e A þ t ý m Effects of Sleep Hygiene Eduction on Subjective Sleep Qulity nd Acdemic Pefomnce l n i j i O O i g in Uyku Hijyen Eğitiminin Subjektif Uyku Klitesi ve Akdemik Pefomnsı Üzeine Etkilei h c s Re l Uyku Hijyeni Eğitiminin Etkilei / Effects of Sleep Hygiene Eduction Ekn Melih Shin 1, Levent Oztuk 2, Demet Gulec Oyekcin 3, Aysegul Uludg 4 1 Deptment of Fmily Medicine, Cnkkle Onsekiz Mt Univesity Fculty of Medicine, Cnkkle, 2 Deptment of Physiology, Tky Univesity Fculty of Medicine, Edine, 3 Deptment of Psychity, Cnkkle Onsekiz Mt Univesity Fculty of Medicine, Cnkkle, 4 Deptment of Fmily Medicine, Cnkkle Onsekiz Mt Univesity, Fculty of Medicine, Cnkkle, Tukey Özet Amç: Uyku poblemlei öğencile sınd oldukç sık göülmekle bilikte üçte bi ünivesite öğencisi yetesiz uyuduğunu ifde etmektedi. Uyku klitesi ve gündüz uykululuğun kdemik pefomnst düşmeye neden olduğu bilinmektedi. Bu nedenle uyku hijyeni eğitiminin biinci sınıf tıp fkültesi öğencileinin uyku klitesi ve kdemik pefomnsı üzeine etkisini ştımk mçlnmıştı. Geeç ve Yöntem: Çlışmd 131 biinci sınıf tıp öğencisinin kendilei tfındn bildiilen uyku veilei ve kdemik pefomns bilgilei lındı. Çlışmy lınn bütün öğencilee uyku klitesi değelendimesinde Pittsbug Uyku Klitesi Ölçeği ile gündüz uykululuk hlini değelendimede Epwoth Uykululuk Ölçeği uygulndı. Öğencile iki gub yıldı ve müdhele gubun 30 dkiklık ypılndıılmış uyku hijyeni eğitimi veildi. Genel kdemik pefomnslı yıl sonundki not otlmlı ile değelendiildi. Bulgul: Öğencilein otlm Pittsbugh uyku klitesi indeksi punı 7.9 ± 3.5 ve 106 (% 82.8 ) ile 5 pundı. Müdhele sonsınd kötü uyku klitesi olnld uyku hijyeni eğitiminin uyku klitesi ve kdemik pefomns dh etkili olduğu gözlendi. Ttışm: Uyku hijyeni eğitimi tıp fkültesi öğencileinin subjektif uyku klitesi ve kdemik pefomnsını ttıbilmektedi. Anht Kelimele Uyku Klitesi; Uyku Hijyeni; Eğitim; Tıp Fkültesi Öğencisi; Akdemik Pefomns Abstct Aim: Sleep poblems e common in students with one thid of univesity students epoting insufficient sleep. It is known tht sleep qulity nd dytime sleepiness cuse decsing cdemic pefomns. Fo this eson we imed to investigte the effects of sleep hygiene eduction on sleep qulity nd cdemic pefomnce of fist ye medicl students. Mteil nd Method: Self-epoted sleep dt nd cdemic pefomnce of 131 fist gde medicl students wee collected. To ll students enolled Pittsbug Sleep Qulity Scle in the ssessment of sleep qulity nd Epwoth Sleepiness Scle fo ssessment of dytime sleepiness in the evlution.the students wee divided into two subgoups nd the intevention goup eceived 30 minute stuctued sleep hygiene eduction. Globl cdemic pefomnce ws ssessed by gde point vege t the end of the ye. Results: Men Pittsbugh sleep qulity index scoe of the students ws 7.9±3.5 nd 106 (82.8% ) of then hd scoe 5.Afte intevention,.the wose the initil sleep qulity, the moe impovement by the sleep hygiene eduction on sleep qulity nd cdemic pefomnce. Discussion: An eduction on sleep hygiene might impove subjective sleep qulity nd cdemic pefomnce of medicl students. Keywods Sleep Qulity; Sleep Hygiene; Eduction; Medicl Student; Acdemic Pefomnce DOI: 10.4328/JCAM.2728 Received: 18.08.2014 Accepted: 10.09.2014 Published Online: 10.09.2014 Coesponding Autho: Aysegul Uludg, Çnkkle Onsekizmt Univesitesi Tıp Fkültesi, Aile Hekimliği Anbilim Dlı, Tezioğlu Yeleşkesi, Çnkkle, Tükiye. T.: +90 2862180018 F.: +90 2862635957 GSM: +905337305535 E-Mil: dysegululudg@gmil.com Jounl of Clinicl nd Anlyticl Medicine 1
Uyku Hijyeni Eğitiminin Etkilei / Effects of Sleep Hygiene Eduction Intoduction Sleep poblems e common in both school-ge childen nd young dult univesity students, with lmost hlf of secondy school students epoting poo sleep qulity especilly on Sundy nights [1] nd one thid of univesity students epoting insufficient sleep [2]. Exmintion nxiety, lte-night studying, socil ctivities, compute-bsed pplictions, pt-time jobs, nd intenet oveuse might be mong the potentil cuses of iegul sleep-wke pttens o indequte sleep in univesity students. Iegul sleep-wke cycles hve been shown to be chcteized by get phse delys on weekends nd shot sleep dution on weekdys [3-4]. Sleep is of pticul inteest mong medicl students, s they encounte incesed cdemic pessues nd stess levels. Exm nxiety, envionment nd iegul schedules my contibute to poo sleep qulity [5], which in tun my hve negtive impct on cdemic pefomnce [6]. Also medicl students helth hbits hve n impct on thei cdemic pefomnces, emotionl djustment, nd futue functioning s physicins. Reduced sleep quntity o qulity eithe in the fom of sleep depivtion o sleep estiction, hs negtive effects on the tempol blnce between the cicdin pcemke nd homeosttic sleep dive, inducing sleepiness nd decese in neuobehviol pefomnce with enegy loss, ftigue, difficulty in concentting, nd memoy lpses [7]. Mnbe et l. hve studied the consequences of iegul sleep pttens nd found tht students who slept t lest 7.5 hou pe night but kept n iegul sleep schedule epoted highe levels of dytime sleepiness thn students who slept the sme mount of time nd kept eltively egul sleep schedule [8]. Medeios et l. hve epoted tht iegulity of the sleep-wke cycle s well s depivtion of sleep influenced the cdemic pefomnce of medicl students [9]. Futhemoe, they suggested tht it is necessy to ethink the school schedules nd to guide the students sleeping hbits with the gol of educing the negtive effects on thei lening. In fct, sleep poblems mong univesity students e ssocited with poo sleep hygiene nd guiding infomtion on helthy sleep nd sleep hygiene might impove self-weness of individul sleep helth. Thus, cdemic pefomnce of students might be ffected positively by impoving sleep hygiene. In most studies insufficient sleep nd iegul sleep wke pttens hd been extensively documented in younge dolescents, nd lso close eltionships between sleep qulity nd physicl nd mentl helth hve been shown. It hs been suggested tht intevention pogms fo sleep distubnce in this popultion should be consideed [10] but thee e not mny inteventions in highe eduction egding the fomtion of positive study envionment nd cpcity to ech infomtion imed t incesing cdemic success of the students. The im of this study ws to investigte the pevlence of sleep qulity poblems, detect the eltion of sleep qulity nd cdemic pefomnces nd investigte the effects of stnddized sleep hygiene eduction nd to compe pe- nd postintevention exmintion pefomnces of fist gde medicl students. Mteil nd Method Study popultion nd initil ssessments The study subjects wee 131 fist ye medicl students of Tky Univesity Fculty of Medicine consisting of 61 mles nd 70 femles. All pticipnts ttended the sme school schedules, with clsses beginning t 08.30 on weekdys. Pio to pticiption ech student filled out n identifiction fom with pesonl infomtion, including thei dily ctivities, sleep chcteistics, nd homewok schedules. The pticipnts lso filled out Pittsbugh sleep qulity index (PSQI) to detemine subjective sleep qulity nd Epwoth sleepiness scle (ESS) to quntify the level of dytime sleepiness. Scoes of the finl exms of the fll semeste wee used s mkes of cdemic pefomnce. Duing the fll semeste ll pticipnts mintined thei sleeping hbits without ny intevention. By the end of the fist semeste, the student list ws put to n ode ccoding to PSQI scoes nd students wee ssigned to intevention nd contol goups in tun. Any student who did not ccept to ttend to the intevention let to be in contol goup nd the next student ws ttened to the intevention goup. The goups wee confimed to be equivlent in tems of ge, gende, cdemic pefomnce, nd scoes of PSQI nd ESS. The stuctued sleep hygiene eduction ws given to intevention goup in the beginning of sping semeste. Scoes of the finl exms of the sping semeste wee gin collected. Two students who did not ttend sping finl exms wee dopped out of the study. Effects of the intevention, i.e. sleep hygiene eduction, on sleep qulity nd cdemic pefomnce wee nlyzed. The study ws ppoved by Ethics Committee of Tky Univesity nd the Diectoy of Medicl School. Sleep hygiene intevention The intevention goup consisting 56 students wee tken to ound-tble meetings of sleep hygiene eduction in smll goups consisting of 5-10 students. The sme investigto (LO) povided stuctued 20-minute semin on sleep hygiene including topics of sleep dution, sleep continuity, impotnce of egul sleep-wke schedules, nps, nd sevel fctos tht might ffect sleep helth such s coffee, lcohol, execise, nd dugs. Then, students hd the oppotunity to sk questions on sleep duing the emining 10 minutes. Ech session lsted 30-minutes. Instucto ws blinded to the cdemic pefomnce nd sleep sttus of the intevention goup. Contol goup consisted of the emining students tht hd no eduction on sleep hygiene. Initil sleep chcteistics of the two goups e given in Tble 1. The intevention nd the contol goups wee simil in tems of globl cdemic pefomnce, PSQI scoe, ESS scoe, nd the numbe of filed lessons. Tble 1. Genel bseline chcteistics of the study goups (n=131)*. Vible Intevention goup (n=56) Contol goup (n=75) Age. y 18.5 18.1 Gende. M/F 24/32 37/38 PSQI scoe 8.3±3.6 7.5±3.4 ESS scoe 7.4±3.8 8.1±4.4 GAP. % 73.6±6.7 73.1±11.1 NFL. n 0.8±1.3 1.1±2.2 PSQI: Pittsbugh sleep qulity index; ESS: Epwoth Sleepiness Scle; GAP: Globl cdemic pefomnce; NFL: The numbe of filed lessons * Thee e no significnt diffeences in ny of the pmetes 2
Uyku Hijyeni Eğitiminin Etkilei / Effects of Sleep Hygiene Eduction Pittsbugh sleep qulity index nd Epwoth sleepiness scle Pittsbug Sleep Qulity Index (PSQI) is self-epoted questionnie tht ssesses sleep qulity nd sleep distubnce ove one-month peiod [11]. It compises of 19 individul items geneting seven component scoes: subjective sleep qulity, sleep ltency, sleep dution, hbitul sleep efficiency, sleep distubnces, use of sleeping mediction nd dytime dysfunction. The sum of scoes fo these seven components yields one globl PSQI scoe. Pesons with globl PSQI scoe lowe thn 5 e consideed s good sleepes; whees, globl scoes highe thn 5 indicte poo sleepes. A Tukish tnsltion including the elibility nd vlidity studies of this scle hve been peped nd dministeed in Tukish smple [12]. Epwoth sleepiness scle is n 8-item questionnie tht quntifies dytime sleep popensity. Ech item is scoed between 0 = none, nd 3 = high chnce of doze. ESS scoe vies between 0 nd 24. Highe ESS scoes indicte highe tendency to sleep o incesed dytime sleepiness. Assessment of cdemic pefomnce All finl exmintion scoes of the fll semeste wee ecoded s pecent vlue of complete scoe. Thee wee seven lessons in the fll semeste including intoduction to medicl pctice, deontology nd histoy of medicine, chemisty, medicl physics, medicl biology, medicl teminology, nd compute. In the sping semeste, ll finl exmintion scoes of intoduction to medicl pctice, psychology, histology nd embyology, physiology, ntomy, biochemisty, nd medicl genetics wee lso ecoded. All scoes wee veged to obtin globl cdemic pefomnce (GAP) scoe. Fo ll lessons, student must hve t lest 60 points ove 100 to be successful in ou eduction system. Thus, the numbe of filed lessons ws used s nothe mke of cdemic pefomnce. Sttisticl nlysis All dt wee digitlized nd nlyzed. Desciptive sttistics wee expessed s mens ± stndd devitions (SD). Diffeences of the vibles between two semestes wee tested by epeted mesues t test o Wilcoxon signed-nk test. Diffeences of the vibles between intevention nd contol goups wee tested by independent smples t test o Spemn Chi Sque. Coeltions mong vibles wee tested by Peson coeltion nlyses. A p vlue smlle thn 0.05 ws ccepted s sttisticlly significnt. Results Genel bseline chcteistics nd initil sleep chcteistics of the two goups e given in Tble 1. The intevention nd the contol goups wee simil in tems of globl cdemic pefomnce, PSQI scoe, ESS scoe, nd the numbe of filed lessons. Fll semeste men globl PSQI scoe of the students ws 7.9±3.5; 106 (82.8%) of them obtined the scoe of 5 o moe in PSQI epesenting poo sleep qulity. Men ESS scoe of the students ws 7.8±4.2; 39 (29.8% ) of them hd n ESS scoe of 10 o moe epesenting dytime sleepiness. Men GAP scoe of the 119 students (90.8%) who ttended the fll tem finls of the 8 lessons ws 73.3 ± 9.4 (29-90). Thee wee 79 (59.8%) students who hd been successful in ll lessons. Twenty nine (22.0%) students filed one lesson, 15 students (18.2%) filed 2 o moe lessons. A significnt coeltion ws detemined between the fll semeste GAP scoe nd globl PSQI scoes of the students (Peson coeltion =-0,214; p=0,020); howeve, no coeltion ws detemined with the ESS scoe nd GAP scoe. No significnt diffeence ws detemined between the numbe of filed lessons o stte of success in ll lessons nd PSQI o ESS scoes. Men GAP scoes (73.1 ± 7.6) of subjects who obtined the scoe of 5 o moe in PSQI epesenting poo sleep qulity ws lowe comped to subjects with noml sleep qulity (78.3 ± 5.9) (t=2,865; p=0,005). The te of being successful in ll lessons ws lowe in subjects who obtined the limit scoe of 5 o moe in PSQI epesenting poo sleep qulity [57.5%] comped to subjects with noml sleep qulity (81.8%) (χ2=4,542; p=0,033). Thee ws no diffeence in the men GAP scoes of subjects nd the te of success in ll lessons ccoding to the ESS scoes. Sping semeste students men globl PSQI scoe ws 7.6±3.5; nd men ESS scoe ws 7.4±3.7. Men GAP scoe of 129 (98.4%) students who enteed sping tem finls of 7 lessons ws 75.6 ± 9.4 (35-93). A totl of 91 (70.5%) students pssed ll lessons. Seventeen (13.2%) students filed one lesson, 21 students (16.3%) filed 2 o moe lessons. Thee ws no diffeence between the study nd contol goups in the pmetes of men GAP scoes, te of success in ll lessons, globl PSQI nd ESS scoes of the sping tem. Dt of the goups ccoding to the semeste e documented in Tble 2. Tble 2. Sleep nd cdemic pefomnce scoes of the goups by semestes Intevention Goup Contol Goup Vible Fll semeste Sping semeste Fll semeste Sping semeste PSQI scoe 8.3±3.6 7.6±3.6 7.5±3.4 7.5±3.4 ESS scoe 7.4±3.8 7.8±3.9 8.1±4.4 7.2±3.6 GAP % 73.6±6.7 74.9±8.8* 73.1±11.1 76.1±10.0* NFL. n 0.8±1.3 0.3±1.1 1.1±2.2 0.9±1.8* PSQI: Pittsbugh sleep qulity index; ESS: Epwoth Sleepiness Scle; GAP: Globl cdemic pefomnce scoe; NFL: The numbe of filed lessons; *p<0.05 Men GAP scoes of the fll nd sping semestes wee diffeent in the intevention goup (Wilcoxon Z=-2,723; p=0,006); whees, globl PSQI nd ESS scoes did not diffe. Significnt diffeence ws detemined in the men GAP scoes of the fll nd sping tems of the contol goup (Wilcoxon Z=-3,892; p<0,001); whees no diffeence ws detemined in globl PSQI nd ESS scoes. The diffeence in the globl PSQI scoes of the two semestes hd significnt negtive coeltion with the bseline globl PSQI scoe (Peson coeltion =-0.581; p<0.001). Although it did not ech sttisticl significnce, this coeltion ws moe mked in the intevention goup comped to the contol goup (Figue 1). Although the elted tes of coeltion wee not sttisticlly significnt, the tes of decese in globl PSQI scoe nd incese in GAP scoe wee slightly highe in the study goup comped to the contol goup (Figue 2). 3
Uyku Hijyeni Eğitiminin Etkilei / Effects of Sleep Hygiene Eduction Figue 1. The sctte gphic shows bseline globl PSQI scoes (x xis) vesus globl PSQI scoe diffeences between pe- nd post-intevention (y xis). The wose bseline sleep qulity the moe impovement by intevention; nd the intgoup diffeence in intevention goup ws highe thn in the contol goup. Figue 2. The sctte gphic shows the globl PSQI scoe diffeences between pe- nd post-intevention (x xis) vesus the diffeence in pecent globl cdemic pefomnce scoes (y xis). The gete the decese in PSQI scoe, the gete the incese in cdemic pefomnce. The slope of continuous line indictes tht pefomnce incese in the intevention goup is moe pominent. Discussion The stuctue of medicl eduction itself is likely to contibute to disuptions in students helth hbits. Although sleep depivtion is common occuence duing the lte clinicl yes nd esidency, chnges in sleep hbits my occu s ely s the fist ye s students djust thei sleep schedules in fvo of studying [13]. High pevlence of dytime sleepiness, poo sleep qulity nd psychologicl distess hs been documented mong medicl students nd it hs been suggested tht by weness of the high pevlence nd possible impct of excessive dytime sleepiness on the medicl students will help to the teching stffs to mnge sleep eduction nd sleep hygiene especilly to those who wee identified s potentil individuls [14]. Zilinwti et l. investigted the dytime sleepiness nd sleep qulity mong Mlysin medicl students nd found high pevlence of excessive dytime sleepiness, 35.5% comped to 14.8 of the Mlysin genel popultion [14] nd thei esult ws slightly lowe thn (42.4%) those expeienced by the Bzilin medicl students [6] nd they lso epoted significnt ssocition between dytime sleepiness nd dvese cdemic pefomnce. Bick et l. found tht ove one hlf of thei smple (50.9%) met the clinicl cutoff of the PSQI fo poo sleep qulity [15]. Similly in ou study, students hve highe veges of dytime sleepness nd poo sleep qulity. Veldi et.l investigted the sleep poblems mong medicl students nd found tht sleep qulity ws ssocited with cdemic pogess, leisue ctivity nd living conditions nd lso sleep qulity ws not ssocited with students dily o nightly woklod [16]. While dytime sleepiness posed significnt poblem fo students nd ws ssocited both with sleep disodes nd wok while studying [16]. Chonic ptil sleep loss hs negtive effects on neuocognitive pefomnce, mood, nd helth. Sleep depivtion mong dolescents cuses n incese in inttentive behvio nd dytime sleepiness my ffect mood, behvio, nd cdemic pefomnce [17]. As known sleep hygiene efes to list of behvios, envionmentl conditions, nd othe sleep-elted fctos tht cn be djusted s stnd-lone tetment o component of multimodl tetment fo ptients with insomni. Sleep hygiene efes to list of ules defining behvious nd envionmentl conditions tht impove sleep qulity. These sleep-elted fctos cn be djusted to get bette sleep. Thee e plenty of vesions with dditions to nd/o deletions fom oiginl list [18]. In bief, ll sleep hygiene ecommendtions include egul bedtime/wketime, voidnce fom lcohol nd cffeine, conditions of sleeping envioment [bed comfot, tempetue, noise, dkness, nd execise timing. Indequte sleep hygiene ecuited fom ICSD definition [19] included dytime npping, extended mounts of time spent in bed, scheduling execise too close to bedtime, fequent use of the bed fo non-sleep-elted ctivities [eding, sncking, wtching television, etc ], lcohol, tobcco o cffeine consumption just befoe the bedtime. Simil to the litetue, ou study esults demonstted the eltionship between sleep qulity nd cdemic success. The semin pogm povided in ou study to incese the qulity of sleep of students poved success in decesing the globl PSQI scoes of the students epesenting n impovement in sleep qulities in students with pominently impied sleep qulity t bseline. The size of the impiment in sleep qulity detemines the size of the benefit to be obtined. The slight positive chnges obseved in qulity of sleep wee somewht eflected to the cdemic success. Any impovements in dytime sleepiness wee less in the study goup thn in the contol goup nd gin not sttisticlly significnt. This esult suggests tht the sleep hygiene eduction did not tget dytime sleepiness nd dytime sleepiness does not elted to cdemic pefomnce. Ou smll smple size hs pevented some of the esults gining sttisticl significnce nd the esults should be confimed in othe studies with gte smple sizes using PSQI scoe the thn dytime sleepness s mke of cdemic pefomnce. In conclusion, sleep qulity is impotnt fo cdemic pefomnce mong medicl students. In genel, subjective sleep qulity mesued by PSQI of medicl students is bove the cut off vlue fo poo sleep qulity. Any intevention imed to incese cdemic pefomnce should tget sleep qulity but 4
Uyku Hijyeni Eğitiminin Etkilei / Effects of Sleep Hygiene Eduction not dytime sleepness. This study fo the fist time give some clues tht sleep hygiene eduction my impove subjective sleep qulity nd thus cdemic pefomnce of medicl students. Competing inteests The uthos decle tht they hve no competing inteests. Refeences 1. Aguil FS, Almoncid FMR, Montede AML, Gci JMA, Mtinez PR, Nvo AIM. Sleeping hbits nd sleep disodes duing dolescence: eltion to school pefomnce. Aten Pimi 2005;35(8):408-14. 2. Bn DJ, Lee TJ. Sleep dution, subjective sleep distubnces nd ssocited fctos mong univesity students in Koe. J Koen Med Sci 2001;16(4):475-80. 3. Lck L. Delyed sleep nd sleep loss in univesity students. J Am Coll Helth 1986;35(5):105-10. 4. Vldez P, Rmiez C, Gci A. Delying nd extending sleep duing weekends: sleep ecovey o cicdin effect? Chonobiol Int 1996;13(3):191-8. 5. Feng GS, Chen JW, Yng XZ. Study on the sttus nd qulity of sleep-elted influencing fctos in medicl college students. Zhonghu Liu Xing Bing Xue Z Zhi 2005;26(5):328 331. 6. Rodigues RN, Viegs CA, Abeu E, Silv AA, Tves P. Dytime sleepiness nd cdemic pefomnce in medicl students. Aq Neuopsiquit 2002;60(1):6-11. 7. Dinges DF, Kibbs NB. Pefoming while sleep: effects of expeimentlly-induced sleepiness. In: Monk T, edito. Sleep, Sleepiness nd Pefomnce.2nd ed. New Yok, USA: John Wiley & Sons;1991. p.97-128. 8. Mnbe R, Bootzin RR, Acebo C, Cskdon MA. The effects of egulizing sleep-wke schedules on dytime sleepiness. Sleep 1996;19(5):432-41. 9. Medeios AL, Mendes DBF, Lim PF, Aujo JF. The eltionships between sleepwke cycle nd cdemic pefomnce in medicl students. Biologicl Rhythm Resech 2001;32(1):263-70. 10. Lund HG, Reide BD, Whiting AB, Pichd JR. Sleep pttens nd pedictos of distubed sleep in lge popultion of college students J Adolesc Helth 2010;46(2):124 32. 11. Buysse DJ, Reynolds CFIII, Monk TH, Bemn SR, Kupfe DJ. The Pittsbugh Sleep Qulity Index: new instument fo psychitic pctice nd esech. Psychity Res 1989;28(2):193-213. 12. Aggün MY, K H, Anl O. The vlidity nd elibility of the Pittsbugh Sleep Qulity Index. Tukish Jounl of Psychity 1996;7(2):107-15. 13. Bll S, Bx A. Self-ce in medicl eduction: effectiveness of helth-hbits inteventions fo fist-ye medicl students. Acd Med 2002;77(9):911 7. 14. Zilinwti AH, Teng CL, Chung YC, Teow TL, Lee PN, Jgmohni KS. Dytime Sleepiness nd Sleep Qulity Among Mlysin Medicl Students. Med J Mlysi 2009;64(2):108-10. 15. Bick CA, Seely DL, Plemo TM. Assocition Between Sleep Hygiene nd Sleep Qulity in Medicl Students. Behviol Sleep Medicine 2010;8(2):113 21. 16. Veldi M, Aluoj A, Vs V. Sleep qulity nd moe common sleep-elted poblems in medicl students. Sleep Med 2005;6(3):269 75. 17. Hnsen M, Jnssen I, Schiff A, Zee PC, Dubocovich ML. The impct of school dily schedule on dolescent sleep. Peditics 2005;115(6):1555-61. 18. Stepnski EJ, Wytt JK. Use of sleep hygiene in the tetment of insomni. Sleep Med Rev 2003;7(3):215-25. 19. Ameicn Sleep Disodes Assocition. The Intentionl Clssifiction of Sleep Disodes, Revised: Dignostic nd Coding Mnul. Rocheste: Ameicn Sleep Disodes Assocition, 1997. 5