What are the 9 Abnormalities of Development?

All babies achieve some fundamental milestones during the first few months of their development. If these milestones are not achieved, then it hints to some underlying development abnormality. Read this blog post to understand all the 9 types of development abnormalities.

Development and abnormalities related to it are an important and indispensable part of Pediatrics. 

Abnormalities of Development (3 ‘D’ S)

1. Delay
2. Dissociation
3. Deviancy 

Developmental Delay

• When child’s performance in 1 or more domains is significantly below average or what is expected.

Developmental Dissociation

• Substantial difference in the rate of development of milestones in 2 or more domains
• Example: Isolated speech delay is a developmental dissociation since only language is hampered while all other domains are normal.

Developmental Deviancy

• Developmental milestones occurring out of sequence.
• Example: If Crawling comes before sitting.

Developmental Red Flags

• The upper time limit by which the milestones should usually be attained.

Gross motor	Upper limit	Usual time
Sitting with support	9 months	6 months
Standing with support	12 months	9 months
Walking with support	15 months	12 months

Fine motor	Upper limit	Usual time
Pincer graspmonths	12 months	9 months
Scribbling	24 months	15 months

Social	Upper limit	Usual time
Social Smile	6 months	2-3 months
Waving bye-bye	12 months	9 months

Language	Upper limit	Usual time
Babbling	12 months	6 months
Single words	15-16 months	1 year

• If these milestones are not attained by this time, then there is probably some underlying abnormality of development.

Important causes of Development delay (“CDGP PIC”)

1. C - Chromosomal abnormalities (Trisomy 21, 13, 18)
2. D -Developmental brain abnormalities (lissencephaly- brain appears smooth due to less gyri & sulci, myelomeningocele)
3. G - Genetic syndromes (Fragile X Syndrome, Rett syndrome, Prader Willi syndrome Nooram syndrome)
4. P - Perinatal factors: Asphyxia, HIE (Hypoxic Ischemic Encephalopathy)
5. P - Postnatal factors and acquired: (CNS Trauma, infections, Hypothyroidism,  malnutrition)
6. I - Inborn errors of Metabolism: Maple Syrup Urine Disease, organic Acidemia, Tay sachs disease, GM Gangliosidosis, Mucopolysaccharidosis
7. C - Congenital infections: TORCH group (Toxoplasmosis, Other agents, Rubella, CMV, Herpes)

Developmental Assessment

Developmental quotient [D.Q.]

• D.Q = Developmental age/Chronological age x 100
• E.g. A child of 6 years of age has attained milestones of that of a 3 year old only. Calculate D.Q.  

Solution: DQ = 3yr/ 6yr x 100 = 50

Screening Tests for Developmental Assessments

1. P - Phatak’s Baroda Screening Tests
2. A - Ages & stages questionaire
3. R - Revised DDST (Denver Developmental Screening Test)
4. T - Trivandrum development screening chart

Definitive Tests for Intellectual & Developmental Assessment

Name of test	Age group
Vineland adaptive behavior scale II	Birth to 89 years
Bayley scale for Infant development II	1 month-3.5 years
Stanford Binet Intelligence scale	2 years-85 years
Wechsler Intelligence Scale for Children	6 years-17 years

Intelligence Quotient (IQ)

• IQ = Mental age/ Chronological age x 100

Degree	IQ Level
Mild ID	51 – 70
Moderate ID	36 – 50
Severe ID	21 – 35
Profound ID	0 – 20

Moron	50 – 70
Imbecile	30 – 50
Idiot	< 30

• The term mental disability is no longer used now. 
• It has been replaced by the term intellectual disability.

Intellectual Disability

• Significant impairment in intellectual functioning and social adapting

And that is it! That is everything you need to know about development abnormalities and its types. For more interesting and informative posts like these, keep reading PrepLadder blogs!