Psychological Medicine
camb idge.o g/psm
Re iew A icle
Ci e his a icle: Fe nández-Al a ez J, G assi
M, Colombo D, Bo ella C, Cip esso P, Pe na G,
Ri a G (2021). E icacy o bio- and
neu o eedback o dep ession: a me a-
analysis. Psychological Medicine 1–16. h ps://
doi.o g/10.1017/S0033291721004396
Recei ed: 29 No embe 2019
Re ised: 29 Sep embe 2021
Accep ed: 7 Oc obe 2021
Keywo ds:
Dep ession; bio eedback; neu o eedback;
hea a e a iabili y; hea a e a iabili y
bio eedback; MRI neu o eedback;
me a-analysis
Au ho o co espondence:
J. Fe nández-Al a ez,
E-mail: ja e [email p o ec ed]
© The Au ho (s), 2021. Published by
Camb idge Uni e si y P ess. This is an Open
Access a icle, dis ibu ed unde he e ms o
he C ea i e Commons A ibu ion licence
(h p://c ea i ecommons.o g/licenses/by/4.0/),
which pe mi s un es ic ed e-use, dis ibu ion
and ep oduc ion, p o ided he o iginal a icle
is p ope ly ci ed.
E icacy o bio- and neu o eedback o
dep ession: a me a-analysis
J. Fe nández-Al a ez1,2, M. G assi3,4, D. Colombo2, C. Bo ella5, P. Cip esso6,7,
G. Pe na3,4,8,9 and G. Ri a1,6
1
Depa men o Psychology, Ca holic Uni e si y o he Sac ed Hea , Milan, I aly;
2
Depa men o Basic Psychology,
Clinic and Psychobiology, Uni e si a Jaume I, Cas ellón, Spain;
3
Depa men o Clinical Neu osciences, He manas
Hospi ala ias, Villa San Benede o Menni Hospi al, FoRiPsi, Albese con Cassano, Como, I aly;
4
Depa men o
Biomedical Sciences, Humani as Uni e si y, Rozzano, Milan, I aly;
5
Cibe Fisiopa ología Obesidad y Nu ición,
CB06/03 Ins i u o Salud Ca los III, Mad id, Spain;
6
Applied Technology o Neu o-Psychology Lab, IRCCS Is i u o
Auxologico I aliano, Milan, I aly;
7
Depa men o Psychology, Uni e si y o Tu in, Tu in, I aly;
8
Depa men o
Psychia y and Beha io al Sciences, Mille School o Medicine, Uni e si y o Miami, Miami, FL, USA and
9
Resea ch
Ins i u e o Men al Heal h and Neu oscience and Depa men o Psychia y and Neu opsychology, Facul y o
Heal h, Medicine and Li e Sciences, Uni e si y o Maas ich , Maas ich , he Ne he lands
Abs ac
Backg ound. Fo many yea s, bio eedback and neu o eedback ha e been implemen ed in he
ea men o dep ession. Howe e , he e ec i eness o hese echniques on dep essi e symp-
oma ology is s ill con o e sial. Hence, we conduc ed a me a-analysis o s udies ex ac ed
om PubMed, Scopus, Web o Science and Embase.
Me hods. Two di e en s ings we e conside ed o each o he wo objec i es o he s udy:
A i s g oup comp ising s udies pa ien s wi h majo dep essi e diso de (MDD) and a second
g oup including s udies a ge ing dep essi e symp oma ology educ ion in o he men al o
medical condi ions.
Resul s. In he i s g oup o s udies including pa ien s wi h MDD, he wi hin-g oup analyses
yielded an e ec size o Hedges’g=0.717, while he be ween-g oup analysis an e ec size o
Hedges’g=1.050. Mode a o analyses indica e ha ea men e icacy is only signi ican when
accoun ing o expe imen al design, in a o o andomized con olled ials (RCTs) in com-
pa ison o non RCTs, whe eas he ype o neu o eedback, ial design, yea o publica ion,
numbe o sessions, age, sex and quali y o s udy did no in luence ea men e icacy. In
he second g oup o s udies, a small bu signi ican e ec be ween g oups was ound
(Hedges’g= 0.303) in a o o bio- and neu o eedback agains con ol g oups. Mode a o ana-
lyses e ealed ha ea men e icacy was no mode a ed by any o he sociodemog aphic and
clinical a iables.
Conclusions. Hea a e a iabili y (HRV) bio eedback and neu o eedback a e associa ed wi h
a educ ion in sel - epo ed dep ession. Despi e he ac ha he ield has s ill a la ge oom o
imp o emen in e ms o esea ch quali y, he esul s p esen ed in his s udy sugges s ha bo h
modali ies may become ele an complemen a y s a egies o he ea men o MDD and
dep essi e symp oma ology in he coming yea s.
Majo dep essi e diso de (MDD) ep esen s a wo ldwide leading cause o disabili y, wi h
mo e han 300 million people a ec ed (WHO, 2017). No only does i en ail a majo impac
on people’s quali y o li e and social unc ioning (Ange meye , Holzinge , Ma schinge , &
S engle -Wenzke, 2002; Gili e al., 2013; IsHak e al., 2013; Zuelke e al., 2018), bu also
MDD is s ongly ela ed wi h a as a ay o o he men al diso de s, mainly anxie y diso de s
(Wa son, 2009), as well as a g ea numbe o medical condi ions, including ch onic physical
illnesses (Kang e al., 2015) and neu ological diseases (Raskind, 2008).
Al hough psycho he apy (Cuijpe s, C is ea, Ka yo aki, Reijnde s, & Huibe s, 2016), psy-
chopha macology (Cip iani e al., 2018) and he combina ion o he p e ious wo
(C aighead & Dunlop, 2014) ha e shown o be e icacious, he e is s ill much oom o
imp o emen . A ound 40–50% o pa ien s do no espond o ea men (Cuijpe s e al.,
2014) and a hi d o hose who do espond p esen elapses (Beshai, Dobson, Bock ing, &
Quigley, 2011; Bu cusa & Iacono, 2007). Besides, i is es ima ed ha 75% o dep essed people
emain un ea ed (WHO, 2017). Hence, i is o u mos impo ance o de elop new modali ies
o ea men ha can help o o e come he a o emen ioned obs acles (Kazdin & Blase, 2011).
In his sense, bio eedback is conside ed one o he exis ing mind-body in e en ions ha
may os e he b idging o physiological and psychological in e en ions. Bio eedback echni-
ques en ail a signal (e.g. ideo, audio display o ac ile) connec ed o a physiological p ocess
ha enables he pe son o be awa e o no mally unconscious physiological ac i i y (B owne,
2015). In his sense, indi iduals a e p o ided wi h explici in o ma ion o a ce ain psycho-
physiological p ocess in o de o os e i s egula ion.
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Bio eedback has p incipally been used in he medical
ealm, al hough he e is also a long-s anding adi ion o esea ch
on bio eedback echniques o men al diso de s (Leh e &
Ge i z, 2014; Sacche & Go lib, 2016). In pa icula ,
pos - auma ic s ess diso de and subs ance use diso de a e
among he mos esea ched condi ions (Schoenbe g & Da id,
2014). Di e en physiological p ocesses ha e been implemen ed
o bio eedback p ocedu es, including bo h he cen al and
au onomous ne ous sys ems. Elec omyog aphy bio eedback
(EMGB), skin conduc ance bio eedback o hea a e a iabili y
bio eedback (HRVB) a e some o he mos used pe iphe al
esponses, while elec oencephalog aphic (EEG) and unc ional
magne ic esonance imaging neu o eedback ( MRI-NF) a e wo
o he mos common echniques using neu al ac i i y (Sacche
& Go lib, 2016).
Ample e idence demons a ed ha di e en psychophysio-
logical p ocesses a e impai ed in pa ien s wi h MDD. Wi h ega d
o he neu oci cui y, unc ional impai men s ha e been iden i ied
in p e on al, limbic, s ia al, halamic and basal o eb ain s uc-
u es (P ice & D e e s, 2010). O pa icula impo ance o neu-
o eedback, he e is consis en e idence om EEG esea ch
demons a ing ha dep essi e indi iduals p esen highe
le -hemisphe ic alpha ac i i y, including hypoac i a ion in he
le p e on al a ea. In his ega d, an imp o emen o he dep es-
si e symp oma ology has been obse ed a e a neu o eedback-
based aining o his asymme y (Linden, 2014). Likewise, neu-
oimaging and b ain s uc u al esea ch indica e ha people
wi h dep ession p esen se e al abno mali ies. Fo ins ance, he
amygdala has been iden i ied as an impo an a ge in neu o eed-
back in e en ions o dep ession due o i s ole in emo ional p o-
cessing and esponding, in e ac ing wi h di e en co ical and
subco ical a eas and ha ing shown o be a key ma ke o he
onse and eco e y o MDD (Young e al., 2018).
Likewise, ca diac ac i i y has p o en o g ea ly con ibu e o
he gene al physiological dys egula ion o dep essed pa ien s,
and no only o be a co ela e o he neu al dys egula ion
(Thaye & Ma he , 2018). Hea a e a iabili y (HRV), in pa -
icula he high equency (HF) o he spec al domain, is consid-
e ed o index ca diac agal one and hus o be a ele an ma ke
o MDD. Resea ch in his domain indica es ha dep ession is
associa ed wi h lowe es ing HF-HRV and lowe LF/HF a io
(Hamil on & Alloy, 2016; Kemp e al., 2010).
Taken oge he , hese esul s indica e ha NF and HRVB con-
s i u e wo echniques ha ga he consis en heo e ical suppo o
jus i y a psychophysiological in e en ion. Indeed, he e a e a
numbe o quali a i e e iews (Hammond, 2005; Linden, 2014;
Sacche & Go lib, 2016; Young e al., 2018) ha ha e ga he ed
he a ailable s udies o neu o eedback and bio eedback o
MDD and dep essi e symp oma ology. Ne e heless, o he bes
o ou knowledge, no s udy has me a-analy ically es ablished
he ex en o which his app oach is e icacious o MDD and
dep essi e symp oma ology, espec i ely.
Apa om calcula ing he o e all e ec o bio- and neu o eed-
back in e en ions o MDD, his s udy also aims o calcula e he
e ec o all bio- and neu o eedback s udies ha included dep es-
si e symp oma ology as a seconda y ou come measu e in subjec s
su e ing om o he condi ions han MDD.
Main esea ch ques ions
(1) Wha is he pooled e idence o he e ec i eness o bio- and
neu o eedback o MDD?
(2) Wha is he pooled e idence o he e ec i eness o bio- and
neu o eedback o dep essi e symp oms in bo h medical and
men al/psychia ic condi ions o he han MDD?
(3) Wha mode a o s explain possible sou ces o he e ogenei y
among he e ec sizes?
Ma e ials and me hods
The sys ema ic e iew has been de eloped in acco dance wi h
P e e ed Repo ing I ems o Sys ema ic Re iews and
Me a-Analyses (PRISMA) (see Supplemen a y 1) (Mohe e al., 2009).
Sea ch s a egy
Fi s , a icles we e iden i ied h ough comp ehensi e sea ches o
he ollowing da abases: PubMed, Scopus, Web o Science and
Embase. The las upda e was in Decembe 2018. Re e ences lis s
o e iew a icles we e also conside ed o po en ial unde ec ed
s udies and g ay li e a u e has also been examined ( o he sea ch
s ing see Appendix 2).
Eligibili y c i e ia
This s udy ollows a wo-s ep le el s uc u e, and hus wo di e -
en eligibili y c i e ia ha e been conside ed. To add ess he i s
aim, o iginal a icles in English epo ing da a o he e icacy o
bio- and neu o eedback in he ea men o MDD we e consid-
e ed. To selec s udies, he e m “clinical dep ession”u ilized in
he DSM 5 (Ame ican Psychia ic Associa ion, 2013) was consid-
e ed, which comp ises MDD and dys hymic diso de . All s udies
ha ei he es ablished a diagnosis o dep ession using a s anda -
dized diagnos ic in e iew (such as he SCID, CIDI, o SCAN) o
pa icipan s who p esen ed ele a ed symp oms o dep ession
based on sel - epo measu es we e conside ed o inclusion. )
S udies ha included subjec s aking psychopha macology o
ecei ing any o he ac i e ea men such as ho mone he apy
o psycho he apy we e excluded.
To add ess he second aim, s udies ha measu ed dep essi e
symp oma ology h ough a psychome ically alida ed ins umen
and ha p esen ed a condi ion o bio- o neu o eedback in a an-
domized con olled ial we e conside ed o inclusion. The
objec i e o including his second laye o s udies was o de e -
mine he ex en o which dep essi e symp oms a e ea ed
h ough bio- and neu o eedback echniques in o he men al dis-
o de s and pa icula ly in medical s udies. In o he wo ds, all
s udies assessing dep essi e symp oma ology as a seconda y ou -
come measu e we e comp ised.
Unpublished s udies, con e ence pape s and p oceedings, he-
sis and a icles published in non-pee - e iewed we e excluded
om he s udy selec ion in bo h sea ches.
S udy selec ion p ocedu e
One e iewe comple ed all da abase sea ches o bo h objec i es
a he same ime. All esul s we e expo ed o EndNo e and dupli-
ca es we e elimina ed. A e ha , wo e iewe s (JFA and DC)
sc eened independen ly all i les and abs ac s o iden i y po en-
ially ele an a icle o any o he wo objec i es. Two di e en
olde s we e c ea ed, one o each objec i e. F om he o al
amoun o s udies ha we e included o u he examina ion,
he wo independen e iewe s ead ull ex s o de e mine i
he eligibili y c i e ia we e ul illed. Disag eemen s we e esol ed
2 J. Fe nández‐Al a ez e al.
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h ough discussion, and i necessa y, a hi d e iewe was
consul ed.
Quali y assessmen o s udies
Coch ane Collabo a ion Risk o Bias ool has been used o assess
sou ces o bias in andomized con olled ials (RCTs). Ou con-
side ed c i e ia en ail lack o alloca ion/concealmen , lack o
blinding, incomple e accoun ing o ou come o pa ien e en s,
and selec i e ou come epo ing.
E ec size calcula ion and coding o s udies
We es ima ed he e ec size o bo h he di e ence in change
be ween he g oups as well as he p e-pos change wi hin he bio-
eedback g oups by using Hedges’g, a a ia ion o Cohen’sd
which akes in o accoun o biases associa ed wi h small sample
sizes (Hedges & Olkin, 1985). When he g oup mean, s anda d
de ia ion (S.D.), a iance o s anda d e o o he mean, and a
numbe o subjec s we e a ailable o each g oup, hese da a
we e p e e ably used o calcula e he e ec size. When some o
hese da a we e missing, we looked o o he da a allowing o
he e ec size compu a ion, such as uns anda dized mean di e -
ences, and p alues. I mul iple measu emen s o dep ession
we e used in he same s udy, a pooled e ec size was calcula ed
in o de o include in he me a-analyses only a single e ec size
o each s udy. The pooled es ima e o he e ec size was calcu-
la ed as he a e age o he di e en e ec sizes o each measu e.
The a iance o he pooled es ima e was also calcula ed as he
a e age o he di e en a iances o he e ec sizes; as he co ela-
ions among he measu es a e o en no epo ed in he pape s,
such app oach ep esen s he mos conse a i e way o calcula e
he pooled e ec size a iance (i.e. he s a egy ha leads o he
la ges a iances o he es ima e o he pool e ec size, assuming
a pe ec co ela ion among measu es). Simila ly, a pooled e ec
size was calcula ed and included in he mea -analysis i ei he
mul iple bio eedback o con ol g oups we e used in he s udy.
In addi ion, he ollowing s udy cha ac e is ics we e coded and
included in he analyses as mode a o s: (1) sex (% o emale sub-
jec s in he con ol g oup); (2) age (mean age in he con ol
g oup), (3) leng h o ea men (numbe o sessions), (4) ype
o bio eedback in e en ion (hea a e a iabili y bio eedback o
neu o eedback) (5) yea o publica ion, (6) expe imen al design
( andomized-con ol ial), (7) me hodological quali y o s udies.
Coding o mode a o s 1–3 may be no possible o all s udies. In
such case, a “no a ailable”was be inse ed.
Two o he au ho s independen ly pe o med he compu a ion
o e ec sizes and any disc epancy was esol ed be o e analysis,
wi h he in ol emen o a hi d au ho in case o pe sis en
disag eemen .
Me a-analy ic s a is ics
Each s udy e ec size was weigh ed by i s in e se a iance ( he
sum o he wi hin-s udy a iance and an es ima e o he be ween-
s udies a iance), gi ing a la ge weigh ing o s udies wi h la ge
sample sizes han hose wi h small sample sizes. Be o e excluding
a s udy because i was no possible o calcula e he e ec size due
o a lack o enough s a is ical de ails epo ed in he pape , we
ied o con ac he co esponding au ho (only o s udies
published less han 10 yea s ago) asking o he missing de ails.
O he wise, he s udy was excluded om he analyses.
The pooled e ec sizes we e es ima ed using andom-e ec s
models (Res ic ed Maximum-Likelihood Es ima ion), wi h con i-
dence in e als and s a is ical es calcula ed wi h Knapp–Ha ung
me hod (Knapp & Ha ung, 2003), which hypo hesizes po en ial
signi ican he e ogenei y among s udies. A signi icance le el o
0.05 was applied.
Q s a is ic and I
2
index we e used o in es iga e he he e ogen-
ei y o he e ec sizes among s udies. The signi icance le el o he
Q s a is ic was se a 0.1 o adjus o he limi ed s a is ical powe
o his es (Pe i i, 2001). I
2
can be in e p e ed as he pe cen age
o he o al a iabili y in a se o e ec sizes ha canno be a ib-
u ed only o he sampling e o wi hin s udies. I he Qs a is ic
esul ed signi ican o I
2
sugges ed he e ogenei y, we checked
whe he he sou ce o his he e ogenei y migh ha e been a ibu-
ed o one single e ec size ou lying om all o he s. In his case,
we epea ed he me a-analy ic analyses one-by-one emo ing each
e ec size. The e ec size was conside ed ou lying when i s exclu-
sion om he analyses yielded a esolu ion o he he e ogenei y,
and i s inclusion du ing he emo al o o he e ec sizes did no .
Finally, mode a o s we e included in he me a-analysis in
o de o y explaining possible sou ces o he e ogenei y among
he e ec sizes. Mode a o s we e conside ed only i hey we e
a ailable in a leas ou independen s udies. Conside ing he lim-
i ed numbe o s udies expec ed o be included in he cu en
me a-analyses, mode a o analysis will be pe o med sepa a ely
o each mode a o .
Publica ion bias
Publica ion bias was assessed by isual inspec ion o he unnel
plo s and by he Egge ’s eg ession es (one- ailed po <0.05
was conside ed o indica e he p esence o he bias) (Egge ,
Da ey Smi h, Schneide , & Minde , 1997). We also used he
im-and- ill me hod om Du al and Tweedie (Pe e s, Su on,
Jones, Ab ams, & Rush on, 2007) o de e mine he na u e o
po en ial publica ion bias and o compu e an es ima ed e ec
size ha accoun s o i .
Resul s
Included s udies
As illus a ed in he PRISMA low cha (Fig. 1), a o al o 11 786
eco ds ha e been e ie ed om he ini ial da abase sea ches.
A e emo ing all duplica ed a icles, he i s sc eening s ep
(examina ion o i les and abs ac s) iden i ied 7235 e e ences
ha we e o po en ial in e es o ou me a-analysis. Such a p ocess
was ca ied ou by wo e iewe s and yielded 18 and 24 e e ences,
o each o he espec i e s eps o ou s udy. A o al numbe o 22
pape s ul illed he inclusion c i e ia and we e inally included in
he s udy. 24 pape s we e excluded because hey did no sa is y
he inclusion c i e ia (desc ibed in Fig. 1). The whole p ocedu e
was independen ly done by wo e iewe s (JFA and DC).
A lowcha o he gene al inclusion p ocedu e is epo ed in
Fig. 1. No eply was ecei ed om any au ho we con ac ed o
ob ain missing da a. Desc ip ions o all he included s udies
wi h ele an a iables and s udy-le el cha ac e is ics coded
o each s udy a e epo ed in Tables 1–3, o each s ep o he
s udy.
Psychological Medicine 3
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E icacy o bio- and neu o eedback o MDD (le el 1)
P e-pos be ween-g oup e ec sizes
Fo he p e-pos be ween-g oup analysis compa ing he bio- and
neu o eedback and con ol g oups, he andom-e ec s analyses
yielded an o e all e ec size o Hedges’g= 0.717 (95% CI
0.2121–1.1224, = 3.357, p= 0.0121) (Fig. 2), indica ing a g ea e
e icacy o bio- and neu o eedback compa ed o con ol ea -
men s in he ea men o MDD. In o al, his me a-analysis
was based on eigh s udies and 176 pa ien s. No e idence o sig-
ni ican he e ogenei y was ound conside ing he Q s a is ics (Q=
8.193, p= 0.316), while I
2
esul ed o 29%, indica ing a small
po en ial he e ogenei y among he e ec sizes o he single s udies
(Higgins, 2003).
Mode a o analyses and publica ion bias
The e ec o all mode a o s esul ed s a is ically non-signi ican
(see Table 4). The occu ence o publica ion bias was no
sugges ed by any o he es s used (T im and Fill analysis) sugges s
ha no s udies needed o all o he igh o le o he mean o
make he plo symme ical, and Egge ’s es esul ed no signi i-
can ( p= 0.4365) as well as by isual inspec ion o he unnel
plo (Fig. 3).
P e-pos wi hin-g oup e ec sizes
Fo he p e-pos wi hin-g oup analysis o he sole bio eedback
ea men , he andom e ec s me a-analysis yielded an o e all
wi hin-g oup e ec size o Hedges’g= 1.050 (95% CI 0.492–
1.608, = 5.991, p= 0.001) (Fig. 4), which indica es a signi ican
e icacy o bio- and neu o eedback in imp o ing MDD symp om-
a ology (n= 110). No e idence o signi ican he e ogenei y was
ound conside ing he Qs a is ics (Q= 3.353, p= 0.340), and
also I
2
(13%) sugges s a e y limi ed he e ogenei y among he
e ec sizes o he single s udies.
Fig. 1. Flowcha o included s udies in he me a-analysis.
4 J. Fe nández‐Al a ez e al.
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Table 1. Be ween e ec sizes o Neu o- and bio eedback o dep essi e symp oma ology in all condi ions
Coun y
Type
o BF Con ol g oup Design
Mean
age BF
Mean
age CG
Sample size
(BF/CG)
%o
emale
BF
%o
emale
CG Ins umen
N . o
sessions
Risk o
bias (A/C;
LB; IA;
SOR)
Young e al.
(2017)
USA MRI Placebo RCT/Double-Blind,
placebo-con olled
32 31 36 (19/17) 66% 75% Composi e o 3
scales (HDRS;
MADRS; BDI-II)
2 +/+/+/+
Choi e al.
(2011)
Sou h Ko ea EEG Placebo RCT/Single-blind 28.46 28.54 23 (12/11) 20% 57% Composi e o 2
scales (HDRS &
BDI-II)
5 + /U/ + / +
Li e al.
(2015)
China/USA MRI Regula
ehabili a ion
a
RCT 54.38 59.64 24 (13/11) 62% 27% HDRS 3 imes/w.
o 4–6w
U/U/U/ +
Caldwell and
S e en
(2018)
USA HRV Psycho he apy
ac i e
RCT 20.09 20.64 20 (10/10) 100% 100% Beck Dep ession
In en o y-II
5 U/U/U/ +
Yuan e al.
(2014)
USA MRI NF based on Le
HIPS
Case–con ol 38 35 27 (13/14) 79% 85% HDRS 1 + /U/ + / +
Linden e al.
(2012)
UK/
Ne he lands
MIR &
EEG
Heal hy subjec s /
image y p ocedu e
Expe imen al design 48.37 48.5 16 (8/8) 0% 37% HDRS-17 4 U/U/U/ +
Zo e e al.
(2016)
USA MRI Placebo RANDOMIZED/
Double-Blind,
placebo-con olled
41 34 13 69% 85% P o ile o Mood
S a es
2 + /U/ + / +
Mehle e al.
(2018)
Ne he lands MRI Ac i a ion o highe
isual p ocesses
.RCT 47.19 46.94 32 (16/16) 69% 62,5% HDRS-17 5 + / + / + / +
A/C, Alloca ion/concealmen ; Beck Dep ession In en o y–II; BF, bio eedback; CG, Con ol g oup; EEG, elec oencephalog am; MRI, unc ional magne ic esonance imaging; HAD, Hamil on Dep ession Ra ing Scale; HIPS, ho izon al segmen o
in apa ie al sulcus; HRV, Hea a e a iabili y; IA, Incomple e accoun ing o ou come o pa ien e en s; LB, Lack o blinding; MADRS, Mon gome y-Åsbe g Dep ession; RCT, andomized con olled ial; N . o sessions, Numbe o sessions; SOR, Selec i e
Ou come Repo ing.
aHamil on Dep ession Ra ing Scale (17-i ems).
Psychological Medicine 5
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Mode a o analyses
Among he mode a o s (see Table 5), only he expe imen al design
esul ed in ha ing a signi ican e ec in mode a ing he o e all
wi hin-g oup e ec size (F= 126.582, p= 0.008). The wi hin-g oup
e ec size o bio eedback ea men s esul ed signi ican bo h in
andomized-con olled s udies (Hedges’g = 1.391, 95% CI 1.216–
1.566, = 34.164, p< 0.001) and in non- andomized s udies
(Hedges’g= 0.783, 95% CI 0.630–1.566, =22.045, p=0.002),
wi h he la e esul ing signi ican ly g ea e han he o me .
Publica ion bias
T im and Fill analysis indica ed ha one s udy would need o all
o he le o he mean o make he plo symme ical, while no
s udies on he o he side. This sugges s ha he o e all e ec
size calcula ed in he wi hin-g oup analysis may be in la ed by
he lack o inclusion in he me a-analysis o some un epo ed
s udy, as i is also e idenced by isual inspec ion o he unnel
plo (Fig. 5). Howe e , he andom-e ec s me a-analysis
pe o med adjus ing o missing s udies s ill yielded a signi ican
o e all e ec size (Hedges’g= 1.196, 95% CI 0.985–1.407,
= 11.102, p< 0.0001), wi h only a e y small educ ion o i s
p e ious magni ude. Ins ead, no e idence o publica ion bias
was sugges ed by he Egge ’s es ( p= 0.281)
E icacy o bio eedback o dep essi e symp oms in o he
condi ions (le el 2)
P e-pos be ween-g oup e ec sizes
Fo he p e-pos be ween-g oups analysis compa ing he bio- and
neu o eedback and con ol g oups, he andom-e ec s analyses
yielded a signi ican o e all e ec size o Hedges’g= 0.303 (95%
CI 0.121–0.484, = 2.217, p= 0.003) (Fig. 6), indica ing a g ea e
e icacy o bio- and neu o eedback compa ed o con ol ea -
men s o dep essi e symp oms (n= 736). No e idence o signi i-
can he e ogenei y was ound conside ing he Qs a is ics (Q=
4.350, p= 0.993), and also I
2
(0%) sugges s a lack o he e ogenei y
among he e ec sizes o he single s udies.
Mode a o analyses and publica ion bias
The e ec o all mode a o s esul ed s a is ically non-signi ican
(Table 6) and no occu ence o publica ion bias was sugges ed
by any o he es s used (T im and Fill analysis sugges s ha no
s udies needed o all o he igh o le o he mean o make
he plo symme ical, and Egge ’s es esul ed no signi ican
wi h a p= 0.911) as well as by isual inspec ion o he unnel
plo (Fig. 7).
Table 2. Wi hin e ec sizes o Neu o- and bio eedback o dep essi e symp oma ology in all condi ions
Coun y
Type
o BF Design
Mean
age
Sample
size
Pe cen
emale Ins umen
N . o
sessions
Risk o
bias (A/
C; LB;
IA;
SOR)
Young
e al.
(2017)
USA MRI RANDOMIZED/
Double-Blind,
placebo-con olled
32 19 66%/
75%
Composi e o 3
scales (HDRS;
MADRS; BDI-II)
2+/+/
+/+
Choi
e al.
(2011)
Sou h
Ko ea
EEG RANDOMIZED/
Single-blind
28.46 12 20%/
57%
Composi e o 2
scales (HDRS &
BDI-II)
5 + /U/
+/+
Yuan
e al.
(2014)
USA MRI Case–con ol 38 13 79%/
85%
Hamil on
Dep ession
Ra ing Scale
1 + /U/
+/+
Zo e
e al.
(2016)
USA MRI RANDOMIZED/
Double-Blind,
placebo-con olled
41 13 69%/
85%
P o ile o Mood
S a es
2 + /U/
+/+
A/C, Alloca ion/concealmen ; BF, bio eedback; CG, Con ol g oup; EEG, elec oencephalog am; MRI, unc ional magne ic esonance imaging; IA, Incomple e accoun ing o ou come o pa ien
e en s; LB, Lack o blinding; RCT, andomized con olled ial; N . o sessions, Numbe o sessions; SOR, Selec i e Ou come Repo ing.
Fig. 2. P e-pos be ween-g oup e ec sizes in le el 1.
6 J. Fe nández‐Al a ez e al.
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Table 3. Be ween e ec sizes o Neu o- and bio eedback o dep essi e symp oma ology in all condi ions
Coun y
Type
o BF Compa ison condi ion Popula ion Sample size
Pe cen
emale Ins umen N . o sessions
Risk o bias
(A/C; LB; IA;
SOR)
Hallman e al. (2011) Sweden HRV Con ol (check i WL) Ch onic neck
pain
23 (HRV 12;
CG 11)
91% HADS 10 U/U/ + / +
Pa on e al. (2013) I aly HRV Daily counseling sessions A e ca diac
su ge y
pa ien s
26 (HRV 13;
CG 13)
22.5% CES-D 5 (45’) U/U/U/ +
Penzlin e al. (2015) Ge many/
USA
HRV CBT Addic ion
(alcohol)
43 (HRV 24;
CG 19)
¿?¿? BDI-II 6 (20’)+/+/+/+
Ra anasi ipong e al.
(2015)
USA/
Thailand
HRV WL Heal hy
popula ion
60 (HRV 30;
CG 30)
97% CES-D 1
a
+ /U/U/ +
Swanson e al. (2009) USA HRV Quasi- alse alpha- he a
bio eedback
Hea Failu e 29 (HRV 15;
CG 14)
80% CES-D 6 (45’) + /U/ + / +
Zucke e al. (2009) USA HRV P og essi e muscle
elaxa ion
PTSD 38 (HRV 19;
CG 19)
44.7% BDI-II 4 weeks once a
day o 20’a
home
+ / + /U/ +
Schönbe g e al. (2017) Ge many Neu o Sham neu o eedback ADHD 75 (NBF 37;
CG 38)
44% BDI-II + / + / + / +
Schönbe g e al. (2017) Ge many Neu o Me a-cogni i e g oup
he apy g oup
ADHD 75 (NBF 37;
CG 38)
44% BDI-II 30 + / + / + / +
Hsueh e al. (2016) Taiwan Neu o Sham neu o eedback Memo y
enhancem.
25; 25 60% BDI-II 12 + / + /U/ +
Lackne e al. (2016) Aus ia /
UK
Neu o T aining sessions (di e en
psycho he apeu ic aspec s)
Addic ion
(alcohol)
25 (NF 13;
CG 12)
0% BDI-V (modi ied
e sion o BDI)
12 + / + /U/ +
Menella e al. (2017) I aly Neu o Ac i e con ol aining Heal hy
popula ion
32 (NF 16;
CG 16)
100% BDI-II 7 (45’) + / + /U/ +
Dehghani-A ani
e al. (2013)
I an Neu o TAU (medica ion) Addic ion
(opia e)
20 (NF 10;
CG 10)
No in o GHQ-28 30 + / + /U/ +
Choob o oushzadeh
e al. (2015)
I an Neu o TAU (medica ion) Mul iple
schle osis
24 (NF 12;
CG 12)
50% HADS 16 + / + /U/ +
Yu e al. (2018) Taiwan HRV Medicine Co ona y A e y
Disease
210 (105
HRV; 105
CG)
12% HRV
10.20%CG
BDI-II 6 (60’) + /U/ + / +
A/C, Alloca ion/concealmen ; ADHD, A en ion De ici Hype ac i i y Diso de ; BDI, Beck Dep ession In en o y; CES-D, Cen e o Epidemiologic S udies Dep ession Scale; CG, Con ol g oup; GHQ, Gene al Heal h Ques ionnai e; HADS, Hospi al Anxie y and
Dep ession Scale; HRV, hea a e a iabili y; IA, Incomple e accoun ing o ou come o pa ien e en s; PTSD, Pos T auma ic S ess Diso de ; RCT, andomized con olled ial; NF, Neu o eedback; N . o sessions, Numbe o sessions; LB, Lack o blinding;
SOR, Selec i e Ou come Repo ing TAU, T ea men as usual; Wai ing Lis .
a
One session wi h he apis s and hen ou weeks o use a home h ee imes a day.
Psychological Medicine 7
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P e-pos wi hin-g oup e ec sizes
P e-pos wi hin-g oup analysis o he sole bio eedback ea men s
could no be pe o med because only one s udy (Kayi an, Du sun,
Du sun, E mu lu, & Ka amü sel, 2010) sa is ied all he inclusion
c i e ia o his pa o he me a-analysis.
Discussion
To ou knowledge, his is he i s me a-analysis o bio- and neu-
o eedback echniques o he ea men o MDD and dep essi e
symp oms. Taken oge he , hese indings sugges ha bio- and
neu o eedback cons i u e e ec i e in e en ions o bo h indi i-
duals wi h clinical dep ession and wi h seconda y dep essi e
symp oma ology. Besides, he esul s a e in line wi h he indings
o p e ious quali a i e e iews (Hammond, 2005; Linden, 2014;
Sacche & Go lib, 2016; Young e al., 2018).
Bio- and neu o eedback o MDD
While he wi hin-g oup analyses yielded an e ec size o Hedges’
g=0.717, he be ween-g oup analysis e ealed an e ec size o
Hedges’g=1.050. The mode a o analyses indica e ha ea men
e icacy is only signi ican when accoun ing o expe imen al
design, in a o o RCTs in compa ison o non-RCTs. The ac
ha all o he mode a o s we e non-signi ican may indica e ha
esul s can be gene alized o a ange o social and clinical
cha ac e is ics.
Ne e heless, hese esul s mus be aken wi h cau ion gi en
ha only one RCT has been conduc ed o MDD using HRVB
(Caldwell & S e en, 2018), and hus making i di icul o con-
clude ha his echnique is e ec i e o MDD. Addi ionally,
many o he iden i ied s udies a ge ing clinical dep ession wi h
HRVB could no be included due o se e al easons, such as he
absence o a con ol g oup o he ac ha pa icipan s we e aking
an idep essan s. So a , a conside able numbe o s udies ha e p e-
iously indica ed ha HRVB is e ec i e o dep ession, equen ly
e e ing o he esea ch conduc ed by Ka a idas e al. (2007)o
Siepmann, Aykac, Un e dö e , Pe owski, and Mueck-Weymann
(2008). While i is ue ha bo h in e en ions we e e ec i e,
none o hem had ei he a con ol condi ion, in bo h cases
pa ien s we e unde psychopha macological ea men and he
samples we e unde powe ed.
Con e sely, neu o eedback ga he ed mo e e idence. The exis -
ing s udies o neu o eedback comp ised bo h s udies b ough
o h o EEG (Cheon, Koo, & Choi, 2016; Choi e al., 2011)
and MRI (Li e al., 2015; Linden e al., 2012; Mehle e al.,
2018; Young e al., 2014,2017). Among he EEG s udies, he a -
ge was o egula e he on al asymme ic ac i a ion inc easing
he ela i e le on al ac i i y and consequen ly o imp o e
dep essi e symp oma ology. In he case o he MRI s udies,
some o hem a ge ed he amygdala (Young e al., 2014,2017)
and o he s he insula and la e al p e on al a eas (Mahle e al.,
2018), all o which a e in ol ed in he egula ion o emo ions
(Sebas ian & Ahmed 2018). F om his poin o iew, emo ion
egula ion is a well-es ablished ansdiagnos ic ac o ha explains
bo h he appea ance and main enance o a as a ay o a ec i e
diso de s (Aldao, Nolen-Hoeksema, & Schweize , 2010), includ-
ing MDD and dep essi e symp oms. In eg a ing he e idence
Fig. 3. Funnel plo be ween analyses in le el 1.
Fig. 4. P e-pos wi hin-g oup e ec sizes in le el 1.
8 J. Fe nández‐Al a ez e al.
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Table 4. Mode a o s be ween analysis le el 1
INTERCEPT MODERATOR
MODERATOR
In e p e a ion o he
es ima e Es ima e SE p
95% CI
lowe
bound
95% CI
highe
bound
In e p e a ion o he
es ima e Es ima e SE al p al
95% CI
lowe
bound
95% CI
highe
bound
Type o eedback Es ima ed e ec size o
h bio eedback
0.996 0.591 1.686 0.143 −0.450 2.443 Es ima ed e ec size
di e ence be ween
neu o eedback and h
bio eedback
−0.321 0.640 −0.503 0.633 −1.886 1.243
Randomized con ol
ial
Es ima ed e ec size o
non- andomized
con ol ials
0.958 0.322 2.973 0.025 0.170 1.747 Es ima ed e ec size
di e ence be ween
andomized and
non- andomized con ol
ials
−0.452 0.430 −1.051 0.334 −1.503 0.600
Yea o publica ion Es ima ed e ec size o
s udies published in
2011
1.459 0.406 3.593 0.011 0.465 2.452 Es ima ed change o he
e ec size o e e y yea o
publica ion a e 2011
−0.167 0.076 −2.214 0.069 −0.352 0.018
Numbe o sessions Es ima ed e ec size
wi h 4 sessions
0.717 0.228 3.144 0.020 0.159 1.276 Es ima ed change e ec size
change o e e y addi ional
session
0.025 0.066 0.379 0.718 −0.136 0.186
A e age age o
bio eedback g oup
Es ima ed e ec size a
a e age age o 40 yea s
0.724 0.230 3.144 0.020 0.161 1.288 Es ima ed e ec size change
o e e y addi ional yea o
he mean age
0.003 0.025 0.109 0.917 −0.059 0.064
Pecen age o emale
subjec s in he
bio eedback g oup
Es ima ed e ec size
wi h only male subjec s
1.473 0.419 3.518 0.013 0.448 2.498 Es ima ed e ec size
di e ence be ween only
emale and only male
subjec s
−1.362 0.651 −2.092 0.081 −2.954 0.231
Quali y o he s udy Es ima ed e ec size
wi h low isk o bias
0.210 0.284 0.741 0.487 −0.485 0.906 Es ima ed e ec size
di e ence e ec size
be ween unknown/high and
low isk o bias
0.738 0.369 1.997 0.093 −0.166 1.642
Psychological Medicine 9
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Pe na,G.,G assi,M.,Caldi ola,D.,&Neme o ,C.B.(2018).The e olu iono
pe sonalized psychia y: Will echnology make i happen soone ? Psychological
Medicine,48(5), 705–713. h ps://doi.o g/10.1017/S0033291717002859.
Pe e s, J. L., Su on, A. J., Jones, D. R., Ab ams, K. R., & Rush on, L. (2007).
Pe o mance o he im and ill me hod in he p esence o publica ion
bias and be ween-s udy he e ogenei y. S a is ics in Medicine,26(25),
4544–4562. h ps://doi.o g/10.1002/sim.2889.
Pe i i, D. B. (2001). App oaches o he e ogenei y in me a-analysis. S a is ics in
Medicine,20(23), 3625–3633. h ps://doi.o g/10.1002/sim.1091.
Po ges, S. W. (2007). The poly agal pe spec i e. Biological Psychology,74(2),
116–143. h ps://doi.o g/10.1016/J.BIOPSYCHO.2006.06.009.
P ice, J. L., & D e e s, W. C. (2010). Neu oci cui y o mood diso de s.
Neu opsychopha macology,35(1), 192–216. h ps://doi.o g/10.1038/npp.2009.104.
Rami ez, R., Palencia-Le le , M., Gi aldo, S., & Vam akousis, Z. (2015).
Musical neu o eedback o ea ing dep ession in elde ly people. F on ie s
in Neu oscience,9(OCT), 1–10. h ps://doi.o g/10.3389/ nins.2015.00354.
Raskind, M. A. (2008). Diagnosis and ea men o dep ession como bid wi h
neu ologic diso de s. The Ame ican Jou nal o Medicine,121(11), S28–S37.
h ps://doi.o g/10.1016/j.amjmed.2008.09.011.
Ra anasi ipong, P., Kaewboonchoo, O., Ra anasi ipong, N., Hanklang, S., &
Chumchai, P. (2015). Bio eedback in e en ion o s ess, anxie y, and
dep ession among g adua e s uden s in public heal h nu sing. Nu sing
Resea ch and P ac ice,1–5. doi: 10.1155/2015/160746.
Repe o, C., Gaggioli, A., Palla icini, F., Cip esso, P., Raspelli, S., & Ri a, G.
(2013). Vi ual eali y and mobile phones in he ea men o gene alized
anxie y diso de s: A phase-2 clinical ial. Pe sonal and Ubiqui ous
Compu ing,17(2), 253–260. h ps://doi.o g/10.1007/s00779-011-0467-0.
Rosen eld, J. P. (2000). An EEG bio eedback p o ocol o a ec i e diso de s.
Clinical EEG and Neu oscience,31(1), 7–12. h p://dx.doi.o g/10.1177/
155005940003100106.
Sacche , M. D., & Go lib, I. H. (2016). Recen de elopmen s and u u e di ec-
ions. Expe Re iew o Neu o he apeu ics,16(9), 1003–1005. h ps://doi.o g/
10.1111/2041-210X.12.
Schoelle , F., Be and, P., Ge y, L. J., Jain, A., Ho owi z, A. H., & Zenasni, F.
(2019). Combining i ual eali y and bio eedback o os e empa hic abil-
i ies in humans. F on ie s in Psychology,9(Feb ua y), 1–5. h ps://doi.o g/
10.3389/ psyg.2018.02741.
Schoenbe g, P. L. A., & Da id, A. S. (2014). Bio eedback o psychia ic diso -
de s: A sys ema ic e iew. Applied Psychophysiology and Bio eedback,39(2),
109–135. h ps://doi.o g/10.1007/s10484-014-9246-9.
Schönenbe g, M., Wiedemann, E., Schneid , A., Schee , J., Logemann, A.,
Keune, P. M., & Hau zinge , M. (2017). Neu o eedback, sham neu o eed-
back, and cogni i e-beha iou al g oup he apy in adul s wi h a en ion-de -
ici hype ac i i y diso de : A iple-blind, andomised, con olled ial. The
Lance Psychia y,4(9), 673–684. doi: 10.1016/S2215-0366(17)30291-2.
Sebas ian, C. L., & Ahmed, S. P.. (2018). Neu obiology o emo ion egula ion.
In An hony R. B., Adam J. C., Ru h E. M., & Pia R. (Eds.), The Wiley
Blackwell Handbook o Fo ensic Neu oscience (Vol. 1, pp. 125–140). Wiley
Blackwell.
Siepmann, M., Aykac, V., Un e dö e , J., Pe owski, K., & Mueck-Weymann,
M. (2008). A pilo s udy on he e ec s o hea a e a iabili y bio eedback
in pa ien s wi h dep ession and in heal hy subjec s. Applied
Psychophysiology and Bio eedback,33(4), 195–201. h ps://doi.o g/10.1007/
s10484-008-9064-z.
Swanson, K. S., Ge i z, R. N., B own, M., Spi a, J., Gua ne i, E., & S ole niy,
L. (2009). The e ec o bio eedback on unc ion in pa ien s wi h hea ail-
u e. Applied Psychophysiology and Bio eedback,34(2), 71–91. doi: 10.1007/
s10484-009-9077-2.
Thaye , J. F., & Lane, R. D. (2009). Claude Be na d and he hea -b ain con-
nec ion: Fu he elabo a ion o a model o neu o isce al in eg a ion.
Neu oscience & Biobeha io al Re iews,33(2), 81–88. h ps://doi.o g/10.
1016/j.neubio e .2008.08.004.
Thaye , J. F., & Ma he , M. (2018). How hea a e a iabili y a ec s emo ion
egula ion b ain ne wo ks. Cu Opin Beha Sci.,19,98–104. doi: 10.1016/
J.COBEHA.2017.12.017.
Thibaul , R. T., Li shi z, M., & Raz, A. (2016). The sel - egula ing b ain and
neu o eedback: Expe imen al science and clinical p omise. Co ex,74,
247–261. doi: 10.1016/j.co ex.2015.10.024.
Thibaul , R. T., & Raz, A. (2017). The psychology o neu o eedback: Clinical
in e en ion e en i applied placebo. Ame ican Psychologis ,72(7), 679–
688. doi: 10.1037/amp0000118.
Thibaul , R. T., & Raz, A. (2018). A consensus amewo k o neu o eedback
esea ch (and he pe ils o un ounded neu o educ ionism): Reply o
Micoulaud-F anchi and Fo e (2018). Ame ican Psychologis ,73(7), 936–
937. doi: 10.1037/amp0000366.
Wa son, D. (2009). Di e en ia ing he mood and anxie y diso de s: A quad i-
pa i e model. Annual Re iew o Clinical Psychology,5(1), 221–247. h ps://
doi.o g/10.1146/annu e .clinpsy.032408.153510.
WHO. (2017). Dep ession and o he common men al diso de s: Global heal h
es ima es. Wo ld Heal h O ganiza ion.
Young, K. D., Siegle, G. J., Zo e , V., Phillips, R., Misaki, M., Yuan, H., …
Bodu ka, J. (2017). Randomized clinical ial o eal- ime MRI amygdala
neu o eedback o majo dep essi e diso de : E ec s on symp oms and
au obiog aphical memo y ecall. Ame ican Jou nal o Psychia y,174(8),
748–755. h ps://doi.o g/10.1176/appi.ajp.2017.16060637.
Young, K. D., Zo e , V., Phillips, R., Misaki, M., D e e s, W. C., & Bodu ka, J.
(2018). Amygdala eal- ime unc ional magne ic esonance imaging neu o-
eedback o majo dep essi e diso de : A e iew. Psychia y and Clinical
Neu osciences,72(7), 466–481. h ps://doi.o g/10.1111/pcn.12665.
Young, K. D., Zo e , V., Phillips, R., Misaki, M., Yuan, H., D e e s, W. C., &
Bodu ka, J. (2014). Real- ime MRI neu o eedback aining o amygdala
ac i i y in pa ien s wi h majo dep essi e diso de . PLoS ONE,9(2).
h ps://doi.o g/10.1371/jou nal.pone.0088785.
Yu, L.-C., Lin, I.-M., Fan, S.-Y., Chien, C.-L., & Lin, T.-H. (2018). One-yea
ca dio ascula p ognosis o he andomized, con olled, sho - e m hea
a e a iabili y bio eedback among pa ien s wi h co ona y a e y disease.
In e na ional Jou nal o Beha io al Medicine,25(3), 271–282.
doi: 10.1007/s12529-017-9707-7.
Yuan, H., Young, K. D., Phillips, R., Zo e , V., Misaki, M., & Bodu ka, J..
(2014). Res ing-s a e unc ional connec i i y modula ion and sus ained
changes a e eal- ime unc ional magne ic esonance imaging neu o-
eedback aining in dep ession. B ain Connec i i y,4(9), 690–701. doi:
10.1089/b ain.2014.0262.
Zo e , V., Yuan, H., Misaki, M., Phillips, R., Young, K. D., Feldne , M. T., &
Bodu ka, J. (2016). Co ela ion be ween amygdala BOLD ac i i y and
on al EEG asymme y du ing eal- ime MRI neu o eedback aining in
pa ien s wi h dep ession. Neu oImage: Clinical,11, 224–238. doi: 10.1016/
j.nicl.2016.02.003.
Zucke , T. L., Samuelson, K. W., Muench, F., G eenbe g, M. A., & Ge i z, R. N.
(2009). The e ec s o espi a o y sinus a hy hmia bio eedback on hea a e
a iabili y and pos auma ic s ess diso de symp oms: A pilo s udy.
Applied Psychophysiology and Bio eedback,34(2), 135–143.
Zuelke, A. E., Luck, T., Sch oe e , M. L., Wi e, A. V., Hinz, A., Engel, C., …
Riedel-helle , S. G. (2018). The associa ion be ween unemploymen and
dep ession – esul s om he. Jou nal o A ec i e Diso de s,235(Ma ch),
399–406. h ps://doi.o g/10.1016/j.jad.2018.04.073.
16 J. Fe nández‐Al a ez e al.
h ps://doi.o g/10.1017/S0033291721004396
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