Prenatal and Perinatal Factors Associated with Brain Disorders

Mental retardation (MR) affects 850,000 children

Cerebral palsy (CP) afflicts 750,000 children

Handicapped children constitute nearly 10% of all school-age children

Neurologic and communicative disorders affect 42 million Americans and cost our society approximately $144 billion per year

Definitions

Cerebral Palsy

A nonprogressive motor deficit of early onset

Type of CP determined by

Location of cerebral palsy, birth injury, epilepsy, fetal asphyxia, fetal distress, perinatal injury, medical malpractice lesion(s)

Nature of insult

Timing of occurrence

Relative ability of CNS to compensate

Prevalence: 2/1,000

Associated neurologic disease with CP cerebral palsy, brain injury asphyxia

(1) Severe MR: 20%

(2) Mild MR: 20-30%

(3) Seizures: 30-40

Salient risk factors

(1) Prematurity

(2) Perinatal asphyxia

CP is the only brain disorder clearly associated with perinatal,

primarily hypoxia

Mental Retardation

a. Defined as an IQ score of two standard deviations (SDs) below the

mean of 100 (SD = 15)

b. Varying degrees of mental retartdation based on IQ scores

(1) Mild MR: 70-55

(2) Moderate MR: 55--40

(3) Severe MR: 40-25

(4) Profound MR: <25

c. Prevalence of severe MR: 4 per 1,000

d. Associated neurologic diseases with mental retardation

(1) <20% haveCP

(2) 13% have seizures

e. The timing of the presumed insult can occur prenatally and/or during

the developing years of childhood

f. There are few correlations between mild MR and perinatal events

g. Certain perinatal events correlate with severe retardation, particularly in

those individuals with concurrent CP

h. Salient risk