Developmental delay

Developmental delay refers to the delay in 1 of the 4 developmental domains. When considering the timeframes in which they should achieve certain milestones in those domains, there are 2 definitions to be aware of:

• Median age of acquisition - this is when half of the standard population of children would have achieved said milestone.
• Limit age - the age at which the milestone should be achieved and after which we consider there to be developmental delay. 97.5% of the population achieve the milestone at the limit age.

Let’s look at the 4 domains of development:

1. Gross motor
2. Fine motor and vision
3. Speech and language
4. Social and emotional

If a single area is implicated it is known as specific developmental delay. If it is more than a single area, then it is known as global developmental delay (GDD).

GDD may be indicative of an underlying diagnosis such as:

• Down syndrome
• Fragile X syndrome
• Foetal alcohol syndrome
• Rett syndrome
• Metabolic disorders

Pathophysiology

As there are numerous causes of developmental delay, we will simply use this section to outline some causes of developmental delay:

Other causes of developmental delay may include:

• Prematurity
• Autism spectrum disorder
• Hypothyroidism
• Idiopathic

😷 Presentation

We will take a look at the features of developmental delay with respect to the 4 domains of development:

Gross motor

The gross motor skills are the most obvious area of developmental progress.

Over time, a child normally will develop the following gross motor skills:

• Acquisition of tone and head control
• Loss of primitive reflexes
• Sitting
• Locomotor patterns
• Standing, walking and running
• Hopping, jumping and peddling

🚩 Red flags of gross motor development:

• No head control by 4 months
• Not sitting unsupported by 9 months
• Not standing with support by 12 months
• Not walking independently by 18 months

The red flag age of 18 months for walking applies to children who crawled as their early mobility pattern. Children that bottom-shuffle tend to walk later than crawling children. 50% of bottom-shufflers walk independently by 18 months, and 97.5% by 27 months.

Late-walking children need to be assessed to exclude cerebral palsy, global developmental delay, primary muscle disorders, joint hyper mobility or developmental dysplasia of the hip.

Fine motor and vision

Seeing as fine motor skills require good vision, vision is grouped together in this group.

Over time, a child normally will develop the following fine motor and vision skills:

• Visual alertness, fixing and following
• Grasp reflex and hand regard (when babies watch their own hand)
• Voluntary grasping, pincer movement, and pointing
• Handles objects with both hands and transfers objects from hand to hand
• Writing, cutting and dressing

🚩 Red flags of fine motor and vision development:

• Showing hand preference before 12 months
• Not fixing and following by 3 months
• Not reaching for objects by 6 months
• Not transferring between hands by 9 months
• No pincer grip by 12 month

Hearing, speech and language

Over time, a child normally will develop the following hearing, speech and language skills:

• Sound recognition, and vocalisation
• Babbling
• Single words, understands simple requests
• Joining words, phrases
• Simple and complex conversation

🚩 Red flags of hearing, speech and language development:

• No polysyllabic babble by 7 months
• No consonant babble by 10 months
• Not saying 6 words with meaning by 18 months
• Not joining words by 2 years
• No 3 word sentence by 2.5 years

It is important to differentiate between speech delay and speech disorder:

• Speech delay - when speech is developing in a normal sequential pattern but occurring later than is typical.
• Speech disorder - when there is atypical language acquisition significantly disrupting communication across settings.

Social, emotional and behavioural

Over time, a child normally will develop the social, emotional and behavioural skills:

• Smiling, and socially responsive
• Separation anxiety
• Self-help skills, feeding, dressing and toileting
• Peer group relationships
• Symbolic play
• Social/communication behaviour

🚩 Red flags of social, emotional and behavioural development:

• Not smiling by 8 weeks
• No fear of strangers by 10 months
• No self-feeding or using spoon by 18 months
• No symbolic play by 2-2.5 years
• No interactive play by 3-3.5 years

🔍 Investigations

The aim of investigating developmental delay is to explore 3 aspects:

1. Cause of delay
2. Prognosis
3. Treatment options

🥇 First-line investigations include:

🥈 Second-line investigations may include:

These investigations may be helpful as directed by the first-line investigations, or if the cause is still unknown.

• Karyotyping and DNA analysis
• Metabolic screens
• MRI and EEG

A premature baby should be assessed from it expected date of delivery. The anticipated skills of a 9-month-old baby who was born 2 months early should be of that of a 7-month-old baby. Correction is not required after 2 years of age as the prematurity is no longer a a representative and significant proportion of the child’s life.

🧰 Management

• Refer to community paediatrician for detailed developmental assessment and holistic assessment of the child and the family. One may use a Griffiths Scales of Child Development (for cognitive development measures) or the Schedule of Growing Skills (SOGS) to measure the child against.
• Specialist therapies:
• Speech and language therapy
• Occupational therapy
• Portage practitioners - home-visiting educational service for pre-school children with special educational needs.
• Orthoptist
• Hospital paediatrician (if there is any acute issue or deterioration)
• Treat underlying cause