It was gradual. As The origin indicates, the damage was done in a week or two after Shantanu’s birth. Though the parents were initially mindful for a trouble of some or the other kind, but its severity was to be discovered in the years to come.
When he was 6 months old, Shantanu was not able to perform physical activities similar to normal children his age, such as crawling, or using hands and fingers, or speaking, but could hear and see (which was evident by his pointing at objects like fan, tubelight, etc with his eyes, whenever asked). He was then taken to Choithram hospital for treatment, and thus began his physiotherapy under the able guidance of Dr Sudhir Kothari. Dr Kothari not only counseled for physical treatment, but also educated in other CP related aspects, like Speech therapy, education at home and effective parenting for such children. Gradually it became clear that physiotherapy could not cure Shantanu’s disability but was still vital for his proper metabolism. Many other treatments - Allopathy, Acupressure, Pyramid Therapy, Reiki, Magnet Therapy, Homeopathy, Naturopathy, Sleep Therapy, MRI scan to detect scope for neurosurgery - followed over the years, to no avail.
It was Dr Kothari who first identified that Shantanu was not mentally retarded and insisted on testing his IQ. The diagnosis was correct and Shantanu’s IQ was estimated at 92+ (‘+’ implies actual IQ is greater than the estimated figure due to restriction in physical ability like drawing shapes and all) at the age of 6 years. This was Shantanu's first step towards normality.