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Well, I am not aware of any such treatment modality that has come up lately , in fact neither do any other psychiatrists and therapists would vouch for any such treatment. Unfortunately there is no such vest , which can be used for treating ADHD in kids , and i believe the health professional who told you this must be trying to impress you , i suggest next time you meet him/her just ask about the scientific basis with which this vest is going to act and ask if he could show you some patients who have been receiving such treatment.
As of now , we still have either pharmacological treatment( medications) or Psychotherapy ( Counselling in lay terms) as the 2 most effective treatment options for ADHD IN KIDS AS WELL AS IN ADULTS.
The medications which work best in ADHD are the Psycho stimulants such as Adderall (amphetamines) and Ritalin (methylphenidate).
And the best psychotherapies used for ADHD are-- Cognitive behavioural therapy (CBT), Behaviour therapy , Interpersonal therapy, Family therapy, Psycho education for care givers, School based therapy and intervention, Parent training and education.
So , i suggest if you have a kid in your family who is suffering from ADHD , it would be better if he/ she is put on proper authentic treatment ,as mentioned above under the supervision of a Psychiatrist , and try not to heed advise from such health professionals , who i feel do not understand the gravity of situation and the angst of the family who has a kid suffering from ADHD.
I hope my answer serves your query according to your satisfaction.