Apart from she is not turn left and right side, you have not mentioned any other problem
I can understand your worries,
Don`t panic. Calm down, be courageous and get her treated.
Though i don't doubt the diagnosis made by your doctor as he would be in a better position to assess the condition of your child than me,
BERRA test for Hearing evaluation in child, and it is very difficult to clinically asses hearing loss
. May be it is reason she is not turning, That is why your doctor advise to do BERA test.
I would advice:
May be it is due to delay milestone , or any other condition, It required closely supervision.
Watch for 6 month milestone- sitting with own support,Reaching out for object with one hand, Recognizes stranger/ stranger anxiety
, Monosyllables (ba da pa),ah-goo sounds,
If possible. you can get back to me with the progress in case u need further suggestions.
I wish your child good health
Regards; Dr.Sagar Mhatre