A 5 month old boy baby is having persistent head lag, born by LUCS due to less liquer, birth weight being 2.4 kg, now he is 6.9 kg. No history of birth injury, difficult delivery. Developed jaundice at day 6 of life, cured by phototherapy for 24 hrs.

Now he can roll over, taking feed adequately, appropriate social smile but neck holding not achieved. What type of investigation needed here? Can physiotherapy help in this situation?Please share your valuable opinion.