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

Vol.:(0123456789)
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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
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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
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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
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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
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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.