Hypersensitivity is when children are extremely reactive to sensory stimulation. They may find these stimuli overwhelming. Sunlight could be too bright or a noise level that would not bother others could make them cover their ears. Hyposensitivity is when children are under-sensitive to stimulation.
Symptoms of hypo sensitivity are;
a high pain threshold.
bumping into walls.
touching things.
putting things into their mouth.
giving bear hugs.
crashing into other people or things.
I think my youngest has a bit of both hyper and hypo sensitivity; she has an extremely high pain threshold, but is on the other side sensitive for loud noises and darkness

Children with some genuine medical conditions such as epilepsy do not grow out of some sensory issues. e.g. some types of lighting such as down lights, the older type of fluro lights and flashing on emergency vehicles. I have witnessed this with children and it is not nice for a child to suddenly fall to the floor and somebody think the child is asleep on the floor if he’/she is not jerking, Some react to loud noises. Some children with some degrees of Autism or ASD are very sensitive to some things too,

Hypo-sensitivity is like adhd with the kids needing to be constantly moving, jumping, being active. They may have a habit like flicking on/off light switches etc.

Could you provide more detail to help with possible answers – an explanation of hypo-sensitivity may help?

I don’t know what this is. My son was super sensitive to any changes in his environment and my daughter had many issues with jewellery and belt buckles etc. They grew out of most of it