#ASD #HDtDCS #Neuromodulation
#SensorySensitivity #SocialCognition
Autism spectrum disorder (ASD) is a
neurodevelopmental condition characterized by
persistent difficulties in social
interaction, communication, and repetitive or restricted behaviors. Many
autistic children also experience
sensory processing abnormalities, including
hypersensitivity (strong reactions to certain sounds, textures, lights, etc.)
or
hyposensitivity (seeking intense stimulation, low reactivity to sensations).
Despite affecting up to 90% of children with ASD, these sensory issues are
still too often overlooked in intervention protocols.
Recent studies suggest that these sensory
features could play a key role in how children respond to behavioral or
cognitive therapies. They may impact a child's engagement, tolerance, and
ability to generalize learned skills.
Against this backdrop, a new study was launched
to explore the potential of a personalized neuromodulation approach. This
method targets stimulation to the brain’s central region (Cz), which is
involved in both sensory regulation and social interaction.
Stimulating for better socialization?
Seventy-two children aged 4 to 12, diagnosed with ASD, participated in the
study and were divided into three groups:
- Active HD-tDCS + typical sensory integration
- Active HD-tDCS + sensory integration disorder (SID)
- Sham HD-tDCS
Stimulation was administered in 15 sessions (20
minutes each, at 1 mA). Effects were measured using the Social Responsiveness
Scale (SRS) and the Short Sensory Profile (SSP). A secondary analysis
classified the children based on tactile sensitivity: hypo-reactive,
hyper-reactive, or typical.
The results revealed that the effects of
stimulation varied depending on the child's sensory profile. Children with
typical sensory integration or
tactile hyposensitivity showed
significant
improvements in social skills, especially in
communication,
social cognition,
and
adaptive behaviors. These children also tolerated the stimulation well,
with no major adverse effects reported.
In contrast, children with
tactile
hypersensitivity experienced much more limited benefits.
No significant
improvements were observed in social metrics. Furthermore, these children
showed
increased reactivity to the treatment, with reported
side effects such
as
irritability, burning sensations, and skin discomfort, suggesting
lower
tolerance to HD-tDCS in this subgroup.
These findings emphasize the importance of
considering autistic children's sensory profiles before implementing brain
stimulation, to maximize benefits and avoid adverse reactions.
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A spark for the social brain
Autism spectrum disorders are marked by impaired social interaction, often
coupled with atypical sensory processing. These sensory abnormalities, still
largely underrepresented in therapeutic strategies, may influence the
effectiveness of neuromodulatory interventions. A key challenge today is
identifying targeted approaches capable of modulating the brain networks
involved in social cognition.
This study aimed to evaluate the effects of
high-definition transcranial direct current stimulation (HD-tDCS) on the social
skills of autistic children, depending on their tactile profile. The findings
show that this approach improves social abilities in children with typical
sensory profiles or tactile hyposensitivity. However, for hypersensitive
children, the stimulation was less effective and less well tolerated.
These results confirm the
close link between
social cognition and sensory integration, and that poorly tailored stimulation
may be ineffective—or even uncomfortable. More personalized protocols,
including cathodal stimulation for hypersensitive children, could enhance
outcomes and improve tolerability. In the future, this approach could be
integrated into broader care strategies and combined with educational
interventions.
Read next: Boosting the social brain?
