My niece just went for her 12 month check the doctor was really concerned with the growth spurt in her head and questioned my sister about motorskills?

Needs more tests: Your doctor will want to determine whether this is normal growth spurt or whether there conditions causing high pressure in the skull or high growth hormone levels.

Depends: A sudden growth spurt does not necessarily mean something bad. However, if it is in the context of developmental or motor delays, then it could be something worth investigating. If everything else is fine, and its just a growth spurt, then it may be ok to just observe and see how things go by the next visit.

Macro vs hydrocephal: Your niece's pediatrician has been following her head circumference on a growth chart. If the growth curve of head circumference is crossing percentile lines concern would be about hydrocephalus or other causes of macrocephaly. Question about motor skills is to seee if there is an indication of concern about the rapid growth. There may be a place for a CAT scan or MRI