De elopmen al Cogni i e Neu oscience 44 (2020) 100803
A ailable online 29 May 2020
1878-9293/© 2020 The Au ho s. Published by Else ie L d. This is an open access a icle unde he CC BY-NC-ND license
(h p://c ea i ecommons.o g/licenses/by-nc-nd/4.0/).
Head mo ion du ing MRI asks is educed in child en and adul s i
pa icipan s ake b eaks
Tobias W. Meissne
a
,
b
,
*, Jon Walb in
c
,
d
, Ma isa No d
b
,
e
, Kami Koldewyn
c
, Sa ah Weigel
a
a
TU Do mund Uni e si y, Facul y o Rehabili a ion Sciences, Depa men o Vision, Visual Impai men s & Blindness, Emil-Figge-S . 50, 44227, Do mund, Ge many
b
Ruh Uni e si y Bochum, Facul y o Psychology, Uni e si €
a ss . 150, 44801, Bochum, Ge many
c
Bango Uni e si y, School o Psychology, De elopmen al Social Vision Lab, Pen all Road, Bango , LL57 2AS, Wales, Uni ed Kingdom
d
Uni e si y o Coimb a, Facul y o Psychology and Educa ion Sciences, P oac ion Lab, Rua Col�
egio No o, 3000-115, Coimb a, Po ugal
e
S an o d Uni e si y, Psychology Depa men , 450 Se a Mall, S an o d, CA, 94305, USA
ARTICLE INFO
Keywo ds:
Mo emen
Da a quali y
Pedia ic neu oimaging
Mock scanne aining
S udy design
De elopmen
ABSTRACT
Head mo ion emains a challenging con ound in unc ional magne ic esonance imaging ( MRI) s udies o bo h
child en and adul s. Mos pedia ic neu oimaging labs ha e de eloped expe ience-based, child- iendly s anda ds
conce ning e.g. he maximum leng h o a session o he ime be ween mock scanne aining and ac ual scanning.
Howe e , i is unclea which ac o s o child- iendly neu oimaging app oaches a e e ec i e in educing head
mo ion. He e, we in es iga e h ee main ac o s including (i) ime lag o mock scanne aining o he ac ual scan,
(ii) p io scan ime, and (iii) ask engagemen in a da ase o 77 child en (aged 6–13) and 64 adul s (aged 18–35)
using a mul ile el modeling app oach. In child en, dis ibu ing MRI da a acquisi ion ac oss mul iple same-day
sessions educes head mo ion. In adul s, mo ion is educed a e inside-scanne b eaks. Despi e hese posi i e
e ec s o spli ing up da a acquisi ion, mo ion inc eases o e he cou se o a s udy as well as o e he cou se o a
un in bo h child en and adul s. Ou esul s sugges ha spli ing up MRI da a acquisi ion is an e ec i e ool o
educe head mo ion in gene al. A he same ime, di e en ways o spli ing up da a acquisi ion bene i child en
and adul s.
1. In oduc ion
“Please emembe : Relax and y no o mo e. He e we go.” In
unc ional magne ic esonance imaging ( MRI) expe imen s, his is o en
he las hing he esea che says be o e s a ing he scanne and he
expe imen . Wha is le o do is hoping o good quali y da a. As MRI is
e y suscep ible o head mo ion du ing he scan (F is on e al., 1996),
hoping o good quali y da a is o en equi alen o hoping o da a wi h
low head mo ion. The impo ance o educing head mo ion du ing da a
acquisi ion has been imp essi ely documen ed in se e al s udies
showing ha head mo ion can lead o misleading esul s (in some cases,
e en a e e ospec i e mo ion co ec ion; Powe e al., 2012; Sa -
e hwai e e al., 2012; an Dijk e al., 2012).
In pedia ic neu oimaging s udies, he gene al p oblem o head
mo ion is especially challenging. Despi e child en’s high mo i a ion o
lie s ill, in mos s udies child en s ill mo e mo e han adul s. This poses a
p oblem o da a quali y in pedia ic neu oimaging especially o g oup
compa isons be ween child en and adul s. E en wi h e ospec i e head
mo ion co ec ion (which is limi ed in i s abili y o co ec o mo ion
Field e al., 2000; F ei e and Mangin, 2001; F is on e al., 1996), g oup
di e ences in head mo ion o en pe sis . This usually leads o he
exclusion o mo ion-a ec ed uns o pa icipan s om da a analysis (e.g.
Meissne e al., 2019; No d e al., 2018; Walb in e al., 2020), hence
equi ing addi ional ime and esea ch unds o achie e an adequa ely
powe ed s udy design.
To minimize mo ion du ing da a acquisi ion, a ious solu ions ha e
been de eloped. Fo s uc u al MRI scans in clinical se ings, seda ion is
o en used. Howe e , his is no an op ion o MRI s udies in esea ch
se ings due o he need o a en i e pa icipan s as well as he unac-
cep able isk o heal h- ela ed side e ec s (de Bie e al., 2010). One se o
solu ions o MRI s udies aims a es aining head mo ion physically.
Res ic i e app oaches including bi e ba s (Menon e al., 1997) o
* Co esponding au ho a : TU Do mund Uni e si y, Facul y o Rehabili a ion Sciences, Depa men o Vision, Visual Impai men s & Blindness, Emil-Figge-S . 50,
44227, Do mund, Ge many
E-mail add esses: [email p o ec ed] (T.W. Meissne ), [email p o ec ed] (J. Walb in), [email p o ec ed] (M. No d ), [email p o ec ed]
(K. Koldewyn), [email p o ec ed] (S. Weigel ).
Con en s lis s a ailable a ScienceDi ec
De elopmen al Cogni i e Neu oscience
jou nal homepage: www.else ie .com/loca e/dcn
h ps://doi.o g/10.1016/j.dcn.2020.100803
Recei ed 23 Oc obe 2019; Recei ed in e ised o m 20 Ap il 2020; Accep ed 27 May 2020
De elopmen al Cogni i e Neu oscience 44 (2020) 100803
2
he moplas ic ace masks (G een e al., 1994), a e conside ed e ec i e
o sho scan du a ions. Howe e , hey educe com o and a e he e-
o e seldomly accep ed in pedia ic neu oimaging. In con as o he
desi ed ou come, he discom o o hese me hods can also lead o mo e
idge ing and wiggling in sea ch o com o (Ze i o, 1996), especially
o longe scans. App oaches ha use indi idually 3D-p in ed s y o oam
head molds a e e ec i e and said o be com o able (Powe e al., 2019),
bu equi e addi ional ime and esea ch unds o each pa icipan . A
less esou ce-in ensi e, ye e ec i e and accep ed solu ion, is o p o ide
ac ile eedback abou pa icipan ’s head mo ion by applying a ape o
ibbon ac oss he head coil ha ouches he pa icipan ’s o ehead
(K ause e al., 2019).
Aside om physical cons ain s, pedia ic neu oimaging g oups o en
adap he s udy p ocedu e o educe child en’s mo ion du ing da a
acquisi ion. The mos p ominen ool is o p ecede he ac ual MRI ses-
sion(s) wi h a scanne aining session (Raschle e al., 2009; Sli e e al.,
1993). Scanne aining sessions a e usually pe o med in a mock
scanne , a cus om-buil o pu chased acsimile o a eal MRI, which lacks
he echnical capabili y o acqui e ac ual da a, bu can play scanne
sounds and has a simila se up o he eal scanne (e.g. head
coil-moun ed mi o , esponse bu ons, e c.). Du ing hese sessions,
beha io al aining is used o each lying s ill in he scanne bo e and
esponding o he ask. The e is a gene al consensus ha a scanne
aining session is bene icial o MRI da a acquisi ion as i educes
child en’s anxie y (Du s on e al., 2009; Raschle e al., 2009; Rosenbe g
e al., 1997). While a educing e ec on head mo ion is also assumed, he
cu en li e a u e has no been able o show his (due o a lack o con ol
g oups ha did no ecei e scanne aining; bu see Ba nea-Go aly
e al., 2014; de Bie e al., 2010; Eps ein e al., 2007 o success a es and
educed mo ion a e scanne aining).
Simila ly, many pedia ic neu oimaging g oups ha e es ablished
expe ience-based guidelines o child- iendly s udy designs in e ms o
he scanning p ocedu e. These usually include keeping uns sho ,
in e spe sing ana omical scans as ask- ee inside-scanne b eaks while
p esen ing en e aining ideo clips, and limi ing he o al scanning
session ime. Mo eo e , based on indings in adul s (Huijbe s e al.,
2017), asks a e designed in an engaging and in e ac i e way a he han
jus equi ing passi e pe cep ion o s imuli. In consequence, a small
body o li e a u e has de eloped ha ecommends scanning p ocedu es
o pedia ic neu oimaging (e.g. G eene e al., 2016; Habibi e al., 2015;
Raschle e al., 2009). Howe e , as o scanne aining, he con ibu ion
o p esumably child- iendly adap a ions in scanning p ocedu es on
minimizing head mo ion has no been in es iga ed so a .
The p esen s udy se ou o iden i y which MRI s udy p ocedu es
con ibu e o educed head mo ion in MRI s udies. Ou aim was o
gene a e da a-d i en sugges ions o op imize s udy p ocedu es o
child en and adul s sepa a ely. To his end we u ilized head mo ion
es ima es de i ed om a s anda d mo ion co ec ion pipeline applied o
77 child en and 64 adul s om h ee MRI s udies a wo si es, and no es
ha yielded demog aphic da a, he da e o scanne aining, and he
sequence o da a acquisi ion. Using sepa a e mul ile el linea models o
child en and adul s, we in es iga ed he e ec o spli ing up da a
acquisi ion in o se e al days o sessions, he e ec o in e spe sing
unc ional da a acquisi ion wi h s uc u al uns and ideo clip b eaks,
he e ec o ime be ween scanne aining and he ac ual scan, and he
e ec o ask engagemen .
2. Me hods
2.1. De ini ion o session, un, and unc ional segmen
In his a icle, we make impo an dis inc ions be ween “session”,
“ un”, and “ unc ional segmen ”. Session co esponds o a con inuous
pe iod o ime spen inside he scanne . A session begins upon en e ing
he scanne and ends as a pa icipan lea es he scanne . Fo example, i
a pa icipan en e s he scanne , akes a b eak ou side he scanne and
e-en e s he scanne , his would cons i u e wo sessions. Run co e-
sponds o a con inuous image acquisi ion sequence. Fo example, a
pa icipan could comple e an expe imen wi h ou MRI uns wi hin a
single session. Func ional segmen co esponds o a pe iod o consecu-
i e acquisi ion o unc ional uns inside he scanne . Fo example, i a
scan p ocedu e in ol es an ana omical T1-scan, h ee MRI uns, wo
di usion-weighed imaging (DWI) sequences, and inally ou mo e MRI
uns, his pa icipan has comple ed wo unc ional segmen s.
2.2. Pa icipan s
Ou s udy included da a om wo neu oimaging cen e s (see 2.3,
Neu oimaging) and h ee de elopmen al cogni i e neu oimaging
s udies, a o al 680 uns om 77 child en and 624 uns om 64 adul s.
Some o he da a has been used o answe ques ions conce ning he
neu ocogni i e isual and social de elopmen in child en and adul s
p e iously (Meissne e al., 2019; No d e al., 2018; Walb in e al.,
2020). The inal analyzed da a se was educed o 626 uns om 77
child en and 470 uns om 54 adul s due o se e al exclusion c i e ia
(see 2.5, Da a exclusion). In child en, he numbe o uns pe pa icipan
anged om 1 o 14 (M ¼8.13, SD ¼3.21), in adul s, he numbe o uns
pe pa icipan anged om 4 o 14 (M ¼8.70, SD ¼3.33). Child en’s
age anged om 6.78 o 13.01 yea s (M ¼9.52, SD ¼1.68), adul ’s age
anged om 18.41 o 35.02 yea s (M ¼21.76, SD ¼2.67). All pa ici-
pan s we e heal hy, had no mal o co ec ed- o-no mal ision, and had
been bo n a e m. No pa icipan epo ed pas o cu en neu ological
o psychia ic condi ions, o had s uc u al b ain abno mali ies. All
pa icipan s as well as child en’s pa en s ga e in o med and w i en
consen o pa icipa e olun a ily.
2.3. Neu oimaging
MRI ook place a he Neu oimaging Cen e o he Resea ch
Depa men o Neu oscience a Ruh Uni e si y Bochum and he Bango
Imaging Cen e a Bango Uni e si y. A Bochum, a o al o 338 uns in
50 child en and 346 uns in 40 adul s we e acqui ed—a Bango , a o al
o 188 uns in 27 child en and 123 uns in 14 adul s we e acqui ed. A
bo h si es, 3.0 T Achie a scanne s (Philips, Ams e dam, The
Ne he lands) and 32-channel head coils we e used (Supplemen a y
Fig. S1). Fo all MRI, we used blood oxygen le el dependen (BOLD)
sensi i e T2*-weigh ed sequences. Ac oss si es and expe imen s, he
ollowing MRI acquisi ion pa ame e s we e cons an :
FOV ¼240 mm �240 mm, ma ix size ¼80 �80, oxel
size ¼3 mm �3 mm �3 mm, TR ¼2000 ms, TE ¼30 ms. Howe e , slice
gap (Bango : 0 mm, Bochum: 0.4 mm), numbe o slices (Bango : 32,
Bochum: 33), slice scan o de (Bango : ascending, Bochum: ascending
in e lea ed), and lip angle (Bango : 83�, Bochum: 90�) di e ed be-
ween si es. Visual s imuli we e p esen ed ia a VisuaS im Digi al goggle
sys em (FOV: 30��24�, 800 �600 pixel, Resonance Technology Inc.,
CA, USA) in Bochum and ia a MR-sa e moni o and mi o sys em (FOV:
25.92��16.90�, 1920 �1200 pixel; Camb idge Resea ch Sys ems, UK)
in Bango . Due o he isual isola ion inhe en wi h he goggle sys em, a
esea che was p esen nex o he scanne bo e opening a all imes o
immedia e e bal con ac and mo ion eedback in Bochum, bu no in
Bango .
Fo each s udy, a ce ain numbe o unc ional uns and s uc u al
scans we e planned. De ails on he expe imen s ha we e done du ing
he unc ional uns as well as he numbe o pa icipan s and uns o
each o he asks a e gi en in he Supplemen a y Tex S1 and Supple-
men a y Table S1. In adul s, expe imen e s ollowed his p o ocol,
checking in wi h pa icipan s a e he comple ion o each expe imen (i.
e. a e mul iple uns) o explain wha would happen nex and only
s opped o di e ed om p o ocol i pa icipan s ac i ely epo ed
eeling unwell. In con as , in child en, we checked in wi h pa icipan s
a e each un o ac i ely inqui e abou hei well-being. Mo eo e ,
nea ing he end o a session, we also ac i ely asked i hey s ill el good
T.W. Meissne e al.
De elopmen al Cogni i e Neu oscience 44 (2020) 100803
3
and eady o do ano he un. This was done in o de o gi e child en he
oppo uni y o exp ess any signs o discom o , which o ou expe ience
child en do no necessa ily u e spon aneously bu some imes only a e
encou aging hem o be open abou i o gi ing hem an explici op-
po uni y. Thus, we dynamically decided when o b eak up acquisi ion
in o sessions o days, when o in e spe se asks wi h a s uc u al scan
accompanied by an en e aining ideo, o when o end he s udy.
2.4. Scanne aining
All child en unde wen a scanne aining in o de o amilia ize
hem wi h he scanne en i onmen and achie e high-quali y scans wi h
as li le mo ion as possible (Supplemen a y Fig. S1). A bo h scanne
si es, p e- eco ded audio o MRI acquisi ion sequences was played
du ing scanne aining o simula e he eal scanne en i onmen and
isual s imula ion was achie ed h ough a mi o sys em a ge ed a a
moni o ou side o he mock scanne bo e.
In o he aspec s, aining sessions di e ed be ween si es. In Bango ,
scanne aining was conduc ed igh be o e scanning and en ailed lying
inside a mock scanne wi h a mo ion sensi i e elec ode placed on he
o ehead o measu e mo emen ac oss h ee ansla ion and h ee
o a ion axes (MoT ak Head Mo ion T acking Sys em; Psychology So -
wa e Tools, 2017). Child en ecei ed isual mo ion eedback ia an on-
sc een cu so ha was con olled by child en’s head mo emen s. Chil-
d en we e ins uc ed o lie s ill and keep he cu so in he middle o a
a ge ci cle, whose diame e allowed o 3 mm head ansla ions in any
di ec ion. Once child en we e able o keep he cu so wi hin his a ge
egion o a imed pe iod o 30 s, child en wa ched a sho anima ed
ideo. When mo emen exceeded 3 mm ansla ion, ideo playback was
paused, p o iding immedia e eedback ha hey had mo ed oo much.
Once child en we e able o wa ch he ideo o a pe iod o 2 min wi hou
a ideo pause, scanne aining was comple ed.
In Bochum, scanne aining was conduc ed be ween one o en days
be o e he MRI s udy o he majo i y o pa icipan s (n ¼48). A mi-
no i y was ained on he same day as he i s scan (n ¼1) o be ween
12 and 35 days be o e he i s scan (n ¼7). T aining began wi h si ing
on he ex ended mock scanne bed, wa ching a sho anima ed ideo
ha in oduced a co e -s o y explaining he asks o be pe o med inside
he scanne , and p ac icing hese asks (bu on-p ess). This was ollowed
by explaining and demons a ing he p ocedu e o en e ing an MRI
scanne wi h a la ge puppe . Nex , child en en e ed he mock scanne
bo e, wa ched a sho anima ed ideo and pe o med se e al p ac ice
ials o he asks p esen ed on a sc een ha was isible ia a mi o
sys em. The esea che s ga e eedback wi h espec o he le el o
mo emen and ask pe o mance h oughou he scanne aining ses-
sion. I was es ablished ha a esea che would gen ly ouch he chil-
d en’s shin in case o excessi e mo ion as a means o mo ion eedback.
Ve bal eedback was g adually dec eased h oughou he session. As
head mo ion du ing he mock scanne session in Bochum was no
quan i ied, eedback was based on he expe imen e ’s obse a ion o
child en’s head mo ion. Once he esea che decided ha mo ion le els
we e accep able and he asks we e unde s ood, scanne aining was
comple ed.
2.5. Da a exclusion
Ou ini ial da ase encompassed all comple ed MRI uns o wo
de elopmen al cogni i e neu oscience s udies conduc ed in Bochum and
one in Bango . Abo ed uns (e.g. due o echnical e o s) we e no
included, as hey we e no e ie ed om he MRI-con olling compu e
and no eliably eco ded in handw i en no es. To ensu e ha ou e-
sul s a e alid and in e p e able, we excluded da a ha would ha e
biased ou analyses (Fig. 1).
In a i s s ep, we excluded en pa icipan s (110 uns) om Bango
ha we e eco ded wi h di e en acquisi ion pa ame e s, i.e. wi h a slice
hickness o 3.5 mm ins ead o 3.0 mm. This di e ence in oxel size
along he z-axis would a ec h ee ou o he six mo ion es ima ion
pa ame e s ( o a ion a ound he y-axis, o a ion a ound he x-axis, and
ansla ion along he z-axis) du ing mo ion co ec ion, leading o sys-
ema ically la ge mo ion es ima es. In a second s ep, we excluded 56
uns ha did no e lec i s - ime MRI expe ience. Fou pa icipan s
had pa icipa ed in bo h Bochum MRI s udies ha a e included in ou
analysis. Pa icipa ion in bo h s udies was sepa a ed by 2–18 mon hs. To
con ol o possible con ounding e ec s o p io scanning expe ience on
mo ion, we excluded all uns o hei second MRI s udy pa icipa ion.
Implemen ing his con ol s ep ensu ed ha we epo on he a he
ypical case—a leas o child en—o a i s - ime MRI s udy pa icipan .
No e ha we could no ule ou he possibili y ha pa icipan s ook pa
in an MRI s udy o a di e en lab be o e, al hough his is highly unlikely
o child en and mos adul s a ou neu oimaging cen e s. In a las s ep,
we excluded 42 es ing-s a e uns. Res ing-s a e uns we e only acqui ed
in one o he h ee s udies, only once pe pa icipan , and in he majo i y
o cases he un was acqui ed a he end o a session. Mo eo e , es ing-
s a e uns we e he only uns in which pa icipan s had hei eyes closed
du ing acquisi ion. This unique se o ci cums ances makes es ing-s a e
uns e y likely o bias ou esul s, as he e is no enough da a o e i-
cien ly model his se o ci cums ances, e.g. as an independen a iable.
2.6. Head mo ion es ima ion
To es ima e head mo ion du ing MRI scans, we used he neu o-
imaging so wa e package B ainVoyage (Ve sion 20.2 o 64bi Win-
dows, RRID: SCR_013057). Fi s , MRI un se ies in DICOM o ma we e
con e ed o he p op ie a y STC and FMR o ma using B ainVoyage
sc ip s. Then, we applied B ainVoyage MRI da a p ep ocessing ools in
hei de aul se ings. Tha is, o slice scan ime co ec ion, we used
cubic spline in e pola ion. Fo 3D mo ion co ec ion, we used a ilinea
de ec ion and sinc in e pola ion app oach wi h a maximum o 100 i -
e a ions o i a olume o he e e ence olume. Resul ing mo ion log
iles con ained six imese ies ep esen ing he es ima ed olume-wise
ins an aneous ansla ion and o a ion o axes x, y, and z in e e ence
o he i s olume o he espec i e expe imen .
Fo each o he six mo ion pa ame e s, we calcula ed a imese ies o
olume- o- olume mo ion, i.e. he di e ence be ween each olume’s
mo ion pa ame e and he p e ious olume’s mo ion pa ame e . Ro a-
ional mo ion was con e ed om deg ee o millime e by calcula ing
displacemen on he su ace o a sphe e o 50 mm adius (app oxima ing
he dis ance om he cen e o he head o he co ex; Powe e al.,
2012). The amewise displacemen o he head posi ion (FD) was
Fig. 1. Da a exclusion s eps and esul ing sample sizes o child en (le , da k
g ay) and adul s ( igh , ligh g ay). Main box wid hs a e in ela ion o he
o iginal o al numbe o uns. Box segmen a ion mi o s he ela i e dis ibu-
ion o adul s. child pa icipan s o uns, espec i ely.
T.W. Meissne e al.
De elopmen al Cogni i e Neu oscience 44 (2020) 100803
4
calcula ed as he sum o he absolu e olume- o- olume mo ion alues
(Powe e al., 2012). FD was shown o ha e a s ong associa ion wi h
mo ion-induced a i ac s (Ci ic e al., 2017). Fo each un, we calcula ed
he mean FD.
Mo eo e , o disc e e one-minu e-in e als (i.e. 30 olumes) wi hin
uns, we calcula ed he pe cen age o high-mo ion olumes wi h FD
abo e he h eshold o 0.3 mm ( olume- o- olume). This h eshold o
high-mo ion olumes was de e mined by ex ensi e explo a ion o ou
da a be o e any s a is ical analysis, and aimed a cap u ing mo ion
“spikes” wi hou impac ing he mo ion “ loo ” olumes as done p e i-
ously (Powe e al., 2019, 2012) and esul ed in plausible a ios o
high-mo ion olumes o child en (M ¼12.80%, SD ¼20.89%) and
adul s (M ¼4.48%, SD ¼12.10%). Fo a isualiza ion o he
high-mo ion olume h eshold, see Fig. 2. No e ha he mo ion “ loo ” is
o en below 0.1 mm FD. Thus, ou h eshold o 0.3 mm allowed o some
mo ion ha is no ca ego ized as a high mo ion “spike” (e.g. Fig. 2,
bo om igh panel) and migh ha e been e en s ic e . The wo head
mo ion measu es—mean FD pe un and equency o high-mo ion
olumes pe minu e o a un—we e in es iga ed in sepa a e analyses.
2.7. P edic o a iables
Ou s udy did no aim o examine age g oup di e ences be ween
child en and adul s, bu o p o ide guidelines o p ac i ione s and e-
sea che s who conduc pedia ic neu oimaging examina ions and/o
expe imen s ha migh also include adul con ol g oups. Thus, we
epo sepa a e analyses o child en and adul s. This app oach enabled
us o include wo mo e p edic o a iables (PVs) o child en, as adul s
did no pe o m scanne aining and we did no expec age e ec s in ou
ange o 1835-yea -old adul s. Fo each age g oup, we assessed wo
head mo ion measu es wi h up o eigh possible p edic o s.
2.7.1. Mean FD
In ou i s analysis, we asked which ac o s would in luence he
mean mo ion du ing a un. Se en PVs we e e alua ed:
�PVs 1–4) P io scan ime encoded he ime in minu es ha a pa ici-
pan had been in he scanne al eady. Tha is, he summed scan ime
o all unc ional as well as s uc u al uns ha had been adminis e ed
1) since he beginning o he unc ional segmen , 2) since he begin-
ning o he session, 3) since he beginning o he day, o 4) since he
beginning o he s udy. Fo de ini ions o session and unc ional
segmen , please e e o Sec ion 2.1, De ini ion o session, un, and
unc ional segmen . No e ha p io scan ime since he beginning o he
day was only analyzed in child en, because while child en we e
scanned on ei he one (n ¼45), wo (n ¼31) o h ee days (n ¼1),
only 2 ou o 54 adul s we e scanned on mul iple (he e: wo) days.
The e o e, ou adul da a did no ha e he equi ed dis ibu ion o
allow any in e ences on b eaking up MRI da a acquisi ion be ween
days in adul s.
Fo example, imagine he complex case o a pa icipan ha comes in
o a second day o MRI scanning (a e 60 min o scanning on he
i s day), akes a ba h oom b eak a e he comple ion o he day’s
i s MRI expe imen (a e 15 min), e-en e s he scanne , com-
ple es he second MRI expe imen (15 min), and is now scheduled
o an inside-scanne b eak, du ing which a di usion-weighed im-
aging sequence is being acqui ed while a ideo clip is p esen ed
(5 min.). The nex MRI un ha is acqui ed would ha e di e en
alues o each o he p io scan ime a iables, e.g. a) p io unc ional
segmen scan ime ¼0 min, b) p io session scan ime ¼20 min, c) p io
day scan ime ¼35 min, and d) p io s udy scan ime ¼95 min.
In gene al, we hypo hesized ha pa icipan s’ mo ion would in-
c ease wi h ime spen in he scanne , bu could be “ ese ” o lowe
mo ion by b eaks. Thus, we es ed he e ec o ou di e en p io
scan ime a iables o de e mine which—i any—way o b eaking up
da a acquisi ion educes subsequen mo ion. Fig. 3 isualizes he
possible main e ec s o p io scan ime a iables. To de e mine he
p io scan ime a iables alues, we e alua ed s uc u ed handw i en
MRI session no es ha s a ed he sequence o acqui ed unc ional and
s uc u al uns and b eaks be ween sessions and days o each
pa icipan . Then, he du a ion o each un was e ie ed om i s
DICOM ile heade . This DICOM heade du a ion always exceeded
he p oduc o epe i ion ime and numbe o olumes, i.e. i included
scanne - and sequence-speci ic p epa a ion ime. We did no include
po en ial b eaks be ween uns ha occu due o no mal ope a ion
ime ha is equi ed o s a a new pa adigm on he s imula ion
compu e o o s a he scanne , how-do-you- eel-inqui ies, o mino
echnical issues, because we did no log hese e en s. Fu he , we did
no include abo ed uns, because we did no sa e his da a no ook
Fig. 2. F amewise displacemen (FD) o he head in mm in h ee example
child en and adul s (g ay w i ing ¼pa icipan IDs). Fo each pa icipan s, one
ep esen a i e un was chosen o show he high-mo ion olume h eshold ( ed
ho izon al dashed line). G ay e ical lines indica e he one-minu e-in e als,
o which he pe cen age o high-mo ion- olumes was calcula ed. (Fo in e -
p e a ion o he e e ences o colou in his igu e legend, he eade is e e ed
o he web e sion o his a icle.)
Fig. 3. Visualiza ion o he e ec o p io scan ime wi h hypo he ical da a.
Each ow shows he e ec o a di e en kind o p io scan ime. Each column
shows a single session, consis ing o ou MRI uns. The do ed e ical line and
poin s on he e ical line deno e inside scanne b eaks du ing which s uc u al
scans we e acqui ed and ideo clips we e p esen ed.
T.W. Meissne e al.
De elopmen al Cogni i e Neu oscience 44 (2020) 100803
5
eliable no es, ende ing a de e mina ion o he du a ion o hese
scans impossible.
�PV 5) Age was de ined in yea s a he i s day o scanning and was
only in es iga ed o child en. This a iable was included o explo e
possible in e ac ions wi h he o he PVs, no o main e ec s o age,
as main e ec s o age a e well es ablished in he ield and would only
lead o an unnecessa ily complex model wi h less powe o de ec
e ec s o in e es .
�PV 6) Scanne aining da e was eco ded as he numbe o days ha
passed since he scanne aining o child en only. We hypo hesized
ha a g ea e ime in e al be ween scanne aining and ac ual MRI
scan would esul in highe mo ion.
�PV 7) Task engagemen encoded how much ac i e engagemen a gi en
MRI un equi ed. We dis inguished i pa icipan s jus had o
passi ely wa ch he display, o i pa icipan s had o pe o m a ask
ha included bu on-p essing. We expec ed ha an ac i e ask
engagemen would esul in educed mo ion due o enhanced
a en ion and less awa eness o a possibly uncom o able si ua ion,
i ching, o o he dis ac ions.
In addi ion o hese main e ec s, we in es iga ed he possible in-
e ac ions be ween he p io scan ime a iables and he o he a iables.
O he wo-way o h ee-way in e ac ions we e no in es iga ed o a oid
o e ly complex and highly compu a ion-in ensi e models and as he
de ec ion o high-o de e ec s would equi e a mo e powe ul s udy
design (Simonsohn, 2014).
2.7.2. High-mo ion olumes
In ou second analysis we asked which a iables would in luence
head mo ion o e he cou se o a un. As decisions on e aining o dis-
ca ding uns o u he analysis a e o en in o med by high-mo ion
olumes wi hin a un a he han a un’s mean mo ion, ins ead o
mean FD, we in es iga ed he pe cen age o high-mo ion olumes o
each minu e o a un (i.e. FD
olume
>0.3 mm; see 2.6, Head mo ion
es ima ion). Consequen ly, eigh PVs we e e alua ed:
�PVs 1–7) All p e ious PVs, i.e. p io unc ional segmen scan ime, p io
session scan ime, p io day scan ime, p io s udy scan ime, age, scanne
aining da e, ask engagemen
�PV 8) Minu e o un coded disc e e one-minu e-in e als wi hin uns,
allowing us o in es iga e he cou se o high- olume mo ion occu -
ence ac oss he cou se o a un.
In addi ion o main e ec s, we in es iga ed he possible in e ac ions
be ween minu e o un and he o he a iables. Again, we did no
in es iga e o he wo- o h ee-way in e ac ions (see 2.7.1, Mean FD)
2.8. S a is ical model
2.8.1. Hie a chical da a s uc u e
We analyzed ou da a using mul ile el linea models (MLMs) due o
he hie a chical ou - o i e-le el g ouping s uc u e inhe en in ou
da a (c . Engelha d e al., 2017; Fig. 4): Mo ion es ima ions o mean FD
pe un a e nes ed wi hin sessions (le el 4), sessions a e nes ed wi hin
days (le el 3), days a e nes ed wi hin pa icipan s (le el 2), and pa -
icipan s a e nes ed wi hin s udies (le el 1). Mo ion es ima ions o
pe cen age o high-mo ion olumes pe minu e o a un a e nes ed
wi hin uns, es ablishing a i h le el. This hie a chical da a s uc u e is
likely o in oduce dependency o obse a ions wi hin a g ouping a i-
able. Fo example, mo ion om wo andomly selec ed uns om he
same pa icipan is likely o be much mo e simila han mo ion om
di e en pa icipan s. In echnical e ms, he esiduals wi hin a g ouping
a iable a e likely o be co ela ed. Thus, he assump ion o independen
esiduals, c ucial o pa ame ic es s, is iola ed. While dependen ob-
se a ions o one le el, e.g. wi hin pa icipan s, could be handled easily
by a con en ional epea ed-measu es ANOVA, his case is a complex
nes ed mul ile el dependency s uc u e ha canno be adequa ely and
alidly handled by a epea ed-measu es ANOVA—bu can be by an
MLM.
2.8.2. MLM c ea ion s ep 1: iden i ying ele an g ouping s uc u es
MLMs we e c ea ed in a da a-d i en p ocess. Fi s , we assessed he
possibili y ha he g ouping a iables would in oduce dependencies in
he da a—and hus con i m he need o an MLM. To his end, we
calcula ed he in aclass co ela ion (ICC, i.e. he p opo ion o he o al
a iance ha is explained by he espec i e g ouping ac o ) o each
g ouping le el o he model and libe ally inco po a ed all g ouping
le els in o ou model ha would explain a leas 1% o he o al a iance
(i.e. ICC �0.01, Supplemen a y Tex S2). Nex , we used he chi-squa e
likelihood a io es and Akaike’s in o ma ion c i e ion (AIC) o es i
he model ha inco po a ed he g ouping s uc u e ac ually had a be e
i o ou da a han he model wi hou he g ouping s uc u e and
included o igno ed he g ouping s uc u e in all subsequen models
acco dingly (Supplemen a y Tex S3).
ICC analysis o mean FD o e he cou se o a s udy indica ed ha in
bo h child en and adul s, he g ouping ac o s pa icipan (child en:
0.487, adul s: 0.376) and session (child en: 0.229, adul s: 0.021)
explained a subs an ial amoun o a iance in he da a, while he
g ouping ac o s s udy and day did no (bo h age g oups <0.001). In bo h
child en and adul s, models ha allowed andom in e cep s o pa ici-
pan and session i he da a signi ican ly be e han a model wi h ixed
in e cep s (child en: Supplemen a y Table S4, adul s: Supplemen a y
Table S5). Thus, he MLMs we e buil wi h andom in e cep s o
pa icipan and session.
ICCs o he pe cen age o high-mo ion olumes ac oss he cou se o
a un in bo h child en and adul s e ealed subs an ial dependency
wi hin he g ouping le els pa icipan (child en: 0.136, adul s: 0.292),
session (child en: 0.275, adul s: 0.037), and un (child en: 0.143, adul s:
0.309), bu no wi hin he g ouping le els s udy (bo h age g oups:
<0.001) and day (child en: <0.001, adul s: 0.004). A andom in e cep
model o pa icipan , session, and un i ou da a be e ha a ixed
in e cep model (child en: Supplemen a y Table S6, adul s: Supple-
men a y Table S7). Consequen ially, he MLMs we e buil wi h andom
in e cep s o pa icipan , session and un.
2.8.3. MLM c ea ion s ep 2: s epwise inclusion o ele an p edic o s
Second, we in oduced he PVs, i.e. main e ec s and selec ed in-
e ac ions ( ixed e ec s), in o he model s epwise, o es i hey
imp o ed he model i signi ican ly. The o de o in oduc ion o mean
FD and high-mo ion olumes MLMs is lis ed in Supplemen a y Tables S2
and S3, espec i ely. I a model including a ixed p edic o led o a be e
model i han he p e ious model wi hou i , he p edic o was included
Fig. 4. Hie a chical da a s uc u e wi h ou le els. Fo isualiza ion pu poses,
only one ic ional subjec is displayed o each s udy.
T.W. Meissne e al.

De elopmen al Cogni i e Neu oscience 44 (2020) 100803
6
in all subsequen models, o he wise i was le ou o subsequen models.
Fo child en’s mean FD MLM main e ec s o p io unc ional segmen
ime, p io session ime, p io day ime, and scanne aining da e, as well as
he in e ac ion e ec s o age �p io session ime and age �p io s udy ime
we e included in he model (Supplemen a y Table S4). Fo child en’s
high-mo ion olumes MLM, main e ec s o minu e o un, p io segmen
ime, p io session ime, p io day ime, and scanne aining da e we e
added o he model (Supplemen a y Table S6). Fo adul ’s mean FD
MLM, main e ec s o p io unc ional segmen ime, p io s udy ime, and a
p io unc ional segmen ime � ask engagemen in e ac ion we e added o
he model (Supplemen a y Table S5). Fo adul ’s high-mo ion olumes
MLM main e ec s o minu e o un, p io segmen ime, and p io session
ime, we e added o he model (Supplemen a y Table S7).
2.8.4. MLM c ea ion s ep 3: assessing he need o pa icipan -speci ic
p edic o e ec s
Thi d, we es ed i he model i imp o ed u he i we le he e ec
o each included main e ec p edic o a y o e pa icipan s ( andom
slopes) and added signi ican andom e ec s o he model acco dingly.
P edic o s scanne aining da e and age we e no conside ed as hey a e
cons an o each pa icipan ’s un. Fu he , we did no i andom slopes
o in e ac ion e ms as his p e en ed he MLMs o con e ge—possibly
because ou da a did no ha e enough powe o i a model o such high
le el o complexi y.
Adding andom slopes ac oss pa icipan s o all main e ec s u he
imp o ed model i in all MLMs and hus was inco po a ed in he inal
models (Supplemen a y Tables S4–S7).
2.9. So wa e
Da a handling and s a is ical da a analysis was pe o med using R
( e sion 3.6.0, RRID: SCR_001905, R Co e Team, 2019) in RS udio
( e sion 1.2.1335; RRID: SCR_000432). Fo MLMs, we used he nlme
package ( e sion 3.1–140, RRID:SCR_015655, Pinhei o e al., 2019).
Figu es we e c ea ed using he ggplo 2 package ( e sion 3.2.0, RRID:
SCR_014601, Wickham, 2016). Reg ession lines and con idence in e al
bands o ixed e ec s isualiza ions, i.e. p edic o e ec plo s, we e
c ea ed using he e ec s package ( e sion 4.1-1, Fox and Weisbe g,
2018). Ma ginal R
2
( o ixed e ec s) and condi ional R
2
( o ixed e -
ec s and andom e ec s combined) goodness-o - i was es ima ed using
he .squa edGLMM unc ion o he MuMIn package ( e sion 1.43.6,
Ba on, 2019), which is based on me hods by Nakagawa and Schielze h
(2013), Johnson (2014), and Nakagawa e al. (2017).
3. Resul s
We e alua ed which a iables would p edic head mo ion du ing
MRI in child en and adul s. We assessed wo measu es o head mo ion
in sepa a e analyses: Fi s , we in es iga ed he cou se o head mo ion
ac oss an MRI s udy in e ms o mean amewise displacemen pe un.
Then, we in es iga ed he cou se o head mo ion o e he cou se o a un
in e ms o he equency o high-mo ion olumes pe minu e. Each
analysis was pe o med sepa a ely o child en and adul s. Reg ession
coe icien s o all main and in e ac ion e ec s included in he MLMs
we e es ed agains ze o using one-sample - es s wi h a signi icance
h eshold o
α
¼0.05.
3.1. Spli ing up da a acquisi ion educes mo ion
3.1.1. Child en
E alua ion o ixed e ec s p edic o s in he inal mean FD MLM
e ealed ha p io session scan ime and a p io s udy scan ime �age
in e ac ion signi ican ly p edic ed FD in child en (Fig. 5, Table 1).
Child en showed g ea e mo ion wi h ongoing session leng h (Fig. 5,
le ). No e ha he o al numbe o sessions in child en anged om 1 o
4 (16 child en did only one session, 55 child en did wo sessions, ou
child en did h ee sessions, and wo child en did ou sessions). In
addi ion, mo ion inc eased wi h s udy leng h in olde child en, bu no
as much in younge child en (Fig. 5, igh ). As ou da a in child en shows
one ob ious ou lie , a pa icipan whose mean FD is a ound 2 mm o all
o he /his i e uns, we es ed i his case would in luence he obse ed
e ec s. Howe e , a eanalysis wi hou his pa icipan only sligh ly
inc eased he e ec o p io session scan ime and did no change he age
�p io s udy scan ime in e ac ion no ably. Thus, he e, we epo he ull
da a se .
3.1.2. Adul s
Fo adul s, e alua ion o ixed e ec s p edic o s in he inal model
e ealed ha p io unc ional segmen scan ime and p io s udy scan ime
signi ican ly p edic ed mo ion (Fig. 6, Table 2). Adul s’ mo ion
inc eased wi h ongoing s udy scan ime (no e ha in 52/54 adul s s udy
scan ime is equal o day scan ime). Mo eo e , he longe unc ional scans
a e acqui ed wi hou an inside-scanne b eak (e.g. h ough a s uc u al
scan wi h elaxing ideo), he mo e adul s mo ed. O iginally, we also
ound ha a ask engagemen �p io unc ional segmen scan ime in e -
ac ion signi ican ly p edic ed mo ion, i.e. o passi e asks, adul s
showed a s eepe inc ease in mo ion han o ac i e asks (Fig. 6, middle,
hick black dashed line). Howe e , as i seemed possible ha his ask
engagemen �p io unc ional segmen scan ime in e ac ion was d i en by
an ex eme inc ease in mo ion a he end o a unc ional segmen in
Fig. 5. P edic o e ec plo s o chil-
d en’s head mo ion ac oss he cou se o
a s udy.Thick magen a lines a e i ed
linea eg ession lines o he ixed e -
ec s p edic o s deno ed on he x-axes.
Shaded magen a a eas show he 95%
con idence band o he eg ession lines.
Each g ay ci cle ep esen s one un. Le :
Head mo ion ac oss he cou se o a ses-
sion. Each ci cle-connec ing line ep e-
sen s a pa icipan ‘s session. Pa icipan s
ha we e scanned in mul iple sessions
a e ep esen ed by mul iple lines. Righ :
Head mo ion ac oss he cou se o a s udy
o 6-9-yea -old and 10-13-yea old
child en. Age bins we e chosen a bi-
a ily o isualize he age �p io s udy
scan ime in e ac ion. Each ci cle-
connec ing line ep esen s one
pa icipan .
T.W. Meissne e al.
De elopmen al Cogni i e Neu oscience 44 (2020) 100803
7
passi e asks in a single pa icipan only (Fig. 6, hin black dashed lines
and squa es), we eanalyzed he MLM wi hou da a om his pa ici-
pan . While all o he e ec s emained s able (Fig. 6, see o e lapping
g een solid and black dashed lines), he ask engagemen �p io unc-
ional segmen scan ime in e ac ion was ende ed insigni ican by he
exclusion o he pa icipan (Fig. 6, see black dashed line ou side o
g een con idence band, Supplemen a y Table S8).
3.1.3. Summa y
Ou esul s demons a e ha head mo ion in child en and adul s can
be educed by spli ing up da a acquisi ion. Howe e , depending on he
age g oup, di e en s a egies seem o be e ec i e. Fo child en, ou
da a sugges s a bene i o spli ing up da a acquisi ion in o mul iple,
sho sessions on he same day and keeping he o e all s udy leng h as
sho as possible. In con as , adul s bene i ed om in e spe sing
expe imen al uns wi h inside-scanne b eaks.
3.2. High-mo ion e en occu ence inc eases wi h un leng h
3.2.1. Child en
Minu e o un signi ican ly p edic ed mo ion in child en, i.e. chil-
d en’s mo ion inc eased wi h inc easing un leng h (Fig. 7, Table 3). Fo
example, in he hi d minu e o a un, he a e age isk o a high-mo ion
olume was a 16.5%, while i inc eased o 18.3% in he six h minu e o
a un. P io day scan ime was also a signi ican p edic o o mo ion.
Howe e , each alue o his un-wise p edic o a ec s each minu e o a
un equally and he e o e does no con ibu e o explaining how mo ion
de elops o e he cou se o a un. Fo example, minu e o un 1, 2, and 3
always ha e he same alues o p io day ime. Thus, as he un-wise p io
day scan ime did no in e ac wi h minu e o un, i s e ec is no o in-
e es in his analysis.
3.2.2. Adul s
Minu e o un signi ican ly p edic ed mo ion in adul s, i.e. adul ’s
Table 1
Fixed e ec s pa ame e es ima es o inal model o child en’s mean mo ion ac oss he cou se o a s udy.
pa ame e β Lowe 95% CI Uppe 95% CI SE d p
In e cep 0.04895 0.01800 0.07990 0.01584 509 3.090 0.002
P io unc ional segmen scan ime 0.00147 0.00170 0.00464 0.00162 509 0.904 0.366
P io session scan ime 0.01564 0.00307 0.02821 0.00644 509 2.430 0.015
P io day scan ime 0.00212 0.00043 0.00467 0.00130 509 1.627 0.104
Scanne aining da e 0.00560 0.01790 0.02909 0.01203 509 0.465 0.642
Age �p io session scan ime 0.00121 0.00245 0.00003 0.00063 509 1.905 0.057
Age �p io s udy scan ime 0.00016 0.00005 0.00028 0.00006 509 2.721 0.007
No e: CI ¼con idence in e al, SE ¼s anda d e o , d ¼deg ees o eedom.
Fig. 6. P edic o e ec plo s o adul ’s
head mo ion ac oss he cou se o a
s udy. Thick g een lines a e i ed linea
eg ession lines o he ixed e ec s
p edic o s deno ed on he x-axes.
Shaded g een a eas show he 95% con-
idence band o he eg ession lines.
Each g ay ci cle ep esen s one un. Le :
Head mo ion ac oss he cou se o a
s udy. Each ci cle-connec ing line ep-
esen s a pa icipan ‘s s udy. Righ :
Head mo ion ac oss he cou se o a
unc ional segmen o passi e and
ac i e MRI asks. Each ci cle-
connec ing line ep esen s one pa ici-
pan ’s unc ional segmen da a acquisi-
ion cou se. Pa icipan s ha we e
scanned on mul iple days, on mul iple
sessions, o wi h mul iple unc ional
segmen s a e ep esen ed by mul iple
lines. Black dashed lines and squa es
show he pa icipan ha d o e he ask
engagemen �p io unc ional segmen
ime in e ac ion. (Fo in e p e a ion o
he e e ences o colou in his igu e
legend, he eade is e e ed o he web
e sion o his a icle.)
Table 2
Fixed e ec s pa ame e es ima es o inal model o adul ’s mean mo ion ac oss he cou se o a s udy.
pa ame e β Lowe 95% CI Uppe 95% CI SE d p
In e cep 0.05030 0.03328 0.06732 0.00869 377 5.787 <.001
P io unc ional segmen scan ime 0.00250 0.00098 0.00401 0.00077 377 3.230 0.001
P io s udy scan ime 0.00087 0.00030 0.00144 0.00029 377 2.990 0.003
Task engagemen �P io unc ional segmen scan ime 0.00185 0.00058 0.00428 0.00124 377 1.491 0.137
No e: CI ¼con idence in e al, SE ¼s anda d e o , d ¼deg ees o eedom.
T.W. Meissne e al.
De elopmen al Cogni i e Neu oscience 44 (2020) 100803
8
mo ion inc eased wi h inc easing un leng h (Fig. 8, Table 4). Fo
example, in he hi d minu e o a un, he a e age isk o a high-mo ion
olume was a 5.3%, while i inc eased o 6.5% in he six h minu e o a
un. P io unc ional segmen scan ime and p io session scan ime we e
also signi ican p edic o s o mo ion. Howe e , as in child en, hese un-
wise p edic o s did no con ibu e o explaining how mo ion de elops
o e he cou se o a un as hey did no in e ac wi h minu e o un and
hus a e no o in e es in his analysis.
3.2.3. Summa y
Ou esul s indica e ha long uns ha e a nega i e impac on da a
quali y: The equency o high-mo ion e en s inc eases wi h ongoing un
leng h o bo h child en and adul s.
3.3. Con ol analysis: Age—bu no mo ion—in luenced he da a
acquisi ion p ocedu e in child en
Da a acquisi ion in e ms o which ask was acqui ed when, he po-
si ions o s uc u al scans, i.e. inside-scanne b eaks, and he numbe o
o al uns was la gely p ede e mined o each s udy and pa icipan .
Howe e , we adap ed ou planning o he equi emen s o he gi en
pa icipan —mainly o child en and only seldomly o adul s. Speci -
ically, pa icipan s we e able o e mina e he s udy, day o session a
any momen . Mos o he ime, e mina ion o a session was done a e
ac i e inqui ing abou he well-being by he esea che s. He e, chil-
d en’s age migh ha e in luenced esea che s’ sensi i i y owa ds well-
being epo s and esea che s’ decision o e mina e. C ucially, subjec-
i e well-being (o bo edom) migh be associa ed wi h mo ion in he
scanne . Thus, i espec i e o epo ed well-being o he child, obse ed
mo ion by he esea che s ( isible om he con ol oom in Bango and
om s anding nex o he scanne bo e in Bochum) migh ha e
in luenced he decision o e mina e he s udy, day, session, o unc-
ional segmen ea ly.
To in es iga e he possible e ec o age and mo ion on he p ocedu e,
we an sepa a e mul iple eg ession analyses o he o al s udy leng h as
well as he o al numbe o acqui ed uns, sessions, and days using
pa icipan s’ age and hei mean pe cen age o high-mo ion- olumes as
p edic o s. We chose he la e p edic o o e mean FD because only
high-mo ion e en s would be isible o he esea che and ac as a
possible indica o o change he p ede ined s udy p o ocol.
The numbe o comple ed uns, sessions, o days was nei he
signi ican ly p edic ed by age, no by high-mo ion olumes (all ps o
age >.0664; all ps o high-mo ion olumes >.1676). Howe e ,
age—bu no he mean pe cen age o high-mo ion olumes—was a
signi ican p edic o o o al s udy leng h (age: β (SE) ¼2.91 (1.29),
¼2.26, p ¼.027; high-mo ion olumes: β (SE) ¼  0.17 (0.16),
¼  1.10, p ¼.275). Thus, i is unlikely ha obse able mo ion du ing
MRI scans was ac o ed in o he decision o de ia e om ou p ede ined
s udy p o ocol, while young age migh ha e been a ac o .
4. Discussion
We iden i ied ac o s ha p edic pa icipan ’s head mo ion in h ee
neu ode elopmen al MRI s udies including da a o 77 child en and 64
adul s. Using MLMs, we in es iga ed he e ec o scanne aining da e,
ask engagemen , as well as p io scan ime since he beginning o he
s udy, day, session, o unc ional segmen . In child en, spli ing MRI da a
acquisi ion in o mul iple sessions educed mo ion. Howe e , mo ion s ill
inc eased ac oss he cou se o a s udy, especially in olde child en. In
adul s, mo ion was educed a e ask- ee inside-scanne b eaks bu —as
Fig. 7. Child en’s head mo ion ac oss he cou se o a un. Each g ay ci cle
ep esen s one minu e bin. Each ci cle-connec ing line ep esen s a pa icipan ‘s
un. Pa icipan s ha we e scanned o mo e han one unc ional un a e ep-
esen ed by mul iple lines. Thick magen a line shows he i ed linea eg ession
line o he minu e o un e ec . Shaded magen a a ea show he 95% con idence
band o he eg ession line.
Table 3
Fixed e ec s pa ame e es ima es o inal model o child en’s equency o mo ion peaks ac oss he cou se o a un.
pa ame e β Lowe 95% CI Uppe 95% CI SE d p
In e cep 1.12857 2.87326 5.13041 2.04301 2290 0.552 0.581
Minu e o un 0.60187 0.15491 1.04884 0.22818 2290 2.638 0.008
P io unc ional segmen scan ime 0.22521 0.01436 0.46478 0.12231 2290 1.841 0.066
P io session scan ime 0.08717 0.18705 0.36138 0.13999 2290 0.623 0.534
P io day scan ime 0.41294 0.22250 0.60339 0.09722 2290 4.247 <.001
Scanne aining da e 0.81829 0.71812 2.35470 0.78436 2290 1.043 0.297
No e: CI ¼con idence in e al, SE ¼s anda d e o , d ¼deg ees o eedom.
Fig. 8. Adul ’s head mo ion ac oss he cou se o a un. Each g ay ci cle ep-
esen s a one minu e bin. Each ci cle-connec ing line ep esen s a pa icipan ‘s
un. Pa icipan s ha we e scanned o mo e han one unc ional un a e ep-
esen ed by mul iple lines. Thick g een line shows he i ed linea eg ession
line o he minu e o un e ec . Shaded g een a ea show he 95% con idence
band o he eg ession line. (Fo in e p e a ion o he e e ences o colou in
his igu e legend, he eade is e e ed o he web e sion o his a icle.)
T.W. Meissne e al.
De elopmen al Cogni i e Neu oscience 44 (2020) 100803
9
in child en—mo ion s ill inc eased ac oss he cou se o a s udy. In bo h
child en and adul s, mo ion inc eased wi h un leng h.
4.1. Spli ing up da a acquisi ion educes mo ion
4.1.1. Child en
Child en’s head mo ion seems o inc ease ac oss he cou se o a
s udy, as p io s udy scan ime p edic ed head mo ion, especially o olde
child en. A he same ime, we did no ind ha p io day scan ime
p edic ed head mo ion, sugges ing ha child en do no seem o bene i
om spli ing up s udies in o se e al days. Al e na i ely, a possible e -
ec o spli ing up s udies in o se e al days was oo small o be de ec ed
wi h he powe o ou s udy. To specula e on possible explana ions, o
child en, he ini ial exci emen o pa icipa ing in an MRI s udy and he
commi men o do e e y hing igh migh be less p onounced a e he
i s day. On he second day, hey migh be less mo i a ed o lie s ill, e.g.
due o he lacking no el y o he si ua ion (simila isual appea ance o
ask demands).
Olde child en showed a la ge inc ease in mo ion wi h inc easing
s udy leng h. Ini ially, his seems unexpec ed. In ui ion would sugges
ha olde child en a e be e a lying s ill o ex ended pe iods o ime.
Howe e , i seems ha his age �p io s udy scan ime in e ac ion could
be d i en by a highe baseline mo ion o young child en a he beginning
o he s udy, which hen does no change as much o e ime. In con as ,
olde child en seem o be able o supp ess he u ge o mo e a he
beginning o a s udy qui e well, and hen g adually elax in o mo ion
le els simila o ha o younge child en. Thus, we cau ion agains
o e in e p e ing his in e ac ion as a cause o plan sho e s udies jus
because olde child en a e scanned, as p edic ed mo ion alues a
maximum s udy leng h we e compa able and ew s udies will plan
s udies wi h mo e han 80 min o pu e scan ime.
Ou esul s indica e ha pedia ic neu oimaging s udies may bene i
om b eaking up da a acquisi ion in o se e al sessions on he same day,
as child en’s head mo ion inc eases wi h ongoing session leng h. So a ,
no o he s udies ha e in es iga ed mo ion ac oss mul iple sessions on
he same day. Ne e heless, single-session s udies in child en ha e ound
ha mo ion inc eases wi h inc easing session leng h in child en (Ach-
e be g and an de Meulen, 2019; Engelha d e al., 2017). Ou s udy
poin s o an impo an dis inc ion ega ding he kind o b eaks ha e-
sea che s can schedule in child en’s MRI scanning p o ocols. While
mo ion can be e ec i ely educed by allowing child en o exi he
scanne , inside-scanne b eaks in MRI da a acquisi ion du ing which
child en canno exi he scanne , bu ins ead wa ch a ideo while a
s uc u al scan is acqui ed, do no seem o educe mo ion a e he b eak.
Possibly, i is impo an o child en o be able o mo e eely, ge
ace- o- ace social in e ac ions, o jus elie e he desi e o oid hei
bladde —none o which a e possible wi hou exi ing he scanne .
Al e na i ely, showing a ideo migh ha e e ec s opposi e o hose
desi ed: Because he ideo is highly engaging, i may lead o educed
mo ion du ing he b eak (Can lon and Li, 2013; Vande wal e al., 2015),
bu any subsequen no mal MRI ask migh be pe cei ed as bo ing due
o a con as e ec , leading o highe mo ion in u n.
In ou expe ience, implemen ing ou side-scanne b eaks (i.e. spli -
ing da a acquisi ion in o mul iple sessions) is e y easible. In ou h ee
s udies, b eaks we e designed o las 5 min ou side o he scanne and we
did no expe ience any p oblems wi h upholding his ime limi . I a
co e s o y o child en is used, he b eak can be inco po a ed in ha
s o y (e.g. in a space jou ney heme he e migh be limi ed ime o a
space walk, main enance, plane isi , e c.). Ou 5-minu e b eaks usually
p olonged he o al s udy by 15 min due o ge ing pa icipan s ou o
and back inside he scanne , and unning ano he su ey scan. In
con as o longe b eaks, such as 20 min o 2 h, hese sho b eaks limi
he addi ional scanne cos s and a oid bo h un easible s udy da e a -
angemen s wi h pa icipan s and pa en s as well as complica ed scan-
ne ese a ion a angemen s. Thus, o s udies wi h mo e han 30 min
o o al aw scan ime, implemen ing a spli in o wo sessions seems o be
a easible and e ec i e way o educing mo ion in child en. Ano he
app oach is o schedule wo o mo e child en back o back, who hen
ake u ns in being in he scanne and aking b eaks. I should be no ed
hough ha his app oach migh equi e addi ional s a o supe ise
child en du ing scanning and b eaks in pa allel.
In ou s udy, we did no ind an e ec o ask engagemen on head
mo ion in child en. This con adic s p e ious indings, which showed
ha child en show less mo ion in engaging asks in con as o less
engaging asks o es ing s a e (Engelha d e al., 2017). This dispa i y
migh be due o di e en de ini ions and aims o he s udies. In ou
analysis, we de ined asks as engaging i pa icipan s had o pe o m a
ask ha included bu on-p essing, and we de ined asks as
non-engaging i pa icipan s jus had o passi ely wa ch he display. We
chose his de ini ion as ou aim was o iden i y aspec s in MRI s udy
designs ha can be ac i ely manipula ed by he esea che . Engelha d
e al. (2017) de ined engaging asks as as -paced, cogni i ely
demanding, o socially engaging. These aspec s a e o en inhe en in a
ask and canno be changed wi hou changing he esea ch ques ion. Fo
example, expe imen s on social de elopmen in child en will need o
ha e a socially engaging componen . Howe e , while esea che s can
decide i a gi en ask will equi e a manual esponse o no , his choice
alone does no seem o a ec head mo ion. Possibly, mo ion- educing
e ec s due o engaging asks ha equi e bu on-p essing o high
a en ion a e also cancelled ou by mo ion-inc easing e ec s due o
exci emen o bu on-p ess- ela ed mo ion.
The ime be ween scanne aining and he ac ual scan does no seem
o be a majo in luence on child en’s head mo ion du ing MRI scans.
Al hough scanne aining iming imp o ed (and hus was added o) he
MLM, i did no eme ge as a signi ican p edic o in he inal model. This
assump ion i s wi h he obse ed in aclass co ela ion o he g ouping
ac o s udy. As all child en in s udy C we e ained on he same day as
he ac ual MRI scan bu all child en (excep o one) in s udy A and B
we e ained be ween 1 and 28 (mean ¼4.30) days be o e he ac ual
MRI scans, a high in aclass co ela ion o he g ouping ac o s udy
would ha e indica ed di e ences be ween s udies (and hus si es) such
as he scanne aining p ocedu e o he scanne aining da e. Howe e ,
we obse ed an ex emely low in e class co ela ion o he g ouping
ac o s udy. Thus, planning scanne aining as close o he ac ual scan
as possible o s ong ecency e ec s, o planning scanne aining some
days be o e he ac ual scan o le i “sink in” seem o be equally e ec i e
(bu also see 4.4, Fu u e di ec ions).
4.1.2. Adul s
Fo adul s, we ound ha head mo ion seems o inc ease ac oss he
cou se o a s udy, as p io s udy scan ime p edic ed head mo ion. While
his esul seems o mi o ou indings in child en, no e ha all bu wo
Table 4
Fixed e ec s pa ame e es ima es o inal model o adul ’s equency o mo ion peaks ac oss he cou se o a un.
pa ame e β Lowe 95% CI Uppe 95% CI SE d p
In e cep 0.80019 1.46836 3.06874 1.15779 1642 0.691 0.490
Minu e o un 0.42562 0.10116 0.75008 0.16559 1642 2.570 0.010
P io unc ional segmen scan ime 0.18341 0.00516 0.36165 0.09097 1642 2.016 0.044
P io session scan ime 0.11631 0.04504 0.18757 0.03637 1642 3.198 0.001
No e: CI ¼con idence in e al, SE ¼s anda d e o , d ¼deg ees o eedom.
T.W. Meissne e al.