Head shaking side to side - 12 months

[FTME92]

My little boy is 12 months old and has been shaking his head side to side on and off for 2
months. It’s usually been quite subtle in the pram, high chair etc and would happen for a couple of days and then disappear for a while.
The last week it has dramatically increased in frequency, and happening at any point. Sometimes he’ll do it when playing and almost laugh at my reaction when I say stop and do it again. You can stop him doing it but to me it looks scary. The first time it happened it seemed to be linked to a tooth and the second a cold, but now it just seems to be constantly here.

Developmentally he’s hitting all his milestones, walking, gestures (pointing, waving, clapping, arms up, cheersing) responding to name, good eye contact, babbling but no words (although sounds like he’s trying to say uh oh when he drops something) he’s not imitating sounds really (which I guess is the one area is behind)

My health visitor and paediatrician have both said they aren’t concerned but I’m so anxious. Just wondered if there’s any positive stories out there of this just being an odd quirk.

My two year old likes to do this sometimes for the joy of feeling their hair whip back and forth.

All the gestures sound like your baby is completely on track for communication. Lots of babies have no words - or words you aren't sure are words - at 12 months, and things will change a LOT in the next six months.

Mine knows it means no. He does it when he's doing something he knows he shouldn't, like shredding the potplants, but also if he doesnt want to eat something. You've turned it into a game with yours!

Do you get the sense he is doing this voluntarily?
There can be lots of reasons for this, but if you are concerned, I would consult with a neurologist and/or a paediatric ophthalmologist. My experience with my son is extremely rare, but in my experience you should trust your gut and investigate with drs until you are satisfied, because very rarely serious things do happen.
My DS developed a headshake just before 12 months... we went to a neurologist, had an EEG - all normal. He was already in glasses by this age. He had nystagmus too (mild eye wobble, which I never really saw). He would shake his head in the high chair & later when he was watching TV - it was definitely involuntary but if I asked him a question say, he would stop... only for it to start again. It passed after some time & we were no longer concerned.
After some months, the shake returned & was more pronounced. Long story short - at age 3 he was diagnosed with a rare brain tumour. After surgery & some time after radiation shrank the tumour, his head shake disappeared. He's now 16 and doing great. The drs in the UK were dismissive of the head shake as being a warning sign, but in the US (where the NHS sent him for treatment) the drs rolled their eyes at the suggestion it wasn't related.

Absolutely not saying it is always something sinister or even a recognised warning sign of a brain tumour, but in our case I'm certain it was related.
This is a helpful guide from the Brain Tumour Charity.
Brain tumour symptoms in children | The Brain Tumour Charity