what is psychomotor skills retardation?

Delayed or decreased development of both mental and motor skills. Psychomotor skills themselves are coordinated muscular movements that are typified by smoothness and precise timing.

The delays are due to central nervous system damage or abnormality. The term refers specifically to delayed development of cognitive skills (like speech) and delayed development of motor skills (such as walking).

Possible causes according to http://www.umm.edu/ency/article/003313.htm :

Common Causes:

BEFORE BIRTH causes include:

asphyxia (insufficient oxygen before or during birth)

cerebral hemorrhage

congenital rubella syndrome

congenital toxoplasmosis

chromosomal abnormalities (excessive numbers or reduced numbers), such as trisomy 13 , trisomy 18, trisomy 21 (Down syndrome)

abnormalities of the chromosome (with normal number of chromosomes), such as Fragile X syndrome, Prader-Willi syndrome, Angelman syndrome

Fetal alcohol syndrome

INFANCY/CHILDHOOD causes include:

infection -- meningitis and/or encephalitis (Organisms can include virus, bacteria, or parasites. Some infectious agents include: HIV infection, Herpes Simplex virus, toxoplasmosis, cytomegalovirus, listeria, H. influenza)

traumatic -- head injury, shaken-baby syndrome, asphyxia (such as near drowning)

non-genetic metabolic disorders -- kernicterus , hypoglycemia, Reye's syndrome, congenital hypothyroidism (untreated)

genetic metabolic disorders -- phenylketonuria (if untreated), histidinemia

intraventricular hemorrhage (as seen in very premature infants)

other heritable disorders -- Tay-Sachs disease , Aicardi syndrome , Niemann-Pick disease.

environmental or toxins -- lead poisoning, methyl mercury exposure (Minamata disease)