Citation: Pallanti, S.; Di Ponzio, M.;
Grassi, E.; Vannini, G.; Cauli, G.
Transcranial Photobiomodulation for
the Treatment of Children with
Autism Spectrum Disorder (ASD): A
Retrospective Study. Children 2022,9,
Academic Editor: Benedetto Vitiello
Received: 8 April 2022
Accepted: 19 May 2022
Published: 20 May 2022
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Transcranial Photobiomodulation for the Treatment of Children
with Autism Spectrum Disorder (ASD): A Retrospective Study
Stefano Pallanti 1, 2, *, Michele Di Ponzio 1, Eleonora Grassi 1, Gloria Vannini 1and Gilla Cauli 3
1Neurodevelopment Division, Istituto di Neuroscienze, 50121 Florence, Italy;
firstname.lastname@example.org (M.D.P.); email@example.com (E.G.);
2Department of Psychiatry, Albert Einstein College of Medicine, Bronx, NY 10461, USA
3Asst Fatebenefratelli Sacco, 20154 Milan, Italy; firstname.lastname@example.org
Children with Autism Spectrum Disorder (ASD) face several challenges due to deﬁcits
in social function and communication along with restricted patterns of behaviors. Often, they also
have difﬁcult-to-manage and disruptive behaviors. At the moment, there are no pharmacological
treatments for ASD core features. Recently, there has been a growing interest in non-pharmacological
interventions for ASD, such as neuromodulation. In this retrospective study, data are reported
and analyzed from 21 patients (13 males, 8 females) with ASD, with an average age of 9.1 (range
5–15), who received six months of transcranial photobiomodulation (tPBM) at home using two
protocols (alpha and gamma), which, respectively, modulates the alpha and gamma bands. They
were evaluated at baseline, after three and six months of treatment using the Childhood Autism
Rating Scale (CARS), the Home Situation Questionnaire-ASD (HSQ-ASD), the Autism Parenting
Stress Index (APSI), the Monteﬁore Einstein Rigidity Scale–Revised (MERS–R), the Pittsburgh Sleep
Quality Index (PSQI) and the SDAG, to evaluate attention. Findings show that tPBM was associated
with a reduction in ASD severity, as shown by a decrease in CARS scores during the intervention
(p< 0.001). A relevant reduction in noncompliant behavior and in parental stress have been found.
Moreover, a reduction in behavioral and cognitive rigidity was reported as well as an improvement
in attentional functions and in sleep quality. Limitations were discussed as well as future directions
autism spectrum disorders; ASD; photobiomodulation; LED; near-infrared; NIR; neuro-
Autism spectrum disorder (ASD) is a complex neurodevelopmental condition typically
characterized by deficits in social and communicative behaviors as well as repetitive patterns
of behaviors (APA 2013) [
]. In addition to such core symptoms, several children and
adolescents with ASD also present severe behavioral difficulties, including aggression, self-
injurious behavior, tantrums, irritability and sleep problems, which usually interfere with
their education and development as well as the wellbeing of caregivers (Hill et al., 2014;
Soke et al., 2016; Baglioni et al., 2016) [
]. Moreover, people with ASD showed attentional
and executive function deﬁcits (Gargaro et al., 2011; Demetriou et al., 2019) [5,6].
While the cause of autism is uncertain, the most widely accepted explanation is that it
is a complex neurodevelopmental disorder characterized by brain network abnormalities.
EEG has shown local overconnectivity and long-range underconnectivity, also involving
the corpus callosum (Barttfeld et al., 2011) [
]. fMRI studies revealed altered functional
connectivity in the default mode network (DMN), a network with a role in interoceptive
awareness and mind wandering and which was implicated in social-cognitive deﬁcits of
autism (Harikumar et al., 2021; Broyd et al., 2009) [8,9].
Children 2022,9, 755. https://doi.org/10.3390/children9050755 https://www.mdpi.com/journal/children
Children 2022,9, 755 2 of 12
The main goal of therapy for children with ASD is the improvement of socio-relational
and communication skills. This goal is pursued through a combination of interventions, such
as speech therapy, parent training, social skills training and cognitive-behavioral therapy
(Chahin et al., 2020) [
]. In the presence of emotional and behavioral dysregulation, a
pharmacological approach is often considered (Eissa et al., 2018; Pallanti et al., 2015) [
Although some medications such as risperidone and aripiprazole have an effect on ASD-
related irritability and aggression (DeVane et al., 2019) [
], they also have important side
effects including sedation, anticholinergic effects, metabolic alterations, weight gain and
involuntary movements (DeVane et al., 2019) [
]. Moreover, they do not target the core
features of ASD.
Recently, there has been a growing interest in the potential of non-invasive brain stimu-
lation in neurodevelopmental disorders, thanks to their ability to modulate neuroplasticity
and enhance cognitive, behavioral and socio-emotional processes (Finisguerra et al., 2019;
Enticott, Pallanti and Hollander, 2018) [14,15].
Among new neuromodulation approaches, transcranial photobiomodulation (tPBM)
is characterized by the noninvasive delivery of low-level light, transcranially. Light pen-
etrates the skin and the skull and then is absorbed into the brain tissue by speciﬁc chro-
mophores, such as water, oxyhemoglobin (HbO2), deoxyhemoglobin (Hb), myoglobin,
melanin, cytochromes, and ﬂavin. The target for light within single neurons is the mito-
chondria, where tPBM stimulates cytochrome c oxidase. The consequence is that light
enhances mitochondrial activity and hence ATP synthesis, leading to an activation of
transcription factors associated with increased functional activity (Salehpour et al., 2018;
Mitrofanis and Henderson, 2020) [
]. Coherently, research has shown that tPBM boosts
brain energy metabolism as well as cognition in preclinical (Mochizuki-Oda et al., 2002;
Konstantinovic et al., 2013) [18,19]
and clinical studies, (Maiello et al., 2019) [
]. tPBM has
been effectively applied in post-stroke rehabilitation (Yang et al., 2018) [
], in patients with
TBI (Figueiro Longo et al., 2020)  and depression (Askalsky and Iosifescu, 2019) .
As far as safety is concerned, in a randomized-controlled study, which included about
1000 patients with stroke (Hacke et al., 2014) [
], no signiﬁcant difference in side effects
was reported between active and sham stimulation with tPBM. Other studies reported
transient headaches, insomnia, irritable mood and a strange taste in the mouth as the most
common side effects (Cassano et al., 2018; 2019) [
]. The risk of thermal injury following
tPBM is minimal and mostly dependent on the parameters and device used (Caldieraro
and Cassano, 2019) .
Speciﬁcally, concerning ASD in adults, a recent study by Ceranoglu and colleagues
] also reported no side effects, with the exception of one out of six patients
who developed a transient headache. They suggested beneﬁcial effects of twice-a-week
Transcranial Light Emitting Diode (LED) Therapy (TLT), a form of PBM, on core social
deﬁcits associated with ASD in adult patients aged 18–55 years, as shown by the reduction
in the restricted interests and repetitive behavior subscale of the Social Responsiveness
Scale (SRS-2) and on measures of social emotional competence and global functioning, with
a good tolerability and adherence rate.
Furthermore, tPBM could also be safely and efficiently used in children and adolescents,
considering that several studies used PBM to treat pediatric samples with no reported or
minimal side effects (Leisman et al., 2018; Mannu et al., 2019; Salgueiro et al., 2021; Noirrit-
Esclassan et al., 2019; Santos et al., 2017) [
]. Furthermore, phototherapy, of which PBM
is a variant—although the wavelength used in phototherapy is lower than in tPBM—has
also been widely adopted in neonates (Faulhaber et al., 2019) [
] and, although some
reported side effects, many were transient and mild.
Concerning ASD specifically, Leisman and colleagues (2018) [
] treated children and
adolescents with ASD administering low-level light therapy (a form of PBM) to the base of the
skull and temporal areas eight times for 5 min and no side effects that necessitate discontinuation
of the therapy were reported. All the participants were evaluated with the Aberrant Behavior
Children 2022,9, 755 3 of 12
Checklist (ABC) and there were no dropouts. Resultsshow a decreased irritability after treatment,
suggesting the potential of PBM also in treatment of children with ASD.
Based on these preliminary ﬁndings, tPBM has been prescripted for home-based
treatment of children and adolescents with ASD on the basis of the principle of the good
clinical practice. Previously, PBM has been used efﬁciently and without side effects in other
studies for home treatment (Chao, 2019; Gavish and Houreld, 2019) [
]. In our study,
the type of tPBM employed (Vielight
Neuro Alpha/Gamma stimulator) stimulates the
default mode network (DMN) (Vielight, 2020) [
] and not only the temporal lobe, as was
the case in the study by Leisman and collegues (2018) .
Psychometrical data were collected. Here, they are reported and analyzed retrospec-
tively, with the aim to examine the clinical proﬁle of children and adolescents with ASD
before and after treatment with tPBM.
2. Materials and Methods
Clinical data of children and adolescent patients with a diagnosis of ASD according to
DSM-5 criteria were extracted from databases containing information on patients of the
psychiatric clinic at the Istituto di Neuroscience, Florence (Italy). It is important to mention
that the database contains only the data of patients who accepted treatment among all the
ones to which was proposed. The diagnosis was conﬁrmed with the Autism Diagnostic
Interview–Revised (ADI–R) and a CARS (Schopler et al., 1980) [
] total score of no less
than 30. tPBM was added to ongoing behavioral or pharmacological treatments, which
were unchanged for at least 1 month at the date of the start of the stimulation and remained
unchanged throughout the stimulation period. Demographical data as well as ongoing
treatments are reported in Table 1.
Demographical data of the patients as well as comorbidities and ongoing treatments (ADHD,
Attention Deﬁcit Hyperactivity Disorder; SAD, Social Anxiety Disorder; ODD, Oppositional Deﬁant
Disorder; CBT, Cognitive-Behavioral Therapy).
PATIENT AGE GENDER COMORBIDITIES MEDICATION OTHER TREATMENTS
1 9 M ADHD Omega-3; Melatonin; Probiotics;
Phosphatidylserine CBT; Speech therapy
2 5 M ADHD; SAD
Melatonin; Probiotics; Phosphatidylserine
CBT; Parent Training
3 7 F ODD Probiotics CBT; Speech Therapy
4 6 F SAD Omega-3 CBT
5 12 M ADHD Omega-3; Probiotics; Phosphatidylserine CBT; Speech Therapy
6 7 F ADHD Melatonin; Phosphatidylserine CBT; Speech Therapy
7 15 M Omega-3; Melatonin; Probiotics CBT; Speech Therapy
8 14 M SAD Melatonin CBT; Speech Therapy
9 7 M ODD CBT; Speech Therapy;
10 7 M ODD; SAD Omega-3; Melatonin; Probiotics
11 8 M Melatonin
12 5 F SAD CBT; Speech Therapy
13 8 F ODD Omega-3 CBT
14 8 M ADHD Phosphatidylserine CBT; Speech Therapy
15 10 M ADHD Probiotics; Phosphatidylserine
16 11 F ADHD; SAD Omega-3; Phosphatidylserine CBT; Speech Therapy
17 7 F ADHD Omega-3; Melatonin; Probiotics;
Phosphatidylserine CBT; Speech Therapy
18 7 M Omega-3; Melatonin CBT; Speech Therapy;
19 14 F ADHD; SAD Omega-3; Probiotics; Phosphatidylserine CBT; Speech Therapy
20 14 M CBT; Speech Therapy
21 10 M ADHD Melatonin; Phosphatidylserine CBT; Speech Therapy
After the complete description of the study to participants’ parents, written informed
consent was obtained in accordance with the Declaration of Helsinki.
Children 2022,9, 755 4 of 12
tPBM was delivered using the commercially available Vielight
brain photo biomodulation stimulator. Two stimulator devices were used: alpha and
gamma. The alpha stimulator device delivers 810 nm near infrared light pulsing at 10 Hz
via the transcranial LED clusters placed on the Photo-Bio-Modulation helmet. The 10 Hz
correlates with alpha brain waves which are produced by the brain during meditation
and relaxation states. The gamma stimulator pulses light at 40 Hz light pulsing frequency
and delivers 810 nm near infrared light via the transcranial LED clusters placed on the
helmet. The frequency of gamma stimulation simulates neural gamma waves which
are correlated with increased cognitive activities. Both protocols were used in order to
exploit the advantages of both and increase attention, improve sleep and reduce irritability
The device is composed of a wearable headset (see Figure 1) with features microchip-
boosted transcranial LED diodes. The tPBM headset consists of four clusters. According
to the 10–20 EEG system, the frontal cluster should be positioned over FPz, the posterior
cluster over Cz and the two lateral ones over T3 and T4. In this way, the four LEDs deliver
the NIR to the subdivisions of the DMN: the medial prefrontal cortex, the precuneus area,
and left and right angular gyrus (Vielight, 202) [
]. The intranasal application is positioned
in the left or right nostril with the clip on the outside to deliver light to the ventral section
of the brain, speciﬁcally to the ventromedial PFC. The support pads should fall naturally
into place around the ears.
Positioning of the tPBM on the head, which is composed of a helmet and a nasal stimulator.
LED diodes emit non-thermal, non-laser light at an intensity that penetrates the scalp,
skull, and meninges to a depth of ~40 mm, stimulating cortical brain areas (Jagdeo et al., 2012;
Tedford et al., 2015) [
] and is powered by three rechargeable NiMH batteries. The
posterior transcranial LEDs have a power of 100 milliwatts (mW) and the anterior tran-
scranial has a power of 75 mW. Each posterior transcranial LED has a power density of
and the anterior transcranial LED of 75 mW/cm
. The beam spot size of
Children 2022,9, 755 5 of 12
each LED is approximately 1 cm
. The energy delivered by posterior transcranial LEDs
is 60 joules (J) and the anterior transcranial LED delivers 45. The energy density of the
posterior transcranial LEDs is 60 J/cm
and 45 J/cm
for the anterior transcranial LED.
The hamma and alpha stimulator devices delivered 240 J during a 20-minute treatment
session. For both gamma and alpha stimulations, an intranasal neurostimulator was used
to simultaneously stimulate ventral brain areas. The intranasal neurostimulator has an
wavelength near infrared light LED that delivers NIR through the nasal channel.
The intranasal LED has a power of 25 mW and a power density of LED of 25 mW/cm
The energy delivered by the intranasal LED is 15 Joules; the energy density is 15 J/cm
Light parameters are summarized in Table 2.
Table 2. Parameters of the Vielight PBM device (LED, Light-Emitting Diode).
Device Parameter LED
Transcranial LED Intranasal LED
Power output 100 mW 75 mW 25 mW
Power density 100 mW/cm275 mW/cm225 mW/cm2
Energy delivered 60 J 45 J 15 J
Energy density per LED
60 J/cm245 J/cm215 J/cm2
The stimulation is painless, non-invasive, and well-tolerated. The PBM devices used
in this study are considered to be non-regulated, “low risk general wellness products,’
according to the “General Wellness: Policy for Low Risk” published by the Food and Drug
Administration in September 2019 .
2.3. Procedure of Administration
Patients received tPBM treatments at home for 5 days a week, for 6 months (from
November 2020 to April 2021). Parents were trained in how to position the tPBM device
and administer the protocols. For the first at-home session, parents were asked to contact
the staff via videocall so that could be possible to control the correct administration of the
protocols and, if necessary, correct possible mistakes. Parents were retrained when necessary
and they were contacted every week by the staff to assess for adverse events. An alpha and
a gamma protocol were administered each day, one in the morning and one in the evening.
Each session had a duration of 20 min, during which children were involved in stimulating
activities (such drawing, coloring, reading, playing games, or doing homework).
2.4. Baseline and Follow-Up Assessments and Outcome Measures
Baseline assessments were performed before the ﬁrst tPBM session and repeated after
three and six months. Safety and tolerability were monitored by assessing adverse events
and vital signs weekly.
The primary outcome was the change from baseline to 3- and 6-month in the Childhood
Autism Rating Scale (CARS) (Schopler et al., 1980; 1988) [
]. The CARS consists of
assessing behaviors associated with autism, with a 15th domain rating the general
impression of autism. Total score ranges from 15 to 60, with scores below
absence of autism, a score ranging between 30 and 36.5 indicating mild-to-moderate autism,
and scores higher than 37 indicating severe autism (Schopler et al., 1988) .
Secondary outcomes were measured using the Home Situation Questionnaire-ASD
(HSQ-ASD), the Autism Parenting Stress Index (APSI), the SDAG (Scala per i Disturbi
di Attenzione/Iperattivitàper Genitori (ADHD rating scale for Parents)), the Monteﬁore
Einstein Rigidity Scale–Revised (MERS–R) and the Pittsburgh Sleep Quality Index (PSQI).
HSQ-ASD (Chowdhury et al., 2015) [
] is a 24-item parent-rated measure of noncompliant
behavior in children with ASD. The scale yields per-item mean scores of 0 to 9 (higher
Children 2022,9, 755 6 of 12
is worse). APSI (Silva and Shalock, 2012) [
] is a 13-item parent-rated measure, which
assesses parenting stress in three categories: core social disability, difﬁcult-to-manage
behavior, and physical issues. SDAG was completed by the parents. Nine items (marked
with odd numbers) explore Inattention (subscale In), and nine items (marked with even
numbers) explore Hyperactivity/Impulsivity (subscale H/I). The frequency and intensity
of the 18 ADHD symptoms are rated on a 4-point Likert scale from 0 to 3 (0, never, 1,
sometimes, 2, often, 3, very often).
MERS–R measures three domains: behavioral rigidity, cognitive rigidity and protest
domain. Behaviors are rated on a scale from 0 to 4. All three domains consist of four items.
Regarding behavioral rigidity and cognitive rigidity, the items are: 1, Time spent engaging
in behavior; 2., Interference due to behavior; 3, Distress due to disruption of behavior; 4,
Degree of control. Regarding the protest domain, the items are: 1, Time spent protesting; 2,
Interference due to protest; 3, Severity of protest; 4, Effort for redirection.
PSQI (Buysse et al., 1989)  is a standardized self-administered questionnaire, that
in this case was completed by parents. It aims to assess sleep problems and its quality.
2.5. Statistical Analysis
The baseline demographic and clinical characteristics of the sample were tabulated with
descriptive statistics. Parametric and non-parametric tests were used according to variables’
distribution to analyze changes in scores over time. For all statistical analyses, the alpha level
of significance was set at 0.05. All the statistical analyses were performed using the statistical
programming language R (version 4.0.5) (R Core Team. R: A Language and Environment for
Statistical Computing. Vienna: R Foundation for Statistical Computing (2021)).
The study included 21 patients (13 males, 8 females). The average age was 9.1 (range 5–15).
As CARS scores, MERS scores and Inattention subscale of SDAG scores were normally
distributed (veriﬁed through the Shapiro–Wilk test), one-way repeated measures ANOVA
was used to determine whether there were differences in scores during time. CARS results
(see Figure 2) showed that they were statistically signiﬁcantly different at the different
time points during tPBM intervention (F (2,40) = 137.143, p< 0.001,
g = 0.02). Pairwise
comparisons using the Bonferroni correction showed that there was a decrease in CARS
score from pre-intervention to three months (p< 0.001) and from pre-intervention to six
months (p< 0.001) as well as from three to six months (p< 0.001).
Figure 2. CARS mean scores at the three timepoints (***: p-value < 0.001).
MERS scores (see Figure 3) showed that they were statistically signiﬁcantly different at
the different time points during tPBM intervention (F (2,40) = 116.308, p< 0.001,
g = 0.55).
Pairwise comparisons using the Bonferroni correction showed that there was a decrease in
Children 2022,9, 755 7 of 12
MERS score from pre-intervention to three months (p< 0.001) and from pre-intervention to
six months (p< 0.001) but not from three to six months (p> 0.05).
Figure 3. MERS mean scores at the three timepoints (***: p-value < 0.001; ns, not signiﬁcant).
SDAG scores (see Figure 4) showed that they were statistically signiﬁcantly different at
the different time points during tPBM intervention (F (2,40) = 39.966, p< 0.001,
g = 0.574).
Pairwise comparisons using the Bonferroni correction showed that there was a decrease in
SDAG scores from pre-intervention to three months (p< 0.001) and from pre-intervention
to six months (p< 0.001) as well as from three to six months (p< 0.001).
Figure 4. SDAG mean scores at the different timepoints (***: p-value < 0.001).
As HSQ-ASD, APSI and PSQI scores were not normally distributed, a Friedman test
was run to determine whether there were differences in scores during treatment. HSQ-ASD
scores (see Figure 5) were statistically signiﬁcantly different at the different time points
during t-PMB intervention (
2(2) = 38, p= < 0.001, W = 0.905). Post hoc analysis revealed
statistically signiﬁcant differences in the scores between baseline and mid- (p< 0.001), and
post-treatment (p< 0.001), and also between mid- and post-treatment (p< 0.01).
Children 2022,9, 755 8 of 12
Median scores of HSQ-ASD and ASPI at the three timepoints (***: p-value < 0.001;
**: p-value < 0.01; ns, not signiﬁcant).
A statistically signiﬁcant difference has also been found in APSI scores (see Figure 4)
during intervention (
2(2) = 39.4, p
0.001, W = 0.938). In this case, post hoc analysis re-
vealed statistically signiﬁcant differences in the scores between baseline and mid- (
and post-treatment (p< 0.001), but not between mid- and post-treatment (p> 0.05).
PSQI scores (see Figure 6) were statistically signiﬁcantly different at the different
time points during t-PMB intervention (
2(2) = 18.9, p
0.001, W = 0.451). Post hoc
analysis revealed statistically signiﬁcant differences in the scores between baseline and
mid- (p< 0.01), and post-treatment (p< 0.01), but not between mid- and post-treatment.
Figure 6. Median scores of PSQI at the three timepoints (**: p-value < 0.01; ns, not signiﬁcant).
As far as safety is concerned, in our study, tPBM sessions were well tolerated: we had
no dropouts, and no patient experienced seizures or syncope, neurological complications,
or other major adverse effects. Occasional headache has been reported by two patients
(9.5% of patients), but the intensity did not require tPBM discontinuation.
The main result of this retrospective study is the reduction in ASD severity as shown
by the decrease in CARS scores after the intervention. Then, a reduction in cognitive
and behavioral rigidity, measured through the MERS–R, and an increase in sleep quality,
measured through the PSQI, were observed. Importantly, attention improved too, as shown
by the reduction in the scores of the inattention subscale of the SDAG. A relevant reduction
in noncompliant behavior as measured by HSQ-ASD has been also found.
Children 2022,9, 755 9 of 12
It is noteworthy to mention that these improvements, which have a great impact on
patients’ lives, allow for a decrease in parental stress, as measured through the APSI, a
result that could lay the foundation for a quieter, more effective growth environment.
It is likely, even if not demonstrable at the moment, that these effects are a consequence
of the combination of the two protocols, alpha and gamma. Indeed, increased relaxation, a
feature of the alpha protocol, would allow for a reduction in rigidity and sleep improvement,
while enhanced cognition effect, an effect of the gamma protocol, would account for
improvements in attentional functions.
The positive effects of tPBM are therefore in line with those reported by Ceranoglu
and colleagues (2022) [
] on adults with ASD, despite the different protocols, devices and
evaluation tools used. Moreover, results are consistent with the study by Leisman and
colleagues (2018) [
]. Regardless, in our study tPBM stimulates not only the temporal lobe
but the DMN, and this can explain the effects reported here that also concern rigidity and
attention. It is signiﬁcant to report that the device used in our study and the one used in
the study by Leisman (Leisman et al., 2018) [
] are different, although they are all forms of
photobiomodulation. In this study, the device uses LEDs, while in the other one laser light
is used. They differ mainly in light emission. Laser is characterized by coherence while
LED is characterized by non-coherence. (Heiskanen and Hamblin, 2018) [
the basic working principle is the same in both and their effects are similar (Brochetti et al.,
]. For our study, we have decided to employ LEDs for the ease of using them at
home and because of the lower safety concern associated with their use (Vielight Device
emits non-thermal light). Moreover, LEDs can irradiate larger areas of tissue, which is
particularly suitable for brain stimulation and speciﬁcally for frontal regions stimulation
(Salehpour et al., 2018) [
]. In addition, an intranasal light delivery method has also
been employed in this study in order to overcome the penetration limitation of LEDs in
comparison to laser.
Results regarding improved attention are consistent with a previous study (Jahan et al.,
], which reported that light irradiation with 850 nm LED source on the right prefrontal
cortex improved attentional performance. Despite the significant results, further studies are
needed to confirm attention improvements through an evoked potential evaluation.
Improvement in autism severity, which eventually corresponds to an improved co-
habitation with their relatives, as a consequence of tPBM, as reported here, could also be
explained due to the potential effect over electrophysiological oscillations. Indeed, EEG
power abnormalities in autism have been reported (Wang et al., 2013) [
] and recently,
tPBM has been shown to modulate neural oscillations (Wang et al., 2019; Zomorrodi et al.,
]. Future studies might deeply investigate this point, by studying the potential
correlation between improvements in autism severity and EEG changes.
Importantly, the results of this retrospective study suggested that tPBM is safe, since
all participants tolerated the stimulations well, even if this technique was previously
associated with treatment-emergent side effects, such as headache, strange taste in mouth
and decreased appetite (Cassano et al., 2019) .
Despite the interesting results, these ﬁndings should be evaluated considering some
limitations. Results could be partly explained by the placebo effect. Indeed, some elements
including regular contact between patients and therapists, and patients‘ expectations to
beneﬁt from treatment (in this case parents’ expectations) have been widely reported in the
literature as contextual factors that can determine an improvement in symptomatology as
the treatment itself (Brody 2018; Kjær et al., 2020) [52,53]. Therefore, further research with
well-designed studies, including a double-blind administration of the intervention, and a
placebo group, is warranted.
Future studies might use neuroimaging techniques, which could help to understand
whether the clinical improvement reported here is associated with functional or matura-
tional changes at the level of a speciﬁc network, as has been shown in Alzheimer’s disease,
where the improvement in clinical manifestation after tPBM treatment was associated with
a reduction in tau and beta-amyloid levels (Chao, 2019) [
]. Furthermore, additional tools
Children 2022,9, 755 10 of 12
that are also able to measure other domains characterizing the ASD might be employed,
in order to better understand, for example, whether the tPBM had a better effect on other
cognitive domains, such as language.
In conclusion, tPBM represents a promising intervention for children and adolescents
with ASD, considering also its practicality and the freedom of movement it offers. If other
studies will conﬁrm our ﬁndings, tPBM could represent a promising device for moving
forward to a more precision medicine approach, on the road to personalized treatment in
the realm of neurodevelopmental disorders.
Conceptualization: S.P.; Formal analysis: M.D.P.; Investigation: S.P., E.G.,
M.D.P.; Data curation: S.P., E.G., M.D.P.; writing—original draft preparation: S.P., M.D.P., E.G., G.V.,
G.C.; Writing—Revision and editing: S.P., M.D.P.; Supervision: S.P., G.C. All authors have read and
agreed to the published version of the manuscript.
Funding: This research received no external funding.
Institutional Review Board Statement: Not applicable.
Informed Consent Statement: Informed consent was obtained from all subjects involved in the study.
Data Availability Statement:
The data presented in this study are available on request from the
corresponding author. The data are not publicly available due to privacy.
The authors would like to thank the Clinical Neuoscience Onlus and Care4Autism
for their support.
Conﬂicts of Interest:
The authors declare no conﬂicts of interest with respect to the research, author-
ship, and/or publication of this article.
American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, 5th ed.; American Psychiatric Publishing:
Arlington, VA, USA, 2013.
Hill, A.P.; Zuckerman, K.E.; Hagen, A.D.; Kriz, D.J.; Duvall, S.W.; van Santen, J.; Nigg, J.; Fair, D.; Fombonne, E. Aggressive
Behavior Problems in Children with Autism Spectrum Disorders: Prevalence and Correlates in a Large Clinical Sample. Res.
Autism Spectr. Disord. 2014,8, 1121–1133. [CrossRef] [PubMed]
Soke, G.N.; Rosenberg, S.A.; Hamman, R.F.; Fingerlin, T.; Robinson, C.; Carpenter, L.; Giarelli, E.; Lee, L.C.; Wiggins, L.D.;
Durkin, M.S.; et al. Brief Report: Prevalence of Self-injurious Behaviors among Children with Autism Spectrum Disorder-A
Population-Based Study. J. Autism Dev. Disord. 2016,46, 3607–3614. [CrossRef] [PubMed]
Baglioni, C.; Nanovska, S.; Regen, W.; Spiegelhalder, K.; Feige, B.; Nissen, C.; Reynolds, C.F.; Riemann, D. Sleep and mental
disorders: A meta-analysis of polysomnographic research. Psychol. Bull. 2016,142, 969–990. [CrossRef] [PubMed]
Gargaro, B.A.; Rinehart, N.J.; Bradshaw, J.L.; Tonge, B.J.; Sheppard, D.M. Autism and ADHD: How far have we come in the
comorbidity debate? Neurosci. Biobehav. Rev. 2011,35, 1081–1088. [CrossRef] [PubMed]
Demetriou, E.A.; DeMayo, M.M.; Guastella, A.J. Executive Function in Autism Spectrum Disorder: History, Theoretical Models,
Empirical Findings, and Potential as an Endophenotype. Front. Psychiatry 2010,10, 753. [CrossRef]
Barttfeld, P.; Wicker, B.; Cukier, S.; Navarta, S.; Lew, S.; Sigman, M. A big-world network in ASD: Dynamical connectivity
analysis reﬂects a deﬁcit in long-range connections and an excess of short-range connections. Neuropsychologia
Harikumar, A.; Evans, D.W.; Dougherty, C.C.; Carpenter, K.; Michael, A.M. A Review of the Default Mode Network in Autism
Spectrum Disorders and Attention Deﬁcit Hyperactivity Disorder. Brain Connect. 2021,11, 253–263. [CrossRef]
Broyd, S.J.; Demanuele, C.; Debener, S.; Helps, S.K.; James, C.J.; Sonuga-Barke, E.J. Default-mode brain dysfunction in mental
disorders: A systematic review. Neurosci. Biobehav. Rev. 2009,33, 279–296. [CrossRef]
Chahin, S.S.; Apple, R.W.; Kuo, K.H.; Dickson, C.A. Autism spectrum disorder: Psychological and functional assessment, and
behavioral treatment approaches. Transl. Pediatr. 2020,9(Suppl. S1), S66–S75. [CrossRef]
Eissa, N.; Al-Houqani, M.; Sadeq, A.; Ojha, S.K.; Sasse, A.; Sadek, B. Current Enlightenment About Etiology and Pharmacological
Treatment of Autism Spectrum Disorder. Front. Neurosci. 2018,12, 304. [CrossRef]
Pallanti, S.; Bencini, L.; Cantisani, A.; Hollander, E. Psychotropic treatment of autism. In Autism Spectrum Disorders; Karger
Publishers: London, UK, 2015; Volume 180, pp. 151–165. [CrossRef]
DeVane, C.L.; Charles, J.M.; Abramson, R.K.; Williams, J.E.; Carpenter, L.A.; Raven, S.; Gwynette, F.; Stuck, C.A.;
Bradley, C.; et al. Pharmacotherapy of autism spectrum disorder: Results from the randomized BAART clinical trial. Pharma-
cotherapy 2019,39, 626–635. [CrossRef] [PubMed]
Children 2022,9, 755 11 of 12
14. Finisguerra, A.; Borgatti, R.; Urgesi, C. Non-invasive Brain Stimulation for the Rehabilitation of Children and Adolescents with
Neurodevelopmental Disorders: A Systematic Review. Front. Psychol. 2019,10, 135. [CrossRef] [PubMed]
Enticott, P.G.; Pallanti, S.; Hollander, E. Transcranial magnetic resonance and noninvasive brain stimulation. In Autism Spectrum
Disorders; Hollander, E., Hagerman, R.J., Fein, D., Eds.; American Psychiatric Association Publishing: Washington DC, USA, 2018.
Salehpour, F.; Mahmoudi, J.; Kamari, F.; Sadigh-Eteghad, S.; Rasta, S.H.; Hamblin, M.R. Brain Photobiomodulation Therapy: A
Narrative Review. Mol. Neurobiol. 2018,55, 6601–6636. [CrossRef] [PubMed]
Mitrofanis, J.; Henderson, L.A. How and why does photobiomodulation change brain activity? Neural Regen. Res.
Mochizuki-Oda, N.; Kataoka, Y.; Cui, Y.; Yamada, H.; Heya, M.; Awazu, K. Effects of near-infra-red laser irradiation on adenosine
triphosphate and adenosine diphosphate contents of rat brain tissue. Neurosci. Lett. 2002,323, 207–210. [CrossRef]
Konstantinovic, L.M.; Jelic, M.B.; Jeremic, A.; Stevanovic, V.B.; Milanovic, S.D.; Filipovic, S.R. Transcranial application of
near-infrared low-level laser can modulate cortical excitability. Lasers Surg. Med. 2013,45, 648–653. [CrossRef]
20. Maiello, M.; Losiewicz, O.M.; Bui, E.; Spera, V.; Hamblin, M.R.; Marques, L.; Cassano, P. Transcranial Photobiomodulation with
Near-Infrared Light for Generalized Anxiety Disorder: A Pilot Study. Photobiomodulation Photomed. Laser Surg.
Yang, L.; Tucker, D.; Dong, Y.; Wu, C.; Lu, Y.; Li, Y.; Zhang, J.; Liu, T.C.; Zhang, Q. Photobiomodulation therapy promotes
neurogenesis by improving post-stroke local microenvironment and stimulating neuroprogenitor cells. Exp. Neurol.
299 Pt A
Figueiro Longo, M.G.; Tan, C.O.; Chan, S.T.; Welt, J.; Avesta, A.; Ratai, E.; Mercaldo, N.D.; Yendiki, A.; Namati, J.; Chico-Calero, I.; et al.
Effect of Transcranial Low-Level Light Therapy vs Sham Therapy among Patients with Moderate Traumatic Brain Injury: A
Randomized Clinical Trial. JAMA Netw. Open 2020,3, e2017337. [CrossRef]
Askalsky, P.; Iosifescu, D.V. Transcranial Photobiomodulation for The Management of Depression: Current Perspectives. Neu-
ropsychiatr. Dis. Treat. 2019,15, 3255–3272. [CrossRef]
Hacke, W.; Schellinger, P.D.; Albers, G.W.; Bornstein, N.M.; Dahlof, B.L.; Fulton, R.; Kasner, S.E.; Shuaib, A.; Richieri, S.P.; Dilly, S.G.; et al.
Transcranial laser therapy in acute stroke treatment: Results of neurothera effectiveness and safety trial 3, a phase III clinical end
point device trial. Stroke 2014,45, 3187–3193. [CrossRef] [PubMed]
Cassano, P.; Petrie, S.R.; Mischoulon, D.; Cusin, C.; Katnani, H.; Yeung, A.; De Taboada, L.; Archibald, A.; Bui, E.; Baer, L.; et al.
Transcranial Photobiomodulation for the Treatment of Major Depressive Disorder. The ELATED-2 Pilot Trial. Photomed. Laser
Surg. 2018,36, 634–646. [CrossRef] [PubMed]
Cassano, P.; Caldieraro, M.A.; Norton, R.; Mischoulon, D.; Trinh, N.H.; Nyer, M.; Dording, C.; Hamblin, M.R.; Campbell, B.;
Iosifescu, D.V. Reported Side Effects, Weight and Blood Pressure, after Repeated Sessions of Transcranial Photobiomodulation.
Photobiomodulation Photomed. Laser Surg. 2019,37, 651–656. [CrossRef] [PubMed]
Caldieraro, M.A.; Cassano, P. Transcranial and systemic photobiomodulation for major depressive disorder: A systematic review
of efﬁcacy, tolerability and biological mechanisms. J. Affect. Disord. 2019,243, 262–273. [CrossRef]
Ceranoglu, T.A.; Cassano, P.; Hoskova, B.; Green, A.; Dallenbach, N.; DiSalvo, M.; Biederman, J.; Joshi, G. Transcranial
Photobiomodulation in Adults with High-Functioning Autism Spectrum Disorder: Positive Findings from a Proof-of-Concept
Study. Photobiomodul Photomed. Laser Surg. 2022,40, 4–12. [CrossRef]
Leisman, G.; Machado, C.; Machado, Y.; Chinchilla-Acosta, M. Effects of Low-Level Laser Therapy in Autism Spectrum Disorder.
Adv. Exp. Med. Biol. 2018,1116, 111–130. [CrossRef]
Mannu, P.; Maiello, M.; Spera, V.; Cassano, P. Transcranial Photobiomodulation for Down Syndrome. Photobiomodulation Photomed.
Laser Surg. 2019,37, 579–580. [CrossRef]
Salgueiro, M.D.C.C.; Kobayashi, F.Y.; Motta, L.J.; Gonçalves, M.L.L.; Horliana, A.C.R.T.; Mesquita-Ferrari, R.A.; Fernandes, K.P.S.;
Gomes, A.O.; Junior, A.B.; Bussadori, S.K. Effect of Photobiomodulation on Salivary Cortisol, Masticatory Muscle Strength, and
Clinical Signs in Children with Sleep Bruxism: A Randomized Controlled Trial. Photobiomodul Photomed. Laser Surg.
Noirrit-Esclassan, E.; Valera, M.C.; Vignes, E.; Munzer, C.; Bonal, S.; Daries, M.; Vaysse, F.; Puiseux, C.; Castex, M.P.; Boulanger, C.; et al.
Photobiomodulation with a combination of two wavelengths in the treatment of oral mucositis in children: The PEDIALASE
feasibility study. Arch. Pédiatrie 2019,26, 268–274. [CrossRef]
Santos, M.; Nascimento, K.S.; Carazzato, S.; Barros, A.O.; Mendes, F.M.; Diniz, M.B. Efﬁcacy of photobiomodulation therapy
on masseter thickness and oral health-related quality of life in children with spastic cerebral palsy. Lasers Med. Sci.
Faulhaber, F.; Procianoy, R.S.; Silveira, R.C. Side Effects of Phototherapy on Neonates. Am. J. Perinatol.
Chao, L.L. Effects of Home Photobiomodulation Treatments on Cognitive and Behavioral Function, Cerebral Perfusion, and
Resting-State Functional Connectivity in Patients with Dementia: A Pilot Trial. Photobiomodulation Photomed. Laser Surg.
133–141. [CrossRef] [PubMed]
Gavish, L.; Houreld, N.N. Therapeutic Efﬁcacy of Home-Use Photobiomodulation Devices: A Systematic Literature Review.
Photobiomodulation Photomed. Laser Surg. 2019,37, 4–16. [CrossRef] [PubMed]
Children 2022,9, 755 12 of 12
Vielight. Available online: https://www.vielight.com/wp-content/uploads/2020/06/Neuros-AG-info-sheet-2020-A-v3.pdf
(accessed on 3 March 2022).
Schopler, E.; Reichler, R.J.; DeVellis, R.F.; Daly, K. Toward objective classiﬁcation of childhood autism: Childhood Autism Rating
Scale (CARS). J. Autism Dev. Disord. 1980,10, 91–103. [CrossRef]
Jadgeo, J.R.; Adams, L.E.; Brody, N.I.; Siegel, D.M. Transcranial red and near-infrared light trans-mission in a cadaveric model.
PLoS ONE 2012,7, e47460.
Tedford, C.E.; DeLapp, S.; Jacques, S.; Anders, J. Quantitative analysis of transcranial and intra-parenchymal light penetration in
human cadaver brain tissue. Lasers Surg. Med. 2015,47, 312–322. [CrossRef]
U.S. Department of Health and Human Services Food and Drug Administration Center for Devices and Radiological Health.
General Wellness: Policy for Low Risk Devices Guidance for Industry and Food and Drug Administration Staff. Document
issued on 27 September 2019. Available online: https://www.fda.gov/regulatory-information/search-fda-guidance-documents/
general-wellness-policy-low-risk-devices (accessed on 8 April 2022).
Schopler, E.; Reichler, R.; Rochen Renner, B. The Childhood Autism Rating Scale; Western Psychological Services: Los Angeles, CA,
Chowdhury, M.; Aman, M.G.; Lecavalier, L.; Smith, T.; Johnson, C.; Swiezy, N.; McCracken, J.T.; King, B.; McDougle, C.J.; Bearss, K.; et al.
Factor structure and psychometric properties of the revised Home Situations Questionnaire for autism spectrum disorder: The
Home Situations Questionnaire-Autism Spectrum Disorder. Autism 2015,54, 281–291. [CrossRef]
Silva, L.M.; Schalock, M. Autism Parenting Stress Index: Initial psychometric evidence. J. Autism Dev. Disord.
Buysse, D.J.; Reynolds, C.F., 3rd; Monk, T.H.; Berman, S.R.; Kupfer, D.J. The Pittsburgh Sleep Quality Index: A new instrument
for psychiatric practice and research. Psychiatry Res. 1989,28, 193–213. [CrossRef]
Heiskanen, V.; Hamblin, M.R. Photobiomodulation: Lasers vs. light emitting diodes? Photochem. Photobiol. Sci.
Brochetti, R.A.; Leal, M.P.; Rodrigues, R.; da Palma, R.K.; de Oliveira, L.; Horliana, A.; Damazo, A.S.; de Oliveira, A.;
Paula Vieira, R.
; Lino-Dos-Santos-Franco, A. Photobiomodulation therapy improves both I nﬂammatory and ﬁbrotic parameters
in experimental model of lung ﬁbrosis in mice. Lasers Med. Sci. 2017,32, 1825–1834. [CrossRef] [PubMed]
Jahan, A.; Nazari, M.A.; Mahmoudi, J.; Salehpour, F.; Salimi, M.M. Transcranial near-infrared photobiomodulation could modulate
brain electrophysiological features and attentional performance in healthy young adults. Lasers Med. Sci.
Wang, J.; Barstein, J.; Ethridge, L.E.; Mosconi, M.W.; Takarae, Y.; Sweeney, J.A. Resting state EEG abnormalities in autism spectrum
disorders. J. Neurodev. Disord. 2013,5, 24. [CrossRef] [PubMed]
Wang, X.; Dmochowski, J.P.; Zeng, L.; Kallioniemi, E.; Husain, M.; Gonzalez-Lima, F.; Liu, H. Transcranial photobiomodulation
with 1064-nm laser modulates brain electroencephalogram rhythms. Neurophotonics 2019,6, 025013. [CrossRef]
Zomorrodi, R.; Loheswaran, G.; Pushparaj, A.; Lim, L. Pulsed Near Infrared Transcranial and Intranasal Photobiomodulation
Signiﬁcantly Modulates Neural Oscillations: A pilot exploratory study. Sci. Rep. 2019,9, 6309. [CrossRef]
52. Brody, H. Meaning and an Overview of the Placebo Effect. Perspect. Biol. Med. 2018,61, 353–360. [CrossRef]
Kjær, S.W.; Rice, A.; Wartolowska, K.; Vase, L. Neuromodulation: More than a placebo effect? Pain
,161, 491–495. [CrossRef]