Child Normal Development

What are the four (or five) domains of child development, and how do they relate to each other?

Main domains are:
1) Gross motor,
2) Vision and fine motor (grouped together because fine motor requires good vision),
3) Hearing, speech and language (grouped because language depends on hearing), and
4) Social, emotional and behavioural.
5) Cognitive domain is also assessed.

What is the difference between "median age" and "red flag age" for developmental milestones, and why is the red flag age more clinically useful?

Median age is the age when 50% of children have achieved a milestone — it is a guide to the expected pattern but does not determine whether a child is outside the normal range.

Red flag age is the age by which 97.5% of children should have achieved a milestone; failure to reach it by this age is a prompt for detailed assessment to determine if investigation or intervention is required.

For example, the median age for independent walking is 12 months, but the red flag age is 18 months.

What are the red flag ages for all key gross motor milestones?

Head control: red flag age 4 months.
Sits unsupported: red flag age 9 months.
Stands with support: red flag age 12 months.
Walks independently: red flag age 18 months.

Key median-age milestones:
marked head lag at newborn; no head lag at 3 months;
sits with round back at 6 months / straight back at 8 months;
crawling at 8–9 months;
cruises along furniture at 10 months;
stands independently at 10 months;
walks unsteadily with broad gait at 12 months;
walks steadily at 15 months;
runs and kicks a ball at 2 years; pedals tricycle at 3 years.

What are the red flag ages for vision and fine motor milestones, and what are the key median-age milestones in this domain?

Red flag ages: Fixes and follows visually — 3 months;
Reaches for objects — 6 months;
Transfers objects hand-to-hand — 9 months;
Pincer grip — 12 months.

Key median-age milestones:
follows moving face/light by 6 weeks;
reaches for toys at 4 months;
palmar grasp at 4–6 months;
transfers toys hand-to-hand at 7 months;
mature pincer grip at 10 months;
makes marks with crayon at 16–18 months;
tower of 3 bricks at 15 months;
tower of 6 bricks at 2 years; tower of 8 bricks or train of 4 at 2.5 years;
copies a circle (3 years), cross (3.5 years), square (4 years), triangle (5 years).

What are the red flag ages for hearing, speech and language milestones, and what are the key median-age milestones?

Red flag ages:
Polysyllabic babble — 7 months; Consonant babble — 10 months;
6 meaningful words — 18 months;
Joins 2 words — 2 years;
3-word sentences — 2.5 years.

Key median-age milestones:
startles to loud noises at newborn;
vocalizes and coos at 3–4 months;
turns to soft sounds out of sight at 7 months;
sounds used discriminately to parents at 10 months;
2–3 words other than "dada/mama" at 12 months;
6–10 words and points to 2 body parts at 18 months;
joins 2–3 words in sentences and >30 words at 2 years;
talks constantly in 3–4 word sentences at 2.5–3 years.

Language sequence: Cry → Coo (2–6 months) → Babble (6–12 months) → Words (1–2 years) → 2-word phrases (2–3 years) → 3–4 word sentences (3–5 years) → Tells stories (5+ years).

What are the red flag ages for social, emotional and behavioural milestones, and what are the key median-age milestones?

Red flag ages:
Social smile — 8 weeks;
Fear of strangers — 10 months;
Feeds self with spoon — 18 months;
Symbolic (pretend) play — 2–2.5 years; Interactive play — 3–3.5 years.

Key median-age milestones:
social smile at 6 weeks;
knows mother/laughs at 4–5 months;
finger feeds and fears strangers at 6–7 months;
waves bye-bye and plays peek-a-boo at 10–12 months;
drinks from cup at 12 months;
holds spoon and gets food safely to mouth at 18 months;
symbolic/imaginative play at 18–24 months;
parallel play evolving to interactive play at 2.5–3 years;
dry by day and pulls off some clothing at 2 years.

Describe the detailed developmental milestones month by month from birth to 6 months across all domains.

Birth: Crying to indicate needs; follows moving objects/light; startles to loud noise; smiles by 6 weeks.
1 month: Raises head slightly in prone; tight palmar grasp; alerts to sound; regards face.
2 months: Visual fixation/follows nearby objects; social smile; coos; holds head in midline (45° from prone).
3 months: Supports head when held erect; opens hands spontaneously; increased interest in surroundings; swings at/reaches for dangling toys.
4–5 months: Rolls front-to-back then back-to-front; supports on wrists; grasps hands together; knows mother; laughing.
6 months: Sits momentarily (C-shaped); transfers objects hand-to-hand using 4 fingers; understands objects (e.g., bottle = feeding time); shows likes/dislikes; recognizes strangers; babbles ("ba ba" sounds).

Describe the developmental milestones from 7 months to 12 months across all domains.

7-8 months: Sits without support (L-shaped); turns to voice; polysyllabic babble.
8 months: Crawls (lion-like) or creeps (worm-like).
9 months: Creeps/crawls or pulls to stand; pincer grasp; interest in picture books; watches others' activities; feeds self; plays peek-a-boo; repetitive sounds "mama dada."
10 months: Waves bye-bye; stands supported; consonant babble.
11 months: Walks supported.
12 months: Stands unsupported; releases object on command; responds to simple instructions; uses trial-and-error to learn; knows what "no" means; comes when called; plays simple games; 1–2 meaningful words (papa, mama); responds to own name.

Describe the developmental milestones from 15 months to 2 years across all domains.

15 months: Walks independently; scribbles; drinks from a cup;
4–6 words; follows commands without gesture; imitates activity; sends kisses.
18 months: Walks unsupported; walks upstairs with one hand held; seats himself in small chair; feeds from a spoon; enjoys picture books; explores environment;
knows names of 4 body parts; index pointing; mimics others; at least 6 meaningful words.

2 years (19–24 months): Runs; kicks large ball; squats; walks up and down stairs 2 feet per step; turns picture book pages one at a time; recognizes details in pictures; uses own name to refer to self; matches 2 objects by colour/shape/size; builds tower of 6 cubes; plays with others; tantrums; aware of physical needs; joins 2–3 words in sentences; speaks >30 words and acquires new words rapidly.

What are the cognitive milestones from birth to 24 months?

Birth–4 months: Oriented to sound; visual tracking; sucking/rooting reflex; shakes a rattle.
5 months: Knows mother.
6–9 months: Mimics actions (e.g., peek-a-boo); transfers objects hand-to-hand; understands what objects are for (e.g., bottle = feeding).
9–12 months: Responds to own name; searches for hidden objects (object permanence).
12–18 months: Points to indicate interest; follows simple commands; uses objects correctly (cup, spoon).
18–24 months: Pretend/symbolic play; identifies body parts; begins problem solving by trial and error; follows 2-step commands.
Piaget's stages: pre-operational thought in preschoolers (egocentric, animistic, magical thinking) → operational/practical thought in school-age → abstract/formal operational thought in adolescence.

What are the key primitive reflexes present at birth, when do they disappear, and what postural reflexes replace them?

Primitive reflexes (present at birth, disappear by ~3–5 months):
Palmar grasp (flexion of fingers when object placed in palm) — disappears by 3 months;
Rooting reflex (turns head when touched near mouth) — disappears by 3 months;
Sucking reflex — disappears by 3 months;
Moro reflex (symmetrical abduction/extension then flexion/adduction of arms on sudden head extension) — disappears by 5 months; ATNR/Asymmetric Tonic Neck Reflex (fencing posture on turning head) — disappears by 3 months;
Placing reflex (steps on surface when dorsum of foot touches it).

Persistence of primitive reflexes may interfere with normal motor development.

Postural reflexes that emerge at 4–12 months: Labyrinthine righting;
Postural support; Lateral propping;
Parachute reflex (arms extend when suspended face-down).

How should prematurity be adjusted for in developmental assessments, and what are the normal locomotor pattern variations in young children?

For premature babies, developmental age should be calculated from the expected date of delivery (EDD), not the actual birth date.

A 9-month-old born 3 months early (at 28 weeks) is expected to have the skills of a 6-month-old.
Correction for prematurity is NOT required after 2 years of age, as the weeks of prematurity no longer represent a significant proportion of the child's life.

Regarding locomotor variation: 83% of infants crawl on all fours before walking, but some bottom-shuffle (often familial) and others commando-crawl/creep. Bottom-shufflers tend to walk later — 50% walk by 18 months and 97.5% by 27 months.

The 18-month red flag for walking applies to crawlers; bottom-shufflers may need individual assessment to exclude cerebral palsy, global developmental delay, muscle disorders, joint hypermobility, or DDH.

What is Global Developmental Delay (GDD), what constitutes it, and why is early detection of developmental delay so important?

GDD is defined as significant delay in two or more of the five developmental domains in children under 5 years of age.
Early detection is important because:
1) Early intervention and treatment have the best outcomes when started in the first 2–3 years of life (the critical period) — benefit decreases significantly after 3–5 years;
2) It provides parents with an explanation for difficulties they observe in their child;
3) It identifies associated findings that help guide comprehensive management.

Early Augmented Intervention Programs include: cognitive sessions, language sessions, gross motor sessions, fine/occupational motor sessions, and social/communication/behavior modification sessions — ideally daily or at least 3 times per week.

What is Intellectual Disability (Intellectual Subnormality/Mental Retardation), how is it classified by IQ, and what adaptive skills are assessed?

Intellectual Disability is defined by significantly below-average cognitive functioning (IQ <70) combined with deficits in adaptive behaviour, presenting before age 18.

IQ classification:
Borderline/Slow learner: IQ 71–89;
Normal/Average: IQ 90–110;
Mild ID: IQ 50–70;
Moderate ID: IQ 35–50;
Severe ID: IQ 20–35;
Profound ID: IQ <20. IQ = (Mental Age ÷ Chronological Age) × 100.

What are the causes of intellectual disability/mental retardation that can be diagnosed by facial appearance, and what is Autism Spectrum Disorder (ASD)?

Conditions diagnosable by facial features include:
1) Down Syndrome (trisomy 21); 2) Microcephaly; 3) Congenital Hypothyroidism (cretinism); 4) Phenylketonuria (PKU) — fair features in dark-skinned families; 5) Severe Hydrocephalus; 6) Total Craniosynostosis.

Autism Spectrum Disorder (ASD) is characterized by a triad of:
1) Defect in language/communication;
2) Defect in socialization;
3) Repetitive behaviours, acts, or interests.

ASD is a spectrum ranging from mild to severe. Screening for ASD is indicated when there are abnormal developmental milestones.
The ADOS (Autism Diagnostic Observation Schedule) and ADI-R (Autism Diagnostic Interview) are gold-standard diagnostic tools.

When is Squint normal in a child and when it should require investigation?

Newborns may appear to squint when looking at nearby objects because their eyes over-converge. By 6 weeks of age, the eyes should move together when following an object,
and by 12 weeks of age there should be no squint present.