obstructive sleep apnea - hypopnea syndrome ( osahs ) is a relatively common condition that may impair physical and mental development in children . in addition to snoring , mouth breathing , night terrors , and apnea , children with osahs may experience a series of concurrent mental and psychological symptoms , including poor self - control , inattention , hyperactivity , memory loss , cognitive decline , and poor academic performance , as well as impaired growth and development [ 17 ] . indeed , research suggests that approximately 2030% of children with osahs experience inattention and hyperactivity . attention deficit hyperactivity disorder typically , one would assume that the mental and psychological abnormalities caused by osahs in children are related to the severity of osahs . however , in our clinical practice , we have found that some children with severe osahs , as indicated by polysomnography ( psg ) , do not have obvious mental and psychological abnormalities , whereas some children with mild osahs have marked mental and psychological abnormalities . we therefore decided to examine which osahs factors are related to concurrent mental and psychological abnormalities in children with osahs . this study aimed to explore the relationship between the severity of osahs and the degree of mental and psychological abnormalities caused by osahs . previously , the impact of osahs on psychological behavior in children has been assessed using a variety of scales , and the degree of impact determined by taking into account physicians observations . unfortunately , due to limitations associated with many factors , ( e.g. , expression capability , education level , observation capability , and subjective consciousness ) , family members descriptions and physicians observations often do not accurately reflect the true disease status of children . integrated visual and auditory continuous performance testing ( iva - cpt ) is commonly used for the diagnosis of adhd in children and adults . subjects provide instant reactions to simple auditory and visual cues given by clicking a mouse , and data are analyzed by computer software to provide quantitative results . therefore , iva - cpt is relatively objective , quantifiable , and easy to perform . in this study , we used the iva - cpt method to measure the full - scale response control quotient ( frcq ) , full - scale attention quotient ( faq ) , and hyperactivity ( hyp ) in children with psg - confirmed osahs before and after surgery . in doing so , we aimed to explore the impact of osahs on psychological behavior , the extent of impact , postoperative recovery , and the relationship between the severity of osahs and the impact of osahs on psychological behavior , as well as postoperative recovery in these children . all patients included in this study were children with osahs who were treated at the department of otorhinolaryngology head and neck surgery , hangzhou first people s hospital affiliated to nanjing medical university from february 2010 to october 2011 . each patient had an at least 2-year history of snoring , mouth - breathing , and/or multiple sleep apneas before admission to our hospital . according to eligibility criteria , the present study was approved by the institutional ethics committee of hangzhou first people s hospital affiliated to nanjing medical university . 1 ) children underwent psg and met the diagnostic criteria for osaha as specified by the otolaryngology chapter of the chinese medical association . 3 ) children were aged 512 years and experienced onset of osahs at 3 years of age . children had not yet entered puberty and had not experienced any major changes in living environment . 4 ) parents agreed to allow their children to participate in the study and provided written informed consent . 5 ) all children underwent physical examination , lateral nasopharynx x - ray , nasopharynx computed tomography , and/or nasopharyngoscopy to confirm that osahs was caused by adenoid hyperplasia with 2/3-complete obstruction of nasopharynx and/or tonsillar hypertrophy with a class ii , iii , or iv of friedman classification . 1 ) congenital anatomical abnormalities of the mouth , nose , or pharynx and/or facial morphology . 3 ) history of chronic disease , including tuberculosis , viral hepatitis , nephrotic syndrome or severe trauma . 6 ) family history of familial short stature , congenital mental retardation , mental illness , or other congenital genetic and metabolic diseases in 3 generations on the maternal or paternal side that can affect physical development . 7 ) diseases with manifestations of obstructive sleep apnea - hypopnea not caused by adenoid and/or tonsillar hypertrophy . children were divided into 2 groups according to the duration of disease : < 5 years and 5 years . psg was performed using an embletta x100 type polysomnography system ( embla , broomfield , co ) . all children underwent continuous psg for more than 7 h prior to surgery and at 3 and 6 months after surgery ( termed the first , second , and third time point ) ; the apnea - hypopnea index ( ahi ) and lowest oxygen saturation ( laso2 ) measures were recorded . patients were also divided into groups by the severity of osahs ( mild : 5 < ahi 10 times / h , moderate : 10 < ahi 20 times / h , or severe : ahi > 20 times / h ) before surgery according the criteria published by otolaryngology chapter of the chinese medical association . psychologists , who were not allowed to obtain patients psg results , administered the iva - cpt to all children before surgery using version 1.1 of the iva - cpt test system ( braintrain , north chesterfield , va ) . the basic principle of the iva - cpt is to observe and record patients responses to 13 min of auditory and visual stimuli , including reaction time , omissions , endurance , and the number of repeats . an assessment conclusion is made by computer using an algorithm . the iva - cpt report contains 6 comprehensive quotients based on a total of 22 original quotients . we selected 3 indicators closely related to our study for analysis : frcq , faq , and hyp . frcq<85 , faq<85 or hyp<100 is considered abnormal . in accordance with the iva - cpt - related diagnostic criteria for adhd , children with abnormal frcq or faq plus abnormal hyp were considered to have mental abnormalities . all patients underwent bilateral tonsillectomy plus adenoidectomy or adenoidectomy alone and were discharge without incident . follow - up psg and iva - cpt assessments were carried out 3 and 6 months after surgery . group means were compared using student s t - test or chi - square test . repeated measures analysis of variance was used to examine the effects of group and time . all analyses were performed using spss19.0 statistical software ( spss inc . , chicago , il ) . all patients included in this study were children with osahs who were treated at the department of otorhinolaryngology head and neck surgery , hangzhou first people s hospital affiliated to nanjing medical university from february 2010 to october 2011 . each patient had an at least 2-year history of snoring , mouth - breathing , and/or multiple sleep apneas before admission to our hospital . according to eligibility criteria , the present study was approved by the institutional ethics committee of hangzhou first people s hospital affiliated to nanjing medical university . 1 ) children underwent psg and met the diagnostic criteria for osaha as specified by the otolaryngology chapter of the chinese medical association . 3 ) children were aged 512 years and experienced onset of osahs at 3 years of age . children had not yet entered puberty and had not experienced any major changes in living environment . 4 ) parents agreed to allow their children to participate in the study and provided written informed consent . 5 ) all children underwent physical examination , lateral nasopharynx x - ray , nasopharynx computed tomography , and/or nasopharyngoscopy to confirm that osahs was caused by adenoid hyperplasia with 2/3-complete obstruction of nasopharynx and/or tonsillar hypertrophy with a class ii , iii , or iv of friedman classification . 1 ) congenital anatomical abnormalities of the mouth , nose , or pharynx and/or facial morphology . 3 ) history of chronic disease , including tuberculosis , viral hepatitis , nephrotic syndrome or severe trauma . 6 ) family history of familial short stature , congenital mental retardation , mental illness , or other congenital genetic and metabolic diseases in 3 generations on the maternal or paternal side that can affect physical development . 7 ) diseases with manifestations of obstructive sleep apnea - hypopnea not caused by adenoid and/or tonsillar hypertrophy . 1 ) children underwent psg and met the diagnostic criteria for osaha as specified by the otolaryngology chapter of the chinese medical association . 3 ) children were aged 512 years and experienced onset of osahs at 3 years of age . children had not yet entered puberty and had not experienced any major changes in living environment . 4 ) parents agreed to allow their children to participate in the study and provided written informed consent . 5 ) all children underwent physical examination , lateral nasopharynx x - ray , nasopharynx computed tomography , and/or nasopharyngoscopy to confirm that osahs was caused by adenoid hyperplasia with 2/3-complete obstruction of nasopharynx and/or tonsillar hypertrophy with a class ii , iii , or iv of friedman classification . 1 ) congenital anatomical abnormalities of the mouth , nose , or pharynx and/or facial morphology . 3 ) history of chronic disease , including tuberculosis , viral hepatitis , nephrotic syndrome or severe trauma . 6 ) family history of familial short stature , congenital mental retardation , mental illness , or other congenital genetic and metabolic diseases in 3 generations on the maternal or paternal side that can affect physical development . 7 ) diseases with manifestations of obstructive sleep apnea - hypopnea not caused by adenoid and/or tonsillar hypertrophy . children were divided into 2 groups according to the duration of disease : < 5 years and 5 years . psg was performed using an embletta x100 type polysomnography system ( embla , broomfield , co ) . all children underwent continuous psg for more than 7 h prior to surgery and at 3 and 6 months after surgery ( termed the first , second , and third time point ) ; the apnea - hypopnea index ( ahi ) and lowest oxygen saturation ( laso2 ) measures were recorded . patients were also divided into groups by the severity of osahs ( mild : 5 < ahi 10 times / h , moderate : 10 < ahi 20 times / h , or severe : ahi > 20 times / h ) before surgery according the criteria published by otolaryngology chapter of the chinese medical association . psychologists , who were not allowed to obtain patients psg results , administered the iva - cpt to all children before surgery using version 1.1 of the iva - cpt test system ( braintrain , north chesterfield , va ) . the basic principle of the iva - cpt is to observe and record patients responses to 13 min of auditory and visual stimuli , including reaction time , omissions , endurance , and the number of repeats . an assessment conclusion is made by computer using an algorithm . the iva - cpt report contains 6 comprehensive quotients based on a total of 22 original quotients . we selected 3 indicators closely related to our study for analysis : frcq , faq , and hyp . frcq<85 , faq<85 or hyp<100 is considered abnormal . in accordance with the iva - cpt - related diagnostic criteria for adhd , children with abnormal frcq or faq plus abnormal hyp were considered to have mental abnormalities . all patients underwent bilateral tonsillectomy plus adenoidectomy or adenoidectomy alone and were discharge without incident . follow - up psg and iva - cpt assessments were carried out 3 and 6 months after surgery . group means were compared using student s t - test or chi - square test . repeated measures analysis of variance was used to examine the effects of group and time . all analyses were performed using spss19.0 statistical software ( spss inc . , chicago , il ) . 19 children were either lost to follow - up , had incomplete follow - up , or did not complete iva - cpt assessment . therefore , complete data were available for 51 children ( 35 males and 16 females ) . a total 26 children had a course of disease 5 years , whereas 25 children had a course of disease < 5 years . there were 16 , 16 , and 19 children in the mild , moderate , and severe osahs groups , respectively . a total of 42 patients underwent bilateral tonsillectomy plus adenoidectomy and 9 patients underwent adenoidectomy alone . there were no significant differences in preoperative age , sex , bmi , or course of disease among children with differing levels of osahs severity ( table 1 ) . the mean frcq , faq , and hyp results for the 3 time points are shown in table 2 . the mean values of the 3 indicators were normal or close to normal by 6 months after surgery . the effect of group / disease severity was significant for faq , but not frcq or hyp . there was no significant group - by - time interaction for frcq , faq , or hyp ( table 3 ) . the mean ahi and laso2 results for the 3 time points are shown in table 4 . there were significant effects of time , group / disease severity , and the group - by - time interaction for both ahi and laso2 ( tables 4 and 5 ) . generally , disease severity and course of disease are 2 factors that can determine the treatment efficacy and prognosis in most diseases ; osahs is no exception . because concurrent poor self - control , attention deficit , and hyperactivity in children with osahs may affect quality of life , therefore , it is necessary to understand the relationship between the severity of these complications and osahs severity , as well as the course of disease . previously , the impact of osahs on children psychological behavior was often assessed using a variety of scales , and the degree of impact was determined by considering physicians observations . used the eyberg child behavior scale and the global quality of life scale to assess 100 and 39 children with osahs , respectively , and found that the incidence of abnormal behaviors was significantly higher in children with osahs compared with children in the control group . used the achenbach child behavior scale to assess preoperative and postoperative self - control , attention , and hyperactivity in children with osahs and found that abnormalities were significantly improved after surgery . due to limitations in various factors , including expression capability , education level , observation capability , and subjective consciousness , family members descriptions and physicians observations often do not always objectively , accurately , and quantifiably reflect the true disease condition of children . therefore , scales are only appropriate for qualitative assessment ; performing more accurate quantitative analysis is difficult . the iva - cpt is a relatively objective and accurate test for diagnosing of adhd that produces quantitative results . the test is easy to administer and has associated sensitivity and specificity of up to 92% and 90% , respectively . however , the test must be performed under the guidance of professional examiners to ensure consistency and accuracy . in this study , the iva - cpt was used to assess the effects of osahs on self - control , attention , and hyperactivity in children , and to determine how these factors change after intervention . we chose to use the iva - cpt because this means of assessment is relatively objective , quantifiable , and simple to use . the accuracy of iva - cpt results may to a certain extent be affected by examiner and subject factors . children s medical histories were reviewed before testing to exclude mental abnormalities possibly caused by drugs or non - osahs factors . the examiner repeated the instructions and demonstrations so that the children could fully understand and perform proficiently . as computer use is common in everyday life , all children were able to complete the test easily , which helped maximize the accuracy of the study results . the criteria for abnormalities referred to the iva - cpt - related diagnostic criteria for adhd  abnormalities were considered to be present if any of the 2 main indicators , frcq or faq , were abnormal and hyp was abnormal . our results showed that the mean psychological behavioral indicators were below the lower limit of normal in children with osahs of differing levels of severity . in all 3 groups , the effects time were significant for frcq , faq , and hyp , and pair - wise comparisons of the 3 indicators between each of the 2 time points also showed significant differences . the results indicate that children with osahs had significantly abnormal self - control , attention , and hyperactivity before surgery , and that these abnormalities improved with time after surgery . we also found that the group effects for frcq and hyp were not significant , but the group effect for faq was significant . the group - by - time interaction was not significant for any of the 3 indicators . these results suggest that the severity of osahs was related to the degree of attention deficit . however , the group effects for frcq and hyp were not significant , and there were no group - by - time interactions for frcq , faq , and hyp . therefore , there is no definite association between osahs severity and degree of psychological abnormality and postoperative recovery of this abnormality . differences in the 3 indicators between the second and third time points were greater than those between the first and second time points , indicating that postoperative recovery of psychological abnormalities in children was more rapid during the period 36 months after surgery than during the period 03 months after surgery . we found that there were significant effects of group , time , and group - by - time interaction for both ahi and laso2 . the changes in ahi and laso2 from time point 1 to 2 were greater than those from time point 2 to 3 , indicating that postoperative recovery was more rapid during 0 to 3 months after surgery than during 3 to 6 months after surgery . this pattern of change is different from that observed in the recovery of psychological abnormalities in these children . this suggests that after surgery , patients quickly recover from respiratory obstruction , and after 3 months they will show a substantial decline in ahi . however , psychological abnormalities cause long - term damage ; children begin to recover slowly , and then recovery accelerates . the above results were quite useful to clarify the impact of pediatric osahs severity and surgery intervention on psychological and behavioral abnormalities and surgery outcomes , but we should also attach importance to a limitation that 19 subjects dropped - out , which is a high rate . of these , 10 parents thought that there might be no need for their children to follow up due to good recovery after the operation . the remaining 3 patients could not be reached though their registered addresses and phone numbers . therefore , only some of the 19 patients had follow - up psg and iva - cpt assessments after surgery . to allow more definitive conclusions , osahs might have a significant impact on self - control , attention , and hyperactivity in children . the severity of osahs is not closely related to the severity of psychological and behavioral abnormalities caused by osahs , or to the postoperative recovery of these abnormalities . therefore , according to osahs severity alone , it may be extremely difficult to determine the severity of pediatric psychological and behavioral abnormalities caused by osahs or to predict postoperative recovery .