Developmental Disorders and Mental Retardation

Mental Retardation (MR)

intelligence: can be measured as the IQ, but the younger you are, the less accurate the tests are

IQ = 100 is average
normal variation is a bell-shaped curve
asymmetry on the left side of the curve is not normal variation and is due to syndromes such as PDD and mental retardation
important to remember that mental retardation could be due to normal variation (mild retardation)

mental retardation: syndrome highlighted by early onset related to disability and cognitive dysfunction

no disability Þ no mental retardation

consequence: there are more kids with MR than adults because it is easier to function at a low cognitive level in the adult world than in the children’s world

diagnostic criteria: reduced general intellectual functioning

IQ < 70, impaired adaptive functioning, onset prior to age 18

remember: IQ < 70 without dysfunction Þ no mental retardation

differential: impaired senses, PDD, communication disorders, learning disorders, motor disorders

classification: rule of 15s

mild: IQ 70 - 55; part of normal Gaussian curve
moderate: IQ 40; not normal distribution; due to a syndrome
severe: IQ 25; profound: IQ < 25

Causes of Mental Retardation

idiopathic; normal variation; accounts for majority of cases
genetic: Downs and Fragile X are the most common
intrauterine: ETOH, infection, other drugs?
perinatal: asphyxia, hemorrhages, infection

Comorbidity: from associated psychiatric disorders: mood disorders, disruptive behavior disorders

Treatment: educational, rehabilitative, supportive psychotherapy, family therapy

Pervasive Developmental Disorders

Three main areas of disability/deficiency

(1) reciprocal skills of social interaction: eye contact, conversational skills, understanding and use of non-verbal cues

(2) communication skills: language development

there is a poor prognosis in autism if language hasn’t developed to a meaningful level by age 6

(3) stereotyped or severly circumscribed activities, behaviors or interests - examples:

autistics are comfortable with routine, more change = more distress
they may become fixated on a subject (i.e. are only able to converse about one subject)

Common characteristics of most PDD

mental retardation: moderate is most common in autism, but how do you test someone who can’t communicate?
profound dysfunction: disruptive, aggressive, or self-injurious behavior; anxiety; dysfunctional sleep/wake cycles

the need for routine is also very hard on families and caregivers (remember Rainman?)

seizures: significant co-morbidity; 1/3 of PDD patients will develop a seizure disorder by age 18

Five disorders classed under PDD - all are 3x more prevealent in boys as girls, except Rett’s which is only found in girls

(1) Autistic Disorder: most common; early onset; 4/10,000; familial pattern may be seen; moderate MR

patiens have deficits in all three areas above

(2) Asperger’s disorder: second most common; early onset; 2/3 deficits above Þ no delay in speech development

language develops, but empathy, non-verbal communication, etc are lacking
stereotomies are very prominent

(3) Childhood Disintegrative Disorder: later onset; child seems to develop normally, then seems to lose skills

(4) Rett’s Disorder: like CDD, associated with a decline in development, occurs only in girls

(5) PDD NOS (not otherwise specified)

Diagnosis, Etiology, and Treatment

etiolgy: neurobiologic; MRI and MRS in autistic patients differ from controls; may be familial, but a link to poor parenting or ‘refrigerator mother’s’ is a bunch of bunk

diagnosis is clinical - no diagnostic test is currently available

differential includes: schizophrenia, schizoid, mental retardation, selective mutism speech/language disorders, deafness/eyesight deficiencies

no cure is available; treatment consists of rehabilitation, education (of parents, too), behavioral treatments, and medications to treat positive symptoms; psychotherapy is not helpful (they can’t communicate)