligrafía respiratoria es comparable a la polisomnografía para el diagnóstico de pacientes adultos con moderado a alto pretest clínico para SAHOS, siendo su exactitud diagnóstica superior al 90%. Asimismo, la PR se acepta actualmente para el seguimiento de pacientes con SAHOS a quienes se les ha indicado una intervención terapéutica tal como reducción de peso, terapia posicional, un dispositivo de avance mandibular o CPAP. La introducción de la PR ha permitido un rápido acceso al diagnóstico y por ende al tratamiento, especialmente en centros que no disponen de PSG y en pacientes que por sus condiciones no pueden trasladarse a una unidad de sueño

Pulse oximetry for the detection of obstructive sleep apnea syndrome: can the memory capacity of oxygen saturation influence their diagnostic accuracy?

Objective. To assess the diagnostic ability of WristOx 3100 using its three different recording settings in patients with suspected obstructive sleep apnea syndrome (OSAS). Methods. All participants (135) performed the oximetry (three oximeters WristOx 3100) and polysomnography (PSG) simultaneously in the sleep laboratory. Both recordings were interpreted blindly. Each oximeter was set to one of three different recording settings (memory capabilities 0.25, 0.5, and 1 Hz). The software (nVision 5.1) calculated the adjusted O2 desaturation index-mean number of O2 desaturation per hour of analyzed recording ≥2, 3, and 4% (ADI2, 3, and 4). The ADI2, 3, and 4 cutoff points that better discriminated between subjects with or without OSAS arose from the receiver-operator characteristics (ROCs) curve analysis. OSAS was defined as a respiratory disturbance index (RDI) ≥ 5. Results. 101 patients were included (77 men, mean age 52, median RDI 22.6, median BMI 27.4 kg/m(2)). The area under the ROCs curves (AUC-ROCs) of ADI2, 3, and 4 with different data storage rates were similar (AUC-ROCs with data storage rates of 0.25/0.5/1 Hz: ADI2: 0.958/0.948/0.965, ADI3: 0.961/0.95/0.966, and ADI4: 0.957/0.949/0.963, P NS). Conclusions. The ability of WristOx 3100 to detect patients with OSAS was not affected by the data storage rate of the oxygen saturation signal. Both memory capacity of 0.25, 0.5, or 1 Hz showed a similar performance for the diagnosis of OSAS.

Gender and perception of dyspnea. The role of the variation in the forced expiratory volume in one second.

During bronchoconstriction women perceive more breathlessness than men. The aims of study were 1) to evaluate if quality of dyspnea in bronchoconstriction was different in women and men 2) to assess if gender difference in the perception of dyspnea could be related to the level of bronchoconstriction. 457 subjects (257 women) inhaled methacholine to a 20% decrease in FEV1, or 32 mg/ml. Dyspnea was evaluated using the modified Borg scale and a list of expressions of dyspnea. Borg scores were recorded immediately before the challenge test baseline and at the maximum FEV1 decrease. The prevalence of descriptors of dyspnea reported by women and men was similar. Dyspnea was related to the level of FEV1 (FEV1: OR 1.05, 95%CI 1.01-1.09, p 0.0095), females (OR 2.90, 95%CI 1.33-6.33, p 0.0072), younger subjects (OR 0.93, 95%CI 0.89-0.97, p 0.0013) and body mass index (BMI) (OR 1.11, 95%CI 1.01-1.23, p 0.023). As the FEV1 fell less than 20% from baseline, only the FEV1 was significantly associated with dyspnea (FEV1:OR 1.15, 95%CI 1.07-1.24, p 0.0002). Instead, if the FEV1 fell higher > or = 20%, the presence of dyspnea was related to the degree of bronchoconstriction (FEV1: OR 1.04, 95%CI 1.01-1.09, p 0.0187), females (OR 3.02, 95%CI 1.36-6.72, p 0.0067), younger subjects (OR 0.92, 95%CI 0.88-0.96, p 0.0007) and BMI (OR 1.12, 95%CI 1.01-1.23, p 0.023). The quality of dyspnea during the bronchoconstriction was similar in women and men; women showed a higher perception of dyspnea than men only when the FEV1 fell more than 20% from baseline.

Gender and perception of dyspnea: The role of the variation in the forced expiratory volume in one second / Género y percepción de disnea: el rol de la variación del volumen espiratorio forzado en un segundo

During bronchoconstriction women perceive more breathlessness than men. The aims of study were 1) to evaluate if quality of dyspnea in bronchoconstriction was different in women and men 2) to assess if gender difference in the perception of dyspnea could be related to the level of bronchoconstriction. 457 subjects (257 women) inhaled methacholine to a 20% decrease in FEV1, or 32 mg/ml. Dyspnea was evaluated using the modified Borg scale and a list of expressions of dyspnea. Borg scores were recorded immediately before the challenge test baseline and at the maximum FEV1 decrease. The prevalence of descriptors of dyspnea reported by women and men was similar. Dyspnea was related to the level of FEV1 (ΔFEV1: OR 1.05, 95%CI 1.01-1.09, p 0.0095), females (OR 2.90, 95%CI 1.33-6.33, p 0.0072), younger subjects (OR 0.93, 95%CI 0.89- 0.97, p 0.0013) and body mass index (BMI) (OR 1.11, 95%CI 1.01-1.23, p 0.023). As the FEV1 fell less than 20% from baseline, only the ΔFEV1 was significantly associated with dyspnea (ΔFEV1:OR 1.15, 95%CI 1.07- 1.24, p 0.0002). Instead, if the FEV1 fell higher ≥ 20%, the presence of dyspnea was related to the degree of bronchoconstriction (ΔFEV1: OR 1.04, 95%CI 1.01-1.09, p 0.0187), females (OR 3.02, 95%CI 1.36-6.72, p 0.0067), younger subjects (OR 0.92, 95%CI 0.88-0.96, p 0.0007) and BMI (OR 1.12, 95%CI 1.01-1.23, p 0.023). The quality of dyspnea during the bronchoconstriction was similar in women and men; women showed a higher perception of dyspnea than men only when the FEV1 fell more than 20% from baseline.

Durante la broncoconstricción las mujeres perciben más disnea que los hombres. Los objetivos del estudio fueron evaluar: 1) si la calidad de la disnea durante la broncoconstricción fue diferente en mujeres y hombres, 2) si la diferencia entre sexos en la percepción de disnea podría relacionarse al nivel de broncoconstricción. 457 sujetos (257 mujeres) inhalaron metacolina hasta un descenso del FEV1 ≥ 20% o 32 mg/ml. La disnea fue evaluada mediante escala de Borg y una lista de expresiones de disnea. El Borg fue registrado en forma basal y con el máximo descenso del FEV1. La frecuencia de descriptores de disnea informados por mujeres y hombres fue similar. La disnea estuvo relacionada al grado de broncoconstricción (ΔFEV1: OR 1.05, 95%CI 1.01-1.09, p 0.0095), sexo femenino (OR 2.90, 95%CI 1.33-6.33, p 0.0072), edad (OR 0.93, 95%CI 0.89-0.97, p0.0013) e índice de masa corporal (IMC) (OR 1.11, 95%CI 1.01-1.23, p 0.023). Cuando el FEV1 cayó menos del 20%, solo el ΔFEV1 se asoció con disnea (ΔFEV1: OR 1.15, 95%CI 1.07-1.24, p 0.0002). En tanto que si el FEV1 cayó ≥ del 20%, la disnea estuvo relacionada al grado de broncoconstricción (ΔFEV1: OR 1.04, 95%CI 1.01-1.09, p 0.0187), sexo femenino (OR 3.02, 95%CI 1.36-6.72, p 0.0067), edad (OR 0.92, 95%CI 0.88-0.96, p 0.0007) e IMC (OR 1.12, 95%CI 1.01-1.23, p 0.023). La calidad de la disnea durante la broncoconstricción fue similar en hombres y mujeres; las mujeres tuvieron mayor percepción de disnea que los hombres solo cuando el FEV1 descendió más del 20%.

Utility of ApneaLink for the diagnosis of sleep apnea-hypopnea syndrome.

Portable sleep studies may play an important role to take decisions on patients referred for suspicion of Sleep Apnea-Hypopnea Syndrome (SAHS). The aim of this study was to evaluate the diagnostic accuracy of automated analysis of ApneaLink in patients with suspicion of SAHS. All participants (75) performed the ApneaLink and polysomnography (PSG) simultaneously in the sleep laboratory. The two recordings were interpreted blindly. The ApneaLink software calculated: (1) risk indicator (RI)-a combination of apnea/hypopnea index (AHI) plus inspiratory flow limitation events and (2) the AHI. ApneaLink and SAHS were defined in three ways: AHI or respiratory disturbance index (RDI) >or= 5, 10 and 15 respectively. ROC curves analysis was performed. The sensitivity (S), specificity (E) and positive and negative likelihood ratio (LR+, LR-) for the different thresholds for RI or AHI were calculated; 66 patients were included (47 men, mean age 51, median RDI 10.6, mean BMI 29.3 kg/m2). The best cut off points of RI were: SAHS = RDI >or= 5: RI > 9 (S 80%, E 100%, LR- 0.20); SAHS =RDI >or= 10: RI > 13 (S 92%, E 93%, LR+ 13.7 LR- 0.089); SAHS = RDI >or= 15 =: RI > 16 (S 93.5%, E 91%, LR+10.9, LR- 0.071). The AHI had a similar diagnostic accuracy to RI for the different definitions of SAHS. The RI and AHI obtained from automated analysis of ApneaLink were highly sensitive and specific to diagnose moderate to severe SAHS.

Utility of ApneaLinkTM for the diagnosis of sleep apnea-hypopnea syndrome / Utilidad del ApneaLinkT para el diagnóstico del síndrome apnea-hipopnea del sueño

Portable sleep studies may play an important role to take decisions on patients referred for suspicion of Sleep Apnea-Hypopnea Syndrome (SAHS). The aim of this study was to evaluate the diagnostic accuracy of automated analysis of ApneaLinkT in patients with suspicion of SAHS. All participants (75) performed the ApneaLink and polysomnography (PSG) simultaneously in the sleep laboratory. The two recordings were interpreted blindly. The ApneaLink software calculated: (1) risk indicator (RI)-a combination of apnea/hypopnea index (AHI) plus inspiratory flow limitation events and (2) the AHI. ApneaLinkT and SAHS were defined in three ways: AHI or respiratory disturbance index (RDI) = 5, 10 and 15 respectively. ROC curves analysis was performed. The sensitivity (S), specificity (E) and positive and negative likelihood ratio (LR+, LR-) for the different thresholds for RI or AHI were calculated; 66 patients were included (47 men, mean age 51, median RDI 10.6, mean BMI 29.3 kg/m²). The best cut off points of RI were: SAHS = RDI = 5: RI > 9 (S 80%, E 100%, LR- 0.20); SAHS = RDI = 10: RI > 13 (S 92%, E 93%, LR+ 13.7 LR- 0.089); SAHS = RDI = 15 =: RI > 16 (S 93.5%, E 91%, LR+ 10.9, LR- 0.071). The AHI had a similar diagnostic accuracy to RI for the different definitions of SAHS. The RI and AHI obtained from automated analysis of ApneaLinkT were highly sensitive and specific to diagnose moderate to severe SAHS.

Los equipos portátiles para estudios del sueño pueden tener un rol importante para tomar decisiones en pacientes con sospecha de Síndrome Apneas-Hipopneas del Sueño (SAHS). El objetivo del estudio fue evaluar la exactitud diagnóstica del análisis automático del ApneaLinkT en pacientes con sospecha de SAHS. Setenta y cinco sujetos realizaron simultáneamente el ApneaLinkT y una polisomnografía (PSG) en el laboratorio de sueño. Los dos registros fueron interpretados en forma ciega. Un programa calculó: (1) el índice apnea/hipopnea (IAH), (2) el indicador de riesgo (IR)-IAH más respiraciones con limitación al flujo aéreo. ApneaLinkT y SAHS fueron definidos como: IAH o IPR (índice de perturbación respiratoria) = 5, 10 y 15 respectivamente. Se calcularon la sensibilidad (S), especificidad (E) y razón de probabilidad positiva y negativa (RP+, RP-) para los diferentes puntos de corte fueron calculadas. Se incluyeron 66 pacientes (47 varones, edad media 51, IPR mediano 10.6, IMC medio 29.3 kg/m²). Los mejores puntos de corte del IR fueron: SAHS = IPR = 5: IR > 9 (S 80%, E 100%, RP- 0.20); SAHS = IPR = 10: IR >13 (S 92%, E 93%, RP+ 13.7 RP- 0.089); SAHS = IPR = 15: IR > 16 (S 93.5%, E 91%, RP+ 10.9, RP- 0.071). El IAH tuvo una exactitud diagnóstica similar al IR para las diferentes definiciones de SAHS. El IR y el IAH obtenidos del análisis automático del ApneaLinkT fueron muy sensibles y específicos para diagnosticar SAHS moderado a grave.

Overestimation of thoracic gas volume during the airway resistance maneuver. A potential error in the diagnosis of air trapping.

There are no data published about the agreement between the measurement of thoracic gas volume (TGV) during the airway resistance (TGV-Raw) and the conventional technique described by Dubois. The aim of this study was to establish the agreement between both methods to measure TGV. We studied eighty consecutive subjects. Only sixty-six performed acceptable plethysmography maneuvers. The patients were measured with a constant volume plethysmograph (Medical Graphics 1085 DL). TGV was performed in the same patient with two techniques: 1) during the airway resistance (Raw) measurement (TGV-Raw) and 2) during quiet breathing at the end of expiration (TGV). The panting frequency was 1 to 2 Hz with both maneuvers. The differences between both techniques were expressed in percentage (deltaTGV %) and absolute values (deltaTGV). The TGV-Raw of the whole group was higher than TGV (3.69 +/- 1.08 l vs 3.28 +/- 1.05 l, p < 0.001). Similarly, the subgroups of patients had a greater TGV-Raw than TGV (Normal: 3.44 +/- 0.77 l vs 2.98 +/- 0.72 l , p < 0.001; Obstructive: 4.08 +/- 1.19 l vs 3.71 +/- 1.15 l, p < 0.001; Restrictive: 2.62 +/- 0.49 l vs 2.25 +/- 0.51 l, p < 0.01). There was a considerable lack of agreement between the TGV-Raw and TGV, with discrepancies of up to +0.95 l or +34%. The deltaTGV % was similar between the patients' subgroups and between the subjects with different degree of airflow obstruction (Normal: 16.5 +/- 10%, Obstructive: 10.8 +/- 9.4%, Restrictive: 18 +/- 14.3%, p NS; mild obstruction: 10.7 +/- 11%, moderate obstruction: 12.3 +/- 5.7, severe obstruction: 10.1+/- 6.6, p NS). In conclusion, TGV-Raw was larger than TGV. This was because the patients generally panted at a volume above FRC when performing the TGV-Raw maneuver. TGV-Raw should not be used to estimate FRC because FRC would be overestimated and the diagnosis of air trapping may be erroneous.

Overestimation of thoracic gas volume during the airway resistance maneuver. A potential error in the diagnosis of air trapping.

There are no data published about the agreement between the measurement of thoracic gas volume (TGV) during the airway resistance (TGV-Raw) and the conventional technique described by Dubois. The aim of this study was to establish the agreement between both methods to measure TGV. We studied eighty consecutive subjects. Only sixty-six performed acceptable plethysmography maneuvers. The patients were measured with a constant volume plethysmograph (Medical Graphics 1085 DL). TGV was performed in the same patient with two techniques: 1) during the airway resistance (Raw) measurement (TGV-Raw) and 2) during quiet breathing at the end of expiration (TGV). The panting frequency was 1 to 2 Hz with both maneuvers. The differences between both techniques were expressed in percentage (deltaTGV

) and absolute values (deltaTGV). The TGV-Raw of the whole group was higher than TGV (3.69 +/- 1.08 l vs 3.28 +/- 1.05 l, p < 0.001). Similarly, the subgroups of patients had a greater TGV-Raw than TGV (Normal: 3.44 +/- 0.77 l vs 2.98 +/- 0.72 l , p < 0.001; Obstructive: 4.08 +/- 1.19 l vs 3.71 +/- 1.15 l, p < 0.001; Restrictive: 2.62 +/- 0.49 l vs 2.25 +/- 0.51 l, p < 0.01). There was a considerable lack of agreement between the TGV-Raw and TGV, with discrepancies of up to +0.95 l or +34

. The deltaTGV

was similar between the patients subgroups and between the subjects with different degree of airflow obstruction (Normal: 16.5 +/- 10

, Obstructive: 10.8 +/- 9.4

, Restrictive: 18 +/- 14.3

, p NS; mild obstruction: 10.7 +/- 11

, moderate obstruction: 12.3 +/- 5.7, severe obstruction: 10.1+/- 6.6, p NS). In conclusion, TGV-Raw was larger than TGV. This was because the patients generally panted at a volume above FRC when performing the TGV-Raw maneuver. TGV-Raw should not be used to estimate FRC because FRC would be overestimated and the diagnosis of air trapping may be erroneous.

Effect of the definition of hypopnea on apnea/hypopnea index.

The objective of this study was to determine whether different decreases in oxygen saturation (SaO2) or the presence of electroencephalographic arousals (EEGA) in the definition of hypopnea modify hypopnea index and apnea/hypopnea index and the prevalence of obstructive sleep apnea/hypopnea syndrome (OSAHS). A total of 20 polysomnographies performed in patients with OSAHS were analyzed. There are four different definitions of hypopnea: > or = 30% reduction in airflow or 50% decrease in abdominal movement associated with decreases SaO2 > or = 3% (type 1); decreases SaO2 > or = 3% or EEGA (type 2); decreases SaO2 > or = 4% (type 3); decreases SaO2 > or = 4% or EEGA (type 4). The prevalence of OSAHS was calculated for an apnea/hypopnea index (AHI) > or = 10 and > or = 15. Hypopnea index (HI) and AHI types 2 and 4 were higher than type 3 (HI: type 2: 20 +/- 10.6, type 4: 18.6 +/- 10, type 3: 11.4 +/- 10, p < 0.001; AHI: type 2: 23.3 +/- 11.6, type 4: 21.4 +/- 11.2, type 3: 14.7 +/- 11.6, p < 0.001). No differences were observed between HI and AHI types 1 and 2 (HI: type 1: 17.4 +/- 10, type 2: 20 +/- 10.6; AHI: type 1: 20.6 +/- 11.8, type 2: 23 +/- 11.6, p > 0.05). The prevalence of OSAHS was 30-55% in type 3, 70-85% in type 4 (p < 0.05), and 70-85% in types 1 and 2 (p > 0.05). In our patient's population, the presence of EEGA in the definition of hypopnea significantly increased the HI, the AHI and the prevalence of OSAHS when associated with a > or = 4% decrease in SaO2.

Effect of the definition of hypopnea on apnea/hypopnea index.

The objective of this study was to determine whether different decreases in oxygen saturation (SaO2) or the presence of electroencephalographic arousals (EEGA) in the definition of hypopnea modify hypopnea index and apnea/hypopnea index and the prevalence of obstructive sleep apnea/hypopnea syndrome (OSAHS). A total of 20 polysomnographies performed in patients with OSAHS were analyzed. There are four different definitions of hypopnea: > or = 30

reduction in airflow or 50

decrease in abdominal movement associated with decreases SaO2 > or = 3

(type 1); decreases SaO2 > or = 3

or EEGA (type 2); decreases SaO2 > or = 4

(type 3); decreases SaO2 > or = 4

or EEGA (type 4). The prevalence of OSAHS was calculated for an apnea/hypopnea index (AHI) > or = 10 and > or = 15. Hypopnea index (HI) and AHI types 2 and 4 were higher than type 3 (HI: type 2: 20 +/- 10.6, type 4: 18.6 +/- 10, type 3: 11.4 +/- 10, p < 0.001; AHI: type 2: 23.3 +/- 11.6, type 4: 21.4 +/- 11.2, type 3: 14.7 +/- 11.6, p < 0.001). No differences were observed between HI and AHI types 1 and 2 (HI: type 1: 17.4 +/- 10, type 2: 20 +/- 10.6; AHI: type 1: 20.6 +/- 11.8, type 2: 23 +/- 11.6, p > 0.05). The prevalence of OSAHS was 30-55

in type 3, 70-85

in type 4 (p < 0.05), and 70-85

in types 1 and 2 (p > 0.05). In our patients population, the presence of EEGA in the definition of hypopnea significantly increased the HI, the AHI and the prevalence of OSAHS when associated with a > or = 4

decrease in SaO2.

Effect of the definition of hypopnea on apnea/hypopnea index

The objective of this study was to determine whether different decreases in oxygen saturation (SaO2) or the presence of electroencephalographic arousals (EEGA) in the definition of hypopnea modify hypopnea index and apnea/hypopnea index and the prevalence of obstructive sleep apnea/hypopnea syndrome (OSAHS). A total of 20 polysomnographies performed in patients with OSAHS were analyzed. There are four different definitions of hypopnea: > or = 30% reduction in airflow or 50% decrease in abdominal movement associated with decreases SaO2 > or = 3% (type 1); decreases SaO2 > or = 3% or EEGA (type 2); decreases SaO2 > or = 4% (type 3); decreases SaO2 > or = 4% or EEGA (type 4). The prevalence of OSAHS was calculated for an apnea/hypopnea index (AHI) > or = 10 and > or = 15. Hypopnea index (HI) and AHI types 2 and 4 were higher than type 3 (HI: type 2: 20 +/- 10.6, type 4: 18.6 +/- 10, type 3: 11.4 +/- 10, p < 0.001; AHI: type 2: 23.3 +/- 11.6, type 4: 21.4 +/- 11.2, type 3: 14.7 +/- 11.6, p < 0.001). No differences were observed between HI and AHI types 1 and 2 (HI: type 1: 17.4 +/- 10, type 2: 20 +/- 10.6; AHI: type 1: 20.6 +/- 11.8, type 2: 23 +/- 11.6, p > 0.05). The prevalence of OSAHS was 30-55% in type 3, 70-85% in type 4 (p < 0.05), and 70-85% in types 1 and 2 (p > 0.05). In our patients population, the presence of EEGA in the definition of hypopnea significantly increased the HI, the AHI and the prevalence of OSAHS when associated with a > or = 4% decrease in SaO2 (AU)

Effect of the definition of hypopnea on apnea/hypopnea index

The objective of this study was to determine whether different decreases in oxygen saturation (SaO2) or the presence of electroencephalographic arousals (EEGA) in the definition of hypopnea modify hypopnea index and apnea/hypopnea index and the prevalence of obstructive sleep apnea/hypopnea syndrome (OSAHS). A total of 20 polysomnographies performed in patients with OSAHS were analyzed. There are four different definitions of hypopnea: > or = 30% reduction in airflow or 50% decrease in abdominal movement associated with decreases SaO2 > or = 3% (type 1); decreases SaO2 > or = 3% or EEGA (type 2); decreases SaO2 > or = 4% (type 3); decreases SaO2 > or = 4% or EEGA (type 4). The prevalence of OSAHS was calculated for an apnea/hypopnea index (AHI) > or = 10 and > or = 15. Hypopnea index (HI) and AHI types 2 and 4 were higher than type 3 (HI: type 2: 20 +/- 10.6, type 4: 18.6 +/- 10, type 3: 11.4 +/- 10, p < 0.001; AHI: type 2: 23.3 +/- 11.6, type 4: 21.4 +/- 11.2, type 3: 14.7 +/- 11.6, p < 0.001). No differences were observed between HI and AHI types 1 and 2 (HI: type 1: 17.4 +/- 10, type 2: 20 +/- 10.6; AHI: type 1: 20.6 +/- 11.8, type 2: 23 +/- 11.6, p > 0.05). The prevalence of OSAHS was 30-55% in type 3, 70-85% in type 4 (p < 0.05), and 70-85% in types 1 and 2 (p > 0.05). In our patient's population, the presence of EEGA in the definition of hypopnea significantly increased the HI, the AHI and the prevalence of OSAHS when associated with a > or = 4% decrease in SaO2