Data-driven profiles of attention-deficit/hyperactivity disorder using objective and ecological measures of attention, distractibility, and hyperactivity

Vol.:(0123456789) 1 3 Eu opean Child & Adolescen Psychia y (2024) 33:1451–1463 h ps://doi.o g/10.1007/s00787-023-02250-4 ORIGINAL CONTRIBUTION Da a‑d i en p o iles o a en ion‑de ici /hype ac i i y diso de using objec i e andecological measu es o a en ion, dis ac ibili y, andhype ac i i y Pila Fe nández‑Ma ín1,2 · RocíoRod íguez‑He e a1,2 · RosaCáno as3 · UnaiDíaz‑O ue a4,5 · AlmaMa ínezdeSalaza 6 · Pila Flo es1,2,3 Recei ed: 15 Decembe 2022 / Accep ed: 19 June 2023 / Published online: 30 June 2023 © The Au ho (s) 2023 Abs ac In he pas wo decades, he adi ional nosology o a en ion-de ici /hype ac i i y diso de (ADHD) has been c i icized o ha ing insu icien disc iminan alidi y. In line wi h cu en ends, in he p esen s udy, we combined a da a-d i en app oach wi h he ad an ages o i ual eali y aiming o iden i y no el beha io al p o iles o ADHD based on ecological and pe o mance-based measu es o ina en ion, impulsi i y, and hype ac i i y. One hund ed and en Spanish-speaking pa icipan s (6–16yea s) wi h ADHD (medica ion-naï e, n = 57) and ypically de eloping pa icipan s (n = 53) comple ed AULA, a con inuous pe o mance es embedded in i ual eali y. We pe o med hyb id hie a chical k-means clus e ing me hods o e he whole sample on he no malized -sco es o AULA main indices. A i e-clus e s uc u e was he mos op imal solu ion. We did no eplica e ADHD sub ypes. Ins ead, we iden i ied wo clus e s sha ing clinical sco es on a en ion indices, suscep ibili y o dis ac ion, and head mo o ac i i y, bu wi h opposing sco es on mean eac ion ime and commission e o s; wo clus e s wi h good pe o mance; and one clus e wi h a e age sco es bu inc eased esponse a iabili y and slow RT. DSM-5 sub ypes cu ac oss clus e p o iles. Ou esul s sugges ha la ency o esponse and esponse inhibi ion could se e o dis inguish among ADHD subpopula ions and guide neu opsychological in e en ions. Mo o ac i i y, in con as , seems o be a common ea u e among ADHD subg oups. This s udy highligh s he poo easibili y o ca ego ical sys ems o pa se ADHD he e ogenei y and he added alue o da a-d i en app oaches and VR-based assessmen s o ob ain an accu a e cha ac e iza ion o cogni i e unc ioning in indi iduals wi h and wi hou ADHD. Keywo ds A en ion-de ici /hype ac i i y diso de · Dimensional app oach· Vi ual eali y· CPT· Clus e analysis In oduc ion The diagnos ic and s a is ical manual o men al diso de s (DSM) has adi ionally concep ualized he diagnosis o a en ion-de ici /hype ac i i y diso de (ADHD) as consis - ing o wo symp om domains o ina en ion and hype ac i - i y/impulsi i y. Based on six ou o nine c i e ia cu -o s, DSM delimi s h ee ADHD subg oups: p edominan ly ina - en i e (ADHD-IA), p edominan ly hype ac i e-impulsi e (ADHD-HI), and combined (ADHD-C) p esen a ions. None- heless, in he pas wo decades, he diagnos ic alidi y o his axonomy has been s ongly c i icized o ha ing insu i- cien disc iminan alidi y [1, 2]. Se e al s udies ha e ound simila neu opsychological p o iles be ween ADHD-C and ADHD-IA sub ypes [3–7]. These sub ypes seem also no o di e om he ADHD-HI sub ype on he le el o ina en ion o unc ional ou comes [8, 9]. Besides, using DSM c i e ia, * Pila Flo es [email p o ec ed] 1 Depa men o Psychology, Facul y o Psychology, Uni e si y o Alme ia, Ca e e a de Sac amen o S/N, La Cañada de San U bano, 04120Alme ía, Spain 2 Heal h Resea ch Cen e (CEINSA), Uni e si y o Alme ia, Alme ía, Spain 3 Neu o ehabili a ion andAu onomy Cen e Impa ables, Alme ía, Spain 4 Depa men o Psychology, Maynoo h Uni e si y, Maynoo h, I eland 5 In e na ional Uni e si y o La Rioja (UNIR), Log oño, Spain 6 Child andAdolescen Men al Heal h Uni , To ecá denas Uni e si y Hospi al, Alme ía, Spain 1452 Eu opean Child & Adolescen Psychia y (2024) 33:1451–1463 1 3 ADHD sub ypes p esen subs an ial a iabili y in symp om mani es a ion, clinical cou se, and ea men esponse [1, 2]. Such a iabili y is a ibu able o he ca ego ical na u e o DSM diagnosis [10]. The use o nominal c i e ia o diagno- sis means ha es ic i e and sub h eshold symp om p o iles can coexis wi hin he same diagnos ic label. Thus, behind a diagnosis o ADHD-IA, i is possible o ind pa ien s no only wi h a es ic i e ina en i e p o ile bu also hose wi h sub h eshold symp oms o hype ac i i y/impulsi i y (≤ 5 c i e ia). Dimensional app oaches o psychopa hology, such as he Resea ch Domain C i e ia [11] and he Hie a chical Tax- onomy o Psychopa hology [12], eme ged in ecen yea s aiming o disen angle symp om he e ogenei y and c ea e a eliable and clinically use ul nosology o men al heal h. These ini ia i es p opose a da a-d i en al e na i e o DSM and concep ualize psychopa hological p oblems as a spec- um a he han ca ego ies wi h s ic bounda ies o “non- no mali y”. In his sense, he i h edi ion o DSM [13] also ied o adop a dimensional model, o example, by shi ing o ADHD “p esen a ions” om “sub ypes” o ecognize ha symp oma ology is no necessa ily s able ac oss de elop- men , o by including g ades o ADHD se e i y. Howe e , hese modi ica ions ha e no been enough o add ess he exis ing limi a ions and he scien i ic and clinical com- muni ies s ill appeal o a e ised ADHD nosology [14]. On his ma e , da a-d i en app oaches a e being inc eas- ingly encou aged o cla i y wi hin-diagnosis he e ogenei y in ADHD. P e ious esea ch has iden i ied no el ADHD subg oups using pa en epo s o empe amen ai s o pe o mance-based measu es o execu i e unc ioning ( o a de ailed e iew see [15]). None o hese s udies ha e ob ained ADHD p o iles cong uen wi h DSM nosology. Howe e , i should be no ed ha hey ha e no a emp ed o de ine ADHD p o iles using pe o mance-based measu es o he co e symp om domains on which he cu en ADHD nosology is based. The inco po a ion o quan i a i e meas- u es o ina en ion, impulsi i y and hype ac i i y o his ield migh be use ul o unde s anding he alidi y p oblems o ADHD sub ypes, as he cu en o ganiza ion o symp oms is g ounded in pa en s and eache epo s [2, 16, 17]. This app oach migh help o guide ADHD nosology e aming, as well as o add ess o he impo an esea ch conce ns, such as he deba e on whe he a pu ely (“ es ic ed”) ina en i e ADHD sub ype exis s and o wha ex en should i be con- side ed a dis inc a en ion diso de [18–20]. Con inuous Pe o mance Tes s (CPTs) a e among he mos popula pa adigms o assess a en ional impai men s and impulsi i y du ing sus ained a en ion asks [21]. In hese asks, child en ha e o de ec in equen a ge s imuli among a sequence o non- a ge s imuli o an ex ended cou se o ime. S anda d a iables o CPT pe o mance include omission e o s, commission e o s, mean eac ion ime (RT), and S anda d De ia ion o RT (SDRT). Al hough CPTs ha e p o ed o be use ul o complemen he clinical diagnosis o ADHD [22], and o moni o he e ec s o pha - macological in e en ions [23–25], hey ha e been c i icized o ha ing poo ecological alidi y and low sensi i i y and speci ici y a es [26]. In ecen yea s, hese limi a ions ha e been o e come by he inco po a ion o i ual eali y (VR) echnology. Acco ding o Kessels (2019) [27], ecological alidi y e e s, on he one hand, o he abili y o a es o demand he same cogni i e esou ces o e e yday ac i i- ies, in o he wo ds, o ec ea e he con ex in which impai - men s appea spon aneously. On he o he hand, i is also unde s ood as he abili y o a es o p edic he examinee’s unc ional abili ies in daily li e ac i i ies, e en i i does no esemble e e yday si ua ions. Al hough, indeed, a CPT is no a common ask in an academic con ex , i demands he a en ional esou ces necessa y o esemble school asks. Thus, one o he con ibu ions o VR has been o embed he CPTs in i ual class ooms, as academic se ings a e he usual scena io in which concen a ion p oblems a e e e ed o by eache s and pa en s [21, 28]. Besides, VR echnology has enabled he inco po a ion and quan i ica- ion o wo domains o in e es o ADHD: mo o ac i i y and a en ional dis ac ion. Hype ac i i y is a ep esen a i e ADHD ai [13] bu con en ionally measu ed using subjec- i e in o man a ings gi en he lack o well-es ablished and s anda dized objec i e me hods. Using mo ion senso s inco - po a ed in he glasses, Pa sons e al. [29] epo ed inc eased head u nings du ing ask pe o mance in ADHD child en, especially in he dis ac o s condi ion. Real-wo ld dis ac e s (e.g., pape ai plane lying, whispe s, a ca passing) du - ing ask pe o mance ha e been demons a ed o nega i ely impac CPT pe o mance in ADHD child en in compa ison o una ec ed pee s, in e ms o inc eased a es o omission e o s, commission e o s, slow RT, and inc eased SDRT [29–32]. Pe haps he mos inno a i e con ibu ion in his ield has come h ough he i ual CPT AULA (“class oom” in English), he only alida ed i ual CPT o child en om 6 o 16yea s [33]. AULA acks head mo emen s in ela- ion o ask s imuli so he es is no limi ed o epo ing he le el o mo o ac i i y, i in o ms abou how much ime child en spen looking a en i onmen al dis ac o s (ex e - nal dis ac ions) and he numbe o e o s hey commi when he a en ional ocus is well-di ec ed o a ge s imuli (in e nal dis ac ions). This is a ele an aspec o he s udy o a en ional lapses in ADHD since he endency o ge dis ac ed wi h sel -gene a ed hough s [34, 35] has been uniquely add essed h ough a ing scales o hough p obes [35, 36]. Conside ing he highligh ed ad an ages, subs an ial e idence shows CPTs embedded in i ual eali y p o ide inc eased ecological alidi y, a mo e accu a e cha ac e iza- ion o ADHD pe o mance, and a g ea e abili y o disc im- ina e be ween child en wi h and wi hou ADHD [21, 32, 37]. 1453Eu opean Child & Adolescen Psychia y (2024) 33:1451–1463 1 3 Taken oge he , in he p esen s udy we uni ied cu en ends in da a-d i en d i en app oaches wi h he ad an ages o i ual CTPs. We aimed o iden i y no el beha io al p o- iles o ADHD based on ecological and pe o mance-based measu es o ina en ion, impulsi i y, and hype ac i i y, h ough he applica ion o explo a o y clus e ing analyses o he main ou come measu es o he i ual CPT AULA. CPTs a e commonly inco po a ed in neu opsychological assess- men p o ocols o ADHD so we expec ed o ind p o iles ha could se e as a guide o diagnosis and in e en ion planning. Based on p io sub yping s udies, we expec ed be ween h ee o six subg oups o indi iduals wi h dis inc a en ional con ol p o iles in ADHD and heal hy-ma ched pa icipan s [38–41]. Me hods P ocedu e Da a we e d awn om a da abase p ope y o ou esea ch eam which includes, om 2016 onwa ds, diagnos ic in o - ma ion, ques ionnai es, IQ, and AULA pe o mance on Spanish-speaking child en and adolescen s wi h neu ode- elopmen al diso de s, mos ly ADHD, and TD pa icipan s. This da abase con ains da a om ou ine clinical assess- men s a a neu o ehabili a ion cen e ha includes he i ual CPT AULA in diagnos ic assessmen p o ocols. Families a e in i ed o sha e he da a o esea ch pu poses be o e he assessmen . Child en and adolescen s e e ed o his clinic o possible ADHD unde go a neu opsychological assess- men by a 10yea s expe ienced child neu opsychologis [RC]. A pa en s’ semi-s uc u ed in e iew o ga he medi- cal and clinical in o ma ion, beha io al a ings [S eng hs and Di icul ies Ques ionnai e (SDQ) [42]], Escalas Magal- lanes de E aluación del T as o no po Dé ici de A ención con Hipe ac i idad (EMTDA-H) [43], Beha iou Ra ing In en o y o Execu i e Func ion (BRIEF) [44], and obse - a ions we e used o de e mine DSM-5 c i e ia o ADHD. The da abase also includes da a om a la ge esea ch p o- jec examining execu i e unc ions in ADHD. We ec ui ed ADHD and TD child en h ough mailing lis s om public heal h and educa ion se ices. Families willing o pa ici- pa e comple ed a phone in e iew o assess s udy eligibil- i y. ADHD and TD pa icipan s unde wen he same clinical assessmen by a ained doc o a e-le el heal h psychologis [PFM]. Pa en s comple ed a clinical in e iew (The Kid- die Schedule o A ec i e Diso de s and Schizoph enia (K-SADS-PL-5) [45] and a se o a ing scales [SDQ [42], ADHD Ra ing Scale-5 (ADHD-RS-V) [46], Child Beha io Checklis (CBCL/6-18) [47], Conne s 3 ADHD Index [48]] o de e mine DSM-5 c i e ia o ADHD. School in e iews and epo s we e ob ained whene e possible du ing bo h ec ui men p ocedu es. All pa en s/legal gua dians, and child en o e 12yea s o age, p o ided e bal and w i en in o med consen . Pa ici- pan s we e assessed indi idually by an expe ienced psychol- ogis [RC and PFM]. The i ual CPT was always adminis- e ed i s o a oid a igue e ec s on a en ional pe o mance. Families ecei ed a b ie assessmen epo . E hical app o al was ob ained om local Ins i u ional E hics Commi ees. Fo he goal o his s udy, we selec ed child en wi h a ail- able sco es on he SDQ, as i is he only sha ed ADHD a ing scale ac oss ec ui men p ocedu es. Pa icipan s We selec ed child en wi h a p ima y diagnosis o ADHD and TD con ols. Two expe ienced psychologis s a ed ADHD diagnosis as ‘p esen ’, ‘sub h eshold’ o ‘absen ’ ollow- ing he abo emen ioned diagnos ic p ocedu es. As child ADHD symp oms a e bes concep ualized as a con inuum [49, 50], we included child en wi h sub h eshold p o iles in he ADHD g oup because hey expe ience incapaci a - ing symp oms (p esence o 3–5 c i e ia) al hough hey do no each cu -o c i e ia [51]. TD pa icipan s mus ha e no psychia ic his o y. Unce ain diagnoses we e con e - enced o consensus and excluded in case o disag eemen . We excluded child en om bo h g oups i hey ha e neu o- logical illness, auma ic b ain inju y o gene ic diso de s; a diagnosis o in ellec ual disabili y, au ism spec um diso - de , o psychosis; senso y o mo o impai men s ha p e en comple ion o he ask; IQ < 70; o any cu en o p e ious pha macological ea men o ADHD symp oms, as long as medica ion imp o es CPT pa ame e s a bo h compu e ized and i ual eali y se ings [23–25]. All pa icipan s we e medica ion naï e because child en had no been p esc ibed medica ion a he ime o es ing o child/pa en s’ objec ion o medica ion. The inal sample included 110 pa icipan s: 57 child en wi h ADHD and 53 TD con ols ma ched by age and IQ (Table1). We did no ha e child en wi h he ADHD-HI sub- ype due o i s low p e alence, i is an imp obable diagnosis a e p eschool ha usually e ol es in o a combined p esen- a ion [2, 52]. The ADHD g oup sco ed signi ican ly highe han he TD g oup on all he scales o he SDQ. Measu es Ad anced i ual‑ eali y es AULA Using a head-moun ed display (Samsung Gea VR), child en a e placed in a i ual class oom, si ing a a desk and look- ing a he blackboa d. Child en i s pe o m a usabili y ask ( ind and pop balloons) o ge used o he 3D en i onmen . 1454 Eu opean Child & Adolescen Psychia y (2024) 33:1451–1463 1 3 They nex comple e wo asks (180 ials, 20% a ge s, each). Fi s , hey mus p ess he bu on whene e hey see on he blackboa d o hea any s imulus o he han he a ge (“apple”) (No-Go pa adigm). Second, hey a e ins uc ed o p ess he bu on whene e he a ge (“se en”) appea s (Go pa adigm). Ta ge s imuli ha e a low p obabili y o occu - ence, so No-Go and Go asks, espec i ely, gene a e con- di ions o o e and unde -s imula ion in ended o p oduce high- as and low-slow esponse a es. Du ing ask pe o - mance, usual isual (e.g. s uden passing a no e, aising he hand), audi o y (e.g. whispe s, ca passing), and combined (e.g. pen d ops, eache ’s walk) dis ac ing s imuli om he school en i onmen andomly appea (no in e e ing wi h i ems’ p esen a ion) o inc ease ecological alidi y. Each pa adigm is p eceded by a p ac ice un. Task speci ica ions ha e been published elsewhe e [21]. The comple e admin- is a ion las s a ound 20min. AULA p o ides adi ional measu es o CPT pa adigms such as: Omissions, missing esponses o he a ge s imuli (as an index o ina en ion); S anda d de ia ion o Reac ion Time (SDRT) (a common index o esponse inconsis ency [54]; Mean hi RT (o en used as a measu e o la ency o esponse); and Commissions, esponses o non- a ge s imuli ( ela ed o esponse inhibi ion). Besides, using he mo e- men senso s placed in he i ual glasses, AULA egis e s how much and when he child mo es he head, and how a he head de ia es om he a en ional ocus ( he black- boa d, whe e isual a ge s imuli appea ). This in o ma ion is exp essed in h ee no el a iables: Head mo o ac i i y, de ined as he sum o he a e ages o he h ee o a ions (angles) o he X, Y and Z axes o he head and consid- e ed a quan i a i e measu e o o al head mo emen s du ing he en i e ask; De ia ion o a en ional ocus, de ined as he amoun o ime in milliseconds ha he child shi s he a en ion ocus o any s imuli in he class oom o he han he blackboa d and in e p e ed as an index o ex e nal dis- ac ions (en i onmen al s imuli) [30]; and Quali y o a en- ional ocus, de ined as he o al numbe o isual omission and commission e o s ha pa icipan s commi when he a en ional ocus is well-di ec ed o he blackboa d, and in e p e ed as a en ional lapses due o in e nal dis ac o s ( hough s). AULA pe o mance is quan i ied on no malized -sco es ( anging om 20 o 80) no m- e e enced by age and sex g oups [55]. T-sco es ≤ 40 a e in e p e ed as a e y good pe o mance; -sco es be ween 41 and 60, as a e age sco es; -sco es be ween 61 and 70 (low pe o mance), as a isk o a en ion p oblems; and -sco es be ween 70 and 80, as a high isk o a en ion p oblems ( e y low pe o mance). AULA has eliabili y, speci ici y, and sensi i i y a es abo e 90% [21] and an excellen con e gen alidi y wi h goal s anda ds such as he Conne s’ CPT [56], he D2 es [57], and he Faces-Di e ences Pe cep ions Tes [58]. S eng hs anddi icul ies ques ionnai e (SDQ)‑pa en s’ e sion Pa en s comple ed he SDQ [42], an in e na ional and eli- able scale o sc een emo ional and beha io al p oblems in child en and adolescen s aged 4–17yea s. I con ains 25 i ems di ided be ween i e scales: emo ional symp oms, conduc p oblems, ina en ion/hype ac i i y, pee ela ion- ship p oblems, and p osocial beha io . S a is ical analysis All analyses we e un in R so wa e [59]. Clus e ing app oach We applied hyb id hie a chical k-means clus e ing analyses o iden i y speci ic subg oups o a en ional con ol among ADHD and TD pa icipan s. This algo i hm i s compu ed Table 1 Sample cha ac e is ics G oup-le el compa isons we e assessed ia es s and Chi-Squa e es s a Pa icipan s ec ui ed om he clinic we e adminis e ed ull-scale IQ as pa o a ecen diagnos ic assessmen while all o he pa icipan s comple ed a sho o m (Vocabula y and Block Design) which co - ela es abo e 0.90 [53] b Fou pa icipan s had a sub h eshold p o ile ‡ p < 0.001 † p < 0.01 *p < 0.05 Cha ac e is ic ADHD (n = 57) TD (n = 53) Demog aphics Age, mean (SD) 9.47 (2.93) 10.34 (2.92) Gi ls, n (%) 18 (31.58)†32 (60.38) IQ, mean (SD)a102.19 (13.53) 108.81 (17.76) Eu opean o igin, n (%) 54 (94.74) 53 (100.00) ADHD-Combined, n (%) 31 (54.38) ADHD-Ina en i e, n (%)b26 (45.62) Como bid diso de s, n (%) Speci ic lea ning diso de 10 (17.54) Language diso de 1 (1.75) Opposi ional de ian diso de 1 (1.75) SDQ subscales–pa en s, mean (SD) Emo ional symp oms 3.77 (2.33)†2.55 (2.59) Conduc p oblems 2.86 (2.18)‡1.42 (1.61) Ina en ion/hype ac i i y 6.11 (2.19)‡2.98 (2.25) Pee p oblems 2.39 (2.31) 1.59 (1.61) P osocial beha io 7.98 (1.94)* 8.70 (1.69) To al di icul ies 15.07 (6.57)‡8.34 (5.79) 1455Eu opean Child & Adolescen Psychia y (2024) 33:1451–1463 1 3 hie a chical clus e ing o selec a en a i e numbe o clus e cen oids. We used Wa d’s me hod (Euclidean dis ance) o agglome a ion o minimize wi hin-clus e a iance in each i e a i e s ep. Then, clus e membe ship was de e mined h ough k-means analysis, s a ing he i e a ion p ocess in he p e iously de ined clus e cen oids ins ead o in andom seeds. This combina ion o clus e ing me hods o e comes he limi a ions o each [60] and has been p e iously used by ou g oup o iden i y no el pheno ypes o compulsi e beha io [61] and decision-making [62]. The algo i hm was pe o med o e he whole sample on he no malized -sco es o AULA main indices (Omissions, SDRT, De ia- ion o a en ional ocus, Mean RT, Commissions, and Head mo emen s). We did no include he Quali y o a en ional ocus because AULA p o ides his index o NoGo and Go pa adigms sepa a ely ins ead o as a global index. We examined se e al clus e solu ions (k) anging om 3 o 6 subg oups acco ding o p e ious sub yping s udies [38–41]. We inspec ed each clus e solu ion and decided on an app op ia e cu -o guided by he majo i y ule o hi y clus e ing alida ion indices [63]. G oup‑le el compa isons G oup-le el di e ences we e es ed ia obus models o ANOVA on 20% immed means and 2000 boo s ap sam- ples o be e con ol o Type I e o [64, 65]. We pe o med one-way ANOVAs o compa e pe o mance in AULA’s main ou come measu es acco ding o DSM sub ype and Clus e membe ship, as well as clus e s’ demog aphics. Two-way mixed ANOVAs [66] we e used o assess he e ec o G oup (DSM sub ype/Clus e ; be ween-subjec s ac o ) and Task pa adigm (No-Go s Go ask; wi hin-subjec s ac o ) on he a iable Quali y o a en ional ocus. All pos -hoc es s applied Benjamini–Hochbe g co ec ion o mul iple com- pa isons. Signi icance le el was se a p < 0.05. Resul s DSM p o iles o a en ional con ol ADHD-C and ADHD-IA sub ypes showed a low-pe - o ming p o ile in AULA main indices (Fig.1). Robus one-way ANOVA e ealed signi ican e ec s o all ou - come measu es excep o commission e o s. Tes s a is- ics and mean di e ences o each pos -hoc compa ison a e de ailed in Supplemen a y Ma e ial (TableS1). Pos - hoc es s adjus ed o mul iple compa isons showed ha ADHD-C child en ob ained signi ican ly wo se sco es han TD con ols in all measu es excep o commission e o s. Simila ly, ADHD-IA child en ob ained signi ican ly wo se sco es han TD con ols in all measu es excep o com- mission e o s and de ia ion om he a en ional ocus. When compa ing sub ypes, pos -hoc es s e ealed ha ADHD-C child en spen signi ican ly mo e ime de ia - ing he a en ional ocus and pe o med signi ican ly mo e head mo emen s han ADHD-IA child en. Conce ning he a iable Quali y o a en ional ocus, a obus wo-way mixed ANOVA e ealed main e ec s o DSM sub ype [TWJ(2, 35.45) = 4.23, p = 0.02] and ask pa a- digm [TWJ(1, 62.58) = 15.82, p < 0.001] bu no in e ac ion e ec [TWJ(2, 40.83) = 0.53, p = 0.57]. Conce ning be ween- subjec s e ec s, pos -hoc es s co ec ed o mul iple com- pa isons e ealed ha ADHD-C pa icipan s had a signi i- can ly lowe pe o mance han TD pa icipan s ega dless o ask pa adigm (p = 0.02). We did no ind signi ican di e ences be ween ADHD-C and ADHD-IA sub ypes. Conce ning wi hin-subjec s e ec s, sco es on he Quali y o a en ional ocus we e signi ican ly highe du ing he Go pa adigm (p < 0.001). Mean alues o each clus e pe ask pa adigm a e de ailed in Table2. Fig. 1 A en ional con ol p o iles measu ed by he i ual CPT AULA o ADHD-Combined (ADHD-C), ADHD-Ina en i e (ADHD-IA), and ypically de eloping (TD) pa icipan s. 20% immed mean alues o AULA main indices ( -sco es): omission e o s, s anda d de ia ion o eac ion ime (SDRT), ime de ia ing he a en ional ocus om he blackboa d, mean RT, commission e o s, and o al head mo emen s. E o ba s ep esen he 20% immed s anda d e o o he mean. T-sco es ≥ 61 ep esen a clinically low pe o mance. Dashed lines indica e cu -o s o isk o a en ion p ob- lems (> 60 = a isk; > 70 = high isk) 1456 Eu opean Child & Adolescen Psychia y (2024) 33:1451–1463 1 3 Da a‑d i en p o iles o a en ional con ol Bes clus e solu ion We g aphically inspec ed clus e solu ions anging om 3 o 6 subg oups. Fo each k solu ion, we ep esen ed he pe o mance p o iles in AULA main indices and he pe cen age dis ibu ion o each clus e in ADHD and TD g oups (Fig. S1). Fo k = 3, hyb id k-means analyses iden- i ied one low-pe o ming subg oup cons i u ed by 72.22% o ADHD pa icipan s; one subg oup wi h a e age sco es (cons i u ed by 80.65% TD pa icipan s); and one sub- g oup wi h in ac pe o mance bu ele a ed SDRT and slow RT ( o med by 52% TD pa icipan s). Fo k = 4, clus- e analyses di ided he low-pe o ming clus e in o wo ADHD pheno ypic subg oups, espec i ely, cons i u ed by 89.92% and 48.19% ADHD pa icipan s. Fo k = 5, he clus e wi h a e age sco es was spli in o a e age and high- pe o mance subg oups. Finally, o a solu ion o k = 6, clus e analyses e ealed one subg oup wi h high le els o head ac i i y, a high endency o de ia e he a en ional ocus, and ele a ed SDRT. Acco ding o he majo i y ule among hi y clus e ing alida ion indices, he i e-clus e s uc u e was he bes clus e solu ion (Fig. S2) o explaining CPT pe o mance among ADHD and TD pa icipan s. This s uc u e demon- s a ed he highes in e nal consis ency as s a ed by nine well- alida ed indices (TableS2). We also conside ed i a pa simonious solu ion o desc ibe ADHD subpopula ions. Pheno ypic cha ac e iza ion Figu e2A depic s he sco es o he i e clus e s ob ained in AULA’s main indices. Clus e s we e labeled acco ding o hei pe o mance, ollowing he clinical cu -o poin s p o ided by he alida ion s udy. We obse ed wo low- pe o ming subg oups wi h an opposi e pe o mance p o- ile in la ency o esponse and esponse inhibi ion. These clus e s we e, espec i ely, labeled ADHD-Slow P ocess- ing (ADHD-SP; n = 24; 87.5% ADHD pa icipan s) and ADHD-Impulsi e (ADHD-IMP; n = 28; 57.14% ADHD pa icipan s). The clus e s showing a e age sco es we e labeled A e age (n = 17; 70.58% TD pa icipan s) and High pe o me s (n = 17, 88.24% TD pa icipan s) as he la e g oup had be e sco es in omissions, commissions, and head ac i i y. Finally, he i h clus e was labeled Slug- gish (n = 24; 54.16% ADHD pa icipan s) as i showed a ela i ely a e age pe o mance in all a iables bu sligh ly clinically ele a ed sco es in mean RT and SDRT. Figu e2B illus a es he pe cen age dis ibu ion o pa icipan s om each clus e in ADHD and TD g oups. 64.91% o he ADHD sample belonged o ADHD-SP and ADHD-IMP clus e s, while 28.81% belonged o he Sluggish clus e . 50.94% o TD pa icipan s we e ound in he A e age and High pe - o ming clus e s. 20.76% o TD pa icipan s belonged o he Sluggish clus e . Robus one-way ANOVA showed s a is ically signi ican di e ences in all AULA ou come measu es among clus e s, yielding la ge e ec sizes. Tes s a is ics and mean di e - ences o each compa ison a e included in he Supplemen- a y Ma e ial (TableS3). Signi ican pos -hoc compa isons a e adjus ing o mul iple compa isons a e ep esen ed in Fig.3. B ie ly, ADHD-SP and ADHD-IMP clus e s signi i- can ly di e ed in omissions, mean RT, commission e o s, Table 2 Mean alues o Quali y o a en ional ocus acco ding o DSM sub ype 20% immed mean alues (no malized -sco es) and S anda d De ia- ion a e p esen ed. Low sco es (≥ 61) a e bold aced Task pa adigm ADHD-C ADHD-IA TD NoGo ask 57.63 (10.30) 56.75 (9.48) 52.67 (11.53) Go ask 62.32 (8.64) 59.69 (10.82) 55.27 (9.36) Fig. 2 A en ional con ol p o iles measu ed by he i ual CPT AULA acco ding o he i e-clus e solu ion. A 20% immed mean alues o AULA main indices ( -sco es): omission e o s, s anda d de ia ion o eac ion ime (SDRT), ime de ia ing he a en ional ocus om he blackboa d, mean RT, commission e o s, and o al head mo emen s. E o ba s ep esen he 20% immed s anda d e o o he mean. T-sco es ≥ 61 ep esen a clinically low pe o - mance. Dashed lines indica e cu -o s o isk o a en ion p oblems (> 60 = a isk; > 70 = high isk). B Pe cen age dis ibu ion o each clus e in ADHD and TD g oups 1457Eu opean Child & Adolescen Psychia y (2024) 33:1451–1463 1 3 and de ia ion om he a en ional ocus. Bo h clus e s di - e ed om a e age and high pe o me s in mos ou come measu es. The Sluggish clus e p esen ed an in e media e p o ile, as his clus e sco ed signi ican ly wo se han a e - age and high pe o me s bu signi ican ly be e han ADHD- SP and ADHD-IMP clus e s. In he Quali y o a en ional ocus, he ADHD-SP clus- e ob ained a clinically low sco e in bo h NoGo and Go pa adigms, while he ADHD-IMP clus e only eached a clinically low pe o mance in he Go ask. Mean alues o each clus e a e de ailed in Table3. A obus wo- way mixed ANOVA e ealed signi ican main e ec s o ask pa adigm [TWJ(1, 53.14) = 22.42, p < 0.001] and clus e p o ile [TWJ(4, 31.04) = 18.93, p < 0.001], as well as a signi i- can Task × Clus e in e ac ion e ec [TWJ(4, 30.73) = 30.73, p = 0.02]. Conce ning ask pa adigm, pos -hoc es s adjus ed o mul iple compa isons e ealed no signi ican di e ences be ween ADHD-SP and ADHD-IMP clus e s nei he in he Go no in he NoGo ask. In he No-Go ask, high pe o me s showed a signi ican ly be e sco e han he o he clus e s. ADHD-SP pa icipan s ob ained a sig- ni ican ly wo se pe o mance han a e age pe o me s. In he Go ask, ADHD-SP and ADHD-IMP clus e s ob ained a signi ican ly wo se pe o mance han a e age pe o m- e s. The ADHD-SP also showed a signi ican wo se sco e han Sluggish pe o me s. In his ask, high pe o me s ob ained a signi ican ly be e pe o mance han ADHD- SP, ADHD-IMP and Sluggish pa icipan s. Rega ding wi hin-subjec s e ec s, pos -hoc analyses showed ha ADHD-IMP and High pe o me s ob ained a signi ican ly wo se sco e in he Go ask in compa ison wi h he NoGo ask. No di e ences in ask pa adigm we e e ealed o ADHD-SP, Sluggish and A e age pe o me s. Fig. 3 Pos -hoc compa isons be ween he ob ained clus e s in he main indices o he i ual CPT AULA. 20% immed mean alues o AULA main indices ( -sco es) a e p esen ed. E o ba s ep esen he 20% immed s anda d e o o he mean. T-sco es ≥ 61 ep esen a clinically low pe o mance. Dashed lines indica e cu -o s o isk o a en ion p oblems (> 60 = a isk; > 70 = high isk). *Signi ican di - e ences a e adjus men o mul iple compa isons using Benjamini– Hochbe g co ec ion Table 3 Mean alues o quali y o a en ional ocus acco ding o clus e membe ship 20% immed mean alues (no malized -sco es) and S anda d De ia ion a e p esen ed. Low sco es (≥ 61) a e bold aced Task pa adigm ADHD-SP ADHD-IMP Sluggish A e age High NoGo ask 61.44 (8.23) 56.67 (5.89) 54.56 (10.07) 53.36 (7.64) 40.36 (7.79) Go ask 63.50 (6.73) 64.00 (8.58) 55.06 (8.16) 55.09 (8.71) 49.64 (5.07) 1458 Eu opean Child & Adolescen Psychia y (2024) 33:1451–1463 1 3 Clus e s’ cha ac e is ics Clus e s did no di e in IQ bu did in age (F = 6.69, p = 0.01) and sex dis ibu ion (p = 0.01) (Table4). We ound ha DSM-5 sub ypes o ADHD we e simila ly dis ibu ed ac oss clus e p o iles. ADHD-SP and ADHD-IMP clus e s ob ained signi ican ly highe sco es in he Ina en ion/Hype - ac i i y subscale (F = 6.24, p = 0.003) and he To al di icul- ies sco e (F = 3.72, p = 0.03) o he SDQ. Discussion In he p esen s udy, we used he i ual CPT AULA o ob ain an objec i e and ecological assessmen o a en ional con ol, impulsi i y, and hype ac i i y in a sample o 57 medica ion-naï e ADHD child en and 57 TD con ols. Fi s , we compa ed he pe o mance o ADHD-C and ADHD-IA sub ypes o es he disc iminan alidi y o DSM-5 c i e ia. We ound ha bo h sub ypes showed -sco es abo e he clinical cu -o (> 60) in mos AULA ou come measu es, and signi ican ly di e ed om TD con ols. Howe e , hey showed an indis inguishable pe o mance p o ile. We did no obse e meaning ul di e ences in a iables ha a e heo e i- cally supposed o disc imina e be ween hem, such as mo o ac i i y (as an index o hype ac i i y) o commission e o s (as an index o esponse disinhibi ion). This da a migh sup- po he idea ha DSM-5 c i e ia a e use ul o de ec ing ADHD indi iduals wi h unc ional impai men s, bu he axonomy is no sensi i e enough o disc imina e among ADHD-C and ADHD-IA sub ypes [2, 67]. Then, we p o- ceeded o iden i y no el beha io al p o iles o ADHD using clus e ing analyses on he main ou comes o he i ual CPT AULA. We ound ha ADHD and TD child en we e eg ouped in o i e clus e s ha cu ac oss DSM sub ypes. Mos ADHD child en belonged o wo clus e s wi h AULA sco es abo e he clinical cu -o ( -sco e > 60). These clus e s, ADHD-SP and ADHD-IMP, we e cha ac e ized by Table 4 Clus e s’ demog aphic cha ac e is ics 20% immed means a e p esen ed a Fou pa icipan s had a sub h eshold p o ile b Signi ican e ec s a e adjus men o mul iple compa isons using Benjamini–Hochbe g co ec ion ‡ p < 0.001 † p < 0.01 *p < 0.05 Cha ac e is ic ADHD-SP (1) ADHD-IMP (2) Sluggish (3) A e age (4) High (5) Signi ican compa isonsb Demog aphics n24 28 24 17 17 Age, mean (SD) 9.25 (2.61) 8.25 (1.88) 10.08 (3.09) 10.71 (2.69) 12.41 (3.08) 5 > 1†, 3* 2 < 3*, 4*, 5‡ Gi ls, n (%) 9 (37.50) 8 (28.57) 9 (37.50) 12 (70.59) 12 (70.59) p = 0.01 IQ, mean (SD) 98.96 (12.69) 105.04 (16.08) 105.58 (15.07) 108.94 (19.55) 111.18 (15.91) Eu opean o igin, n (%) 23 (95.83) 26 (92.86) 21 (87.05) 17 (100.00) 17 (100.00) Typically de eloping, n (%) 3 (12.50) 12 (42.86) 11 (45.84) 12 (70.58) 15 (88.24) ADHD-combined, n (%) 14 (58.33) 12 (42.86) 2 (8.33) 2 (11.77) 1 (5.88) ADHD-ina en i e, n (%)a7 (29.17) 4 (14.28) 11 (45.83) 3 (17.65) 1 (5.88) Como bid diso de s, n (%) Speci ic lea ning diso de 5 (20.83) 1 (3.57) 2 (8.33) 2 (11.77) 0 (0.00) Language diso de 0 (0.00) 1 (3.57) 0 (0.00) 0 (0.00) 0 (0.00) Opposi ional de ian diso de 0 (0.00) 1 (3.57) 0 (0.00) 0 (0.00) 0 (0.00) SDQ subscales-pa en s, mean (SD) Emo ional symp oms 4.08 (2.36) 2.96 (2.33) 3.00 (2.45) 2.12 (2.29) 3.59 (3.10) Conduc p oblems 3.00 (2.45) 2.79 (2.22) 1.75 (1.51) 1.29 (1.57) 1.41 (1.58) Ina en ion/hype ac i i y 6.33 (1.50) 5.00 (2.57) 4.50 (2.62) 2.94 (2.70) 3.29 (2.59) 1 > 3*, 4‡, 5‡ 2 > 4*, 5* Pee p oblems 2.92 (2.28) 1.82 (1.88) 1.79 (2.04) 1.18 (1.81) 2.12 (1.83) P osocial beha io 8.13 (1.68) 8.29 (1.65) 8.29 (1.68) 8.65 (2.03) 8.41 (2.53) To al di icul ies 16.29 (6.36) 12.50 (6.27) 11.04 (6.56) 7.53 (7.08) 9.82 (6.77) 1 > 3†, 4‡, 5* 2 > 4* 1459Eu opean Child & Adolescen Psychia y (2024) 33:1451–1463 1 3 ele a ed sco es in omission e o s, inc eased SDRT, and a high endency o spend ime dis ac ed by ex e nal s imuli (De ia ion om he a en ional ocus). These esul s sup- po ex ensi e li e a u e on in a-indi idual a iabili y in RT as a common ea u e among ADHD sub ypes [54, 68, 69], as well as he nega i e impac o ex e nal dis ac ing s imuli on a en ion pe o mance [32, 70–72]. Mo eo e , ADHD-SP and ADHD-IMP clus e s also showed clini- cally high le els o head mo o ac i i y. This esul could ha e no able implica ions o ADHD axonomy as app oxi- ma ely hal o ou ADHD sample belonged o he ina en i e sub ype. I is ema kable ha we ound high a es o head mo o ac i i y, abo e he clinical cu -o , in bo h ADHD- C and ADHD-IA sub ypes, as well as in he wo ADHD pheno ypic clus e s. We migh sugges ha child en wi h ADHD-IA can display inc eased head mo o ac i i y du - ing challenging asks al hough hey do no each he cu -o c i e ia o impulsi i y/hype ac i i y symp oms. This inding is in ag eemen wi h he concep ualiza ion o hype ac i i y as a non-ubiqui ous beha io igge ed by highly cogni i ely demanding ac i i ies, such as CPTs [73–76]. In addi ion, his would also be in line wi h he idea ha a es ic i e ina en i e ADHD sub ype migh no exis [18–20]. These indings migh explain why p e ious s udies ha e epo ed no di e ences in quan i iable measu es (e.g., ac ig aphs) o g oss mo o ac i i y be ween ca ego ical ADHD sub ypes [75, 77–79]. Pa en s’ epo s o hype ac i i y symp oms may no be consis en wi h he quan i a i e in o ma ion ob ained by objec i e mo ion measu emen s [22] so ou indings sup- po he aluable and complemen a y in o ma ion ha objec- i e mo emen migh add o clinical diagnosis. ADHD-SP and ADHD-IMP clus e s we e only dis in- guishable by he la ency o esponse (mean hi RT) and esponse inhibi ion (commission e o s). While he ADHD- SP clus e was cha ac e ized by a clinically signi ican slow RT and an adequa e a e o commission e o s, he ADHD- IMP clus e showed adequa e mean RT bu ele a ed commis- sions. This opposing pe o mance p o ile migh sugges ha la ency o esponse and esponse inhibi ion migh be use ul domains o dis inguish be ween ADHD subpopula ions. I migh be cong uen wi h p e ious sub yping indings disso- cia ing p ocessing speed and in e e ence con ol in ADHD [38, 39, 80]. Conce ning in e nal dis ac ions (Quali y o a en ional ocus), b ie ly, we obse ed ha ADHD-SP pa - icipan s had signi ican ly mo e a en ional lapses (in e ms o isual omissions and commission e o s) ha ing he a en ional ocus well-di ec ed o a ge s imuli. This g oup ob ained clinically low sco es ega dless o NoGo and Go pa adigms. The ADHD IMP clus e , in con as , jus each a clinically low pe o mance in his domain in he Go ask. We migh hypo hesize ha child en wi h an ADHD-SP p o ile, in which a slow la ency o esponse is p ominen , p esen agg a a ed a en ional impai men s du ing CPT pe o mance, in e ms o sco es abo e he clinically high- isk cu -o ( -sco e > 70), and a e mo e suscep ible o bo h ex e nal and in e nal dis ac o s. We migh sugges a g ea e implica ion o mind-wande ing expe iences o sluggish cog- ni i e empo ea u es in his subg oup [34, 81]. Those chil- d en wi h an ADHD-IMP p o ile, howe e , seem o be p one o ge dis ac ed by in e nal s imuli only in mono onous and low- esponse a e ( igilance) asks. Fu he s udies should employ di ec measu es o in e nal dis ac ibili y o explo e he con ibu ion o in e nal s imuli o a en ional impai - men s in child en wi h ADHD and i s po en ial ela ionship wi h sluggish cogni i e empo o mo i a ional p ocesses. The iden i ica ion o wo clus e s wi h good pe o mance, mainly cons i u ed by TD child en, allowed us o in e p e he clinical signi icance o he abo e-men ioned ADHD p o iles. ADHD-SP and ADHD-IMP child en signi ican ly di e ed om clus e s wi h good pe o mance. Besides, he pe o mance p o ile o he ADHD-SP clus e closely esem- bled ha o Sluggish and high-pe o ming subg oups, in he same manne ha he ADHD-IMP clus e mi o ed a e age pe o me s. We obse ed his pa allelism be ween clinical and non-clinical clus e s in all ou come measu es o he i - ual CPT AULA excep o mo o ac i i y. As ADHD-SP and ADHD-IMP clus e s a e he only ones s uggling wi h ask pe o mance, we migh sugges ha hey expe ience a clini- cally signi ican inc ease in head mo emen s o mee ask demands [74]. These esul s may ein o ce he dimensional cha ac e o ADHD [49, 50, 82], and sugges ha beha io al a iabili y du ing CPT pe o mance migh be simila ly dis- ibu ed in indi iduals wi h and wi hou ADHD. Finally, using he SDQ o ex e nally alida e ou i e clus e s, we ound ha ADHD-SP and ADHD-IMP pa - icipan s had highe impai men sco es in he ina en- ion/hype ac i i y and o al di icul ies scales o he SDQ ques ionnai e. Howe e , we did no obse e signi ican di e ences in emo ional, conduc , and pee p oblems. We should no e ha he e a e scales mo e adequa e han he SDQ, such as he CBCL/6-18 [47], o pe o m a mo e exhaus i e examina ion o in e nalizing and ex e nal- izing beha io s. Howe e , p e ious clus e ing s udies ha e epo ed no di e ences be ween clus e s in ADHD and dep essi e symp oms [83], o ex e nalizing, social, and academic p oblems [38]. As such, AULA pe o - mance does no en i ely co ela e o pa en s’ a ings in he ADHD Ra ing Scale-IV [84]. This could co obo a e he assump ion ha pe o mance-based measu es and a ing scales add ess di e en bu complemen a y in o - ma ion [85]. Neu opsychological measu es o execu i e unc ions seem o be weakly associa ed wi h subjec i e a ings o ina en ion, impulsi i y, and hype ac i i y [86, 87]. Ques ionnai es such as he SDQ migh be use ul o iden i y indi iduals wi h ADHD symp oms bu a e no speci ic enough o de ec speci ic beha io al pa e ns.