“As little is yet known about the best ways to utilise TDCS, there is no
training program or licensing regime for clinicians applying the technique.
Inadequately trained clinicians might misidentify suitable sites for
stimulation — an important issue as different cognitive abilities may be
subserved by different brain areas at different stages across the lifespan.
They might also fail to ensure that stimulation parameters are within safety
guidelines.

“At best, this situation could result in the exploitation of vulnerable
patients or parents for financial gain; at worst, it may risk long-term
damage to the brain and exacerbate the disadvantage, potentially worsening
other psychological functions.

“For example, repeated stimulation of the parietal cortex in order to increase
numerical competence during developmental stages when the prefrontal cortex
is more important might not only fail to give any improvement but it could
even worsen performance and lead to atypical brain development.

“Like other types of atypical experience during sensitive periods, the
stimulation of the wrong brain area might induce abnormal patterns of brain
activity in this brain region and interconnected areas, and increase
metabolic consumption in brain areas that are irrelevant to the specific
psychological function.

“Hence, research into the safety and potential hazards of TDCS in children is
urgently needed."

Researchers also claim there are doubts over whether the technique should
be used on the developing brains of young people. They believe that
enhancing abilities in one part of the brain could impact on the
capabilities of other parts.

"To date, most research on cognitive enhancement has focused on
improving average or impaired abilities. However, such enhancement may come
at a cost in some cases. Highly-developed capacities I certain cognitive
domains in some individuals are accompanied by reduced functioning in
others. It would be premature to allow children, or their parents, to make
the choices that lead to higher functioning in one domain (such as language)
at a cost to functioning in other valuable domains (such as face
recognition), as they might lack understanding of the ways in which the
development of cognitive abilities may depend on earlier cognitive
functions, as well as on brain organisation."

This could lead to parents being tempted to use the treatment to improve
their children’s academic ability in one area at the expense of another.

"Depending on how bad the negative effects of an enhancement are, it
might be appropriate to block parents’ access to the enhancement. Those
involved in the professional use of TDCS should not facilitate the choices
of parents if the side effects are sufficiently bad, or sufficiently ill
understood. If TDCS does enhance some abilities at a cost to others, then
assessing its ethical permissibility will involve weighing its costs and
benefits."